Stephen B. Baines, Associate Professor (
Ph.D., Yale University, 1993
Aquatic ecosystem ecology, ecological stoichiometry
Lab Website: Baines Lab Website
I am an ecosystem ecologist interested in how organism characteristics, ecological
processes and factor acting over regional scales combine to shape aquatic biogeochemical
cycles that involve carbon and trace elements. My current research foci can be divided
into three areas.
First, I try to understand variability in the elemental composition of microscopic organisms that form the base of open water food webs - namely phytoplankton, bacteria and protozoa -- and how this variability may also influence nutrient cycles or the transfer of contaminant elements through food-webs. I do so with field and laboratory experiments using radioisotopes, biokinetic modeling of contaminant accumulation by organisms, ecological stoichiometric modeling of food-web and recycling dynamics and X-ray fluorescence microscopic measurements of the elemental content of individual plankton cells collected from nature.
Second, I study how the use of dissolved organic matter (DOM) as an energetic subsidy by aquatic consumer organisms can allow them to sidestep the negative feed-backs that typically occur in predator-prey systems, potentially leading to persistent reductions in the resource base upon which other consumer organisms depend. Because many toxic trace elements form complexes with dissolved organic matter, uptake of DOM by organisms also exposes them to contaminant metals and alters the movement of these contaminants through aquatic ecosystems. I am interested in how "bioavailability" of DOM varies over space and time, the sources of bioavailable fractions, and how the characteristics of the surrounding landscape may affect the susceptibility of lakes and rivers to transformative change by invasive organisms.
Finally, I use statistical analysis of long-term data sets to determine the degree to which the dynamics of neighboring ecosystems are synchronized by regional climate. This approach allows me to gauge the relative importance of extrinsic forces, local context and intrinsic dynamics as drivers of ecosystem variables. This question is important not only for the interpretation of long-term ecological data, but also generally in the effective monitoring and management of lakes, rivers and coastal embayments.