Dr. Ivan Valiela of the MBL Ecosystems Center will receive the Coastal and Estuarine Research Federation’s Odum Lifetime Achievement Award. The award recognizes Dr. Valiela’s contributions to the understanding of coastal marine ecosystems, addressing critical management questions, serving the scientific community, and educating multiple generations of students.
This award is named for the three outstanding ecologists in the Odum family (Drs. Howard T., Eugene P. and William E. Odum, III), and it recognizes the lifetime achievements of a scientist whose sustained accomplishments have made critically important contributions to our understanding of estuaries and coastal ecosystems.
Dr. Valiela conducted groundbreaking saltmarsh studies in the Great Sippewissett Marsh and was the lead principal investigator for the Waquoit Bay Land Margin Ecosystem Research Project that assessed groundwater transport and nutrient loading to Waquoit Bay on Cape Cod. He was among the first to clearly demonstrate the coupling between watersheds and their receiving estuaries, and his 1992 paper on this topic in Estuaries remains the most highly cited paper ever published by the journal, with more than 440 citations. This work led to models of coastal nutrient loading that are widely used to assess the status of coastal ecosystems and to develop policies to reduce nutrient loading. This contribution is typical of Dr. Valiela’s scholarship. His work advanced basic scientific principles but typically has an applied angle that focuses on improving the quality of coastal environments.
“This award is richly deserved,” said Ecosystems Center Director Christopher Neill, “Ivan has been an extradordinarily influential coastal ecologist both with his science an in the students he he’s trained. I had the good fortune of attending Ivan’s Marine Ecology class at MBL in 1983. It was my introduction to Woods Hole and it made a career in research both exciting and possible.”
Locally, Dr. Valiela’s work provides much of the scientific basis for understanding Cape Cod’s nitrogen pollution problem, Dr. Neill said. “The models he developed also allow us to explore alternative futures and will help towns begin to solve this difficult problem.”
In collaboration with John Teal of the Woods Hole Oceanographic Institution, Dr. Valiela began a salt marsh fertilization experiment at Great Sippewissett marsh in 1971, an experiment that continues to this day. The scores of manuscripts that have resulted from the Sippewissett Marsh research have defined much of what we know about saltmarsh biogeochemistry and community ecology. Dr. Valiela also co-taught the summer Marine Ecology course with Dr. Teal at MBL from 1975 to 1983. The decades of research that he conducted in Waquoit Bay system have contributed to the understanding of the causes and consequences of coastal eutrophication. Dr. Valiela also elucidated the critical role of macroalgal blooms in coastal eutrophication and eelgrass decline He has also worked in tropical ecosystems, and was among the first to estimate the global destruction of mangrove forests.
Dr. Valiela continues to pursue research in both temperate and tropical habitats. In one current project, he leads a team of scientists working in Panama to evaluate how varying amounts of watershed deforestation affect coastal mangrove wetlands and nearshore coastal waters.
He has written over 300 papers, a number of which are seminal papers in the fields of coastal marine ecology and biogeochemistry. He has also authored three books, Marine Ecological Processes, a widely-used textbook, Doing Science, a book geared to young scientists, and Global Coastal Change, an overview of overfishing, eutrophication, introduced species, and sea level rise in coastal regions.
Dr. Valiela taught in the Boston University Marine Program at MBL from 1969 until 2008 when he joined the Ecosystems Center. He has advised 12 master’s and 43 doctoral students, many of whom have gone on to highly successful careers.
The Odum award will be presented at the meeting of the Coastal and Esutarine Research Federation’s meeting in San Diego, California in November.
Scientists at the Arctic Long-Term Ecological Research project, which is based at the Ecosystems Center, are studying the increase in wildfires on the Arctic tundra. A recent paper by Adrian Rocha, Ed Rastetter, Gus Shaver and others reports that recently the size and frequency of wildfires in Alaska’s arctic north has increased dramatically because of changes in climate and dryness of the tundra.
When a wildfire occurs, there are both positive and negative effects on future climates. One effect is that the soil gets darker, which leads to warming, more decomposition of organic carbon, and release of CO2; yet it also leads to growth of more plants that will take up CO2 and preserve the carbon in plant parts for many years.
