Book Readings: Week 10

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

Since this is my final week blogging about these two books, there wasn't much left to read! All that was left for me to read this week was the final chapter in The Tide and the afterword in The Sea Around Us. Because these readings were pretty light, I will end this final blog post on my Marine Resources with some final thoughts on both books.

In The Tide this week, Aldersey-Williams focuses on how coastlines will be affected in the future due to sea level rise and erosion. Indeed, the title of his final chapter is "Diluvion." The word is an obscure term that refers to formerly solid land which is now lost under the high-tide line.

Aldersey-Williams returns to his local coast for this chapter: the coast of Norfolk in England. He talk about how locals believe that the erosion of the seaside cliffs at Hopton-on-Sea has been accelerating due to changes in tidal currents that came about due efforts made to enlarge a harbor located nearby, just up the coast. The author explains that to prevent further erosion, large boulders are being placed in the waters at the foot of the cliffs, so that they can block the incoming wave energy and protect the cliffs from being battered.

Aldersey-Williams' description of Hopton-on-Sea made me think of Pillar Point Harbor, the harbor on the San Mateo County coast that I visited all the time as a child. Because of the way the southern breakwater of the outer harbor at Pillar Point has effectively cut off the southward flow of sediments since it was installed about fifty years ago, there is now a massive buildup of sand within the harbor, while just south of the breakwater, Surfer's Beach has been disappearing rapidly due to massive erosion. Like Hopton-on-Sea, Pillar Point is a reminder that both human engineering and society's interests are more often than not anathema to the health of our oceans and coastal environs.

Also, the description of boulders being used to block wave energy made me think of the shoreline and near-shore restoration work my colleagues and I do at the Boyer Lab, and how actions taken to fixed localized problems could have consequences "downstream." I appreciated that Aldersey-Williams points out that using boulders to essentially stop cliff erosion might mean that other parts of the coast might end up eroding faster because it will have stopped receiving the input of sediment it is accustomed to getting from the eroding cliffs.

Aldersey-Williams ends his book back at the spot where he began, at the place near his home where he sat for a day to observe a full tidal cycle. By using the example of coastal erosion, which simultaneously can ruin people's homes while also providing opportunities for scientific research, Aldersey-Williams makes his final point: that the tide is an irresistible force that can both create and destroy in the same action.

I finished The Sea Around Us last week so this week all I had left to read was the afterword. The afterword was written in 1989 by marine biologist Jeffrey Levinton, nearly forty years after the original printing of The Sea Around Us. In this section of the book, Levinton presents a quick summary of some of the developments in marine science since the last edition of The Sea Around Us.

There are many interesting discoveries that Levinton discusses, but in particular I enjoyed reading about Vestimentiferans, the huge tube worms which live close to deep ocean hot vents and can grow to over five feet long. Also, I was fascinated to read that genetic analysis was used to prove that eels living in the Sargasso Sea were actually hybrids born from the matings of American and European eels that encountered each other during their migratory journeys.

Ultimately however, the most important part of Levinton's afterword for me was his closing statement on how we must do more to protect our oceans. It is truly unfortunate that some of the main threats the ocean faced in 1989, at least according to Levinton, are exactly the same as the problems the ocean faces today: input of sewage and other forms of nutrient pollution, harmful toxin, oil spills, and plastic ocean. Levinton's closing remarks highlight the fact that we humans have always known what we must do to protect and preserve our environment for the future, and that it's simply a question of finally putting in the effort needed to get it done.

Looking back over these last ten weeks, I have to say I had a great time reading these two books. While it was often hard to find the time to read, I don't think I would have finished two such dense books in the space of a few months had I not been tasked to do so for this Marine Resources class. I have fallen out of the habit of reading over the last few years and I appreciate that blogging about these two books has helped to get me back into the habit.

Also, I enjoyed reading both books concurrently because it was nice to switch between two different worlds and two different tones on a regular basis: While Aldersey-Williams was writing in the present, bringing in mythology, history, and firsthand accounts to bear as he talked about the tides, Rachel Carson was writing in the 1950s, and she wasn't just writing about the tides but about the oceans as a general subject of interest. Aldersey-Williams' tone was more conversational and informal, while Carson employed a style of writing that, while accessible, was much more formal and stylistic compared to Aldersey-Williams'.

Overall I had a great time with these books and I'm already itching to explore some of the books listed in the "Further Reading" section of The Sea Around Us, as well as some in The Tide's bibliography! Many thanks to Dr. Ellen Hines for a great class. I hope all my blog visitors enjoyed reading about these two books!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 9

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

I don't have much left to read in Carson's The Sea Around Us; in fact, this week I'm reading the final chapter! For next week, which is my last week blogging about these two books, I'll be discussing the afterword and my final thoughts on the The Sea Around Us.

In the final chapter of her book, Carson "zooms out" her narrative. What I mean by that is that instead of addressing specific topics related to the world's oceans, she discusses the ocean at a higher, more holistic level and speaks of it in broader terms.

Fittingly, Carson begins with the ancient Greek concept of Okeanos (Oceanus), the all-encompassing world ocean at the ends of the known world, which surrounded the world with its endless stream. As a Greek mythology buff, I've known for a long time that the ancient Greeks considered Poseidon, god of the sea, to preside over the Mediterranean, the sea which the Greeks understood fairly well, whereas Okeanos represented the waters of the Atlantic and ultimately all far-off waters outside the ancient Greeks' comfort zone.

Starting with this mythical foundation, Carson takes us on a whirlwind trip through history to show her readers how the ocean has influenced humanity century after century. She starts with the Greek poet Homer, who work the Odyssey is, in the most literal sense, a story about a prolonged voyage at sea. Carson then mentions the seagoing Phoenicians, who flourished as a society for centuries before the common era.

Moving forward in time, Carson mentions the Norwegian maritime explorer Ottar, who was active around 870 CE, and the Vikings who sailed not just to Greenland but also all the way down south and into the Mediterranean. She then pays homage to the bravery and navigational skills of the Polynesian sailors who traversed the Pacific, hopping from island to island in their small boats and settling on them centuries before famed explorers like Columbus and Magellan made their long journeys. Carson states that besides using the stars, the sun, and the moon to guide themselves on their journey, the Polynesian explorers may very well have watched and followed the migratory patterns of birds traversing the Pacific.

Carson then mentions, in brief, attempts in the 19th century made by explorers to reach the North and South Poles, before ending in the 20th century, her present time. She makes a point to mention that modern sailing guides and other resources on the world's oceans are a blend of modern knowledge and knowledge gleaned from the past, stretching all the way back in one continuous stream back to antiquity.  I love that she ends The Sea Around Us with the concept of the all-encircling stream, telling her readers that the sea lies all around us, touching all aspects of our lives and reminding us of our own marine origins, which we have in common with all life on Earth.

This week in The Tide, Aldersey-Williams begins by talking about various classic works of literature which mention the idea of a "Maëlstrom," a swirling, dark, submerged vortex of water that can carry people off to their doom. In Dutch the word roughly translates to "grinding stream," and the term is now used in all Scandinavian languages to describe a marine whirlpool.

After reading Edgar Allan Poe's "A Descent into the Maëlstrom," the author Jules Verne was inspired to include the concept in his famed work, Twenty Thousand Leagues Under the Sea. In the book, Captain Nemo's submarine, called Nautilus, is unexpectedly caught in the Maëlstrom while it is submerged off the coast of Norway. A "Norway Maëlstrom" is also briefly mentioned in Moby-Dick.

