Benthic diatoms Dr. Merryl Alber University of Georgia

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

malber@uga.edu https://marsci.uga.edu/directory/people/merryl-alber https://orcid.org/0000-0002-9467-4449 Georgia Coastal Ecosystems LTER Project

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

gcelter@uga.edu https://gce-lter.marsci.uga.edu/ Dr. Merryl Alber University of Georgia

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

malber@uga.edu https://marsci.uga.edu/directory/people/merryl-alber https://orcid.org/0000-0002-9467-4449 Principal investigator 1994-01-01 2004-12-31 Dr. Merrilee Thoresen University of Georgia

Graduate research assistant 1994-01-01 2004-12-31 2026

M. Thoresen, (Ph.D. student, UGA) and M. Alber (UGA) examined the trophic linkage between benthic diatoms and oysters, Crassostrea virginica. They compared direct observations of variability in the benthic diatoms in the seston over oyster reefs and in the guts of oysters over two years from five sites along the length of the Duplin River. When expressed as a percent of total diatoms, there was a significant correlation between the proportion of benthic diatoms in seston and in oysters. Over the course of the study, benthic diatoms accounted for between 18 and 59% of the diatoms in seston and between 11 and 53% of diatoms in the guts of oysters. There was a remarkably consistent seasonal and spatial pattern of abundance in this system. Near the headwaters (at Hunt Camp), benthic diatoms accounted for 46% of the diatoms in both the seston and the oysters during fall and winter and only 26% during spring and summer. At the mouth (Marsh Landing), benthic diatoms accounted for 21% of the diatoms in seston over the entire year, and between 25 and 30% of the diatoms in oysters. These observations are supported by stable isotope observations of oyster tissues, and suggest that resuspended benthic diatoms are a potentially important component of the diet of suspension-feeding oysters.

Question 2: How do the spatial and temporal patterns of biogeochemical processes, primary production, community dynamics, decomposition, and disturbance vary across the estuarine landscape, and how do they relate to environmental gradients? (more information)

LTER NSF Duplin River Georgia Hunt Camp Marsh Landing GCE benthic diatoms oysters stable isotopes Overall geographic extent of the research project -81.301987 -81.263124 31.486493 31.410854 1994-01-01 2004-12-31

National Science Foundation grant number OCE-9982133 and NOAA NERRS graduate student fellowship

estuary marsh complex Duplin River - Duplin River transect used for GCE quarterly hydrographic monitoring surveys. Nominal profiling stations are defined at various locations along the Duplin River west of Sapelo Island, Georgia. -81.301987 -81.263124 31.486493 31.410854 Thoresen, M. and Alber, M. 2004. Presentation: Utilization of Benthic Diatoms by Oysters (Crassostrea virginica). Semiannual Meeting of the Southeastern Estuarine Research Society. Southeastern Estuarine Research Society, 15-17 April 2004, Ft. Pierce, FL. http://gce-lter.marsci.uga.edu/public/files/pubs/Thoresen_SEERS_2004.pdf Thoresen, M. 2004. Temporal and spatial variation in seston available to oysters and the contribution of benthic diatoms to their diet in the Duplin River, Georgia. Ph.D. Dissertation, University of Georgia, Athens, Georgia. 220 pp. http://gce-lter.marsci.uga.edu/public/files/pubs/Thoresen_Merrilee_PhD_2004.pdf Thoresen, M. and Alber, M. 2003. Presentation: Benthic diatoms in seston and eastern oysters: patterns of spatial and seasonal abundance in a tidal inlet (Duplin River, Georgia, USA). 2003 Estuarine Research Federation meeting. Sept. 14-18, 2003, Seattle, WA. Thoresen, M., Alber, M. and Nelson, J.R. 2002. Presentation: Microalgal food resources of oysters: are benthic diatoms important to an estuarine suspension-feeder?. Joint Workshop of the National Estuarine Research Reserve System and National Estuarine Research Reserve Association. October 2002, Falmouth, Mass. Thoresen, M., Alber, M. and Nelson, J.R. 2001. Presentation: Microalgal food resources of oysters: are benthic diatoms important to an estuarine suspension-feeder?. ERF 2001: An Estuarine Odyssey. Estuarine Research Federation, Nov. 4-8, 2001, St. Pete Beach, Florida.