Seasonal to interannual variability in phytoplankton biomass and diversity on the New England Shelf: In situ time series for validation and exploration of remote sensing algorithms

Heidi M Sosik, Woods Hole Oceanographic Institution, hsosik@whoi.edu (Presenter)
Hui Feng, University of New Hampshire, hui.feng@unh.edu

Dynamic physical forcing and complex interactions with adjacent land masses and slope seas combine to make coastal ecosystem change especially challenging to detect and understand. From both biogeochemical and ecological perspectives, the biomass and functional diversity of the phytoplankton are especially important characteristics. Certain types of phytoplankton play key roles in carbon and nutrient cycles at the same time that changes in dominant taxa or size classes may indicate shifts in food web structure and ecologically and societally important trophic transfers (e.g., to commercially important or nuisance species). MODIS chlorophyll products (as phytoplankton biomass indices) can only inform us about part of this ecological complexity and more information is required about the composition of the phytoplankton community. While new approaches and remote sensing products are emerging, in situ time series and validation data sets remain sparse and incomplete. We have recently begun a project to address this challenge with unique phytoplankton time series observations made possible by new sensor technology deployed at an ocean observatory on the New England Shelf, the Martha’s Vineyard Coastal Observatory. We are using time series to explore and evaluate algorithms that can be applied to MODIS ocean color data, extending beyond phytoplankton biomass to the possibility of functional group or size-class-dependent biomass retrievals. Our observations focus on phytoplankton and optical properties with the combination of automated submersible flow cytometry, automated above water ocean color radiometry (AERONET-OC), and intermittent boat-based water sampling. This combination allows us to separate evaluation of in-water algorithms and properties from possible complications with MODIS-based normalized water leaving radiance retrievals in US northeast coastal waters (likely associated with aerosol property variability). Preliminary analyses indicate strong seasonal dynamics in this system with shifts in phytoplankton community structure that are reflected directly in optical properties.

Presentation Type:  Poster

Session:  Coupled Processes at Land-Atmosphere-Ocean Interfaces   (Mon 4:00 PM)

Associated Project(s): 

• Sosik, Heidi: Seasonal to Interannual Variability in Phytoplankton Biomass and Diversity on the New England Shelf: In Situ Time Series for Validation and Exploration of Remote Sensing Algorithms ...details

Poster Location ID: 86