After discussing these works of fiction, Aldersey-Williams asks: Is the Maëlstrom a real thing? In the 18th century, the Swedish scholar Carl Linnaeus attempted to sail out to where the Maëlstrom was thought to be located, but he was unable to find a boat to travel the final leg of the journey and so was ultimately unsuccessful. A mere two decades later, the Bishop of Bergen, Erik Pontopiddan, wrote in his Natural History of Norway that a strange and violent current existed off the coast of Norway, one which could suck objects down into the depths and hold them there for hours before spitting them back out again. In Twenty Thousand Leagues, Verne poetically referred to the Maëlstrom as "Navel of the Ocean."

These tales about the Maëlstrom really drove home for me the way in which the tides, with their awesome natural power, can inspire deep emotions and ertistic expression. Indeed, it struck me how similar the legends around the Maëlstrom seemed to be to the Greek myth of Charybdis, the famed whirlpool in the Mediterranean which Aldersey-Williams addressed in earlier parts of his book.

Another whirlpool with mythological connections is the Corryvreckan, located between two islands off the coast of Scotland. According to Gaelic mythology, the Corryvreckan is the washtub of Cailleach, the creator goddess. However, what I found really impressive about Corryvreckan is that it wasn't until a mere six years ago that the mystery was solved as to why there was a whirlpool at all off the coast of Scotland:

Aldersey-Williams states that oceanographers conducted a bathymetric survey which revealed that the origins of the whirlpool lay in a long, undersea cliff. As the tide comes in, large amounts of water well up the cliff face, and as they flow over the top of the cliff, they are forced to flow faster than the shallow water already present there. Conversely, as the tide goes out, the water flows back over the cliff edge and plunges down the cliff face, creating a sucking action. Ultimately, learning that an undersea cliff wall explains the behavior of water in "Cailleach's washtub" was something I found quite entertaining.

This section of The Tide culminates in Aldersey-Williams visiting the "Navel of the Ocean" himself. The author travels to Norway and rides in a powerboat out to the very place in open waters where the Maëlstrom is supposed to be located.

Once there, Aldersey-Williams states that there doesn't seem to be any whirlpool at all, with no evidence of any downward vortex. In fact he says that the surface of the water is actually pretty flat. However, he also describes the location as eerie, and points out that had he come during different weather conditions his impressions of the location might be different. He also states that even though the waters are especially flat, they are not actually calm in the slightest. Indeed, the waters surrounding the boat all appear to be flowing in a clockwise orbit, as if the boat was in the middle of a gyre.

Even though Aldersey-Williams didn't find an actual, functioning whirlpool at the site of the Maëlstrom, I thought his description of the area was impressive. He really managed to convey the eerie nature of the place and the feel that there was potential danger lurking under the water's surface.

Finally, Aldersey-Williams moves on from Norway to Sweden, specifically to the capital city of Stockholm. I was fascinated to learn that Stockholm is actually a city that consists of 14 different islands and that these islands are connected by dozens of bridges, as well as locks that help to regulate water flow. Although there are of course key differences, this unique, insular geography makes me think of Stockholm as a city that is similar to Venice in that they are both intimately connected to the water.

I was particularly fascinated by the fact that Stockholm experiences almost no tides to speak of: Aldersey-Williams explains that the largest tidal ranges tend to be no more than 3 cm! Also, thanks to a centuries-old practice of marking the height of the water on stone gauges, Stockholm is blessed with a large data set on mean sea levels and sea level rise that stretches back to the 1700s! It is ironic that Stockholm contains such a rich history of sea levels, considering that the city's insular geography makes it especially vulnerable to climate change-induced sea level rise.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 8

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

This week in The Tide, Aldersey-Williams begins by discussing the works of George Crabbe, an English poet who was active in the 1770s to 1830s. Aldersey-Williams discusses Crabbe, who was based in the coastal town of Aldeburgh in Suffolk, England, because the tide and the coast were recurring themes in Crabbe's work. In fact, in one of the stanzas of Crabbe's work The Borough, the poet described in detail the type of vegetation he saw in the intertidal zone, providing a very vivid image of ecological zonation from the water line to above the high tide line. It was a nice example of how the sea influences the minds of people not just on a scientific level but an artistic, emotional one.

Aldersey-Williams goes on to make the case, quite convincingly, that in Crabbe's time the tides were imbued with symbolism related to sin, punishment, and mortality, and that symbolically, the tides in literature often served as a moral warning. It makes sense that because of their awesome power and capacity to cause injury and even death, the tides would be connected to themes of retribution for sin and take on other religious connotations. Indeed, the story of the biblical flood, the Christian god's punishment for humanity's evil, is perhaps the ultimate representation of how the tides are connected to the themes of sin and death.

After leaving Crabbe and Aldeburgh, the author takes us to Normandy, where he discusses the role of tides in D-Day, the pivotal day in World War II when Allied forces invaded northern France. I was very impressed to read that the D-Day landings were actually carefully planned using tidal calculations that took into account eleven different types of harmonic oscillations that create the local tides. For perspective though, Aldersey-Williams points out that modern tide tables involve anywhere between 60 to 100 different harmonic cycles!

German forces had positioned tank traps and other obstacles on the beaches of Normandy to thwart the Allied forces and induce them into landing at low tide, which would have forced the soldiers to advance a long way up a large stretch of exposed beach, making themselves easy targets for snipers. However, the Allied forces realized that they could use particularly high, rising tides to carry their boats over most of these obstacles, and that after they unloaded their soldiers high up on the beaches, the ships could retreat back over the traps while the waters were still high. I was impressed by the planning that must have gone into taking this (ultimately successful approach), because, as the author points out, the invasion had to be planned for a spring tide and timed exactly right so that there would not be loss of the element of surprise if the ships ended up having to wait for the right moment.

In contrast to this successful endeavor, Aldersey-Williams recounts how American forces failed to capture the island of Tarawa (now called Kiribati) from the Japanese because they disregarded the tides. Despite the fact that some in the Allied forces advocated waiting out a neap tide to invade Tarawa because higher tides would allow the ships to pass more ably over the coral reefs and onto the beaches, this advice was disregarded by those higher up in the chain of command. The attempt to take Tarawa ended in disaster, with ships being stranded on the reef for a few days. These two contrasting tales are a good reminder of the need to understand, study, and ultimately respect nature.

Switching gears, Aldersey-Williams talks about the California grunion, a fish whose breeding cycle is synchronized exclusively to spring tides. Female grunion utilize the crashing waves to fling themselves onto beaches in order to lay their eggs (or spread their milt, in the case of males) in the upper high-tide zone. Impressively, the grunion do this in the days just after the highest high tide (after the full moon or new moon), so that as the days progress the high tides get lower and lower, preventing the fertilized eggs from being washed away. It's not until just before the next highest high tide approaches, just under two weeks later, that the eggs, now developed enough, are stimulated by the motion of the waves to hatch into larvae, which are then able to be carried away into the ocean by the waves of the next peak spring tide.

