Comparing Species Assemblages of Deposited Epiphytic and Benthic Foraminifera in North Sound, Grand Cayman, Cayman Islands

Abstract

Tropical islands that are in the paths of tropical storms need large sandy shores to protect inland settlements and habitats. The balance between gains and losses of sediment along shorelines (sediment budget) is, especially in areas like the Cayman Islands without major rivers or other inflows of new sediment, often made up almost entirely of the shells and tests of marine organisms. In North Sound, most of the sediment is generated from the shells of bivalves, gastropods and foraminifera, the latter of which can be found crusting on sea grasses or on the sea floor.

In this project, samples from two sediment cores taken from different locations in North Sound were examined, and the species assemblages compared. Core B15 is closer to the coral reef fringing North Sound, and so was expected to have more reef-dwelling foraminifera than core B9, which is farther from the reef and closer to the inland shore. The locations are also affected by different water circulation patterns, varying inputs of fresh seawater from the ocean and different current speeds.

The results were not as expected, with core B9 actually containing more reef-dwelling species than core B15. Potential explanations for this include B9 being in an area with a slower current, allowing more of the foraminifera to settle, and inversely the same foraminifera being swept away from the B15 position. B15 also had far more shells from other invertebrates such as bivalves, which suggests it may be more nutrient rich.

Presented in absentia on April 27, 2020 at "Student Research Day" at MacEwan University in Edmonton, Alberta. (Conference cancelled.)

Faculty Mentor: Hilary Corlett

Department: Earth and Planetary Sciences

NOTE: This work is available as an abstract only