The setting sun shoots light straight down the West River. Autumn's last leaves ignite all along the shore. Summer is ending on this quiet Western Shore river just south of Annapolis.
It should have been a better summer.
With drought conditions sending little runoff into the river all summer long, the waters should have looked cleaner, clearer. Instead, warm weather brought an unwanted crop of algae blooms.
"I've never seen so many mahogany tides," says Bob Gallagher. Gallagher is the riverkeeper for the West River and Rhode River. He oversees a team of citizen monitors to watch water quality and to look out for the rivers' health. One thing he doesn't want to see is a mahogany tide — a reddish-brown algal bloom that can cause fish kills.
For the past couple of years Gallagher and his team have measured the vital signs of these two rivers — oxygen levels, bacteria, suspended sediment. They also consult data collected by the Maryland Department of Natural Resources and others, including the Smithsonian Environmental Research Center and the National Oceanic and Atmospheric Administration.
For Gallagher, this summer raised questions that the data don't seem to answer. "This was a strange summer," he says. In particular, they expected to see clearer water because of the drought. "That's not the way it turned out," he says. Even though dissolved oxygen levels were slightly better than the year before, the water was cloudy, and there were those worrisome mahogany tides.
With so little runoff, why didn't the rivers run a little clearer in the summer of 2007? Where did all those algae come from — not only in the main Bay, but in the shallower water of the tributaries? Why wasn't it a better summer?
Thirty years ago we could not have answered these questions. Can we answer them now?
Tom Malone looks out the window of his 12th story office in Silver Spring, Maryland. Behind him loom other steel-and-glass office towers wrapped with dark windows, as if the buildings themselves were wearing sunglasses.
He swivels back to his desk and pokes at his computer's keyboard. He's trying to get on the network, and it's not working. He knows there's a sharp irony in this, given why he's here.
Malone, whose longish hair and beard are going gray, is a key figure in the fight for global advanced observing systems. He has taken time from his position as a university researcher to serve as the Deputy Director of Research for the National Office for Integrated and Sustained Ocean Observations. He's leading a charge to expand the nation's capacity to observe changes in the world's oceans and coastal waters, using buoys, satellites, ships, and underwater vehicles. He testifies before Congressional committees. He wrangles with policy makers and officials at every level. In about an hour he has a conference call with two admirals. And his computer's not working.
Malone's leg jiggles as he speaks. He seems in a hurry even when sitting still. There must be times when he wishes he were back on the water, doing the research that's been his life for more than thirty years.
Malone's career in oceanography began back in the 1960s working in the blue waters of the Pacific. There he studied the effects of nutrients on tiny floating plants called phytoplankton, from the equator to the California coast. He found that when currents brought up nutrients from deeper waters — known as upwelling — larger forms of plankton thrived. It is these larger forms that support food chains leading directly to fish. He was also among the first to discover the importance of very small phytoplankton (or picoplankton) in the ocean's overall productivity, something previously overlooked.
During this period, Malone saw that to understand how marine food webs work as part of the earth's carbon cycle meant understanding how ocean physics and biology interact. And to do that required close observations — at least once a month, he says, or more often if possible. That posed a challenge in the open ocean.
Malone had a chance to get closer to his subject when he accepted his first academic appointment back East, at the City College of New York. There he started a research program on the Hudson River estuary and the coastal waters of the New York Bight. In these shallower waters he could study how phytoplankton respond to nutrients from human sources — mostly from sewage discharge. He could observe up close how they move through the estuary and onto the continental shelf.
Here in the shallows Malone discovered the delicate dance of nutrients, phytoplankton, and estuarine currents that leads to the summertime loss of oxygen. With this new understanding he was able to show, for example, that a harmful algal bloom that developed over several months and spread over the entire New York Bight was not caused by nutrients from sewage discharges, as many assumed. Instead, it was fed by an unusual circulation pattern that brought nutrients into the Bight from deep waters of the North Atlantic.
He had turned his training as a blue water oceanographer toward the shallows.
Malone first came to the Chesapeake in 1983 after persuasive conversations with a gregarious Welshman named Ian Morris, then President of the University of Maryland Center for Environmental and Estuarine Studies (now the UM Center for Environmental Science, UMCES). Part of the attraction, he says, was that Morris was also wooing a physical oceanographer named Bill Boicourt. Here was another researcher interested in how physics and biology interact to shape shallow-water ecosystems.
