Talk on Larvae and Surf

Surf and rocky shore habitat.\Photo by Jeffergray.

The Hatfield Marine Science Center (HMSC) offers a series of research seminars, aimed primarily the scientists and students but open at no cost to the public.

As part of this series, oceanographer Alan Shanks of the Oregon Institute of Marine Biology will speak on how intertidal communities are shaped by the interactions of plankton (such as the larvae of organisms that settle in tidepools) and the surf zone.  The talk takes place on Thursday, April 11, 3:30 in the Guin Library Seminar Room at the HMSC (2030 S.E. Marine Science Dr. in Newport’s South Beach area).

Here is the HMSC’s description of Dr. Shanks’ subject matter:

“The size of bottom-up subsidies, food and larvae, from the ocean has a profound impact on intertidal community structure and populations. Alongshore variations in subsidies have been attributed to variation in coastal oceanographic conditions, but also might be due to variations in surfzone hydrodynamics. We have tested this hypothesis in a variety of ways.  What we have found is 1) the concentrations of larval settlers and coastal phytoplankton are significantly and one or more orders of magnitude higher in more dissipative than more reflective surf zones, 2) the concentrations of larval settlers and coastal phytoplankton are more than an order of magnitude lower in more reflective surf zone than in the waters just seaward of the surf zone, 3) the settlement of barnacles is orders of magnitude higher in more dissipative than reflective surf zones, 4) barnacle populations structure varies with surfzone hydrodynamics – population densities are orders of magnitude higher at more dissipative surf zones, 5) growth and reproductive output of barnacles and mussels varies with surfzone hydrodynamics – growth rates and reproductive output are far higher at more dissipative than reflective surf zones, 6) densities of benthic macro-algae are far higher at more reflective than dissipative surf zones.  Surfzone hydrodynamics is a major driver of intertidal community structure and function. The effect of surfzone hydrodynamics appears to be far larger than alongshore variation in coastal oceanographic conditions. Even over short alongshore distances (10s to 100s of meters) communities vary with the hydrodynamics of the adjacent surf zone.”