It's difficult to deduce exactly how organisms like the grunion carry this "tidal memory" in their bodies, and how they know, without any conscious knowledge about the monthly tidal rhythms, when to perform which behaviors. Aldersey-Williams argues that it's probably not related to the light that comes from the moon, or the height of the tides, but to gravity itself. He refers to John Steinbeck, who wrote in The Log from the Sea of Cortez that in Precambrian times, when single-celled life in the seas were beginning to form multicellular organisms, the tides were much stronger because the moon was orbiting much closer to the Earth at the time, exerting a much stronger gravitational pull. Steinbeck asserts that it's the "memory" of this gravitational pull that is imprinted on the genetic makeup of many organisms.

One of the reasons the story of the grunion stood out to me this week was because in a previous blog post I recounted how Rachel Carson talks about the grunion in The Sea Around Us. Indeed, Aldersey-Williams does namecheck Carson after discussing the grunion and talks about the Rachel Carson Reserve, which are protected barrier islands off the coast of North Carolina where Carson once made observations of various birds that timed their hunting for various fish species to coincide with the rising tides that brought their prey into the shallows. The reserve is now part of the North Carolina National Estuarine Research Reserve.

I don't have much left to read in Carson's The Sea Around Us, so this week I only read a short chapter on the various dissolved minerals of significance that are present in the ocean, such as Na (sodium), Ca (calcium), and Si (silicon).

Carson asserts that the saltiness of the seas have been increasing over time, as water flowing seaward from rivers and streams collects minerals on its journey. As someone who took a class on chemical oceanography last year, I was particularly interested by Carson's description of how the mineral content of freshwater in rivers and creeks were wildly, fundamentally different to that of ocean waters. In particular, ocean water are far more depleted in calcium and silicon because various animals use those minerals to build their body parts: foraminifera, mollusks, and corals use calcium, while diatoms use silica for their shells.

I was amused to read Carson imagine, in a lighthearted tone, how humans might extract gold and silver from seawater. According to Carson, there is about $93 million in gold in a cubic mile of seawater and $8.5 million in silver. Considering that The Sea Around Us was first published in the 1950s, these are staggering dollar values. While this is an entertaining thought, Carson quickly points out that the cost and effort required to treat all that seawater just to extract these two metals would make the whole endeavor economically unfeasible.

Finally, what I found particularly interesting this week was Carson's discussion of iodine, and how ubiquitous it seems to be in the ocean: not just in the water, but in all manner of organisms and seaweeds. Carson states that iodine in the ocean is in a constant state of flux, being oxidized, reduced, and being bound to or unbound from organic molecules. It would seem that iodine atoms are part of the various process of energy transfer in the oceans. Carson also points out that living organisms, including terrestrial ones, have become increasingly dependent on iodine and that it plays an important role in their basic metabolic processes. This seems to hearken back to an era when all life on Earth was marine in nature, and was suspended in an environment where iodine was readily available.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 7

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

I don't have much left to read in Carson's The Sea Around Us, as it is a considerably shorter book than The Tide, so I am only blogging about small portions of the book from here on out since my intent is to read and blog about both books concurrently. Last week, I finished the middle portion of Carson's book, titled "The Restless Sea." This week, I begin "Man and the Sea Around Him." In this final section of book, Carson focuses on the relationship between humans and the seas, and how we are affecting the global ocean (most often for the worse, and not better).

I was shocked to learn that back in the 1950s when Carson was writing her book, people were actually talking about trying to control, influence, and even modify through human engineering the paths of major ocean currents, like the Oyashio in the Pacific and the Gulf Stream in the Atlantic. The idea behind modifying the Gulf Stream was to bring its waters closer to the mainland of the northern United States in the hopes of producing warmer weather. It blows my mind that anyone would seriously entertain playing with such major global processes just to enjoy nicer weather, and I'm glad such ideas aren't as easily entertained these days when it comes to ocean currents.

When I read Carson's descriptions of how the ocean can regulate regional climates, I wasn't surprised by the concept that the ocean often has a moderating effect on climate, ensuring that coastal environments are never too extreme in weather. It's a process that I've read about many times. However, the concept of "marine deserts" being created by the ocean was new to me. Such deserts occur in places like the coasts of Chile and Peru, where cold, moist air situated over cold, upwelled water moves inland. Although this cool air carries moisture, it heats up as it travels inland and rises instead of falling. Because of this, the moisture in it cannot be captured as rain so rainfall in the region is very limited, creating desert conditions. Only an El Niño event, which brings warmer, moist air that sinks as it moves inland can bring major amounts of rainfall, often with disastrous consequences.

Finally, what I found particularly interesting this week was Carson's description of the "Pettersson tidal theory," a theory which states that there is a tidal cycle which lasts 1,800 years. This cycle could explain why centuries rife with extreme weather events and cooler climates seem to be followed by centuries of less and less extreme weather events, culminating in centuries of warmer, milder weather which then swings back to cooler, more extreme weather to complete the cycle. Carson describes how Greenland in the year 984 CE was described as a temperate, mild, even fruit-laden land, and year only a few centuries later in the 1300s became significantly covered in ice and snow. She points out that these swings in climate were mirrored all across Europe, and that since that cold period we have been experiencing warmer and warmer weather, though we are still about four centuries away from the warmest and mildest weather in the cycle.

Part of what I found interesting about this discussion of the Pettersson cycle was that there was absolutely no mention of the anthropogenic factors affecting climate. Carson was writing in the 1950s when the understanding of humanity's role in global warming was minimal at best, and granted, in 1950 the Earth did not have the elevated levels of greenhouse gases in the atmosphere as it does now. Nevertheless, it was strange to read about a 1,800-year cycle of cooling and warming in the Earth's climate that made no mention of the role of humans.

In The Tide this week, Aldersey-Williams starts off by talking about the River Elbe in Hamburg, Germany. Hamburg is home to Germany's largest port, and Aldersey-Williams says that alterations made to the river over time to make it easier for larger and larger transport vessels to navigate the water have also made it easier for the effects of high tide to reach further upriver.

Unfortunately, these alterations also made the areas near the river more vulnerable to flood event, and hundreds of people died along the river during an extreme flood event as recently as 50 years ago, even far inland. It's a sobering reminder of how the alterations or "engineering" we do to our environment for our convenience can be detrimental to us in the long-term, and how ultimately we cannot beat the forces of nature. Indeed, Aldersey-Williams says that because of the soft-sediment nature of the Elbe, the banks and course of the river are constanty shifting, requiring constant dredging and maintenance to maintain the convenient shipping channel that is desired.

I was entertained to read about how the Boston Tea Party, a key event in early US history, was influenced by the tides. Aldersey-Williams writes that when the tea was being thrown overboard at night, the tide was actually very low, and so the chests filled with tea that were thrown overboard weren't traveling out to sea but instead gathering in piles in the harbor in the exact places where they were tossed. Men were even ordered to into the waters to break up the chests and swish the loose tea further out to sea using paddles. Because the event happened at low tide, the chests didn't have an opportunity to really disperse far and wide and many of them actually washed back up on shore nearby, from where they were surreptitiously taken by residents who took the tea home for personal use.

Another of Aldersey-Williams' stories I enjoyed was that of the Japanese empress Jingu, who ruled around the year 200 CE and conquered Korea around that time. According to myth, Jingu used jewels given to her by Shinto gods to control the tides to successfully battle Korean warships and decimate the opposing soldiers. While the story of jewels are clearly a myth, it's interesting to see how this and other war stories from history that Aldersey-Williams recounted in earlier chapters (such as with Viking invasions of the British isles) are rooted in the factual context of one party having a greater knowledge of the tides than the other.