Another effect is that the tundra is shaded by the increased leaves and plant litter, which leads to cooling, but a counteracting warming of the soil in winter caused by an increase in snow thickness trapped by more shrubs.
There is also an increase in the depth of thaw each summer that leads to increased erosion and breakdown of soil organic matter. Our current research in arctic Alaska investigates the balance of these and other processes that will change the effect of the tundra on the climate.
Rocha, AV; Loranty, MM; Higuera, PE; Mack, MC; Hu, FS: Jones, BM; Breen, AL; Rastetter, EB; Goetz, SJ; Shaver, GR. 2012. The footprint of Alaskan tundra fires during the past half-century: Implications for surface properties and radiative forcing. Environmental Research Letters. doi:10.1088/1748-9326/7/4/044039
Nathan Wilson, Associate Research Scientist, and the biodiversity informatics and web development team working on the Encyclopedia of Life have joined the Ecosystems Center.
EOL has been at MBL since 2007. MBL was one of the five founding institutions that launched this ambitious attempt to create a web page for every species of life on earth. The idea grew out of an idea put forward by Edward O. Wilson: "I wish we will work together to help create the key tools that we need to inspire preservation of Earth's biodiversity. And let us call it the 'Encyclopedia of Life.' " Other projects that Nathan Wilson's team works on include the Embryo Project Encyclopedia, the History of MBL (website coming soon!), and the Global Names project.
"The biodiversity informatics team has skills that range from data management to website development and interests across biodiversity science, citizen science and database architecture," said Ecosystems Director Chris Neill. "The core work of EOL at MBL will continue, and we see potential to develop ways to collaborate with them across modeling projects, LTER data management, water quality monitoring and in other areas."
Senior Scientist Christopher Neill has been named director of the Ecosystems Center. Chris is also the Phyllis and Charles M. Rosenthal Director of the Brown-MBL Partnership and director of the Brown-MBL Graduate Program in Biological and Environmental Sciences.
He received a B.S. from Cornell University, and a M.S. and Ph.D. from the University of Massachusetts Amherst. He first came to MBL as a student in the summer Marine Ecology course in 1983. He joined the MBL as a post-doctoral research associate in 1991 and later established a research program in the Amazon. Chris directs the Hands-on Environmental Laboratory for the MBL’s Logan Science Journalism Program, and has written a column on ecology and the environment for The Falmouth Enterprise newspaper. He was awarded a Bullard Fellowship by Harvard University in 2010 and a Fulbright Fellowship to Brazil in 2007. He is a member of the American Association for the Advancement of Science, The Ecological Society of America, The American Institute for Biological Sciences, and the American Geophysical Union. He currently serves as the president of Falmouth Associations Concerned with Estuaries and Saltponds and as a board member of BiodiversityWorks.
Chris succeeds Hugh Ducklow, who held the post since 2007, and has moved to the Department of Earth and Environmental Sciences at Columbia University.
Led by senior scientist Anne Giblin and postdoctoral scientist Inke Forbrich, Ecosystems Center scientists have built a 40-foot instrumentation tower at the Plum Island Long Term Ecological Research site in northern Massachusetts to allow them to make year-round measurements of net ecosystem carbon exchange.
The particular site was chosen to ensure that measurements can take place even during winter. Due to potentially harsh climate conditions and ice drift, measurements so far have been restricted mostly to the growing season.
Salt marsh ecosystems are among the most productive ecosystems worldwide and these data will help to understand and quantify the ecosystem carbon uptake and release. While marsh grasses take up considerable amounts of carbon during the growing period, the marsh is expected to release CO2 during winter.
The long term goal of these measurements is a better understanding of carbon cycling in the Plum Island Estuary and how the system can adjust to the projected sea level rise. Sea level is predicted to increase, and the scientists are interested in how these changes affect the salt marsh ecosystem. "The major question here is whether the marsh can keep up with a rising sea level by both sedimentation and peat accumulation. Since previous studies have shown that the sedimentation rate at Plum Island is relatively low, we will have a closer look at the carbon cycling in the salt marsh," Inke Forbrich said.
