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Cross-Chapter Boxes
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- By Jean-Pierre Gattuso, France, Ove Hoegh-Guldberg, Australia, Hans-Otto Pörtner, Germany
- Intergovernmental Panel on Climate Change (IPCC)
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- Book:
- Climate Change 2014 – Impacts, Adaptation and Vulnerability: Part A: Global and Sectoral Aspects
- Published online:
- 05 January 2015
- Print publication:
- 29 December 2014, pp 97-166
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- Chapter
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Summary
Coral reefs
Coral reefs are shallow-water ecosystems that consist of reefs made of calcium carbonate which is mostly secreted by reef-building corals and encrusting macroalgae. They occupy less than 0.1% of the ocean floor yet play multiple important roles throughout the tropics, housing high levels of biological diversity as well as providing key ecosystem goods and services such as habitat for fisheries, coastal protection, and appealing environments for tourism (Wild et al., 2011). About 275 million people live within 30 km of a coral reef (Burke et al., 2011) and derive some benefits from the ecosystem services that coral reefs provide (Hoegh-Guldberg, 2011), including provisioning (food, livelihoods, construction material, medicine), regulating (shoreline protection, water quality), supporting (primary production, nutrient cycling), and cultural (religion, tourism) services. This is especially true for the many coastal and small island nations in the world's tropical regions (Section 29.3.3.1).
Coral reefs are one of the most vulnerable marine ecosystems (high confidence; Sections 5.4.2.4, 6.3.1, 6.3.2, 6.3.5, 25.6.2, and 30.5), and more than half of the world's reefs are under medium or high risk of degradation (Burke et al., 2011). Most human-induced disturbances to coral reefs were local until the early 1980s (e.g., unsustainable coastal development, pollution, nutrient enrichment, and overfishing) when disturbances from ocean warming (principally mass coral bleaching and mortality) began to become widespread (Glynn, 1984). Concern about the impact of ocean acidification on coral reefs developed over the same period, primarily over the implications of ocean acidification for the building and maintenance of the calcium carbonate reef framework (Box CC-OA).
A wide range of climatic and non-climatic drivers affect corals and coral reefs and negative impacts have already been observed (Sections 5.4.2.4, 6.3.1, 6.3.2, 25.6.2.1, 30.5.3, 30.5.6). Bleaching involves the breakdown and loss of endosymbiotic algae, which live in the coral tissues and play a key role in supplying the coral host with energy (see Section 6.3.1. for physiological details and Section 30.5 for a regional analysis).
How does oxidative stress relate to thermal tolerance in the Antarctic bivalve Yoldia eightsi?
- Doris Abele, Claudia Tesch, Petra Wencke, Hans Otto Pörtner
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- Journal:
- Antarctic Science / Volume 13 / Issue 2 / June 2001
- Published online by Cambridge University Press:
- 27 April 2004, pp. 111-118
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- Article
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Short and long-term exposure to elevated temperatures were studied in the Antarctic stenothermal protobranch bivalve Yoldia eightsi (Courthouy) from Potter Cove, King George Island (South Shetland Islands, Antarctica). Above a breakpoint temperature of 2°C – the upper habitat temperature for the Potter Cove Y. eightsi stock – both routine (RMR) and standard metabolic rate (SMR) increased steeply. The fraction of metabolism allocated to SMR, as well as the number of intervals of elevated activity per hour increased significantly with temperature. During acute exposure, ATP concentrations in the foot muscle peaked at 2°C and fell at 5°C, whereas superoxide dismutase (SOD) activity decreased upon warming. Slow stepwise warming to a final temperature of 11°C resulted in a significant decrease of SOD activity. Malondialdehyde concentration increased compared with controls at 0°C. In contrast to the effect of short-term exposure, tissue adenylate concentrations displayed a mild increase at higher temperatures during slow warming, indicating an acclimation response. A switch to anaerobic energy production could not be observed up to 11°C, demonstrating a higher level of thermal tolerance than in other Antarctic ectotherms, or a failure of the relevant pathways in Y. eightsi. The imbalance between pro- and antioxidant processes upon warming indicate oxidative stress to be one feature accompanying early heat stress in Y. eightsi.
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