"The Global Biogeography of Marine Benthic Macroalgae" by Robert Tomasetti
 

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Biology

First Advisor's Name

Heather D. Bracken-Grissom

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Ligia Collado-Vides

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Laurel Collins

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Suzanne Fredericq

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Evelyn E. Gaiser

Fifth Advisor's Committee Title

Committee member

Keywords

life sciences, biology

Date of Defense

6-30-2023

Abstract

Chapter II presents the first global biogeography of marine benthic macroalgae at the species level, while updating the previous largest attempts to map global genus level diversity by twelve-fold the number of localities and 12 percent more genera included. A major finding is that a subset of just 69 algal genera is responsible for half of global algal species diversity, and that these particularly speciose and widespread genera appear to have diversified to a greater degree in tropical waters. Chapter III investigates global endemism patterns in marine benthic macroalgae using two techniques. Traditional measurements of endemism by counting species found only in a single locality (singletons) are compared with a range-restriction approach by mapping the proportion of range-restricted species per equal unit area. Range extensions for species were calculated by designing a global connectivity network for the marine benthic environment that accounted for the short dispersal capacity of algae, temperature gradients, and the geographical separation of oceanic basins. The results of chapter II found differences in algal biodiversity patterns depending upon taxonomic levels (class, genus, or species) and chapter III suggested that biodiversity differences also existed in different temperature zones and oceanic basins. Therefore, chapter IV investigated the role of temperature on biodiversity patterns for marine benthic algae while accounting for geographic area and oceanic basin effects. Together, these chapters reveal that algal biodiversity patterns differ depending upon taxonomic level (reflecting separate evolutionary life histories), broad temperature zones (tropical, subtropical, and temperate), and oceanic basins. Temperature is found to significantly positively correlate to species diversity in marine benthic macroalgae, though the correlation is stronger for the subset of 69 genera found to disproportionately contribute to global algal biodiversity. While most algal genera are found to be temperature generalists, some genera may have invaded the tropics and diversified to a larger extent once there. Thus, while overall algal biodiversity peaks in mid-latitude subtropical to temperate waters in both hemispheres, a subset of genera have higher diversity in tropical waters, with patterns more closely resembling some other coral reef associated organisms.

Identifier

FIDC011199

ORCID

0009-0001-8581-5668

Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

Included in

Biology Commons

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