A long-term, large-scale study by Ecosystems Center scientists of salt marsh landscapes in an undeveloped coastline section of the Plum Island Estuary in Massachusetts has shown that nutrients such as nitrogen and phosphorus can cause salt-marsh loss.
Center scientists Linda Deegan, David Johnson and Bruce Peterson and four other scientists are authors of an article that appeared in the journal Nature on October 18, showing results of their nine-year research study. Septic and sewer systems and lawn fertilizers are often the sources of the nutrients that are causing the disintegration.
“Salt marshes are a critical interface between the land and sea,” Deegan says. “They provide habitat for fish, birds, and shellfish; protect coastal cities from storms; and they take nutrients out of the water coming from upland areas, which protects coastal bays from over-pollution.” Losses of healthy salt marsh have accelerated in recent decades, with some losses caused by sea-level rise and development.
“This is the first study to show that nutrient enrichment can be a driver of salt-marsh loss, as well,” says Johnson, a member of the team since the project began in 2003.
This conclusion surprised the scientists, who added nitrogen and phosphorus to the tidal water flushing through the marsh’s creeks at levels typical of nutrient enrichment in densely developed areas, such as Cape Cod and Long Island.
A few years after the experiment began, wide cracks began forming in the grassy banks of the tidal creeks, which eventually slumped down and collapsed into the muddy creek. “The long-term effect is conversion of a vegetated marsh into a mudflat, which is a much less productive ecosystem and does not provide the same benefits to humans or habitat for fish and wildlife,” Deegan says.
Until this study, it seemed that salt marshes had unlimited capacity for nutrient removal, with no harmful effects on the marshes themselves. “Now we really understand that there are limits to what salt marshes can do,” Deegan says. “And in many places along the Eastern seaboard—such as Jamaica Bay in New York, where marshes have been falling apart for years—we have exceeded those limits.”
The disintegration of the nutrient-enriched marsh in this study happened in several stages, the scientists report. In the first few years, the nutrients caused the marsh grass (primarily cordgrass Spartina spp.) along the creek edges to get greener and grow taller, “just like when you add fertilizer to your garden,” Deegan says. This taller grass also, however, produced fewer roots and rhizomes, which normally help stabilize the edge of the marsh creek. The added nutrients also boosted microbial decomposition of leaves, stems, and other biomass in the marsh peat, which further destabilized the creek banks. Eventually, the poorly rooted grass grew too tall and fell over, where the twice-daily tides tugged and pulled it. The weakened creek bank then cracked and fell into the creek.
By year six of the experiment, the scientists started seeing impacts at higher marsh elevations, above the lower creek banks. Three times more cracks, and bigger cracks, emerged at the top of the banks parallel to the creeks, than in a control marsh where no nutrients were added. Eventually, parts of the higher marsh also broke off and slid down toward the creek (which the scientists call the ‘toupee effect,’ because it leaves behind patches of bare, unvegetated mud). All told, at least 2.5 times more chunks of marsh fell into the creeks in the nutrient-enriched marsh than in the control system.
“We honestly did not anticipate the changes we measured,” says Deegan. “Based on prior small-scale experiments, we predicted nutrient enrichment would cause the marsh grass to grow better and remain stable. But when we allowed different parts of the ecosystem to interact with the nitrogen enrichment over time, the small process changes we saw in the first few years resulted in the creek banks later falling apart. This could not have been extrapolated from the smaller-scale, shorter term studies.”
Nutrient enrichment of coastal areas is known to cause harmful algae blooms, which create low-oxygen conditions that kill off marine life. “Now we understand that nutrient enrichment also causes a very important loss of salt marsh habitat for fish and shellfish,” Deegan says. “This is one more reason why we need better treatment of household waste in our towns and cities.” Individuals can help by not using fertilizers on their lawns and gardens. “If you have a green lawn because you are fertilizing it, you are contributing to loss of salt marshes and ultimately of fish,” Deegan says.
