Interactions between Marine Macrophyte Habitats, Small Invertebrate Fauna, and Pelagic Sargasso Inundations in Tropical Shallow Coastal Systems

Authors

Lowell Andrew Iporac, Florida International UniversityFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Biology

First Advisor's Name

Claudia Collado-Vides

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Joel Trexler

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Oscar Valverdes-Barrantes

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

John Berry

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Charles Amsler

Fifth Advisor's Committee Title

Committee member

Keywords

Macroalgae, epifauna, invertebrates, seagrass, coastal, sargassum, citizen science, habitat, assemblages

Date of Defense

5-23-2023

Abstract

Marine macrophytes form biogenic habitats that maintain the biodiversity of coastal systems such as seagrass beds and sandy beaches. These habitats are used by small invertebrate fauna that provide ecosystem functions and trophic links between macrophytes and secondary consumers. These systems were also challenged with periodic influxes of pelagic sargasso, a region-wide issue affecting the Caribbean since 2011. Very little is known about how these sargasso influxes affected the macrophyte and invertebrate faunal communities. This research investigated the macrophyte habitat characteristics that drive invertebrate faunal communities and how those communities were affected by pelagic sargasso inundations. Initial assessments of habitat types were conducted in South Florida to characterize assemblages of macrophytes composing these habitats and associated fauna. Six unique habitat types were compared, of which red macroalgal mats contained higher faunal richness and abundance than other habitats. This variation of faunal diversity was further investigated by quantifying macrophyte diversity, biomass, and architecture as habitat metrics. These three metrics were further synthesized into a structural complexity index. However, biomass itself explained variation in faunal diversity as well as the structural complexity index. This finding interrogated the use of an index as an accurate predictor of species diversity patterns. These macrophytes can be transported onto intertidal zones and used by terrestrial invertebrate fauna. Thus, seasonal sargasso influxes was hypothesized to be a major contributor to invertebrate faunal resource use. Temperature in sargasso-dominant wrack was lower and more stable than the surrounding beach. There also was evidence of trophic resource use of sargasso by invertebrates, particularly with terrestrial amphipods. The regional scope of pelagic sargasso inundations called for monitoring efforts to investigate spatiotemporal variation in sargasso accumulation levels and species composition. This was accomplished using community-contributed data, where seasonality in sargasso accumulations between 2019 and 2021 was detected, and the Mexican Caribbean had longer seasons and higher accumulation levels than South Florida. This research synthesizes the role of macrophytes providing resources for invertebrate faunal communities in coastal systems that encompassed submerged benthic vegetation and intertidal sandy beaches. These findings could be applicable to investigate further changes of these systems under periodic sargasso inundations.

Identifier

FIDC011122

ORCID

https://orcid.org/0000-0001-6919-3937

Previously Published In

Iporac LAR, Ryan James W, and Collado-Vides L. 2023. Characterization and potential resource use of sargasso-dominant sea wrack by terrestrial invertebrate fauna during sargasso influxes in South Florida. Estuarine, Coastal, and Shelf Science 291: 108414, doi: 10.1016/j.ecss.2023.108414.

Iporac LAR, Hatt DC, Bally NK, Castro A, Cardet E, Mesidor R, Olszak S, Duran A, Burkholder D, and Collado-Vides L. 2022. Community-based monitoring reveals spatiotemporal variation of sargasso inundation levels and morphotype dominance across the Caribbean and South Florida. Aquatic Botany 182: 10.1016/j.aquabot.2022.103546.

Recommended Citation

Iporac, Lowell Andrew, "Interactions between Marine Macrophyte Habitats, Small Invertebrate Fauna, and Pelagic Sargasso Inundations in Tropical Shallow Coastal Systems" (2023). FIU Electronic Theses and Dissertations. 5453.
https://digitalcommons.fiu.edu/etd/5453