Aldersey-Williams then turns his attention to tidal bores, which is essentially a large wave caused by the channeling of an incoming flood tide as it enters a long, narrow, and shallow waterway. In order to talk about tidal bores, Aldersey-Williams travels to the Shubenacadie River, which eventually empties into the Bay of Fundy in Nova Scotia. This bay famously features the largest tidal range in the world, and the tidal bore surges up the Shubenacadie after it enters the bay.

I really enjoyed Aldersey-Williams' descriptions of the scenery as he watched a tidal bore surge up the Shubenacadie. He talks about how the bore is so intense that you can see a difference of at least a foot in the height of the water on either side of a footbridge that crosses the river. The color of the water also changes as the bore surges in, changing from a darker, clearer tone to one that is more opaque and pale brown as the bore lifts sediments off the riverbed and increases the turbidity of the water. In past weeks I talked a lot about how Rachel Carson paints vivid images with her words, and I can say the same for Aldersey-Williams here.

Finally, I was interested but also concerned after learning that the Bay of Fundy is a prime location, due to the massive strength of the tides, for testing out whether or not the energy of the waves and tides can be harnessed for human use. I was relieved to read that such testing is only in its earliest stages, and I appreciated that Aldersey-Williams himself raised concerns about the idea. Besides the fact that underwater turbines to harness tide power would likely adversely affect the bay's sturgeon population and 60 other species of fish, the author points out that while there may be a lot of energy bound up in tidal forces, it is a fraction compared to what is theoretically available to us in other renewable sources, particularly solar and geothermal. I really hope that these attempts to "engineer the ocean" don't make it past the exploratory stage, as I think it could end up being a costly waste of time, not just financially but from an environmental perspective as well.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 6

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

In The Tide this week, Aldersey-Williams starts off by talking about the River Thames. In particular, he points out that London must have been an unlikely port city, since sailing up the Thames could be difficult work thanks to the tides. Even traveling downstream and out to sea on a single ebb tide would be impossible; indeed, sailor's called traveling down the Thames and to the sea "more than a tide's work."

The author then talks about Charles Dickens, and how the fact that he spent his life close to the Thames influenced his writing. Two of Dickens' characters in Our Mutual Friend take advantage of the ebb tide to transport a dead body downstream, and in Great Expectations, Pip imagines being carried away by a strong spring tide. It was a good reminder that for many people, the action of the tides serves as a "backdrop" that helps to shape and inform our daily lives.

Aldersey-Williams then talks about how the Greenwich Observatory, from which we get Greenwich Mean Time, was not only a place where astronomer John Flamsteed and other scholars determined the position of many stars, but a place where these scholars were also able to make direct observations of the tides. Measurements of the orbit of the moon were also made at the observatory, and these measurements as well as Flamsteed's tidal observations would later inform Isaac Newton's work:

Newton had determined that the moon played a far greater role in contributing to the force of the tides than the sun or any other cosmic body, and he regularly asked Flamsteed for his data so that he could refined his model of how the moon influenced the tides. Aldersey-Williams claims that when Newton published the Principia Mathematica, many people who picked up his work did so in order to get a better understanding of the tides in particular.

From here, I moved on to Carson's The Sea Around Us. Last week, I had began the middle portion of the book, titled "The Restless Sea." This week, I finish that section.

Carson discusses the tides and how they're formed in the final part of "The Restless Sea." She begins by talking about the Straits of Messina between Sicily and mainland Italy, one of the few places in the Mediterranean where significant tidal phenomena exist, and talks about how the one of the whirlpools there is connected to the myth of Scylla and Charybdis. I noted that this was strikingly similar to what Aldersey-Williams discussed regarding the Straits of Messina quite early on in his book. Indeed, the way Carson talks about the tides reminded me a lot of The Tide, and knowing that Aldersey-Williams had referenced The Sea Around Us in the beginning of his book, it wouldn't surprise me if the tidal phenomena Carson chose to describe in her work influenced what Aldersey-Williams chose to discuss in his.

One of Carson's points I found important was the apparent paradox of the tides, in that although they are ultimately governed by large, cosmic forces (the gravitational pull of the moon, and to a lesser extent that of the sun), how the tides actually manifest themselves at the local level depends so much on small-scale factors, such as the slope of a beach and the general bathymetry of the local ocean, how open or enclosed a river mouth draining into the sea might be, and how much the tides' power might "buffered" by wetlands or barrier islands.

Probably my favorite part of this section of The Sea Around Us was Carson's description of how friction caused by the tidal forces is actually slowing down the earth's rotation at a steady rate, although that rate is one we cannot discern on a day-to-day basis (our 24-hour day is thought to be about a few seconds longer than it was several millenia in the past). The earth used to rotate much faster on its axis, completing a full rotation in about four hours instead of twenty-four. As the Earth's rotation slows, the moon's centrifugal force causes it to move further and further away from the Earth. According to Carson, the force of the tides decrease as the Earth's rotation slows, and millions of years into the future, the Earth will eventually rotate so slowly that a single day will be as long as a month, and at this point, there will no longer be any tides on Earth.

Carson then moves on to describe some marine organisms that time certain activities to the tides, such as the grunion, a small shiny fish that times its spawning activity on the beaches of California so that their mating and egg-laying occurs during the ebb of spring tides, in the spring and summer months. It was interesting to read about how difficult it has been for scientists to determine exactly why and how certain organisms "know" when a certain tide occurs, and why some organisms may choose to take advantage of spring tides while others choose neap tides.

To this point, Carson ends by talking about a small worm now called Symsagittifera roscoffensis, but which was called Convoluta roscoffensis when The Sea Around Us was written. The small worm has a symbiotic relationship with a unicellular green algae that produces all the food the worm needs via photosynthesis. I looked up the worms online and they are a stunning bright green and lovely to look at. What makes the worm even more fascinating is that at ebb tide, S. roscoffensis rises from intertidal sands so that it can get access to light and photosynthesize the food it needs. As the tide returns, the worms sink back into the sand so that they don't get washed out to the deep ocean.

How does the worm "know" to do this? Carson mentions that when a colony of the worms were taken from the water and placed in tanks with sand for research, the worms would rise from the sands and then sink back into them in time with the tides, even though there was no tidal action in the tank, and even though there was no way for the worms to perceive the sunlight outside. How these tiny worms have the rhythm of the tide imprinted into their bodies is a mystery.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 5

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

Last week, I had finished the first half The Sea Around Us, which was subtitled "Mother Sea." This section of the book serves as Carson's overview of all the different aspects of the oceans she felt it was important for us to know to get a complete picture of the sea.

This week, I began the next portion of the book, titled "The Restless Sea." In this section, Carson drills down into the subject of the movement of the ocean waters, from waves, to currents, and to tides. She begins by discussing waves, primarily surface waves, and discusses at length what (at the time) was cutting edge technology being used to record wave height and strength. In fact, this section of Carson's book seems to be a bit drier than "Mother Sea" as it focuses quite a bit on the actual instrumentation and methods used to study the oceans, but it was still interesting to read about what sort of technology was available for oceanographers in the 1950s to study the ocean (she also discusses technology used by seismologists, because earthquakes can cause tsunami events). At times it was also was surprising to me how technologically advanced ocean research already was at the time, even if by current standards it was somewhat rudimentary.

