Lindsay P. Scheef


mixed zooplankton Interactions among marine zooplankton

The identification of key trophic interactions and abiotic factors that drive the dynamics of aquatic ecosystems is a first step towards understanding how those systems function and how they could respond to change such as temperature increase, exotic species invasion, fishery exploitation, eutrophication, etc. A multivariate autoregressive (MAR) modeling framework has been successfully applied to time series data from freshwater systems to reveal the network of trophic interactions within planktonic communities and to assess ecosystem stability. As part of NSF and NOAA’s CAMEO project, researchers from NCEAS and NWFSC are working to adapt the MAR framework for application to the low resolution, highly variable data typically gathered from marine systems. As a project participant, I will be compiling existing long-term ecological data sets from a variety of marine systems and using the adapted MAR model to compare trophic structure and stability between different marine environments and between marine and freshwater systems. The ultimate goal of this project is to produce new modeling tools that will help us better understand the underlying structure of a wide variety of marine ecosystems and improve our management strategies for those systems.

Benthic distribution of copepod eggs

The resting eggs produced by some species of marine calanoid copepods have been observed to accumulate on the seafloor in areas of high deposition and low resuspension. Seagrass beds are known to be environments that promote the accumulation of fine sestonic particles by inhibiting resuspension but have not been previously investigated as possible reservoirs for copepod resting eggs. Three years of field sampling on a shallow reef in the northern Gulf of Mexico revealed that viable resting eggs of the copepod Acartia tonsa were significantly more abundant in seagrass-colonized sediment than in adjacent unvegetated sediment. Further testing revealed that the unique conditions within seagrass beds, such as decreased water flow and low oxygen conditions, may make them important accumulation sites for resting copepod eggs in shallow areas subject to frequent disturbance. Seagrass-mediated resuspension events could therefore influence the population dynamics of some copepod species and may be essential for local copepod populations reliant on recruitment from benthic resting eggs.
copepod eggcopepod egg Lanark Reef, FL