Chasing Science at Sea

By Ellen Prager


Copyright © 2008 Ellen Prager
All right reserved.

ISBN: 978-0-226-67870-2

Chapter One

An Introduction

FOR CENTURIES, EXPLORERS AND SCIENtists have taken to the high seas or journeyed into the ocean's depths to view, measure, and study its wonders. The methods they use range from a simple bucket swung overboard to a highly sophisticated, remotely operated vehicle towed miles beneath the surface. As modern ocean scientists, my colleagues and I now have an amazing array of technology at our fingertips. From space we can get a snapshot of the entire sea surface at one time, seeing the ocean from a larger perspective than ever before. Meanwhile, molecular technology is enabling us, for the first time, to study in detail the smallest creatures of the sea, the microbes, and examine their role in the overall ocean ecosystem. Genetics are revealing connections between marine populations once thought separate and showing that other organisms have distinct hereditary histories. Remotely operated undersea vehicles (ROVs) are providing unprecedented access to the deep sea, while new autonomous vehicles can be programmed to explore under the ice and in other inaccessible or dangerous environments. With tags tracked via Earth-orbiting satellites or through undersea acoustics, we can now follow the sea's creatures beneath the waves and around the world. But even with such great advances in technology, we must still go into the field to effectively study and understand the ocean.

Technology alone does not avail all we need to know about the sea. The information provided by satellite imagery or computer simulations is literally worthless without real-world observations for input and verification. In the laboratory, we can create and run complex experiments, but we still need to go into the field to determine if the results are realistic and applicable in nature. To tag marine organisms for tracking or to observe their natural behavior, we must go to sea. We need to go into the field to sample sediments, to extract cores for geological study, and to collect water for chemical or biological analyses. In the field, we deploy drifting buoys to track ocean currents, maintain observation platforms and sensors, and monitor long-term change. But going into the field is not just about the planned collection of data or the deployment of equipment; it is also about the unplanned and serendipity. With time spent in, on, or under the ocean come revelations that can prove our previous assumptions wrong, stimulate new lines of investigation, and provide great moments of wonder that inspire a lasting sense of discovery. And as much as going into the field can teach us about the ocean, it also unveils how we learn and the true workings of science.


In school as well as in many textbooks, the scientific method is routinely described as a rather boring, orderly process by which hypotheses are created and then tested. Not a very inspiring notion or one that readily draws students into a related career. At its core, science is simply about observing and then making sense of those observations to better understand the world around us. In contrast to the stereotype, this can be an exciting, challenging process that involves humor and creativity and that evolves with time, taking as many twists and turns as a compelling drama or good suspense novel. Doing science is not about following a cookbook-type procedure; it is about curiosity, questioning, and encountering the unforeseen and unplanned. For many scientists, myself included, what we enjoy most about science is the constant learning involved and the frequent surprises that come with the pursuit of knowledge, especially when working in the field. I can think of no better way to illustrate the joy, frustration, and complexities involved in science than to take a behind-the-scenes look at ocean science, starting with a brief introduction and a few stories from the field.


Most science begins with a question. Bob Ginsburg of the University of Miami's Rosenstiel School of Marine and Atmospheric Science is a world-renowned coral reef geologist and famous for his uncanny ability to ask really great science questions. At a presentation's end, even when I swear he was sleeping throughout, he consistently asks the one question we are all thinking of or wish we were thinking of. He has been known to stand up and in a deep commanding voice simply ask, "So what?" Graduate students fear his insightful questions, and scientists, if not prepared, can be caught off guard. He teaches us all one of the most critical parts of doing science, being able to ask a good, provocative, and relevant question.

In ocean science, questions can be as simple as what geological features or organisms are found at the seafloor in a certain location, or they can be more complex, such as what is the role of the ocean in climate change. Where do research questions come from? In applied science, research is undertaken to address a problem with direct societal impact. In the ocean, examples of applied science include research on harmful algal blooms, invasive species, tsunamis, the ocean's role in global warming and hurricanes, coastal pollution or beach erosion, and fisheries. When research is done to answer a question or gain understanding that is not directly identified with a societal problem, it is known as basic science. Examples of basic science in the ocean include the exploration of deep-sea environments or research on marine mammals, sharks, the biology of corals, and the overall productivity of the ocean. Basic research, however, frequently leads to understanding that can be applied to societal issues. For instance, some bacteria discovered in the deep sea can grow using substances that we consider toxic, while others are able to produce electricity from the surrounding seawater. Scientists are exploring how these microbes might be used for toxic-waste cleanup or to generate power for undersea instrumentation. Development of technology for basic research can also prove beneficial to society.

