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
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