Understory Primary Productivity
Primary Production of Understory Macroalgae and Phytoplankton
Primary production by understory macroalgae and phytoplankton in the kelp forest may be adversely affected by shading, flow attenuation, and other factors associated with the canopy formed by giant kelp. We are investigating how the negative effects of giant kelp on understory algae and phytoplankton interact with wave disturbance and N loading to affect the magnitude and interannual variability of net primary production by the kelp forest ecosystem. Our research involves in-situ measurements of primary production of giant kelp, understory algae, and phytoplankton. Primary production by giant kelp is estimated from measures of accumulation and loss of biomass. Primary production by understory algae is measured by oxygen evolution in closed benthic chambers, whereas phytoplankton production is measured using light and dark bottle incubations with 13 C-labeled bicarbonate as a tracer. Measurements of primary production are taken monthly inside and outside of the kelp forest.