Research

DUWC Research–National Science Foundation Grant Funds Collaborative Study of Differential Nutrient Limitation and It’s Role in Carbon Sequestration

Duke University Wetland Center researchers are taking part in a study entitled "Exploration of the mechanistic basis and biogeochemical implications of differential nutrient limitation among trophic levels" funded by a $930,000 National Science Foundation grant. Principal investigators for the project are DUWC Director Curtis J. Richardson; Scott C. Neubauer, Assistant Director of the Baruch Marine Field Laboratory, University of South Carolina; and P.V. Sundareshwar of the Institute of Atmospheric Sciences, South Dakota School of Mines and Technology (and a DUWC postdoctoral research associate from 2000 to 2003).

The structure and function of ecosystems is governed by the patterns of nutrient limitation of the primary producers (e.g., plants) and heterotrophs (e.g., soil microbes). Often, these groups of organisms are limited by the same nutrient (e.g., phosphorus or nitrogen). However, an increasing body of evidence indicates that different nutrients can limit primary producers and heterotrophs in some ecosystems; this is known as differential nutrient limitation (DNL).

This study examines why DNL occurs in some ecosystems but not others and what the consequences of DNL are with respect to utilization vs. storage of carbon.

These questions are being tested in four wetlands ranging from Rhode Island to Georgia, including both freshwater and saline systems. At each site, a network of field-fertilized experimental plots will be utilized to influence the nature of nutrient limitation. A standardized sampling approach at all sites will emphasize measurements of plant and microbial productivity, phosphorus cycling, and ecosystem metabolism. It is expected that DNL will occur in ecosystems with higher rates of phosphorus mineralization and that DNL will result in less storage of carbon.

This study has implications for ecosystem management and theories of ecosystem development. The research provides a conceptual framework to integrate ecological studies at multiple scales by understanding how ecological stoichiometry (i.e., nutrient ratios) affects the biogeochemical cycles that govern ecosystem energetics.

This project includes a commitment to students from under-represented groups (including American Indians and African-Americans) through a field research-mentoring program that will encourage and advance the participation of these groups in ecosystem studies.

Nicholas School of the Environment

DUWC Research–National Science Foundation Grant Funds Collaborative Study of Differential Nutrient Limitation and It’s Role in Carbon Sequestration
Duke University Wetland Center researchers are taking part in a study entitled "Exploration of the mechanistic basis and biogeochemical implications of differential nutrient limitation among trophic levels" funded by a $930,000 National Science Foundation grant. Principal investigators for the project are DUWC Director Curtis J. Richardson; Scott C. Neubauer, Assistant Director of the Baruch Marine Field Laboratory, University of South Carolina; and P.V. Sundareshwar of the Institute of Atmospheric Sciences, South Dakota School of Mines and Technology (and a DUWC postdoctoral research associate from 2000 to 2003). The structure and function of ecosystems is governed by the patterns of nutrient limitation of the primary producers (e.g., plants) and heterotrophs (e.g., soil microbes). Often, these groups of organisms are limited by the same nutrient (e.g., phosphorus or nitrogen). However, an increasing body of evidence indicates that different nutrients can limit primary producers and heterotrophs in some ecosystems; this is known as differential nutrient limitation (DNL). This study examines why DNL occurs in some ecosystems but not others and what the consequences of DNL are with respect to utilization vs. storage of carbon. These questions are being tested in four wetlands ranging from Rhode Island to Georgia, including both freshwater and saline systems. At each site, a network of field-fertilized experimental plots will be utilized to influence the nature of nutrient limitation. A standardized sampling approach at all sites will emphasize measurements of plant and microbial productivity, phosphorus cycling, and ecosystem metabolism. It is expected that DNL will occur in ecosystems with higher rates of phosphorus mineralization and that DNL will result in less storage of carbon. This study has implications for ecosystem management and theories of ecosystem development. The research provides a conceptual framework to integrate ecological studies at multiple scales by understanding how ecological stoichiometry (i.e., nutrient ratios) affects the biogeochemical cycles that govern ecosystem energetics. This project includes a commitment to students from under-represented groups (including American Indians and African-Americans) through a field research-mentoring program that will encourage and advance the participation of these groups in ecosystem studies.
	Nicholas School of the Environment