Project: The influence of biophysical coupling and cross-scale interactions on ecosystems of the Plum Island LTER

NSF Award Abstract:
Identifying the biological and environmental factors that govern the geographical distribution of organisms is critical for understanding the functioning of natural ecosystems and the myriad benefits that they provide to society. For example, salt marsh ecosystems serve as critical transition zones at the land-sea interface and provide key ecosystem services such as improving water quality via removal of excess nutrients from terrestrial run-off and mitigating coastal erosion via shoreline buffering. This project leverages a combination of field surveys, lab experiments, and mathematical models to predict how the geographical distribution of organisms responsible for these critical ecosystem services is influenced by biological interactions (e.g., competition and predation) as well as environmental factors (e.g., temperature and physical disturbance) that vary with oceanographic currents across a range of New England salt marsh locations. The broader impacts of the project include cross-training of graduate students in biology, statistics, mathematical modeling, and computer programming. In addition, the results of this project will be shared with the Plum Island Ecosystems Long Term Ecological Research (LTER) Network and will be integrated into undergraduate courses in biostatistics, mathematical modeling, and experimental design in order to demonstrate the importance of quantitative and interdisciplinary STEM training for addressing important questions in community and ecosystem ecology. Finally, multiple interactive web modules will be created to enhance the dissemination of the results of this research beyond traditional academic circles, including Northeastern University?s K-12 outreach programs.

The overall aim of this project is to determine whether understanding and predicting the dynamics of multi-trophic salt marsh ecosystems across multiple scales hinges upon the integration of physical oceanographic processes and their influence on the supply of allochthonous inputs. This project will be conducted at NSF?s Plum Island LTER and consists of four objectives: (1) repeated surveys of permanently established study plots across three nested spatial scales to quantify the magnitude of allochthonous inputs and the community structure of both marine and terrestrial food webs, allowing an assessment of whether the spatiotemporal distributions of allochthonous inputs and food web architectures are consistent with their putative physical oceanographic drivers; (2) a field experiment that manipulates a gradient in the magnitude of detrital input as well as top-down control by marine fish across three nested spatial scales, enabling an assessment of whether observed survey patterns are driven by bottom-up vs. top-down processes; (3) a fully factorial lab experiment to further disentangle the role of the top-down control by marine fish vs. terrestrial spiders on key ecosystem processes such as primary production, decomposition, herbivory, and predation across a gradient of detrital inputs; and (4) development of a field-parameterized, spatially-explicit mathematical model to determine the independent and joint influences of bottom-up forcing and top-down control on the salt marsh community structure across scales. By combining models and field experiments in a biophysical-allochthonous input framework, this project will leverage the mechanistic insights traditionally associated with community ecology to reveal the joint influence of local and broad-scale processes on the hierarchically organized dynamics of open ecological systems. This project will help inform resource management for New England salt marshes and promote public education by highlighting the importance of quantitative and interdisciplinary STEM training for addressing important questions in biology.

This project is jointly funded by Biological Oceanography and the Ecosystems Science Cluster.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.