Matt Bracken, Associate Professor
Phone: 781-581-7370 x304
My research evaluates the causes and consequences of biodiversity changes in marine ecosystems, including studies showing how nutrients, consumers, and stress modify diversity in marine communities and how species diversity and identity affect key biogeochemical processes. I am interested in how an interdisciplinary approach to biology, which explores the linkages between processes at different levels of biological organization, can enhance our understanding of how natural systems work. My biodiversity research is one example of this perspective. I study the processes that influence diversity change at the community level, but then take an ecosystem approach in asking how the diversity and identity of organisms influences their roles in mediating the transformation and flux of energy and matter. A related aspect of my work asks how consumers influence the supply of nutrients to primary producers in marine ecosystems.
Kylla Benes, Ph.D. Student
In recent decades, the effects of biodiversity on community and ecosystem processes have gained much attention among ecologists. While studies have revealed the importance of species diversity on ecosystem functioning, fewer studies have examined effects of other measures of biodiversity (e.g., functional diversity, genetic diversity). Since genetic diversity is the foundation of all other levels of biodiversity, understanding its effects is imperative to our understanding of ecological patterns and processes. Using intertidal seaweeds and their associated species assemblages, my research focuses on four themes: 1) genetic diversity and population structure of foundation species, 2) effects of intraspecific variation on population dynamics and stability, 3) impacts of genetic diversity on species diversity, and 4) consequences of genetic diversity on ecosystem functioning. When examining intraspecific diversity effects on communities and ecosystems, it will not only be valuable to investigate broad-level genetic diversity (i.e., genotypic diversity) but also variation in genetic based traits that have consequences for communities and ecosystems to elucidate underlying mechanisms driving patterns. Additionally, it is likely that patterns and processes in nature may be affected by both genetic and ecological effects and quantifying the relative magnitude of these (potentially) interconnected mechanisms will be important to our greater understanding of complex communities and ecosystems.
Brendan Gillis, Ph.D. Student
Due to anthropogenic emissions of CO2, which have increased the amount of carbonic acid in seawater, the world’s oceans are becoming more acidic. The pH level in the oceans has decreased by 0.1 unit since 1850 and is expected to decrease by another 0.3-0.4 units over the next 100 years. This change in pH can alter calcification, metabolic stability, larval development, and photosynthesis rates for a wide variety of marine organisms. Thus, ocean acidification has the potential to have major impacts on organismal physiology, which can then affect community-level interactions. However, higher biodiversity has the potential to buffer communities in the face of stressors. In my Ph.D. research, I propose to examine how species diversity mediates marine community resistance and resilience in response to acidification by crossing elevated versus ambient CO2 treatments with experimental biodiversity reductions in New England tide pools. Most current research on ocean acidification is happening at the organismal level, and my proposed work takes this to the next level of biological organization, examining how entire marine communities are likely to be affected by predicted changes in ocean pH and exploring the potential for more diverse communities to better withstand acidification.
Christine Newton, Ph.D. Student
I have a wide range of research interests in coastal ecology ranging from wetland to subtidal habitats. These fragile habitats provide enormous economic, recreational, and ecological values and need to be carefully monitored and protected. My Master’s research at the University of Rhode Island examined the role that drifting macroalgal blooms played in salt marsh ecosystems and how their impacts altered trophic dynamics. Currently, I am examining the invasion of a new macroalga, Heterosiphonia japonica, in New England waters. This invasive alga can be extremely abundant, comprising 50-90% of the algal biomass where it has invaded (Newton et al. 2013). Therefore, it is likely this invasion will significantly alter subtidal habitats and impact multiple trophic levels. In addition to examining these ecological impacts, I am examining the factors that led to the successful establishment of this invasive species, such as rapid growth, high reproductive rates, and lower palatability than native species. My research uses a combination of manipulative field and laboratory experiments, as I believe both are necessary to thoroughly approach any scientific question.
Valerie Perini, M.S.
Seasonal nutrient fluctuations in coastal waters have been of interest to ecologists for several decades, due to the correspondence of these fluctuations with levels of coastal primary production. Nearshore seaweeds account for a significant percentage of total coastal primary production and play an essential role in nutrient cycling in coastal ecosystems. These seaweeds’ access to nutrients is also an important consideration. Individuals of the same species can develop unique nutrient uptake strategies to deal with variable nutrient access due to their growth at different tide heights. As an undergraduate at Northeastern, I began a project documenting the relationship between seasonal nutrient availability and the tissue nutrient levels of several dominant species of seaweed at East Point, Massachusetts. Additionally, I used herbivore preference manipulations to examine the role of nutrients in mediating herbivory in this community. In my graduate research, I continued this work and expanded it to include nutrient availability to and usage by a variety of seaweeds on local rocky shores. I specifically explored (1) how a single seaweed species adapts to variable nutrient exposure at different tide heights, (2) how multiple species interact in their nutrient usage, especially if they are closely associated, for example, one species growing directly on another as an epiphyte, and (3) how herbivory mediates nutrient usage by seaweeds and nutrient transfer to the rest of the community.
Former Lab Members
Carolina Aguila, M.S. in Biology Student, Northeastern University (Fall 2009-Spring 2011)
Marcy Cockrell, M.S. in Marine Biology Student, Northeastern University (Summer-Fall 2009)
James Douglass, Postdoctoral Research Associate (Summer 2010-Summer 2012)
Annick Drouin, Visiting Ph.D. Student, Laval University (Summer-Fall 2011, Summer 2012)
Adam Fuller, M.S. in Marine Biology Student, Northeastern University (Summer-Fall 2008)
Natalie Low, Undergraduate Intern, Brown University (Summer 2010)
Michael Hutson, Research Intern (Summer 2011)
Molly Roberts, M.S. in Marine Biology Student, Northeastern University (Summer-Fall 2011)
Isaac Rosenthal, Undergraduate Intern (Summer 2012)
Brian Taggart, M.S. in Marine Biology Student, Northeastern University (Summer-Fall 2010)
Robyn Zerebecki, M.S. in Marine Biology Student, Northeastern University (Summer-Fall 2009)