Carson's descriptions of the power of the waves are a bit more picturesque. She talks about the devastation that tsunami events can cause, and how constant wave action is the primary driver of coastal erosion. Her description of how waves can travel from one end of an ocean to the other drove home for me the way in which far off countries and peoples are all ultimately connected by the ocean. (In particular, Carson's description of how a massive earthquake in the Aleutian island chain caused a tsunami event in Hawaii in 1946 was one that really stuck with me.)

Carson then moves on to how the wind, the sun, and the earth's rotation all affect the movement of water. I was surprised to read that European sailors from as early as the first half 16th century already knew of the Gulf Stream, and used it to help their ships return home after forays into the Atlantic. I loved reading about how sailors could see the difference in color and character between the Gulf Stream waters (deep, dark blue, clearer) and the waters of the North Atlantic (lighter green, murky) as they sailed, and how the higher temperature of the Gulf Stream waters often caused massive banks of fog to form as the current traveled north into colder latitudes.

Carson talks about how masses of water can be stratified by temperature and salinity (which ultimately affect the density of the water) and how changes as one travels through one mass of water to another with a different temperature and salinity profile can be quite abrupt. She provides an excerpt of an account written by a sailor in 1944 about how, as his ship crossed from open water into the upwelling zone off the coast of Colombia, the surface waters suddenly changed from being relatively barren to suddenly teeming with life.

Before moving on to talk about the tide, Carson points out that deep ocean currents serve as a global circulation system, connecting the waters of all the world's oceans together. It was a nice reminder of how the planet functions as a single unified system.

It was at this point that I switched focused to Aldersey-Williams' book. In The Tide this week, the author talks about the city of Venice, which is well-known for its vulnerability to floods and rising sea levels. Many parts of the city are flooded on a daily basis.

Aldersey-Williams talks about how Galileo, the great scientist, actually spent a summer in Venice, at the northern end of the Adriatic Sea. I was surprised to learn that it was Galileo's observations of the tides in the Adriatic, along with observations of barges that brought fresh water to Venice for the citizens to drink, that inspired him to advocate for the idea of a Copernican, or heliocentric model of the solar system. By observing how the fresh water in the barges sloshed around in their open containers and how that mirrored the tidal action in the Adriatic Sea, Galileo deduced that the earth must rotate around the sun, and not the other way around. He also claimed that the earth's rotation around its own axis as well as around the sun was the sole cause of the tides.

Strangely, Galileo left out the moon's influence on the tide, and Aldersey-Williams says that perhaps this was because Galileo was so invested in advancing the Copernican theory that he ignored any evidence that might seem to contradict his model. For example, under Galileo's model there was only one high tide per day, whereas in most of the world one saw two high tides in a day. Aldersey-Williams makes a convincing case that Galileo, despite his great scientific achievements, was still limited by his own biases and by his local environment: The Adriatic Sea, which is what Galileo observed, is part of the Mediterranean, where there is a very small tidal range. In the Adriatic, these small lunar tides are essentially masked by the much larger influence of local factors on tidal oscillation such as strong winds and atmospheric pressure changes. In essence, Galileo's failing was in failing to understand that his observations of the Adriatic were not and could not be applicable to all the oceans of the world.

Aldersey-Williams then talks about how intentional flooding through the opening of dikes have been used in a strategic manner in the Netherlands to thwart invaders, even though it meant the destruction of valuable farmland. The threat of strategic flooding kept Kaiser Wilhelm II from invading the country during World War I, and during the Second World War, both sides of the conflict used strategic flooding to cut off or otherwise hamper the opposing forces. In fact, some research shows that a full third of all floods in the Netherlands since the year 1500 have been deliberate, defensive actions.

Then author also talks about about a destructive flood event on the east coast of England in 1953, and another one in Venice in 1966. In both cases, Aldersey-Williams points out that it was not the height of the floods at high tide that was the real problem as it was the fact that the high tide lasted for an incredibly large amount of time, causing sustained damage over the course of hours. Further damage would occur when the unusually high tide would recede as great speed, leaving damage in its wake.

After the 1953 flood, the Thames Barrier was constructed. Aldersey-Williams toured the Barrier in 2014, and learned that although London is now much more prepared for a major flood event than it would have been in 1953, it is actually now much more vulnerable due to the fact that so much development has taken place on land close to the water. Besides being so much closer to the water line, these buildings are situated over former salt marsh habitats which used to serve as a buffer zone for wave energy and as a sort of sponge that could absorb some of the incoming floods. With these marshes lost to development, the water now has nowhere to flow, except further upstream, which increases the destructive power of the floods. This section of the book really stood out to me because as a native of Redwood City and San Mateo County, development on the bayshore, particularly development that replaces valuable wetland habitats, has been a subject I have had to think about my entire life. Out of the nine counties of the San Francisco Bay Area, San Mateo County is the one with the most buildings and communities in the path of flooding and sea level rise, and yet most local governments in the county continue to push for development on the bayshore. It is a worrying state of affairs.

Aldersey-Williams ends by talking about a recent trip he made to Venice, where he learns about some of the new measures taken in the city to mitigate flood events and protect the city. I appreciated learning about how the city now views flood protection and ecological protection of the Venetian lagoon as one and the same, as apparently they did not before. It was inspiring to hear that every effort was being made to ensure that any flood protections put in place would do minimal damage to the local ecosystem, and as someone who works in a wetland restoration lab, I appreciated reading that natural restoration of barrier islands was being explored as a way to help mitigate the strength of flood events.

I also loved the Venetian concept of flood protection design, and how instead of building massive seawalls that would block the view of the water they designed underwater barriers that would only be raised during flood event. Even the buildings that house the controls for the barriers are designed so that they don't rise above the land, ensuring that the protection is as beautiful and unobtrusive as it is hopefully effective.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 4

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

This week in The Tides, Aldersey-Williams recounts the history of Scandinavian invasions of the English coast, such as the Battle of Maldon and the Battle of Fulford. I found it interesting how much the tide influenced the success of these invasions, and how even though the English coast was subjected to a much greater tidal range than the coastlines of Norway and Denmark, the greater seamanship of the Vikings helped them overcome any advantage that local knowledge of the tides might have conferred on the English.

The author then talks about Bede, an incredibly intelligent 9th-century Benedictine monk who investigated many natural phenomena with a scientific approach, including the concept of time. It's through his investigations into time and his attempts to find a consistent method for determining the date of Easter celebrations that he came to study the tides. He noted that the lunar Jewish calendar and solar Roman calendar would sync up every nineteen years, in accordance with one of the slowest measurable tidal rhythms. A century later, Abu Ma'shar al-Balkhi recognized the association of the angle of the moon above the horizon with the tides.

I was particularly interested to hear Aldersey-Williams return to the present day and talk about an art installation at a beach in Liverpool, England. This installation consists of bronze statues of men on the beach that get submerged to varying degrees with each high tide. What interested me about this art installation was that such an art piece would never fly in most of California. Perhaps it would be more likely for such an art piece to exist in Venice Beach or Redondo Beach, where the coast is more urbanized and highly trafficked, but for most of the California coast the idea of installing something man-made in the intertidal zone of a beach, especially something that alters the view of the coast in such a significant way seems unlikely and not in keeping with the culture of coastal preservation that we tend to have here in the Bay Area. In fact, local Liverpudlians pushed to have the art installation stay in place when attempts were made by the local council to remove it due to safety concerns, and I'm pretty confident that wouldn't have happened here in California!

