2014 GSA Annual Meeting in Vancouver, British Columbia (19–22 October 2014)

Paper No. 52-6
Presentation Time: 10:15 AM


HANLEY, Caitlin M., Geosciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 and OLEINIK, Anton, Geosciences, Florida Atlantic University, 777 Glades Rd., Boca Raton, FL 33431

In past decades Artificial reefs (AR) have been constructed along Florida’s southeast coast in an attempt to mitigate the degradation of natural reefs (NR). Ecological success of AR is monitored by fish and coral diversity, but little research assesses the micro benthic community. Large benthic foraminifera have been successfully utilized in environmental surveys of coral reefs due to water quality requirements that mirror those of zooxanthellae corals. The dominance of a specific foraminiferal assemblage indicates the type of environmental conditions found at benthic habitats. The purpose of this study was to compare benthic foraminiferal assemblages of NR and AR along Pompano Beach, FL and determine the dominant species. Five scoop samples were collected during fall 2013 and spring 2014from 2 AR and 1 NR. NR samples contained 97% carbonates and 3% siliclastics with similar percentages at AR. A total of 9 species were identified with Amphistegina lessonii being dominant in fall and Archaias angulatus in spring. The first AR was sampled in spring at 23m. A total of 6 species were identified A. angulatus, Cyclorbiculina compressa, and Quinqueloculina sp. representing dominant taxa. The second AR was also sampled in spring at 37m. Major species were A. lessonii and Quinqueloculina sp. with a total of 3 species identified. Average biogenic contribution on NR and AR was 3% Halimeda sp. 5% mollusk, 5% urchin, 11% foraminifera, 15% sponge spicule, and 61% unidentifiable fragment. Differences in foraminiferal assemblages on NR and AR are likely a result of variation in water quality and depth. A. lessonii have a large latitudinal distribution and a wide tolerance for nutrient and temperature levels. A. angulatus are mainly restricted to the Caribbean and have a smaller range of parameters. NR located closer to shore receive more nutrient rich water runoff. Similarly, AR at greater depths also receive nutrient rich deep waters, thus allowing the opportunistic A. lessonii.to thrive in both environments. A. angulatus may occur seasonally on NR which would explain lower populations found in fall. Continued sampling in fall 2014 and spring 2015 at different sites will provide better understanding of temporal and spatial constraints for these species and provide baseline data for monitoring future changes in coastal reef ecosystems.