That Morris recruited a biological and a physical oceanographer at the same time was no accident. In addition to their individual accomplishments, Morris saw in them the future of estuarine science. He saw the importance of understanding how circulation patterns and mixing affect the Bay's biological productivity — especially of phytoplankton — and how this in turn determines how too many nutrients affect the health of the Chesapeake.
Understanding these interactions could help explain why algal blooms occur in some places and not in others, why they would occur in some years more than others. Even in a dry summer.
Malone stares at his computer screen as if he could see the past recaptured. When he first arrived in Bay country, he could not have foreseen that he would become interim President of UMCES after Morris' tragic death in 1988 at the age of forty-nine. That he would become the Director of the Horn Point Laboratory in 1990 — a position he held for 12 years. That he would step down from that post to work on an integrated observing and prediction system for the oceans, here on the 12th floor of this high-rise office outside Washington, D.C.
When he first came to the Bay, Malone spent time on the water. He and his colleagues — like Michael Kemp from UMCES and Tom Jones from Salisbury State University — motored back and forth across the Bay every week on the 25-foot research vessel Osprey. They ran a zig-zag course from the Eastern Shore to the Western Shore as they worked their way from the Bay bridge at Kent Island down to the mouth of the Patuxent River. Their zig-zags were deliberate. The measurements they took were meant to provide a new dimension for understanding how the Bay works.
In contrast to prior research on the Bay that focused on changes occurring along the axis of the main stem, this effort focused on shifts that occur laterally from shore to shore. Their work showed that water sloshes back and forth between the Eastern and Western shores as water flows up and down the main axis. This led to the discovery that nutrients and oxygen-depleted bottom water from the main channel can slop into shallow waters, stimulating phytoplankton production and causing fish kills during the summer.
Filling the gaps in ocean observing systems, researcher Tom Malone takes time from his post at the University of Maryland Center for Environmental Science to build a national program. Widely known for detailing links between nutrients, algae, and oxygen, he now works with the Intergovernmental Oceanographic Commission to integrate observing and prediction systems. Photograph by Skip Brown.
Sandy Rodgers.
Their work got a major boost in 1985, when federal funds came through for a five-year research initiative to determine why bottom waters in the Bay lose oxygen (become anoxic) during the summer. Managers and others wanted to know what determines the timing and extent of that anoxic zone. The program, administered by the National Oceanic and Atmospheric Administration and the Sea Grant programs of Maryland and Virginia, directed researchers to study the very processes that intrigued Malone and his colleagues. Precisely what mechanisms drive the disappearance of oxygen during the summer months? How much of this is natural and how much is manmade? Is it getting worse and, if so, why?
The results of this work were captured in a landmark book, Oxygen Dynamics in the Chesapeake Bay (see "A Classic Text," below right). Among other findings, the study determined that most of the Bay's nutrient load comes during the winter and spring when river flows and runoff from the land are high — and long before the seasonal onset of oxygen depletion in bottom waters of the Bay. Come spring, as water temperatures and sunlight increase, algae production kicks into high gear. As the waters warm, algae soak up light, drink in nutrients, and bloom.
This spring bloom is nothing new — it's been going on for thousands of years. But because so many nutrients now wash into the Bay from human sources — some six to eight times the amount of nitrogen of pre-Colonial times — the amount of biomass that accumulates during the spring is enormous. It exceeds the capacity of the Bay's herbivores — everything from oysters to menhaden to copepods — to eat it. Most of this algal biomass sinks to the bottom. There bacteria populations explode as they metabolize this organic matter, a process that sucks oxygen from the water.
Malone and his colleagues were able to show that summer anoxia is related to the accumulation of phytoplankton in the Bay during winter and spring (when grazing rates by herbivores are low). They showed that the amount of biomass that accumulates depends on the size of the nutrient load. The bigger the nutrient load, the bigger the spring bloom. Says Malone, "That makes estuaries like Chesapeake Bay particularly sensitive to human activities in their watersheds."
Meanwhile, all through the warmer months, more nutrients enter the Bay and those that came in during winter and spring recycle. All summer algae bloom, fall to the bottom, and decay. As they break down, they release more nutrients to feed more algae blooms.
Long shallow shoulders run along the edges of the Bay's main channels, the hidden history of sea level rise over the past fifteen centuries. The shallows reach into countless tributaries, where depths may drop to only a few feet or disappear altogether as tidal flats go dry twice a day. Writers have called it skinny water. The Bay is nothing if not skinny.
It is in the shallows where underwater grasses once grew in abundance, where oyster bars flourished.
