You are here:
NUTRIENT FLUXES IN THE MICROALGAL-DOMINATED INTERTIDAL REGIONS OF THE LOWER YAQUINA ESTUARY, OREGON (USA)
Citation:
SIN, Y., A. C. SIGLEO, E. SONG, AND Y. KANG. NUTRIENT FLUXES IN THE MICROALGAL-DOMINATED INTERTIDAL REGIONS OF THE LOWER YAQUINA ESTUARY, OREGON (USA). NORTHWEST SCIENCE. Northwest Scientific Association, Tacoma, WA, 81(1):50-61, (2007).
Impact/Purpose:
To investigate the effects of benthic microalgae on sediment nutrient fluxes
Description:
The effects of benthic microalgae on sediment nutrient fluxes were investigated at three sites across the intertidal zone of lower Yaquina Bay. Study sites were selected where microalgae were present but where seagrass and mud shrimp were absent. Sediment columns were collected seasonally from one to three stations from September 1999 through August 2000 to determine the seasonal and spatial range in benthic fluxes. Collected sediments were carried to the nearby laboratory for light and dark incubation experiments. Nitrate fluxes ranged from -122 to -4 ûmol N m-2 hr1, whereas ammonia fluxes ranged from -52 to 101 ûmol N m-2 hr1. The ranges for orthophosphate and silicate were -7.4 to 12 ûmol P m-2 hr1 and -93 to 283 ûmol Si m-2 hr1. The sediments were always a net sink for nitrate. Nitrate uptake rates were highest during the warmest month (August) and lowest during the coldest months (November and January). Nitrate fluxes were not statistically different for light and dark conditions. Ammonium was generally released from sediments into the water column in the dark, whereas it was taken up in the light. The sediments were a net sink for all tested nutrients under light conditions, whereas all nutrients except nitrate were released into the water column in the dark, indicating that ammonia, orthophosphate and silicate were utilized by benthic microalgae at the sediment-water interface in the light.