SGER: Preliminary Studies of Larval Transport using Small Moorings in Coastal Waters

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This SGER award aims to determine the efficacy of small moorings anchored in the nearshore (just beyond the surf zone) of central Oregon for determining patterns of larval abundance and transport in relation to onshore patterns of recruitment and community structure. It is essential to obtain proof that moorings will work, and will provide information that can bear critically on the issue of nearshore larval transport. In agreement with the community of ocean scientists (as reflected in GLOBEC and CoOP mission statements) Dr. Menge contends that the determination of the link between pelagic and benthic environments through the nearshore region, heretofore a `black box,` is one of the most important problems facing biological oceanographers and marine ecologists. Determining abundances of zooplankton has long been hampered by extreme spatial and temporal variation due to plankton patchiness. The use of larval traps, which integrate over long times will provide larval estimates which more accurately reflect patterns of larval delivery to benthic communities. This study will employ inexpensive moorings, anchored in 12 15 m of water between 0.5 and 1 km offshore, and will simultaneously sample larval abundances, currents, water temperature, settlement onshore, and temperature onshore. The measurements on the moorings will be taken near the surface and near the bottom to quantify possible stratification of larvae and physical conditions in the water column, which may relate to patterns of onshore/offshore transport during upwelling and relaxation. For comparison with more traditional oceanographic measurements, chlorophyll a, physical conditions, and zooplankton abundance will be sampled using standard methods (Niskin bottles, CTD, plankton nets) each time the moorings are monitored. Satellite imagery will be used to examine the larger scale context in which our smaller scale sampling will take place. This work will test if these moorings will prove to be a powerful and inexpensive tool in studying nearshore ecological and oceanographic processes, particularly in relation to larval transport.