Archive for November, 2013

Predicting the Future of Maine’s Forests

Monday, November 18th, 2013


Understanding how forests function as complex adaptive systems and predicting the future characteristics of Maine’s woods are goals of a project by a team of University of Maine researchers.

The study also aims to improve an open-source forest ecosystem model to help make project insights more transferable to research in other forests.

Erin Simons-Legaard, a post-doctoral research scientist in the UMaine School of Forest Resources, is principal investigator of the project titled “When natural disturbance meets land-use change: An analysis of disturbance interactions and ecosystem resilience in the Northern Forest of New England.”

“We can’t control everything, but it’s important to understand the processes that are controlling what type of forest grows after it’s cut down and identify the underlying interactions between the human decision-making process and ecological dynamics,” Simons-Legaard says. “Once we identify where the interactions are the strongest, we know what pathways we can use if we want to change what our future forests will look like.”

Working with Simons-Legaard on the project are Jessica Leahy, an associate professor of human dimensions of natural resources at UMaine; Kasey Legaard, an associate scientist in the School of Forest Resources; Aaron Weiskittel, an associate professor of forest biometrics and modeling and Irving Chair of Forest Ecosystem Management at UMaine; and Emily Silver, a Ph.D. student in the School of Forest Resources.

The two-year project, which began in July 2013, was awarded a $235,494 National Science Foundation grant.

The relationship between the biophysical and social subsystems is an important factor in understanding how forest ecosystems work as complex systems.

“No two acres of forest are exactly the same unless you plant it — if even then — and that’s because forests are complex,” Simons-Legaard says.

The researchers are creating future projections of the northern half of Maine — about 10 millions acres — by focusing on the interactions between man-made disturbances such as harvesting and development, and natural disturbances such as wind and pests.

Periodically Maine’s northern forests will have an infestation of the eastern spruce budworm — a pest that targets balsam fir and spruce trees, two common and economically important tree species in Maine. During the last outbreak, a lot of spruce-fir forest became infested and was then salvaged. In many areas, fir and spruce were replaced by shade-intolerant northern hardwoods that can establish and grow faster than the softwood trees in open areas. This replacement can occur when spruce-fir forest is harvested before the understory completely develops.

“Researchers are trying to understand what drives that shift from softwood to hardwood and what it might mean for natural resources like wood supply and wildlife habitat,” Simons-Legaard says. “Maine’s northern forest has traditionally been spruce-fir dominated, and a big shift toward hardwood in a historical context would be unprecedented.”

For several years, Simons-Legaard and her husband Kasey Legaard had focused on the state’s two main disturbance agents — harvesting and spruce budworm. Since their research began, the pair noticed more discussion about development and what role it could potentially play in northern Maine.

The researchers decided to include land-use change as a disturbance to take a more comprehensive approach to understanding how forests work.

“Taking this approach means recognizing you have the natural system with its components — trees, soil communities of microbes and bacteria, wildlife community — and they are all interacting. Then you have people interacting in their social system and making decisions. In a forest, the natural system and the human system interact,” Simons-Legaard says.

Learning more about these interactions and how they might be influenced by different disturbances is at the core of the team’s research.

“For the social side the focus is on what influences a landowner’s decision to stop producing timber and develop. That’s what Jessica Leahy and graduate student researcher Emily Silver are focused on; the decision-making process of the landowners,” she says.

To make their results more transferable to other timber-producing forests, the team used an already-established software program instead of creating a project-specific program. The group is using LANDIS-II, a cell-based forest ecosystem model which has an active community of users and developers. Any improvements the researchers make to the software can quickly be distributed to all of its users.

Using a map of initial forest conditions and text files describing the life history characteristics of the area’s tree species, the program creates future projections of the forest by growing trees, dispersing seed, establishing new cohorts of trees and accounting for natural mortality. The program also has extensions that allow the researchers to add disturbances, such as harvesting.

For two years the team has been preparing the input files. The map of the area’s initial conditions of tree species and forest age was created using satellite imagery and U.S. Forest Service’s Forest Inventory and Analysis (FIA) plot data.

Text files created for the 13 most abundant tree species in Maine describe how species’ growth and mortality is influenced by environmental conditions. The files help the program model species establishment and competition after a disturbance.

“These text files have to describe in numerical terms what tree-species competition looks like and how species rank in terms of competitive ability,” Simons-Legaard says.