Fieldwork itself, more often than not, leads to new research questions or areas of investigation. Coming up with more questions than answers can be frustrating, but this is an important part of the process of doing science. For me, this is one of the best parts of doing fieldwork and one of the reasons I have particularly enjoyed working in Florida Bay. It is not the most scenic place I've studied in nor does it host many of the ocean's more charismatic creatures, but nearly every excursion into Florida Bay reveals something new or unexpected. As a researcher with the U.S. Geological Survey in the 1990s, I spent months in Florida Bay studying sediment and wave dynamics with my colleague and good friend, marine geologist Bob Halley.

Florida Bay is the shallow, wedge-shaped region that sits between the southern extent of the Everglades and the western edge of the Florida Keys. Along with its importance environmentally, Florida Bay provides a significant source of economic revenue for the region through recreational and fishing activities. Since the late 1980s, Florida Bay has been under intense scientific scrutiny due to a massive seagrass die-off and subsequent algal blooms, episodic sponge mortalities, and decreases in water clarity. With restoration in mind, over the past several decades, researchers from a myriad of disciplines, agencies, and institutions have focused their efforts on trying to better understand the bay as well as the events that have occurred there.

The first lesson from fieldwork in Florida Bay-it probably shouldn't be called a bay. The area is actually a series of small, shallow embayments separated by an interconnecting network of mudbanks and mangrove islands. Many a boater has become personally and rudely acquainted with these mudbanks, as they can be difficult to see and have the tendency to reach out and grab small boats-or so it would seem. Park rangers patrol Florida Bay, as it is part of Everglades National Park. One ranger tells of a weekend boater who, after running hard aground on a mudbank, proclaimed his innocence because the chart he was using showed that he had been in sufficiently deep water-the problem was probably that his chart was actually a "maplike" place mat he had picked up at a local restaurant. Lesson number two when doing fieldwork in the ocean-Florida Bay or elsewhere-bring along an accurate chart. But truthfully, even with the best of charts, Florida Bay can be difficult to navigate, especially when strong winds stir up the bay's fine carbonate sediments, turning the water the color of a milk shake.

Bob and I spent weeks in Florida Bay mapping seafloor habitats, sampling sediments, and conducting experiments. Much of the data we collected was as expected, but almost every day we would also observe some new phenomenon or see something intriguing. We saw a surprisingly aggressive ray chasing a shark, a rare baby crocodile in the mangroves, and powerful squalls that seemed to come out of nowhere. And just when we thought we had a good handle on the basic sediment, seagrass, and water patterns in the bay, we were once again surprised.

One day while snorkeling in one of the region's small bays, we discovered a surprisingly warm layer of water at the bottom. Based on our understanding of Florida Bay and simple physics, this should not have been the case-or so we assumed. In Florida Bay and elsewhere, warm, therefore less dense, seawater typically resides at the surface above cooler, denser seawater. By afternoon in the tropics, due to the sun's heating, anyone swimming, snorkeling, or diving in shallow water can observe firsthand the development of a warm layer of water at the surface. But rarely do you find warm water at the bottom-the density thing-and this certainly did not jibe with our understanding of water flow in the bay. We had no way to measure it at the time, but the only explanation we could come up with was that the warm water at the bottom was higher in salinity than the overlying water, thus making it denser. How would the salinity of the bottom water increase? Our first thought was that it could be groundwater flowing up from an underground spring-common in the limestone underpinnings of southern Florida-but then it would have been cool and less salty. We continued to ponder the question until later that day when we nonchalantly jumped out of our small boat onto a mudbank.

The water on the crest of the mudbank, only a few inches deep, was scalding hot! Bob and I made a hasty retreat back into the boat and while nursing our scorched toes came up with a theory. During hot, sunny summer days in Florida Bay, the shallow water on top of the mudbanks heats up and is subject to high evaporation, thereby increasing its salinity enough so that the water becomes denser and flows off the mudbank into an adjacent bay, settling at the bottom. We had heard of this density cascading effect in other ocean environments.

