Current Research Interests
I am currently involved in two NSF-funded projects:
Consumer Resource Interactions and Stoichiometrically-Explicit Spiraling (CRISES)
The main objective of the CRISES Project at the Angelo Coast Range Reserve in Northern California is to understand how stream network position influences feedbacks between nutrient cycles, stream metabolism, and consumer-resource interactions. The overall question is where and when are biotic interactions and biological stoichiometry important determinants of nutrient flux in river networks, and what are the consequences for downstream ecological communities? Results so far suggest decreasing severity of nitrogen (N) limitation as streams get larger (i.e. increase in drainage area) leading to an increase in phosphorus (P) uptake as it becomes scarce relative to N. We hypothesize this pattern is the result of higher N fixation in large sunny streams, and demonstrates how a biotic response to an increase in light couples carbon (C), N, and P cycles, altering N and P fluxes to downstream ecosystems.
Furthermore, preliminary data suggest addition of N strongly increases P uptake, but not vice versa, suggesting the possibility of using P uptake as an indicator of future increases in anthropogenic N deposition. The next phase of the project will focus on the impact of consumers on nutrient transport and retention, and the effects of changes in temperature and nutrient supply on N and P cycling. Preliminary data suggest excretion by invertebrate consumers is a significant component of N cycling and has a strong influence on nutrient uptake. Since nutrient excretion is tied strongly to metabolism, changes in stream water temperature are likely to have an important influence on the role of invertebrates in nutrient cycles. The project has so far involved six undergraduate students from St. Olaf College (MN), five from the College of St. Catherine (MN), three from UC-Berkeley, and one from Eastern Washington University, as well as four graduate students and one post-doc. This year eight members of our team presented our first findings in talks and posters at the annual meeting of the Ecological Society of America. This project is currently funded through March 2009, and I plan to submit a renewal proposal in July 2009 to continue this work.
The Polaris Project: Rising Stars in the Arctic (www.thepolarisproject.org)
The allure and mystique of the Arctic, combined with its central role in the global warming issue, make it the ideal place to engage students, the public, and early career scientists in interdisciplinary polar research and education. The Polaris Project is a multifaceted effort that includes a field course and research experience for undergraduate students (rising stars) in the Siberian Arctic; several new arctic-focused undergraduate courses taught by project Co-PIs at their respective colleges across the United States and in Russia; the opportunity for Co-PIs to initiate research programs in the Siberian Arctic; and a wide range of outreach activities. The unifying scientific theme of the Polaris Project will be the impact of climate change on transport and cycling of carbon and nutrients as they move with water from terrestrial uplands to the Arctic Ocean. This is a central issue in arctic system science and the Co-PIs were selected in part because of their potential to bring fresh insights to this complex topic. Thus, the Polaris Project will help train future leaders in arctic research and education, which is essential given the rapid and profound changes underway in the Arctic in response to global warming. The Polaris Project will achieve a broad and lasting impact by engaging multiple audiences through a variety of mechanisms. In addition to new courses and the independent research experience in Siberia, the project’s influence will be expanded by widely distributing all course materials (syllabi, PowerPoints) for use by faculty at other institutions who are interested in developing arctic-focused courses. All project participants will visit K-12 classrooms to convey the excitement of polar research, and materials related to the project will be featured in the GoNorth curriculum (www.polarhusky.com), which is used in thousands of K-12 schools worldwide. The Polaris Project website will feature student blogs to engage a wider audience and sustain a lasting Polaris Project community. We will also work closely with the international IPY project office, which has agreed to feature the Polaris Project in its education and outreach materials. This project and PI partnership will give students an experience that combines the liberal arts learning environment with access to the philosophies and lab facilities of a large research institution. It will also provide liberal arts students with new and highly desired learning opportunities to explore growing interests in Arctic science.
