Seasonal variation in the lipid profile of Acropora millepora at Halfway Island, Great Barrier Reef

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Seasonal variation in the lipid profile of Acropora millepora at Halfway Island, Great Barrier Reef J. A. Conlan1,2



L. K. Bay2 • A. Jones2 • A. Thompson2 • D. S. Francis1

Received: 3 April 2020 / Accepted: 28 August 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract To understand how environmental conditions and reproductive events affect coral energetic status, seasonal variations in lipid and fatty acid profiles of the common scleractinian coral, Acropora millepora, were studied from pre-spawning in November 2009 until postspawning in November 2010 at Halfway Island (in the Keppel Island Group, Southern Great Barrier Reef, Australia). Seasonal chlorophyll levels, photosynthetically active radiation (PAR), rainfall and water temperature were major drivers of the overall coral lipid profile, and this was particularly pronounced in correlations with the important, high-energy lipid, triacylglycerol. This likely reflected changing food sources and feeding modes (i.e. phototrophy vs heterotrophy), which corresponds to the opportunistic feeding behaviour of corals. Water temperature was also a major influencer of the coral fatty acid profile. In particular, saturated fatty acids correlated positively with water temperature, while polyunsaturated fatty acids correlated negatively, reflecting cell membrane fluidity regulation, which is necessary for coral to tolerate changing temperatures. Spawning and maternal provisioning also proved to be a major driver of change in the coral lipid profile. The

mass spawning events in spring for both 2009 and 2010 caused reductions in the important coral egg constituents: wax ester, triacylglycerol, phosphatidylcholine and fatty acid 10:0. Interestingly, lipid accumulation was significantly lower in the 2010 spawn compared to 2009, possibly due to lower PAR and chlorophyll levels, reflecting reduced photosynthetic activity and phytoplankton availability. Regardless, in 2010, resource provisioning to egg production was greater than in 2009, suggesting increased reproductive effort in the face of environmental stress. This study demonstrates the strong influence of opportunistic heterotrophy and autotrophy and maternal provisioning on the coral lipid profile. Such information is fundamental to understanding the environmental and biochemical processes underlying coral health and predicting how anomalous events and climate-driven changes will affect coral reef assemblages. Keywords Lipids  Acropora  Fatty acids  Coral  La Nina

Introduction Topic Editor Morgan S. Pratchett

Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00338-020-02001-w) contains supplementary material, which is available to authorized users. & J. A. Conlan [email protected] 1

School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia

2

Australian Institute of Marine Science, PMB No3, Townsville, QLD 4810, Australia

Phenological observations of corals describe the influence of cyclic and sea