While the incongruously warm water at the bottom in Florida Bay was not the main thrust or even part of our research, it was too intriguing for us to ignore. One day, in between our official studies, we used a small temperature and salinity probe to test the warm water at the bottom of a small embayment. Sure enough, it was higher in salinity than the overlying seawater, thus supporting our density cascading theory for its origin. We never had a chance to do a thorough investigation of the phenomenon, but since then other researchers in Florida Bay have mentioned finding surprisingly warm water at the bottom. We also wondered what the impact of this hot, salty water was on the marine organisms living in the bay's seagrass and sediment.

Florida Bay, like many marine environments, is highly complex, and even with years of study we are just beginning to understand it. For the curious, this is part of the fun of science and especially of working in the field.

I cannot resist the opportunity here to recount one of the most famous stories about how unexpected observations in the field led to new science questions and, in this case, to an entire revolution in our way of thinking about the deep sea. In February 1977 a team of scientists embarked on a cruise to study the Gal��pagos rift, an area of seafloor spreading some 400 miles (644 km) west of Ecuador and 250 miles (402 km) northeast of the Gal��pagos Islands. They were investigating the possible presence of hydrothermal vents, at the time a relatively new concept describing fractures in the seafloor, thousands of feet below the ocean surface, that emit warm chemical- and mineral-rich water.

Once on site, the team of geologists, geochemists, and geophysicists deployed Angus, an ROV, to investigate the rift. With its specialized deep-sea cameras and temperature sensors, Angus was towed just above the seafloor in depths of over 8,000 feet (2,438 m). A titillating spike in water temperature was detected, possibly indicative of a hydrothermal vent, and when photographs taken of the seafloor were developed, an even greater surprise was revealed-clusters of giant clams and hundreds of mussels. Up until this time, the deep sea, far removed from the life-giving powers of the sun, was thought to be much like a desert, devoid of plentiful marine life.

The deep-diving submersible Alvin then arrived on the scene aboard its support ship, the R/V Atlantis out of the Woods Hole Oceanographic Institution. Two scientists and a pilot squeezed aboard Alvin to investigate the possible vent and the strange creatures at the seafloor: little did they know their journey would be one for the history books. Guided by the data provided by Angus, the sub driver steered the undersea vehicle down toward the area of warm water. As they began to get a firsthand look at the seafloor, one scientist reportedly questioned the notion of the deep sea as a desert-because outside the viewport there was an oasis of life. It was an abundance of organisms never before seen at such great depths, and many of the creatures were completely new to human eyes. Along with large clams, the researchers saw white crabs, a purple octopus, and lush gardens of strange foot-long tube worms with white stalks that were topped by bright red, plumelike gills. There wasn't even a biologist on site because the organizers of the expedition didn't expect to find marine life in the rift zone. Rumor has it that when the geologists aboard reported their findings to biologists back on shore, they were highly skeptical, to put it mildly. The team had discovered a previously unknown, even unimagined, ecosystem in the deep sea where organisms thrive on the chemicals and bacteria associated with hydrothermal vents. From this one discovery, a myriad of new scientific questions arose, including whether the deep sea is where life on Earth began, and it created several entirely new fields of research in ocean science. Scientists now estimate that there are some 280 active vent sites within the world's oceans-most of which remain unexplored!


Along with even the best of questions, ocean science, unfortunately, takes money and usually lots of it-ocean research isn't cheap. Time at sea aboard a large research vessel can cost tens of thousands of dollars per day, and even small-boat work takes a fair bit of cash-especially with today's fuel prices. Even the earliest explorers of the sea needed investors and private sponsors to support their voyages of discovery. Today most scientists rely on grants from the government, foundations, or private institutions. Sadly, however, in recent years ocean research and exploration have not been a national priority. This is especially frustrating given our connections to and reliance on the ocean as well as the changes we're causing in the sea. Whereas we spend approximately $17 billion on space exploration and research each year, the nation annually invests only about $700 million on the science of the oceans, which, by the way, cover nearly three-quarters of the earth's surface. Experts estimate that we have explored only about 5 percent of the sea.


Excerpted from Chasing Science at Seaby Ellen Prager Copyright © 2008 by Ellen Prager. Excerpted by permission.
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