Past Seminars

Speaker: Dr. Ian Hartwell, Ecologist
NOAA National Ocean Service
Silver Spring, MD

Abstract:
The research was designed to investigate and document the soft bottom benthic infauna community in a systematic approach in the central California region, and to delineate habitats as defined by the resident biological communities. One objective is to assess what the physical and ecological processes are that enable these highly diverse communities to exist in a seemingly simple habitat that is stable over long periods of time. In contrast, canyons experience periodic sediment sloughing that opens up new habitat space by removing the existing benthic community. The frequency of these natural disturbances are partially dependent on storms, earthquake activity and sedimentation rate, and resident communities are expected to be evolutionarily adapted for periodic disturbance. Submarine canyons are also the conduits to the deep ocean for material accumulated on the shelf. National Status & Trends sediment chemical contaminant data from 2002 indicated a very inhomogeneous distribution of tracer chemicals between the canyon heads in central California. Relative to the continental shelf and Pioneer Canyon stations, DDT and other contaminants were found at higher concentrations in Ascension and Monterey Canyons. Monterey Bay still receives DDT input from terrestrial runoff and may be the source of DDT found in Ascension Canyon. All data indicate a continuous input 30 years after DDT was banned.

In 2004, stable depositional areas of six canyons and five transects across the continental shelf and slope were sampled for benthic community and contaminant concentrations. Sampling in 2005 targeted the axes of the canyon floors and expanded the study area north and south to assess contaminant distributions and benthic community characteristics on a regional basis. Moorings with sediment traps and turbidity flow sensors to monitor sediment transport in Monterey and Soquel Canyons were deployed in 2005. The presence of DDT in Ascension and Ano Nuevo Canyons at comparable concentrations to Monterey Canyon indicates transport of fine-grained materials out of the Monterey Bay system to the shelf to the north. Contaminant concentrations in Carmel canyon and on the shelf south of Monterey Bay did not appear to be elevated above background levels. Contaminant concentrations in the Gulf of the Farallones and Bodega Canyon north of San Francisco do not appear to accumulate organic contaminants despite input from San Francisco Bay. However, chemical contaminants do appear to accumulate in deeper areas below the continental shelf break. Benthic communities are extremely diverse along the continental shelf break. Patterns in benthic communities illustrate gradients with depth and sediment grain size that are confounded with contaminant concentrations. Simple measures of community abundance and diversity do not indicate differences between active and depositional canyon habitats. Detailed community composition assessment is ongoing. Turbidity flows and routine tidal currents result in a highly dynamic benthic habitat, that nonetheless harbors a robust benthic infaunal community.

Speaker: Dr. Edward Rutherford
University of Michigan
School of Natural Resources & Environment
Institute for Fisheries Research

Title: "Hydrologic Research at the Office of Hydrologic Development: Present and Future"

Speaker: Dr. Pedro Restrepo
Chief Scientist, Office Of Hydrology
NOAA National Weather Service

Title: "An approach to establishing aquatic organisms as in situ environmental bioindicators of natural hazards"

Dr. Stephen A. Bortone, Director
Minnesota Sea Grant College Program

Video archive available:
Video: ftp://ftp.glerl.noaa.gov/webcast/2008/bortone/20080131.wmv
PowerPoint: ftp://ftp.glerl.noaa.gov/webcast/2008/bortone/20080131.ppt
Adobe PDF: ftp://ftp.glerl.noaa.gov/webcast/2008/bortone/20080131.pdf