The footprint of Alaskan tundra fires

May 20th, 2013 @

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 and EOL Team Join Ecosystems Staff

March 18th, 2013 @

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."

Chris Neill Named New Director of Ecosystems Center

March 18th, 2013 @

ChrisNeillSenior 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.

Reaching New Heights To Measure CO2

January 21st, 2013 @

Featured Article: Reaching New Heights To Measure CO2

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.

Nutrients Causing Salt Marshes to Disintegrate

October 22nd, 2012 @
Marsh in Plum Island

Marsh slumping at Plum Island (Photo: Kate Morkeski)

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.

Citation:

 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.

 

 

ESA Welcomes First Cohort of Fellows

October 19th, 2012 @
Jerry Melillo

Jerry Melillo

Jerry Melillo and Gus Shaver of the Ecosystems Center have been named Fellows of  the Ecological Society of America (ESA). They are in the first group to be named to the new Fellows program by the 10,000-member society, the world's largest organization of professional ecologists.  A total of 40 Fellows were named. At the same time, ESA also established an Early Career Fellows program honoring young scientists.

“The Fellows and Early Career Fellows programs will recognize the many ways in which our members contribute to ecological research and discovery, communication, education and pedagogy, and to management and policy,” said ESA President Scott Collins.

Both Jerry and Gus have conducted research at the Ecosystems Center for more than three decades. Jerry, distinguished scientist and former co-director of the Center, is also a professor of biology at Brown University. In his research, he studies the impacts of human activities on the biogeochemistry of terrestrial ecosystems. He has studied carbon and nitrogen cycling in ecosystems across the globe, including arctic shrublands in northern Sweden, temperate forests in North America, and tropical forests and pastures in the Amazon Basin of Brazil.  Jerry served as ESA’s President in 2004-2005.

Gus Shaver

Gus Shaver

Gus is a senior scientist at the Center and a professor at Brown. He studies plant growth and nutrition and the role of plants in ecosystem element cycle, focusing his research on Alaskan tundra ecosystems, where low temperatures, low light intensities, low nutrient availability, and a short growing season all interact to limit plant growth. He is lead principal investigator of the Arctic Long Term Ecological Research program, based at Toolik Lake, Alaska.  Gus was ESA’s Vice-President for Science 2004-2007.

2011 Ecosystems Center Annual Report: Read It On-Line

July 24th, 2012 @

Alex Huryn on thermokarstThe 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.

Tales of Young Scientists in the Salt Marsh

July 24th, 2012 @
Tidal marsh

(Photo by Sarah Wilkins)

Greenheads, Dragonflies, Snails, and Tales of Young Scientists in the Salt Marsh

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.

A Land of Extremes

May 25th, 2012 @
Musk Ox

Muskoxen (Ovibos moschatus) on the North Slope of Alaska. (Photo: Alex Huryn)

Land of Extremes Is Colorful Guide to Natural History of the Arctic Tundra

John Hobbie and Alex Huryn, long-time principal investigators on the Arctic Long Term Ecological Research project at Toolik Lake, Alaska, have just finished a book about the natural history of the North Slope of Alaska, the only Arctic tundra in the U. S. The book, Land of Extremes, A Natural History of the Arctic North Slope of Alaska, will be published this September by the University of Alaska Press.

The idea for the book came up in the dining hall at Toolik. Says Hobbie, “I was sitting at the dinner table with Alex, and was struck by the diversity of the expertise there. Scientists who were world experts on birds, mammals, microbes, plants, geology and so on. What an opportunity to bring together all that knowledge about one small region of the Earth – and a very interesting region it is too.”

The first section is devoted to climate, geology, landforms, and ecology; the second provides a guide to the identification and natural history of the common animals and plants and a primer on the human prehistory of the region from the Pleistocene through the mid-twentieth century. The appendix provides the framework for a tour of the natural history features along the Dalton Highway, the road that runs from the Brooks Range to Prudhoe Bay and the Arctic Ocean.

John Hobbie, currently senior scholar the Ecosystems Center, was instrumental in setting up Toolik as a research station in the mid 1970s. He has been going to the North Slope, in fact, since he began conducting his doctoral research in the late 1950s. Like Hobbie, Alex Huryn, professor at the University of Alabama, has carried out research in the Arctic year-round. “Alex is an excellent naturalist, and provided hundreds of color illustrations for the book,” said Hobbie.

Tour Gives Students a Glimpse of Center Research

May 17th, 2012 @
Harbor School

JC Weber explains his laboratory's research in the deep Sargasso Sea to students from the New York Harbor School. (Photo: Debbie Scanlon)

Students from the New York Harbor School visited Woods Hole and the Ecosystems Center last month. JC Weber explained the work that he and Maureen Conte conduct in the Oceanic Flux program. He told students about one aspect, using organic chemical biomarkers extracted from deep sea particulate matter to learn about processes in the mesopelgaic zone of the deep Sargasso Sea.

Matthew Erickson gave an overview of the Palmer Station Long Term Ecological Research project in Antarctica. Research there is focused on the Antarctic pelagic foodweb.

The Harbor School is a small college preparatory school on Governor's Island in New York City. All students must choose a career and technical education program of study from one of these maritime related areas: marine technology, marine science, marine policy or SCUBA diving.