Local Adaptation Signatures in Thermal Performance of the Temperate Coral Astrangia poculata

<p>The Northern Star Coral (<em>Astrangia poculata</em>) is an understudied temperate scleractinian coral that provides unique opportunities to understand the roles of phenotypic plasticity and local adaptation in coral physiological tolerance limits. <em>Astrangia poculata</em> inhabits hard bottom ecosystems from the northwestern Atlantic to the Gulf of Mexico and withstands an annual temperature range up to 20°C. Additionally, <em>A. poculata</em> is facultatively symbiotic and co-occurs in both symbiotic (“brown”) and aposymbiotic (“white”) states. Here, brown and white <em>A. poculata</em> were collected from Virginia (VA) and Rhode Island (RI), USA and exposed to heat (18-32°C) and cold (18-6°C) temperature assays during which photosynthesis (P), respiration (R), and symbiont photochemical efficiency (F_v/F_m) were measured. Thermal performance curves (TPCs) of respiration revealed differences consistent with local adaptation of the RI and VA populations to their natal thermal environments. RI corals exhibited higher respiration rates overall, and higher respiration at 6, 15, 18, 22, and 26°C. Additionally, thermal optimum (T_opt) analyses show a 3.76°C (brown) and 6.88°C (white) greater T_opt in the VA population, corresponding to the warmer <em>in situ</em> thermal environment in VA. In contrast to respiration, no origin effect was detected in photosynthesis rates or F_v/F_m, suggesting a possible host-only signature of local adaptation. This study is the first to consider <em>A. poculata’</em>s response to both heat and cold stress across symbiotic states and geography and provides insight into the effects of future climate change on valuable hard bottom communities along the East Coast of the US.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biological Sciences

Year dc:date.available

2018

Author dc:creator

• Aichelman, Hannah Elise

Contributors dc:contributor

• Daniel J. Barshis
• David Gauthier
• Richard Zimmerman

• Adaptation
• Astrangia poculata
• Countergradient variation
• Metabolism
• Temperate coral
• Thermal performance curve
• Biology
• Ecology and Evolutionary Biology
• Physiology

Statement dc:rights

• <p>In Copyright. URI: <a href="http://rightsstatements.org/vocab/InC/1.0/">http://rightsstatements.org/vocab/InC/1.0/</a> This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).</p>

Identifier

9780438455009

OAI identifier oai:identifier

oai:digitalcommons.odu.edu:biology_etds-1029