Once the files are complete, the information is entered into LANDIS-II, along with the disturbance extensions, to determine what Maine’s forests will look like in the future.

“There’s also a regional focus because we’re trying to understand Maine’s forests better; both the natural components, how they interact, how tree-species competition determines whether a forest comes out as softwood or hardwood, and how Maine’s landowners make their decisions,” Simons-Legaard says.

As spruce budworm begins to make its return and land-use change becomes more frequent, asking the preemptive “what if?” questions are important in determining where Maine’s forests are headed in the next 50 or 100 years, she says.

Contact: Elyse Kahl, 207.581.3747

Ecological Changes, Economic Consequences

Monday, November 18th, 2013


A $1.8 million grant from the National Science Foundation will allow a multidisciplinary team of researchers to examine the impact of rising ocean temperatures on the ecology and economics of the Gulf of Maine.

Led by Andrew Pershing from the University of Maine and Gulf of Maine Research Institute (GMRI), the team will conduct a four-year project as part of the NSF’s Coastal SEES (Science, Engineering and Education for Sustainability) Initiative to support collaborative studies.

“Climate change is impacting the distribution of fish and lobsters in the Gulf of Maine,” Pershing says, “and these ecological changes can have significant economic consequences.”

For instance, record warm ocean temperatures during 2012 prompted lobsters in the Gulf of Maine to migrate shoreward about a month early, making them easier to catch. Lobstermen proceeded to haul in record numbers of the crustaceans, but the overabundance of product on the market tanked the price paid to lobstermen.

There’s a growing realization among scientists that complex problems like climate change and fisheries require us to work with people from other fields,” says Katherine Mills a co-investigator on this study from UMaine and GMRI.

The team includes climate scientists, oceanographers, fishery scientists and economists from UMaine, GMRI, Stony Brook University, NOAA’s Northwest Fisheries Science Center (NWFSC) and NOAA’s National Center for Atmospheric Research (NCAR).

“The Gulf of Maine is an ideal test site to examine relationships between climate change, oceanography, ecology and economics,” Pershing says. In addition to its economically valuable lobster and groundfish fisheries, the Gulf has strong temperature gradients and has been warming rapidly in recent years.

“Rising temperatures impact spatial and seasonal distributions of many fish and invertebrates,” says Janet Nye, an assistant professor at Stony Brook University. Shifts in the distribution and abundance of species drive changes to their interactions with each other, as well as changes to where, when and how many are caught.

As part of its multidisciplinary approach, the project has a dedicated education component through GMRI’s LabVenture! Program that annually reaches 10,000 Maine fifth- and sixth-grade students. The researchers will work with GMRI’s education specialists to develop a hands-on experience that enables students to explore how computer models help scientists understand complex interactions among species and the environment.

In addition to Pershing, Mills and Nye, the team includes Andrew Thomas, Richard Wahle and Yong Chen from the University of Maine; Jenny Sun, Tom Farmer and Frank Chiang from GMRI; Dan Holland from NWFSC; and Mike Alexander from NOAA Earth System Research Laboratory.

Contact: Beth Staples, 207.581.3777

UMaine Marine Scientist Joins Elite International Group of Adventurers

Monday, November 18th, 2013

University of Maine marine scientist Rhian Waller has been named a Fellow in an elite international group of adventurers who encourage scientific discovery while exploring land, sea and space.

Founded in 1904, Explorers Club members attempt to attain new heights and depths; they’ve been the first to reach the moon, North Pole, South Pole, the Mount Everest summit and the deepest part of the ocean.

Waller, an associate research professor in UMaine’s School of Marine Sciences, fits right in. In 2013, National Geographic Magazine celebrated her as a 21st-century risk taker who presses the limits in this “New Age of Exploration.”

Based at the Darling Marine Center (DMC) in Walpole, Maine, Waller has pushed the limits of diving during more than 40 expeditions around the planet. In a submersible, she has plunged to a depth of 3,600 meters to examine corals on the New England Seamount chain.

“I feel extremely honored to have been voted into the Explorers Club, and really pleased to have been recognized for the scientific exploration work I’ve been doing across the globe,” Waller says.

“There are so many conservation issues surrounding the deep ocean, I hope I can use this opportunity to spread the word more widely that the deep sea is important to our whole planet, and does need our protection.”