Aldersey-Williams then gets into the concept of fractal geometry, and how the more closely you observe something the more complex it seems. He brings this up in relation to the fact that how long a coastline is depends on how closely you observe it: Do you follow every minute nook and cranny and curve and kink in the coastline, or do you draw a more generalized boundary? And how do you define the coast? Do you use the low tide line? Or mean high water? Are you keeping in mind that the coastline at a low tide is not necessarily longer than a coastline at high tide if the coastline at low tide is less "kinked"? (Similar concerns around definition affect how we quantify the size of the intertidal zone due to tidal range, slope, etc.)

I appreciated this discussion in the book because we have had similar discussions in my Marine Resources class on how one defines a coast. I also was tickled by how this discussion highlighted how interdisciplinary the study of the tides can be, encompassing history and geometry as well as physics, geology, and other "hard" sciences.

Aldersey-Williams then moves on to Morecambe Bay, the largest intertidal area in Britain. Five rivers flow into it, and there are lots of exposed mudflats, seaweed, eelgrass, birds, and more. Even though it's not feasible at all, it is technically legal to drive across the exposed sands at low tide. Again, I thought about how this would never happen in California. Besides the huge safety risk this would pose, driving through sensitive intertidal areas seems against everything we are taught about the ocean and the coast.

In reality, a huge amount of water flows in and out of the flats of Morecambe Bay. These flows are so powerful that they alter the sands drastically, so much so that a survey map of the flats that is only a few years old will be outdated due to major channels being altered. This means the flats are also dangerous to traverse, but because the flats are home to a vast expanse of lucrative and tasty cockles that are harvestable at low tide, many people venture out onto the flats recklessly. Aldersey-Williams recounts multiple tragic tales of people caught out on the flats who died when they got lost or stuck in the sands and drowned the tides came in. The author makes the point that greater literacy and respect for the tides would be beneficial to public safety.

Aldersey-Williams repeatedly talks about how tides inspired religious scholars, from Bede to Robert Grosseteste. inspired by the religious significance of light, these scholars made the connection between the light of the moon and the tides. Thomas Aquinas was the first scholar to conceptualize the tides as a force, although he did so in order to prop up the idea of the existence of a god (who created the force of the tides) and to discourage the notion of the tides as a knowable, natural phenomenon which didn't need a divine explanation. Finally, the author talks about how the tides could have even played a role in Christian mythology. He says that the most plausible modern explanation for the story of Moses parting the Red Sea is that Moses was likely a person with a good understanding of local tides. Although tides in the Red Sea are generally semidiurnal, local wave effects in the Red Sea basin make for diurnal tides at certain parts of the Red Sea coastline. Aldersey-Williams argues that a wind-influenced, extremely low tide would have exposed quite a bit of land to allow for passage at the north end of the Red Sea, and that a diurnal tidal cycle would have allowed for that low tide to last throughout the whole of an entire night. The author admits that this is all speculation, but it's interesting to think about what role natural phenomena like tides could have played in various legends and myths.

In The Sea Around Us this week, Carson talks about the accumulation of sediment in the ocean, from inorganic sources such as erosion of coastal rock, but also from the descent through the water column of the siliceous and calcareous shells of dead phytoplankton. I like that Carson makes the connection between this accumulation of sediment with the vast layers of sedimentary rock we often see on land, indicating that an ocean used to exist where those rock layers are present. It's interesting to note how new the technology used to obtain sediment cores was when the book was published. The ability to take core samples 70 feet in length only became possible a few years before the original publication of Carson's book.

Carson then moves on to the formation of islands. She moves from one less-traveled island to the next in the oceans and in the Mediterranean (such as Ascension Island in the Atlantic, and Bogoslof Island near Alaska), discussing their formation and sometimes disintegration. I've always had an attraction to islands and island ecosystems and reading Carson's descriptions of these places made me want to travel and see them for myself.

Carson also discusses how these remote islands, products of volcanic activity, were colonized by fauna and flora. I was impressed to learn that living insects and spiders had been captured nearly three miles above the earth's surface, and that scientists were able to obtain such small creatures at such heights before Carson first published her book. Before such discoveries, Charles Darwin showed that he was able to raise various species of plants from a ball of mud lodged in the feathers of a seabird that was able to traverse large distances across the ocean. This ball of mud must have contained the seeds of plants Darwin ended up being able to grow.

I've been saying this every week, but as usual I was entranced by Carson's descriptive writing. I loved her comparison of falling sediment in the oceans to snowstorms and blizzards in the sky, and of accumulated sediment layers to snowdrifts. I also loved reading about what the ocean is like at the surface when there is an underwater volcanic eruption, and Carson's description of the explosion that destroyed Krakatoa in 1883 was captivating. I was shocked to learn that the explosion was heard thousands of miles away in Madagascar, and that the volcanic ash hung in the skies around the globe for at least a year after the explosion, making sunsets around the world a vibrant pinkish-red during that entire time.

Carson's descriptions of island ecosystems and of island flora and fauna are also enthralling. When she discusses the delicacy and uniqueness of such ecosystems and how humans have repeatedly ruined island after island and caused mass extinctions by either resource extraction or the importation of non-native flora and fauna, the anger and passion in her writing is almost palpable, despite her restrained and professional tone. It is easy to see how she came to write Silent Spring a little over a decade after first publishing The Sea Around Us, and as an aspiring environmentalist I find it gratifying to read the words of someone writing in 1951 and see phrases like "nature's balance" and "pattern of life" because it drives home the fact that these are not new concepts in biology and ecology, but foundational and well-established ones.

Carson then moves on to talk about ancient seas, and how over the course of geologic time the sea has risen to cover much of all the continents, then retreated hundreds of feet as water became captured in glaciers during ice ages, and then risen again as glaciers melted. It was good to be reminded of the sea's dynamic nature and how humankind in ancient times experienced very different oceans and coastlines than we do. I also appreciated the point that it would be good to use technology to explore under coastal waters to look for former human coastal settlements that would have been active and thriving when sea levels were much lower. I also liked reading about the fact that even in the most inland places, like at the top of a mountain range, evidence of former oceans can be found as sedimentary layers of rock. It drove home the point that no matter where one is on Earth, one can always find the presence of a sea, although it may be an ancient one.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 3

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

I will spend most of this week's blog post discussing Carson's book, since most of last week's post was spent on The Tides by Aldersey-Williams. This week in The Sea Around Us, Carson is focusing on creatures of the deep ocean, past where light can penetrate.

The first thing that stands out to me about Carson's discussion of the deep ocean is how technology has helped the advancement of the marine sciences since the publication of The Sea Around Us. This edition of Carson's book includes footnotes she wrote ten years after the first edition (published in 1951), and the section on the deep ocean in particular is full of footnotes discussing advances in knowledge of the deep ocean that had been made in that short timeframe. I was struck both by how much scientists didn't know about the oceans in 1951, and by how much they already did know. One of the things I was surprised to find that scientists knew about already in 1951 was the existence of snapping shrimp that use their large claws to make a snapping sound. These shrimp were discovered with the use of hydrophones that recorded their snapping noises.

I was also impressed by how much was learned in the ten years between the first edition and the updated 1961 edition. For instance, Carson mentions in her footnotes the fact that new science was emerging that confirmed the use of sonar/echolocation by marine mammals to find food. Another fun fact she mentions is the capture of a second live coelacanth specimen in 1952, after the first one was discovered in 1938.