And yet most of the monitoring that informs our picture of the Bay has tested deeper waters. Tom Malone realized this when he first set his zig-zag course back and forth across the Bay. So did Walter Boynton. Boynton, an ecologist, always had a special interest in the Bay's small coves and backwaters. Working out of the UMCES Chesapeake Biological Laboratory in Solomons Island, he studies nutrient dynamics and the health of sediments. He's found that he can learn a lot about the quality of the water by studying the health of the sediments lying beneath them.
In waters as shallow as those of the Chesapeake, the link between bottom and top is strong. In the shallows, nutrients in the sediment lie close to the surface. This puts nutrients nearer algae as they float beneath the surface, using light for photosynthesis. In shallow water, dying algae don't have far to sink before gathering on the bottom, where they decompose, releasing more nutrients. And with less volume than deeper waters, the shallows tend to concentrate algal blooms. On the other hand, oxygen can reach the shallows more quickly than in deeper water, and, when waters are clear enough, rooted plants can grow in the shallows and still see the sun.
Things can change fast in the shallows.
With all this and more in mind, during the mid-1990s, ten years after the federal-state Chesapeake Bay Program launched its main monitoring effort, Boynton began a rigorous focus on shallow water monitoring. He used emerging technologies that allowed real-time or near real-time testing from small boats. As the boat traveled along, an intake drew water through a hose and ran it into a monitoring machine. They called it a Data Flow device.
"Walter Boynton deserves a lot of credit for starting the shallow water monitoring effort," says fellow UMCES researcher Michael Kemp. "He and Chris Madden."
Christopher Madden, now at the South Florida Water Management District, developed the package of technologies and techniques for shallow water monitoring. Boynton's group then refined the process.
Boynton started making the case for an ongoing, continuous effort to monitor the Bay's shallows. Given the importance of the shallows to the Bay ecosystem, he argued, the lack of data there represented a huge knowledge gap. His proposal presented a daunting challenge to government agencies, given the extent of shallow habitats in the Chesapeake, but the Maryland Department of Natural Resources (DNR) understood the need.
Since 2002, the Maryland DNR has supported a shallow water monitoring system comprised of fixed monthly monitoring sites and continuous monitoring sites. They call it Eyes on the Bay, and it's impressive (see "Eyes on the Bay").
Donald Boesch, the president of UMCES, agrees that it's a remarkable resource. While preparing for a recent radio talk show in Washington, D.C., Boesch wanted a quick update on conditions during the summer of 2007. It struck him immediately how much information we now have, thanks to efforts like Eyes on the Bay. A quick click tracked conditions in the Patuxent, the Choptank, all around the state. "It's a tremendous tool," he says. "And its potential is probably under-used."
Since 2003 the Virginia Institute of Marine Science (VIMS) and the Chesapeake Bay National Estuarine Research Reserve in Virginia have mounted a similar continuous monitoring program, also available on the web (see "For Further Information").
Those early zig-zag cruises by Malone and others provided wonderful "snapshots," Kemp says. They told us a lot about the sloshing of salty bottom waters up on the edges, including waters devoid of oxygen (or, anoxic) that could harm life on the Bay's shallow shoulders. Now we have running tallies of salinity, oxygen, and other details thanks to dozens of shallow monitoring sites around the Bay.
Over the past thirty years, we have come a very long way.
Understanding why the Bay gasps for air in the summer months has proved one of the major breakthroughs in Chesapeake science. In 1985, the Sea Grant Programs of Maryland and Virginia teamed up with the National Oceanic and Atmospheric Administration to launch a five-year research effort focused on oxygen processes in the Chesapeake. The results of this work were captured in the 1992 book, Oxygen Dynamics in the Chesapeake Bay.
"This book is a classic," says Daniel Conley of Sweden's Lund University. Conley is now using the book to inform a similar effort underway in the Baltic Sea, which also suffers from too many nutrients.
"That book changed the way we look at the Bay," says long-time Bay researcher Larry Harding at the University of Maryland Center for Environmental Science. Before then, he says, we tended to look at the problem in pieces, and for scientists, in experimental terms, project by project. The 1992 book took the wide view, he says, the long view.
Many of the processes detailed in this book are now part of the public's broad understanding of how nutrients, algal blooms, and dissolved oxygen interact in the Bay.
