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Abstract The physiological response to individual and combined stressors of elevated temperature and p CO 2 were measured over a 24-day period in four Pacific corals and their respective symbionts (Acropora millepora/Symbiodinium C21a, Pocillopora damicornis/Symbiodinium C1c-d-t, Montipora monasteriata/Symbiodinium C15 and Turbinaria reniformis/Symbiodinium trenchii ). Multivariate analyses indicated that elevated temperature played a greater role in altering physiological response, with the greatest degree of change occurring within M. monasteriata and T. reniformis. Algal cellular volume, protein and lipid content all increased for M. monasteriata . Likewise, S. trenchii volume and protein content in T. reniformis also increased with temperature. Despite decreases in maximal photochemical efficiency, few changes in biochemical composition (i.e. lipids, proteins and carbohydrates) or cellular volume occurred at high temperature in the two thermally sensitive symbionts C21a and C1c-d-t . Intracellular carbonic anhydrase transcript abundance increased with temperature in A. millepora but not in P. damicornis , possibly reflecting differences in host mitigated carbon supply during thermal stress. Importantly, our results show that the host and symbiont response to climate change differs considerably across species and that greater physiological plasticity in response to elevated temperature may be an important strategy distinguishing thermally tolerant vs. thermally sensitive species.
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This content will become publicly available on October 15, 2026
Impact of warming and suspended terrigenous sediment on the Hawaiian reef coral Montipora capitata
Abstract Coral reefs near high human population areas suffer from sedimentation and increased turbidity due to coastal development. However, there is limited research on how key species respond to turbidity caused by terrigenous sediment and how this response may change with increased water temperatures. This study investigated the effects of ambient and elevated turbidity (+ 26 NTU) in combination with ambient (27.1 °C) and elevated temperature (+ 4.1 °C; 31.2 °C) on the dominant Hawaiian reef coralMontipora capitata, collected from two Kāneʻohe Bay watersheds with distinct environmental histories. Using intermittent flow respirometry, we found that acute (12 h) exposure to elevated turbidity and temperature impacted algal symbionts (Symbiodinium spp.) but not the coral host, suggesting a potential delayed host physiological response. Corals from south Kāneʻohe Bay, where restricted water circulation and urbanization have degraded water quality, were more sensitive to stressors than those from the less-impacted northern sites, indicating that physiological responses vary by location and may be influenced by watershed conditions. The findings suggest that while short-term turbidity and warming impactSymbiodinium spp.immediately, prolonged exposure may lead to cascading effects on the coral host. Understanding these species-specific and location-dependent responses enhances our ability to guide restoration and conservation efforts for coral ecosystems facing both local (turbidity) and global (warming) stressors.
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- Award ID(s):
- 2049406
- PAR ID:
- 10654834
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- Coral Reefs
- Volume:
- 44
- Issue:
- 6
- ISSN:
- 0722-4028
- Page Range / eLocation ID:
- 2065 to 2081
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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