This study could not have been accomplished without the cooperation and fore-sightedness of officials from the towns of Ipswich, Mass., and Rowley, Mass., and the Essex County Green Belt Association, the scientists say.
“They recognized the importance of the work,” Johnson says. “They understood that our work would not affect the much larger Plum Island Estuary, since the area manipulated was small relative to the large area of the sound and the marsh is able to process a lot of the nutrients before they get anywhere near the sound. They realized that whatever we discovered would help their towns, and society in general, make better decisions about treating the excessive nutrient enrichment of our coast.”
This study is part of the Plum Island Ecosystem Long-Term Ecological Research (PIE-LTER) program, supported by the National Science Foundation (NSF). The PIE-LTER conducts basic science and provides information to coastal managers to help them make more informed decisions.
"This is a landmark study addressing the drivers of change in productive salt marsh ecosystems, and a stellar example of the value of supporting LTER sites," says David Garrison, program director in NSF's Division of Ocean Sciences, which supports the LTER program along with NSF's Division of Environmental Biology.
In the next phase of research, the scientists will study the recovery of the nutrient-enriched marsh. “After we stop adding the nitrogen, how long does it take the system to rebound to its natural state?” Deegan asks. This information will be important in reclaiming the health of salt marshes that are currently suffering from nutrient enrichment.
In addition to Deegan, Johnson, and Bruce J. Peterson of the MBL, co-authors of this study in Nature include: R. Scott Warren of Connecticut College; John W. Fleeger of Louisiana State University; Sergio Fagherazzi of Boston University; and Wilfred M. Wollheim of the University of New Hampshire.
Deegan LA, Johnson DS, Warren RS, Peterson BJ, Fleeger JW, Fagherazzi S, and Wolheim WM (18 Oct 2012) “Coastal Eutrophication as a Driver of Salt Marsh Loss” Nature.
The 2011 Ecosystems Center Annual Report features stories on nutrient pollution, climate warming and fisheries. Ed Rastetter writes about the models of nutrient cycling that he has developed, which he uses to predict the effects of thermokarst scars in the Arctic, as shown in the photo (on left). Thermokarst occurs when permafrost thaws and the land surface collapses. Joe Vallino writes about bacteria that control denitrification, the conversion of fixed nitrogen compounds back to nitrogen gas, an important part of the global nitrogen cycle. Linda Deegan tells about the use of new acoustic fish tagging technology to track the coastal migration of "schoolie" striped bass.
The report has updates on our many educational and outreach programs. The Semester in Environmental Science had its largest class ever in 2011, and students in the Brown-MBL Graduate Program in Biological and Environmental Sciences conducted research with their MBL advisors. Ecosystems Center staff also mentored local junior high and high students and judged science fairs, provided guidance to undergraduate interns at the center and in remote field sites, and participated in a mentoring program to encourage diversity in the science community.
Check out the new annual report web site, which also features an update from Ecosystems Center Director Hugh Ducklow, and then sign up for email updates from the Ecosystems Center throughout the year.
If you pay attention to a New England salt marsh in the summer you can see emergence. The greenhead that emerges from the grass. The dragonfly that emerges from the pond. The snail that emerges from the flooding waters. In Plum Island, if you're patient, you can see young scientists emerging from the marsh.
These young, intrepid marsh-minded scientists are part of the the Ecosystem Center's TIDE (Trophic cascades and Interacting control processes in a Detritus-based aquatic Ecosystem) Project, which is nestled within the Plum Island Long Term Ecological Research site. TIDE is a large-scale fertilization project in the salt marshes of the Plum Island Estuary in northern Massachusetts that is currently in its 10th field season.
The project is led by Ecosystems Center senior scientist Linda Deegan, and many center scientists have participated in the project. More importantly, the TIDE Project has provided opportunities for young scientists to get their feet wet (that is, wet, muddy, and mosquito-bitten) in science.
These young researchers write about their experiences in the TIDE blog. From the frontlines of the field, it gives first-hand accounts of the science being conducted.The most recent posting is by David Johnson, a research associate at the center who has been a part of the TIDE Project for 10 years. While greenheads and snails and dragonflies come and go, some who emerge on the marsh stay for a while.