Little light makes it through the turbid waters of the West River, according to these data from a team of volunteer monitors. Much of the river sees too little light for submerged aquatic vegetation (SAV) to grow, and the outlook for 2007 looks no better. Increased monitoring by volunteers, state and federal agencies, and research laboratories is painting a stronger picture of conditions in the shallows. Source: Richard Crenshaw and West River Water Quality Team.
All this tracking provides unprecedented information about nutrient levels, water clarity, salinity, oxygen levels, and other factors. It does not necessarily provide a coherent picture
Consider, for a moment, the riverkeepers.
All around the Bay, riverkeepers are keeping score. Much like the annual report card the Chesapeake Bay Foundation (CBF) uses to grade the whole Bay, riverkeepers are tracking large amounts of data to come up with scores for oxygen, clarity, and other criteria.
In Bob Gallagher's view, data gathering is "haphazard."
"The agencies aren't always looking for what we want," he says. "Their data collection is usually project-driven. Once the project is over, they move to something else."
But even the data gathered by the riverkeepers themselves can confuse. One look at the scorecards for different rivers illustrates the problem. Someone living on the Western Shore, for example, may want to see scorecards for the Magothy, the Severn, the South, the West, and the Rhode. But while information exists for all these rivers, comparisons are tough. One scorecard will use a bar graph, the other a line graph. One will show data relative to the habitat needs of fish or oysters, the other will show the same data as a percentage of a stated goal.
Comparing the health of rivers using these scorecards is a brain tease at best. Biologist Peter Bergstrom understands the problem. Working out of the Annapolis office of the National Oceanic and Atmospheric Administration (NOAA), Bergstrom is pushing a standardized format for all the river scorecards. He has floated suggestions for a common format, where tabulations for oxygen, salinity, bacteria, and other factors will look the same from river to river, from year to year. The University of Maryland Integration and Analysis Network (IAN), located at UMCES, is cooperating with Bergstom and others to develop standard ways of representing data across the board.
Whether or not riverkeepers and others will sign on to a standard tracking scheme remains to be seen.
And there is a more profound problem. Even when data is well organized and standardized, it does not alone provide the answers to some very complex scientific questions.
A rich data stream is very good at "tracking trends," says Michael Kemp. The data tell us, for example, what's up and what's down, he says. Whether it was a "good year" or a "bad year" for oxygen. But, he asks, "What does all that mean?"
In particular, what does it mean for an estuary like the Chesapeake Bay, where nutrient levels, despite some progress, have remained high since Baywide monitoring began in 1985? To make his point, he refers to recent work in Europe by researchers who tracked nutrient loading in about half a dozen European rivers. While they started by tracking nutrient increases, he says, these researchers were fortunate enough to eventually track decreases in nutrient loading. In the Chesapeake, he says, declining nutrient trends are hard to find.
The European example shows that tracking nutrient increases and decreases proved relatively easy. Explaining what happened next is not.
According to two researchers, Daniel Conley from Sweden and Carlos M. Duarte from Spain, nutrient levels declined, but algae levels remained high.
Those rivers did not appear to respond to nutrient reductions. Why not?
Conley and Duarte argued at a recent meeting of the Estuarine Research Federation that the rivers did not respond because something had changed. That something is the climate. Because of global warming, they say, baseline conditions are no longer the same. Trying to return to a prior state would be, in their words, like trying to return to "Neverland."
Their findings reinforce Kemp's point. We can track trends, but it will take our very best science to explain them.
Does Kemp agree that global warming has made returning to a prior state more difficult — if not impossible?
Maybe. But he offers another hypothesis. Kemp suspects that over-fertilized systems — like the Chesapeake — have become stuck in a rut. Some call this a "perverse resilience." In order to move out of this state, he says, we need to reduce nutrients and then provide the Bay with enough time for "self-healing," borrowing a phrase from the Chesapeake Bay Foundation.
To know when the Bay is responding, he says, we need to track the return of positive feedback loops. The return of bottom dwellers and filter feeders. The comeback of underwater grasses. We need to pay close attention to how the Bay is responding to such key factors as nutrient loading, sediment, and climate.
"The action," he says, "will be in the shallows."
It is in the shallows, Kemp argues, that we will see the quickest response and the earliest signs of change.
With no rain to flush them out during hot, dry conditions, tributaries may well become reactors pumping out harmful algal blooms.
The summer of 2007 offered a glimpse of what could happen in the shallows if the climate warms and nutrients continue unabated.
It also revealed why so many algal blooms can show up even in a drought year.