As a Fellow, Waller has access to the Explorer’s Club research collections, including a library and map room, and she’s connected with a global network of expertise, experience, technology, industry and support. The Explorers Club supports exploratory expeditions and provides opportunities for the 3,000 members worldwide to carry an Explorers Club flag on voyages that further the cause of exploration and field science. Since 1918, flags have flown at both the North and South poles and aboard Apollo 11.

The seven founders of the Explorers Club were two polar explorers, a curator of birds and mammals at The American Museum of Natural History, an archaeologist, a war correspondent/writer, a professor of physics and an ethnologist. Today its members — including archaeologists, astronomers, entomologists, mountaineers, zoologists and a now a new deep-sea researcher — conduct explorations and research in more than 60 countries around the globe, and beyond.

For her research, Waller routinely scuba dives in temperatures 35 F and colder. She studies how environmental factors such as climate change, fishing and oil exploration affect deep-sea coral ecology and reproduction, as well as what effect that altered life cycle could have on the rest of the marine ecosystem.

Last summer, Waller was part of a research team that discovered two deep-sea coral communities in the western Jordan Basin and Schoodic Ridge regions of the Gulf of Maine.

Last month, Waller returned from an expedition to Chile. She had traveled to Huinay Scientific Field Station near the northern Patagonian fjords to collect final samples from a yearlong deep-sea coral monitoring program. She’s examining how climate change, salmon farms, fishing and oil exploration affect deep-sea coral reproduction, and what effect any altered life cycle could have on the marine ecosystem.

In her Oct. 11 blog on that trip, Waller wrote that corals, which she calls the rainforests of the ocean, “are not just beautiful to look at … they’re also extremely important to the health of our oceans, and ultimately the health of the planet.”

Next year, Waller will utilize a $381,384 National Science Foundation grant to investigate how Antarctic corals, which provide habitat for thousands of connected species, are coping with warming ocean water.

Contact: Beth Staples, 207.581.3777

Understanding Phytoplankton Paths

Thursday, November 7th, 2013


Two University of Maine researchers are teaming up with a University of California-Berkeley professor to study the sinking rate and trajectories of phytoplankton in relation to particle shape and water turbulence. Phytoplankton provide the food supply at the base of the marine food web and help maintain the health of the atmosphere by absorbing and sequestering carbon dioxide and producing oxygen.

Lee Karp-Boss, a marine scientist and associate professor in the UMaine School of Marine Sciences, is a principal investigator of the project along with Evan Variano, a researcher in the Civil and Environmental Engineering Department at UC Berkeley. Pete Jumars, a UMaine professor of marine sciences and oceanography who is based at the Darling Marine Center (DMC), is a co-principal investigator of the study.

The National Science Foundation recently awarded $409,035 to the UMaine researchers and $315,869 to Variano for the three-year project that began in September 2013.

The purpose of the study, “Collaborative Research: Trajectories and spatial distributions of diatoms at dissipation scales of turbulence,” is to create a better understanding of how turbulence and particle shape affect the sinking velocity and paths of phytoplankton — specifically diatoms.

“Phytoplankton are microscopic organisms that are responsible for food production in the ocean and they account for about half of the oxygen that we breathe,” Karp-Boss says of the plant-like organisms.

Since phytoplankton are photosynthetic organisms and need light, they grow in the upper layer of the water column in oceans where turbulence caused by wind and waves prevails. Many phytoplankton types either can’t swim or have a limited swimming ability and are at the mercy of turbulence.

Turbulence mixes the cells, and if it’s strong and deep enough, transports them out of the illuminated upper layer of the ocean, or photic zone.

“That mixing affects the light fields they experience and that will ultimately determine rates of photosynthesis and production in the ocean,” Karp-Boss says.

Cell components have densities larger than seawater and therefore tend to sink. If phytoplankton sink too quickly, they exit the illuminated zone. Cells that settle away from the photic zone too deep serve as a food supply for organisms in the deep ocean. A fraction of these settling cells may get buried in sediments, effectively removing carbon dioxide from the atmosphere into the interior of the ocean, which explains the interest in the rate phytoplankton sinks, Jumars and Karp-Boss say.

Simple turbulence operates in all directions, carrying phytoplankton up and down. Scientists originally assumed a cell would move up or down at the same average speed in turbulence as it would in still water, but results have shown otherwise. Whether they sink or rise, more intense turbulence makes them move quicker. However, the methods used in the last decade give little insight into the mechanisms behind this acceleration, according to the UMaine researchers.

