BIOLOGICAL OCEANOGRAPHY

Patterns of production in Puget Sound are controlled by nutrients (mainly nitrate), temperature, and the balance between stratification and mixing. In spring, large phytoplankton blooms occur when/where stratification and surface warming occurs and near-surface nutrient concentrations are high. Diatoms dominate phytoplankton blooms; as nutrients are depleted, small flagellates and dinoflagellates become relatively more abundant. 

The zooplankton that are found in Puget Sound consist of a combination of oceanic and estuarine species.  Near freshwater inputs, higher abundances of estuarine taxa are found, but most zooplankton in Puget Sound are marine taxa and they dominate throughout most of the Sound.  The patterns of zooplankton diversity and abundance in Puget Sound are not well known, but are likely to be controlled by circulation, prey availability, and predation.

Eddies, fronts, river plumes, and other circulation features can create strong spatial patterns of phytoplankton and zooplankton biomass.  Gradients from river mouth to marine waters and shallow to deep water occur, all of which are influenced by strong tidally-driven water movement.

METHODS:

We will use a CTD to measure fluorescence profiles and will calibrate the data to convert it to chlorophyll biomass using chlorophyll measured in water collected with Niskin bottle samples. We will use nets to sample zooplankton from Main Basin, Whidbey Basin, and Port Susan.  At some stations, we will use closing nets to sample deep water separately from surface waters to examine differences in zooplankton above and below the pycnocline.

POTENTIAL PROJECTS:

Potential biological projects include:

·    Exploring relationships among vertical profiles of chlorophyll, hydrography or nutrient availability.

·    Comparing phytoplankton/zooplankton community structure between the Main Basin and Hood Canal.

·    Describing patterns of zooplankton biomass, abundance or diversity in the Main Basin or Hood Canal in relation to the hydrography.

·    Determining the relationship between depth distributions of dominant zooplankton taxa and physical and biological variables. (e.g. the relationship between copepod depth distribution and the chlorophyll profile).

Using publicly available data sets to examine spatial and temporal patterns of chlorophyll around Puget Sound.