First, we know from Tom Malone and his colleagues that much of the nutrient loading to the Bay occurs in the cooler months. During most of the winter and spring of 2007 rainfall was, according to the U.S. Geologic Survey (USGS), average or above average. By the time the drought began in early summer, nutrients were already in the Bay.
Second, with very little rain and a lot of sunlight, the tributaries cooked. Since the rivers already had plenty of nutrients in them, they didn't need any more runoff to fuel the summer's blooms — blooms largely of dinoflagellates, some of them toxic.
"It was a banner year for harmful algal blooms," says Allen Place, researcher at the University of Maryland Biotechnology Institute (UMBI). Place, who studies toxic algae at UMBI's Center of Marine Biotechnology in Baltimore, points out that dinoflagellates thrive in still waters. Diatoms can swirl happily in spring runoff, but dinoflagellates don't like agitation. At least that's what he's observed with species he's studied, including the toxic dinoflagellate Karlodinium. He was not surprised to find Karlodinium showing up at fish kills during hot still weather in Baltimore Harbor, in Weems Creek near Annapolis, and down on the Potomac River.
It's widely understood that when algal blooms crash, low oxygen conditions usually follow. But while dinoflagellates can cause dense algae blooms they tend to show up in lower numbers than do springtime diatoms. For this reason, they may form mahogany tides, perhaps even toxic ones that cause fish kills, but not cause the huge drops in oxygen associated with thicker clouds of diatoms or other algae.
This is likely the answer to riverkeeper Bob Gallagher's question about the summer of 2007. Algae bloomed in a dry summer because nutrients were already there from the previous winter and spring. The blooms were largely comprised of dinoflagellates that thrive in hot still weather. These mahogany tides did not cause the kind of oxygen drops associated with the spring bloom because dinoflagellates probably bloomed at densities well below that of spring diatoms.
In the end, this is disturbing news. As long as heavy loads of nutrients run off the land in winter and spring, algae will bloom and cause a loss of oxygen in the Bay's deeper waters. Even worse, despite a dry summer, harmful algae blooms, caused by dinoflagellates, will bloom in the shallows and tributaries. With no rain to flush them out during hot dry conditions, the tributaries may well become reactors pumping out harmful algal blooms.
Place and Kemp are quick to add that for now this still-water scenario is only conjecture. Though their years of research have led them to these explanations, connecting the dots between climatic conditions and the appearance of particular kinds of algae will require a lot of data and a lot of experimentation and analysis. It will, they say, require a lot of synthesis, a lot of thinking.
Kemp is now working at synthesis — trying to make sense of huge amounts of data. To do this, he's partnering with a team of experts he calls "super computer geeks." Experts from Johns Hopkins University, the University of Delaware, Dalhousie University, and the San Diego Supercomputing Center. Kemp and UMCES colleague Ming Li will provide the link between all that computing power and the Bay-related questions they're trying to answer.
Their project, funded by the National Science Foundation (NSF), will serve as a "proof of concept." The idea is to manipulate the huge profusion of data now available from advanced observing systems to achieve a new level of scientific understanding.
With the advent of new technologies, observing systems have proliferated, Kemp says, for everything from climate change to tsunamis. Because of the years of sophisticated research directed at understanding the Bay's oxygen cycle by Malone and many others, the Chesapeake will serve as a national experiment. The Bay will help answer to what degree and in what way we can put new massive data streams to use in answering fundamental science questions.
Their plan is to draw from many different data sources and to organize that data in ways never before possible. Their goal is a new "cyber-infrastructure."
We are clustering (or "federating") different datasets, Kemp says. But this is not just a matter of hooking up piles of data. The key, Kemp says, will be to shape the data in various ways, to ask the right questions of it. While data are always used to create models, these researchers will reconstruct models in various ways to spit out specific information they want. They will target information geared to test particular hypotheses or concrete management choices.
Over the next thirty years, the vast array of observation sites that Malone and others are pushing for will track what happens as we reduce the flow of nutrients into the Bay. It will keep a sleepless watch on the shallows, to see when rivers reach their thresholds of recovery, when algal blooms abate, oxygen levels rise, and water clarity improves.
And more than this, if Kemp and his colleagues are successful, scientists will use a new cyber-infrastructure to explain why change is happening, why the ecosystem is responding, why algae is blooming — or not — even in a dry summer.
Or, if we do not have the political will to reduce the flow of nutrients into the Bay, this new approach will show us precisely where the toxic algal blooms are likely to occur, where the fish kills will be, where the oxygenless dead zones will spread.