Studies conducted by atmospheric scientists have found key components of turbulence are the small eddies or vortices whose friction with the surrounding fluid — air or water — drains away the kinetic energy in turbulence. These eddies spin small water droplets out and make them more likely to collide, Jumars says.

Those findings don’t tell the whole story for phytoplankton because it doesn’t explain how buoyant particles are accelerated upward by turbulence. Testing this requires the ability to track individual phytoplankton cells in three dimensions as they move through eddies.

That’s why Karp-Boss and Jumars teamed with Variano, the UC Berkeley researcher, who with colleagues has developed a system that allows scientists to look at the trajectories of thousands of individual particles as they move.

Variano has developed a borescope with a double iris and video camera that gives the instrument binocular vision and captures the 3-D position of the cell.

“If you capture many quick snapshots, you can put all the frames together and see how this particle is moving in the water. If you calculate the distance and you know the time between frames, you can get velocity. You can also see whether their trajectories are straight or curved and how they settle or rise in the water. It gives us more information than just looking at mean sinking speeds of a population,” Karp-Boss says.

Most of the particles researchers have studied are spherical, while particles in nature are a variety of other shapes.

“Diatoms exhibit a striking morphological diversity, and we argue the shape of the particles will determine the trajectory and how fast they settle,” Karp-Boss says.

Karp-Boss and Jumars hope the project will also teach researchers more about the effects of turbulence on the distribution of phytoplankton cells. Whether the cells are randomly distributed or group together to form patches carries important implications to foraging strategies of grazers that feed on the cells. Turbulence is likely to play a role, but the underlying mechanisms are not yet fully understood.

The researchers will work together at both institutions throughout the project. The tanks design and construction, as well as characterization of the turbulent flows, will be done at UC Berkeley, while the experiments and analysis will be completed at UMaine.

In addition to their research, the PIs plan to hold a workshop at UMaine’s DMC in Walpole, Maine to bring together students from various departments who have similar interests in the dynamics of particles in flows.

“These types of questions are of interest to many STEM fields including  engineering, physics, atmospheric science and — of course — oceanography. Learning from each other’s approaches, models and measurements can greatly enhance understanding of how particles and flows interact,” Karp-Boss says.

Convening students from different fields who deal with particles in turbulent flows at earlier stages of their careers will hopefully give them an opportunity to form lifelong interactions and collaborations across fields. Karp-Boss and Jumars met Variano at a similar conference devoted to this range of topics.

Contact: Elyse Kahl, 207.581.3747

Ocean Acidification and the Aleutian Islands

Thursday, November 7th, 2013

ocean acidification

The National Science Foundation has awarded University of Maine researchers $574,617 to study the effects of ocean acidification on the marine ecosystem of the Aleutian Islands.

UMaine professor Bob Steneck and postdoctoral research associate Doug Rasher, both based at the Darling Marine Center in Walpole, Maine, will work with Jim Estes of the University of California, Santa Cruz to determine whether ocean acidification, ocean warming and food web changes are reshaping species’ interactions in nature and threatening Clathromorphum nereostratum, a slow-growing coralline alga in the subarctic North Pacific Ocean.

During C. nereostratum’s 2,000-year lifetime it accretes massive bioherms, or mound-like reef structures, that form the foundation of the archipelago benthos upon which kelp forests grow. Preliminary research suggests the calcium carbonate skeleton of the coralline alga is weakening due to increased ocean acidification. With the recent ecological extinction of sea otters, the number of sea urchins has increased and, in places, they have grazed the kelp forest, leaving behind barren ancient coralline reefs.

During past cycles of sea otter/urchin/kelp booms and busts when ocean acidity was steady, C. nereostratum fared better. Now in a weakened state, it’s falling prey to urchins, crumbling away through bioerosion.

The three-year study will include a 2104 summer-long research expedition to the western portion of the Aleutians, from Adak Island to Attu Island. Researchers will survey kelp forests and urchin barrens, measure ocean acidity and collect samples of the ancient coralline bioherms.

Subsequent laboratory-based research will include urchin feeding experiments at past and present levels of ocean temperature and acidity to confirm processes driving patterns observed in the field. Additional studies will focus on the bands of calcium carbonate (similar to tree rings) in the coralline samples.

Contact: Linda Healy, 207.563.8220 or Beth Staples, 207.581.3777