File:Coast watch (1979) (20659102425).jpg

Title: Coast watch
Identifier: coastwatch00uncs_6 (find matches)
Year: 1979 (1970s)
Authors: UNC Sea Grant College Program
Subjects: Marine resources; Oceanography; Coastal zone management; Coastal ecology
Publisher: (Raleigh, N. C. : UNC Sea Grant College Program)
Contributing Library: State Library of North Carolina
Digitizing Sponsor: North Carolina Digital Heritage Center

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hardbottoms to reproduce. If there are strong nutri- tional links, then protec- tive zones may also be required in the surround- ing softbottom communi- ties. Ambrose and Posey are also studying the organism development near the areas with groundwater seeps. Scott Snyder is studying several microscopic animals that inhabit the substrate, particularly foraminifera. The research team's scientific instruments are as simple as the sawed-off tops of 55-gallon drums modified to monitor flow of groundwater seepage and as sophisticated as the battery-powered submers- ible through which the scientists investigate, photograph, videotape and collect rocks, sediments, plants and animals. The 168-foot research vessel Edwin-Link is the launching pad for the Florida- based Johnson Sea- Link submersible. The team is studying five geologically diverse sites within Onslow Bay. The field work began in 1991 and will continue through 1994 under currently funded projects. Riggs worked with both Scott and Steve Snyder throughout the 1980s on a National Science Foundation- funded project to study the origins of the continental margin and associated phosphate sediment in Onslow Bay. Sea Grant also funded part of that project. It was then that the scientists
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Hardbottoms Project Team Another significant area of biological study is the benthic — or ocean bottom — sand community in the periphery oj hardbottoms. Hardbottom reefs were once thought of as islands that sustained themselves, but it turns out that the surrounding sand flats or usoftbottom" areas may be critical in sustaining the system's foraging fauna. first got an inkling of the high levels of nutrients in groundwater leaking from the Miocene-age rock bottom and observed the spectacular reefs they are now studying. From that research, the team already had an extensive data set from Onslow Bay that included seismic profiles — or cross-sections — of the rock layers below the seafloor and side-scan sonar images, which when pieced together provide a graphic mosaic much like an aerial photograph of the ocean bottom. Steve Snyder is continu- ing to work with those and new data sets to map the habitats on the seafloor, as well as analyzing the nutrient chemistry of the water column and the seep fluids. The fifth research site, which will be studied this summer, is in an Oligo- cene-age area in the bay, where lithology — or rock formation — is completely different from the previous four study sites. It is a little bit west of the Miocene-age study sites, and it, too, likely has groundwater seeps. "The source of the nutrients in the seep fluid is unknown at this point," says Steve Snyder. "It could be coming from fertilized watersheds on the adjacent coastal plain. The dissolved nutrients then flow into the aquifer system and percolate to the surface someplace on the continental shelf. If that's the case, then we should see nutrient-enriched fluids in this Oligo- cene area as well." If the fluids are actually coming through the phosphate-rich units and stripping out soluble nutrients that were buried there 15 million years ago, then Snyder says the team should see a big difference between the fluid character seeping out of the Miocene 6 MARCH/APRIL 1993

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