Cold Tolerance in Halodule wrightii Across Latitudinally Distinct Populations in the Western Atlantic Ocean
Document Type
Article
Publication Date
10-25-2024
Department
Coastal Sciences, Gulf Coast Research Laboratory
School
Ocean Science and Engineering
Abstract
North Carolina (NC) is in a biogeographic transition zone where climate change is altering the relative abundances (e.g., areal extent, percent cover, biomass) of Zostera marina and Halodule wrightii. Warmer water temperatures are driving losses in Z. marina, leading to increased meadow patchiness. Although water temperatures are rising in NC, heat-tolerant H. wrightii is not filling in bare patches, which may result from abiotic stressors. This study investigated H. wrightii cold tolerance across different populations by quantifying the effects of cold stress on biomass and photosynthetic efficiency during a 3-week laboratory experiment and a 3-month observational study. H. wrightii shoots for the experiment were collected from NC, Mississippi (MS), and Florida (FL) and exposed to 23 °C, 10 °C, and 5 °C. Seagrass was also collected from FL, MS, and at 3 sites in NC during November–January of 2022–2023. Post experiment, there was a significant increase in the belowground biomass in the NC 10 °C treatment but no difference between populations in photosynthetic efficiency. Field metrics displayed population-specific differences, with the northernmost sites having the highest shoot density and belowground biomass per unit area. These findings suggest that H. wrightii at its biogeographic limit may allocate more carbon into belowground material than populations at the central part of the species range in response to thermal stress as a means of winter torpor, which may explain the lack of patch expansion in NC. Cold tolerance in tropical species like H. wrightii may therefore be essential to examine as a limiting factor for the tropicalization of temperate seagrass meadows.
Publication Title
Estuaries and Coasts
Volume
48
Issue
1
Recommended Citation
Stevenson, L. V.,
Kamel, S. J.,
Darnell, K. M.,
Furman, B. T.,
Jarvis, J. C.
(2024). Cold Tolerance in Halodule wrightii Across Latitudinally Distinct Populations in the Western Atlantic Ocean. Estuaries and Coasts, 48(1).
Available at: https://aquila.usm.edu/fac_pubs/21907
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