HR: 0800h
AN: OS11A-0192    [Abstracts]
TI: Using Carbon and Nitrogen Stable Isotopes and Trace Metal Concentrations in Zooplankton to Determine Seasonal and Anthropogenic Influences in the Gulf of Aqaba, Red Sea
AU: * Luo, J Y
EM: luojy@stanford.edu
AF: Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, United States
AU: Paytan, A
EM: apaytan@ucsc.edu
AF: Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, United States
AU: Paytan, A
EM: apaytan@ucsc.edu
AF: University of Santa Cruz, Institute of Marine Sciences, 1156 High St, Santa Cruz, CA 95064, United States
AU: Al-Najjar, T
EM: t.najjar@ju.edu.jo
AF: University of Jordan, Marine Science Station, P. O. Box 195, Aqaba, 77110, Jordan
AB: The Gulf of Aqaba is a narrow, warm, saline, and oligotrophic gulf surrounded by arid deserts and is connected to the northern Red Sea via the Strait of Tiran. The Gulf of Aqaba is characterized by strong seasonal fluctuations in primary production and phytoplankton biomass (Genin et al 1995, Lindell and Post 1995). Primary production in the gulf is unusually high compared with other warm oligotrophic seas under similar nutrient conditions. This study investigates the relative influence of anthropogenic or terrestrial nutrient sources and metal pollution to seasonal and biological variation in zooplankton. Surface zooplankton samples were collected every month during 2004 from one offshore station and ten coastal stations along the northern tip of the Gulf of Aqaba. Samples were separated into three size fractions and analyzed for δ¹³C (TOC), δ¹⁵N, wt.% inorganic carbon (IC), C/N ratios and elemental concentrations of 17 metals (Li, Cd, Pb, U, Mg, Al, P, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr). The results showed that trace metals were highly variable between all months and locations. Site-specific differences were not statistically significant, but monthly differences were observed in 11 elements, suggesting that seasonal effects dominate metal concentrations in zooplankton. Results from the C, N isotopes reveal that calcifying organisms are significantly more abundant in smaller size fractions, and that there is a trophic level difference in δ¹⁵N values that is not present in the δ¹³C values. In addition, δ¹³C values record a small but significant difference between the northern and port sites versus the southern sites, suggesting that the northern and port sites are more anthropogenically impacted. However, the δ¹³C, δ¹⁵N, and C/N all show highly significant seasonal variations, which are probably the dominant factor influencing zooplankton in the Gulf of Aqaba.
DE: 4870 Stable isotopes (0454, 1041)
DE: 4875 Trace elements (0489)
DE: 4890 Zooplankton
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting