Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Geosciences

First Advisor's Name

Laurel S. Collins

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Florentin Maurrasse

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Rene Price

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Ligia Collado-Vides

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Pamela Hallock-Muller

Fifth Advisor's Committee Title

Committee member

Keywords

Foraminifera, Caribbean, Panama, coral reef, seagrass, mangrove, land use, climate, anthropogenic, embayment

Date of Defense

3-24-2021

Abstract

This study used the diversity and distribution of benthic foraminiferal assemblages of Almirante Bay, Caribbean Panama, as environmental proxies to compare modern coral, seagrass and mangrove habitats to mid-Holocene coral reef facies on the island of Isla Colón, to investigate both natural and human-influenced changes.

The modern study associated species and assemblage characteristics with environmental conditions related to degraded water quality. Assemblages were fairly similar among neighboring habitats but differed in species proportions, while several stress-tolerant taxa might indicate eutrophic conditions. Diversity appeared to be regionally controlled by freshwater input irrespective of habitat type, was generally lower near the mainland than the southwest coast of Isla Colón, and was predominantly lower in mangroves than in coral reef and seagrass sediments. These results provide baseline ecologic data for comparisons to past, pristine coastal habitats.

The assemblages from mid-Holocene reef facies were analyzed for their correspondence to marine habitats and dominant invertebrates. Assemblages differentiated seagrass and molluscan mud samples from corals. Reefal assemblages were most diverse and did not distinguish among sediments characterized by different coral taxa, suggesting similar, normal marine conditions and/or mixing of coral fragments. Molluscan mud samples with high total organic carbon content were least diverse, though foraminifera in other molluscan mud samples showed a transition to proximal corals. Epiphytic seagrass taxa were present in relatively greater amounts in seagrass and samples with the corals Porites and Agaricia. The distribution of foraminiferal species suggests this reef was a patch reef similar to those of modern Almirante Bay.

Modern and mid-Holocene foraminiferal assemblages are significantly different with few exceptions. Modern mangroves and mid-Holocene molluscan mud facies were least diverse, while seagrass and reef diversity were near even. Although foraminiferal wall types suggested more freshwater input today, similarities in species assemblages and diversities suggest the modern embayed ecosystem is comparable in water quality to that of the pristine reef that grew prior to human settlement. These results demonstrate the utility and explore the limits of benthic foraminiferal assemblages to assess the impact of anthropogenic disturbance in patch-reef environments, with implications for the preservation and conservation of marine habitats along tropical coastlines.

Identifier

FIDC009718

Previously Published In

Gudnitz, M. N., Collins, L. S., and O'Dea, A., 2021, Foraminiferal communities of a mid-Holocene reef: Isla Colón, Caribbean Panama: Palaeogeography, Palaeoclimatology, Palaeoecology, 562,110042. https://doi.org/10.1016/j.palaeo.2020.110042

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