title: Heterotrophy mitigates the response of the temperate coralOculina arbusculato temperature stress.
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 coralOculina arbusculato thermal stress. Colonies ofO. arbusculafrom Radio Island, North Carolina, were exposed to four feeding treatments (zero, low, moderate, and high concentrations of newly hatchedArtemiasp. 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.
authors: Department of Marine Sciences University of North Carolina at Chapel Hill Chapel Hill North Carolina.
authors: Hannah E
authors: HE
authors: Aichelman
authors: Department of Marine Sciences University of North Carolina at Chapel Hill Chapel Hill North Carolina.
authors: Joseph E
authors: JE
authors: Townsend
authors: Department of Marine Sciences University of North Carolina at Chapel Hill Chapel Hill North Carolina; Department of Marine and Environmental Sciences Northeastern University Nahant Massachusetts; Present address: Scripps Institution of Oceanography University of California San Diego La Jolla California.
authors: Travis A
authors: TA
authors: Courtney
authors: Department of Marine Sciences University of North Carolina at Chapel Hill Chapel Hill North Carolina.
authors: Justin H
authors: JH
authors: Baumann
authors: Department of Marine Sciences University of North Carolina at Chapel Hill Chapel Hill North Carolina; Department of Marine and Environmental Sciences Northeastern University Nahant Massachusetts.
authors: Sarah W
authors: SW
authors: Davies
authors: Department of Marine Sciences University of North Carolina at Chapel Hill Chapel Hill North Carolina.
authors: Karl D
authors: KD
authors: Castillo
keywords: Bleaching; Oculina arbuscula; climate change; coral; heterotrophy; temperate