Heterotrophy mitigates the response of the temperate coral Oculina arbuscula to temperature stress. Issue 18 (31st August 2016)

• Record Type: Journal Article
• Authors: Aichelman, Hannah E.; Townsend, Joseph E.; Courtney, Travis A.; Baumann, Justin H.; Davies, Sarah W.; Castillo, Karl D.
• Is Part Of: Ecology and evolution. Volume 6:Issue 18(2016:Oct.)
• Page Start: 6758
• Page End: 6769
• Publication Date: 2016-08-31
• Subjects: Bleaching -- climate change -- coral -- heterotrophy -- Oculina arbuscula -- temperate; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.2399
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Anthropogenic increases in atmospheric carbon dioxide concentration have caused global average sea surface temperature (SST) to increase by approximately 0.11°C per decade between 1971 and 2010 – a trend that is projected to continue through the 21st century. A multitude of research studies have demonstrated that increased SSTs compromise the coral holobiont (cnidarian host and its symbiotic algae) by reducing both host calcification and symbiont density, among other variables. However, we still do not fully understand the role of heterotrophy in the response of the coral holobiont to elevated temperature, particularly for temperate corals. Here, we conducted a pair of independent experiments to investigate the influence of heterotrophy on the response of the temperate scleractinian coral Oculina arbuscula to thermal stress. Colonies of O. arbuscula from Radio Island, North Carolina, were exposed to four feeding treatments (zero, low, moderate, and high concentrations of newly hatched Artemia sp. nauplii) across two independent temperature experiments (average annual SST (20°C) and average summer temperature (28°C) for the interval 2005–2012) to quantify the effects of heterotrophy on coral skeletal growth and symbiont density. Results suggest that heterotrophy mitigated both reduced skeletal growth and decreased symbiont density observed for unfed corals reared at 28°C. This study highlights the importance of heterotrophy in maintaining coral holobiont fitness under thermal stress and has important implications for the interpretation of coral response to climate change. Abstract : Anthropogenic increases in atmospheric carbon dioxide concentration since the Industrial Revolution have caused global average sea surface temperature to increase, resulting in reduced fitness of the coral holobiont (cnidarian host and its symbiotic algae) including reductions in host calcification and symbiont density. We are only beginning to understand the role of heterotrophy in the coral holobiont response to elevated temperature, particularly for temperate corals. Here, we conducted two common garden experiments and the results suggest that heterotrophy mitigated the negative effects of thermal stress for the temperate coral Oculina arbuscula, highlighting the importance of heterotrophy in maintaining coral holobiont fitness under thermal stress and revealing implications for the interpretation of the coral thermal stress response to climate change.