Carson's asserts that life probably began in the surface oceans, coastal waters, rivers, and swamps, and not in the interior of continents or the interior of the ocean, which she defines as the deep ocean or abyss. I found this interesting because it seems to tie in to the concept of ecotones, which we learned about in our Marine Resources class. Ecotones are transition areas between two ecosystems, and these boundary areas tend to be places of high biological productivity and activity.

After this section, Carson moves on to discuss the topography of the ocean floor, from submarine canyons, to seamounts, trenches, and mid-ocean ridges. Again, I was struck by how much of this section was dependent on technologies that were emerging at the time which allowed for new information about the ocean floor to be uncovered.

As always, I was really taken by Carson's cinematographic descriptions. I loved reading about a "phantom ocean bottom" which was discovered by sonar and which was found to change its depth depending on the time of day. This phantom bottom consisted of a layer of living organisms that rose from the depths at night to feed, while retreating to the deep during the day. Initial explorations of the oceans by sonar, which was being used to sound the depths of the ocean floor, revealed the existence of this layer.

Carson's references to descriptions of bioluminescent squid were also fascinating, as were her descriptions of Architeuthis (the giant squid) and the deep blue of the ocean waters at a depth of 1,000 feet. I also really loved learning about Dogger Bank, a productive fishing area in the North Sea that used to be a strip of land connecting the British Isles to the European mainland during the last ice age. Finally, I found it interesting that Carson mentions the origin of man and evolution as if it were totally non-controversial: It's truly a shame that the public's knowledge and acceptance of evolution in the US seems to have actually declined since 1951, instead of getting better.

After reading Carson's work this week, with its heavy emphasis on the technologies that have assisted in the advancement of knowledge about the ocean (e.g. hydrophones, submarines, and the use of sonar to sound the ocean depths), it felt like a sharp change of tone to switch to Aldersey-Williams' book. This week in The Tide, Aldersey-Williams focuses on the history and legends surrounding the tides:

The author begins by talking about Cnut the Great (or Canute the Great), who was the first and only Danish King of England in the 11th century. Aldersey-Williams recounts a legend about how Cnut took his sycophantic nobles, who claimed that he even had control over the waves and the tides, down to the ocean to observe the waters and prove that he was at the mercy of natural forces–forces which he believed to be the work of his Christian god–just as much as every other person was. The cultural relevance of Cnut is revealed when Aldersey-Williams talks about how coastal businesses in North Carolina successfully lobbied to have all references to sea level rise removed from state legislation, prompting one blog to sarcastically comment that King Canute was unavailable for comment on North Carolina's actions.

Aldersey-Williams then gets into the etymology of the tides. He tells his readers that the word came from the Anglo-Saxon word "tíd," which primarily was used to refer to the passing of a significant amount of time. This meant that the word could also be used to refer to the rhythms of the sea's rising and falling. However, the author points out that more commonly, tides were referred to as "flood" and "ebb." Combinations of these words were used to express more specific kinds of tides, such as "neapflood" for neap tide, "fullflood" for spring tide, "highflood" for high tide, and so on.

This was as far as I went into The Tide this week. Although it was a sharp change of tone from Carson's technology-heavy descriptions of the ocean, it was a nice change of pace to get into the history and etymology of the tides. I'm enjoying reading these two books together because I feel like I'm getting a more holistic, multidisciplinary look at the oceans by doing so.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 2

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

Since I spent the bulk of my previous blog post discussing Carson's book, the bulk of this blog post is dedicated to The Tides by Aldersey-Williams. Before writing this blog post I received a message from the author himself on Twitter, which was a nice and unexpected surprise!

Honoured by this pairing. Thanks!

— Hugh AW (@hughalderseyw) March 9, 2018

Aldersey-Williams actually mentions The Sea Around Us in his book, which makes for a nice connection between the two works. It's one that I didn't realize existed until I started reading them. Indeed, getting a reply from Aldersey-Williams made me wish Rachel Carson was alive now. It would be great to interact with her on social media, and to have her voice prominent in the national discussion around climate change and the environment.

For this week I read Aldersey-Williams' personal observations on a 12-hour tidal cycle. He goes to a local creek in Norfolk, England that empties into the North Sea and observes what happens for a full day. The way he chose what location, day, and tidal cycle to observe reminded me a lot of how people in my lab plan our field work: Since we're a lab focused on wetland restoration, the overwhelming majority of our field work is at the mercy of the tidal cycles.

The author goes into minute, painstaking detail on his observations, which at first seemed excessive. However, I later realized how well this level of detail highlighted the importance of quiet contemplation and active observation in the process of scientific learning. I also liked that Aldersey-Williams pointed out that observing the tides is a multidisciplinary exercise, from the physics of water flow, to biological observations of fauna and flora in the salt marsh and mud flats that were exposed as the tide went out, and even to physical education as he canoed to get a closer look at anything that attracted his attention.

Aldersey-Williams' thoughts on the tides themselves are quite interesting: I liked his descriptions of how water in the same place flowed at different rates, how low tide didn't occur exactly at the midpoint between the two high tides that bracketed his day of observation, and how the landscape and assemblages of flora and fauna shifted as the tides receded and then returned. I also liked his discussion of plant and algal zonation in the salt marsh and in the intertidal region. His admitted lack of knowledge on certain aspects of the tides was a bit surprising to me as a marine biology major, but I actually liked that he admits that, because even as a marine biology major I don't understand everything about the tides either. That's why I'm reading the book!

Also, as someone who works in a wetlands lab, it was fun to read Aldersey-Williams' descriptions of the salt marsh and the mud flats. He even mentions Suaeda (sea blite) and Limonium (sea lavender) and we work with Suaeda and Limonium species in our lab. I hope to be able to track down a copy of Estuary, a short film time-lapse film of the tides by Susi Arnott, which the author mentions.

Aldersey-Williams then takes the reader to the Mediterranean; there are no personal observations here, just the author's take on the role of tides in history. Interestingly, tides are almost non-existent in the Mediterranean, and Aldersey-Williams points out that had that not been the case, surely the ancient Greeks, who had made many advances in mathematics and science, would have come up with an explanation of how tides work. However, they did not, and it wasn't until the Romans sailed to the British Isles in the hopes of expanding their empire and had their ships wrecked by the tides that they began adapting their boats to withstand the tides.

In the few places where tidal phenomena existed in the Mediterranean, myths and legends were used to explain them. The myth of Scylla and Charybdis is purportedly a reference to the Straits of Messina between Sicily and mainland Italy, while legend has it that Aristotle threatened to drown himself in the Euripus Strait between the island of Euboea and Boeotia in mainland Greece. He supposedly made this threat after observing the highly variable tides at the strait and unsuccessfully trying to come up with an explanation for how they worked. Aldersey-Williams explains that perhaps Aristotle was unsuccessful because the geography around the Euripus is such that the tides are starkly different in behavior between the north and south sides of the strait.

It is here where I stopped reading and moved back to Rachel Carson's The Sea Around Us. When I had stopped last week, Carson had been talking about how the ocean changes seasonally. Now, she has moved on to the aphotic zone of the deep ocean, the part of the sea that's beyond the reaches of light coming from the surface.

I did not read far into Carson's book since I spent most of my time on The Tides, but I was once again struck by her vivid, cinematographic writing. I loved her description of how organisms change color as you go from the surface ocean down to the deep, and I love her word choices, like when she speaks of diatom meadows instead of diatom blooms. Also, after reading The Tides, I was struck by how much more scientifically dense Carson's work is: Her writing is peppered with footnotes on top of references to contemporary biologists, research methods, and the history of ocean research. This doesn't mean that The Tides is an inferior book: It just means that the tone and writing style are very different. Aldersey-Williams approaches his work as a layperson and Carson approaches hers as a marine biologist, but they both manage to communicate their experience of the oceans well, and I find both perspectives valuable.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.

