Adaptation to local thermal regimes by crustose coralline algae does not affect rates of recruitment in coral larvae
- 446 Downloads
Crustose coralline algae (CCA) are well known for their ability to induce settlement in coral larvae. While their wide distribution spans reefs that differ substantially in temperature regimes, the extent of local adaptation to these regimes and the impact they have on CCA inductive ability are unknown. CCA Porolithon onkodes from Heron (southern) and Lizard (northern) islands on Australia’s Great Barrier Reef (separated by 1181 km) were experimentally exposed to acute or prolonged thermal stress events and their thermal tolerance and recruitment capacity determined. A sudden onset bleaching model was developed to determine the health status of CCA based on the rate of change in the CCA live surface area (LSA). The interaction between location and temperature was significant (F (2,119) = 6.74, p = 0.0017), indicating that thermally driven local adaptation had occurred. The southern population remained healthy after prolonged exposure to 28 °C and exhibited growth compared to the northern population (p = 0.022), with its optimum temperature determined to be slightly below 28 °C. As expected, at the higher temperatures (30 and 32 °C) the Lizard Island population performed better that those from Heron Island, with an optimum temperature of 30 °C. Lizard Island CCA displayed the lowest bleaching rates at 30 °C, while levels consistently increased with temperature in their southern counterparts. The ability of those CCA deemed thermally tolerant (based on LSA) to induce Acropora millepora larval settlement was then assessed. While spatial differences influenced the health and bleaching levels of P. onkodes during prolonged and acute thermal exposure, thermally tolerant fragments, regardless of location, induced similar rates of coral larval settlement. This confirmed that recent thermal history does not influence the ability of CCA to induce settlement of A. millepora larvae.
KeywordsCrustose coralline algae Coral Settlement Thermal stress Bleaching Sudden onset bleaching model
Funding was provided by the Australian Institute of Marine Science, Futures Project, Appropriation Fund 2233.
- Committee on the Development of an Integrated Science Strategy for Ocean Acidification Monitoring Research, and Impacts Assessment, National Research Council (2010) Ocean acidification: a national strategy to meet the challenges of a changing ocean. The National Academies Press, Washington, D.C.Google Scholar
- Harrington L (2004) Ecology of crustose coralline algae: interactions with scleractinian corals and responses to environmental conditions. PhD thesis, James Cook University, Townsville, AustraliaGoogle Scholar
- Huisman JM, Leliaert F, Verbruggen H, Townsend RA (2009) Marine benthic plants of Western Australia’s shelf-edge atolls. Rec West Aus Mus 77:50–87Google Scholar
- Kleypas JA, Danabasoglu G, Lough JM (2008) Potential role of the ocean thermostat in determining regional differences in coral reef bleaching events. Geophys Res Lett 35:L03613Google Scholar
- Littler MM, Littler DS (1984) Models of tropical reef biogenesis: the contribution of algae. Prog Phycol Res 3:323–364Google Scholar
- Raven J, Caldeira K, Elderfield H, Hoegh-Guldberg O, Liss P, Riebesell U, Shepherd J, Turley C, Watson A (2005) Ocean acidification due to increasing atmospheric carbon dioxide. The Royal Society Special Report, London, pp 1–60Google Scholar
- Siboni N, Abrego D, Seneca F, Motti CA, Andreakis N, Tebben J, Blackall LL, Harder T (2012) Using bacterial extract along with differential gene expression in Acropora millepora larvae to decouple the processes of attachment and metamorphosis. PLoS One 7:e37774PubMedCentralCrossRefPubMedGoogle Scholar
- Tebben J, Motti CA, Siboni N, Tapiolas DM, Negri AP, Schupp PJ, Kitamura M, Hatta M, Steinberg PD, Harder T (2015) Chemical mediation of coral larval settlement by crustose coralline algae. Sci Rep 5 doi: 10.1038/srep10803
- Underwood AJ, Keough MJ (2001) Supply-side ecology; the nature and consequences of variations in recruitment of intertidal organisms. In: Sunderland MA, Bertness MD, Gaines SD, Hay ME (eds) Marine community ecology. Sinauer Associates, pp 183–200Google Scholar