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ELEVATED DISSOLVED SULFIDES IN SURFICIAL SEDIMENTS OF YAQUINA BAY ESTUARY, OREGON
Citation:
Young, D R., J O. Lamberson, AND R. S. Caldwell. ELEVATED DISSOLVED SULFIDES IN SURFICIAL SEDIMENTS OF YAQUINA BAY ESTUARY, OREGON. Presented at 2001 Estuarine Research Federation meeting, St. Petersburg Beach, FL, November 4-8, 2001.
Description:
Dissolved sulfide concentrations were measured in porewater of surficial sediments collected from two exposed intertidal sites in Yaquina Bay, Oregon. Idaho Pt. (IP) is an area where drift green macroalgae is known to accumulate, and the odor of hydrogen sulfide gas (H2S) on the mudflat is common in late summer and fall. Coquille Pt. (CP) is located about one km to the east across the main channel, where H2S odor is uncommon. Surficial sediment samples were collected randomly along lines of fixed elevation monthly between June and December 2000, and analyzed for porewater sulfides, grain size, and TOC and amphipod concentrations. Density and biomass of seagrass (Zostera marina) and green macroalgae (principally Ulva spp. and Enteromorpha spp.) also were measured. Dissolved sulfides were detected only occasionally off CP, and at low levels (1 - 50 ?M). However, between August and November levels of dissolved sulfides exceeding 50 ?M commonly were measured in porewater of surficial sediment from IP. Levels peaked at more than 4000 ?M, two orders-of-magnitude above the reported threshold of toxic effects for intertidal infauna. Accumulation of green macroalgae off IP is a possible cause of the relatively high concentrations of dissolved sulfides measured there.