Book Readings: Week 1

For my Marine Resources class (GEOG 646) at SF State this semester I am reading The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016). Please check out my first Book Reading blog post to read about why I chose these two books and why I chose to blog about them concurrently.

I'm about forty pages into The Sea Around Us and have been loving every word of it so far. Everyone I know who has read Carson's work praises her prose style, and it's with good reason: Even though the tone of her writing can come off very businesslike and almost methodical, Carson's love of the ocean shines through in the vivid, sensory details she uses to describe the seas as well as the staggering variety of organisms and natural phenomena that exist within them. Reading her words made me feel like I was reading the script of a fantastic science documentary series, like Carl Sagan's Cosmos or the BBC's The Blue Planet. As a side note, I am wondering now how much Sagan, of whom I am a big fan, might have been influenced by Carson. In the definitive biography Carl Sagan: A Life, Keay Davidson argues that Sagan anticipated the modern environmental movement in his published writings several year's before Carson's landmark book, Silent Spring (p. 93). However, such writings would still have come well after the first publication of The Sea Around Us.

I like that Carson starts her book quite literally from the beginning, teaching her readers about the very formation of the earth and of the oceans themselves before going into any further detail. She then goes through geologic time, discussing the changes the Earth goes through and how those changes shaped our oceans. After "setting the stage" for her readers in this way, she then begins to discuss the current ocean. She starts by talking about the patterns and activities within the ocean's surface, and then discusses how the ocean changes seasonally. It's after this point where I stopped reading to begin blogging.

It was fun to read Carson's descriptions of various forms of life, from microscopic diatoms all the way up to large creatures like giant squids and cetaceans. Her writing style feels both timeless and of its time: the latter when she mentions species whose names have since changed, and the former when she glides from one part of the globe to the next describing various ocean processes that have been occurring since the oceans first came into being. (Even though I did stop and go to Wikipedia to look up a few names Carson drops into the narrative, such as Phaeocystis and Meganyctiphanes, I didn’t think it was necessary to do so to understand her writing.)

When Carson published her book in 1951, most people thought of the oceans as a vast, hardly changing place, except for at the coastal margins and the surface ocean. Both the coastal margins and the surface were known to be a place of abundant life and constant change, probably because these two portions of the oceans were (and are still) the easiest for humans to observe directly.

However, people's understanding of the oceans shifted quite significantly just a few years later. My copy of Carson‘s book includes a preface she wrote ten years after the original publication of The Sea Around Us, and she explicitly mentions in this preface that a new way of thinking about the ocean has emerged: Instead of viewing the oceans as a vast, mostly unchanging mass of water, people have begun to realize that humans can and are changing the oceans, usually for the worse. Carson in particular is concerned about the dumping of radioactive materials (the waste product of nuclear testing) into the sea. She quite rightly points out that these radioactive materials will linger in the ocean for decades to come, and that instead of being confined to a single area of the globe, they will eventually be circulated throughout the entire world over the course of the ocean's mixing time. Of additional note is the fact that this preface was written just a year before Silent Spring was published, so we know the negative impacts of human activity were on Carson's mind at the time.

I have not read as far into The Tides as I have with Carson's book, but I am enjoying what I've seen so far. In particular, I really appreciate Aldersey-Williams' manifesto of sorts in his introduction: He really wants his readers to get a real, intimate understanding of tides, one that is different from a symbolic, abstract understanding of tides that is based solely on equations or conceptual thought. By providing the history and folklore surrounding tides and by describing tides and tidal phenomena around the world in very physical, sensory terms, Aldersey-Williams endeavors to show us and describe to us the tides as a tangible, visceral experience.

I appreciate this statement of intent from the author because it is exactly why I wanted to read a book about tides in the first place: I feel that I understand the basics of how tides work on an abstract level, but I don't feel that I have the sort of instinctual, innate sense of the tides that comes with regular observations or months and years of tide-dependent research or living.

According to Aldersey-Williams, the concepts of time and tide used to be interchangeable (etymologically as well as otherwise), and the idea of tides as being distinct, time-specific markers for daily ocean fluctuations was a practice that arose later. He then says that he intends to closely observe a 12-hour tidal cycle in order to see at the basic, physical level what sort of changes happen as the waters rise and fall throughout the day. It is around this point that I stopped reading; I'll discuss his observations in the next week's blog post.

Overall I'm really liking both books, and I have to say that at least for now, I've enjoyed reading Carson's work a bit more. Aldersey-Williams is a good writer too, but his style is more conversational and more about his personal experience with the sea. Carson's narrative voice is less personal, but it's exactly that which makes her writing more intimate, because her personality isn't standing between you and her descriptions of the ocean. Although it's a less modern stylistic choice, it resonates with me more.

I'll be blogging again about both books at the same time next week. Stay tuned!

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.
• Davidson, K. (1999). Carl Sagan: A life. New York, NY: John Wiley & Sons, Inc.

Book Readings!

For my Marine Resources class (GEOG 646) at SF State this semester we are required to read two books related to the oceans in some way, whether it be about physical processes, ecology, endangered species, and so on. I chose The Sea Around Us, by Rachel Carson (1951), and The Tide: The Science and Stories Behind the Greatest Force on Earth, by Hugh Aldersey-Williams (2016):

The Sea Around Us is an educational book that describes the world's oceans, as well as the various natural phenomena and organisms that exist within them. I chose this Rachel Carson book partly because it was recommended by our professor, Dr. Ellen Hines, but also because I've never read any of Carson’s work and I feel that I really should have by now! (She wrote the landmark environmental science book Silent Spring, in case you don’t know who she is.) I've always heard that Carson was an eloquent science communicator and that's exactly why I love Carl Sagan, so I'm looking forward to reading her work.

The second book, The Tide, features multiple stories from around the world about the tides and the history and folklore surrounding them. I picked up this book because while I feel that I understand how tides work on an abstract level, I don't have the tides "in my blood" the way some people seem to do. I currently work in a lab where more than one person just seems to know off the top of their head when a low tide is going to occur on a certain day, or at what time of day during a certain season the tides will be best for certain activities. I realize this knowledge isn't an innate gift and that it was probably built up over months and even years of field research, but nevertheless it still seems magical and it represents a mindset that is deeply connected to the rhythms of the moon and the sea. That's a mindset I'd like to cultivate for myself: I'd like to be at that same level of understanding some day.

Anyway, as you can probably tell, I'm ready to get started on these books! I used to be a voracious reader but I haven't read a book that wasn't a textbook in ages, so I'm looking forward to this. My boyfriend is the only person I know who still reads actual, physical, non-textbook books on a regular basis, and I'm excited to be joining that club again.

Expect a blog post on these two books once a week. I will be reading and blogging about both books concurrently because I want to compare science writing from decades ago (Carson) to modern science writing (Aldersey-Williams).

References:

• Aldersey-Williams, H. (2016). The tide: The science and stories behind the greatest force on Earth. New York, NY: W. W. Norton & Company, Inc.
• Carson, R. L. (1951). The sea around us (1989 ed.). New York, NY: Oxford University Press, Inc.