Variation in the morphology, reproduction and development of the habitat-forming kelp Ecklonia radiata with changing temperature and nutrients

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 483:117-131 (2013) - DOI: https://doi.org/10.3354/meps10261 Variation in the morphology, reproduction and development of the habitat-forming kelp Ecklonia radiata with changing temperature and nutrients Christopher J. T. Mabin1,*, Paul E. Gribben2, Andrew Fischer1, Jeffrey T. Wright1 1National Centre for Marine Conservation and Resource Sustainability (NCMCRS), Australian Maritime College, University of Tasmania, Launceston, Tasmania 7250, Australia 2Biodiversity Research Group, Climate Change Cluster, University of Technology Sydney, Sydney, New South Wales 2007, Australia *Email: cjmabin@amc.edu.au ABSTRACT: Increasing ocean temperatures are a threat to kelp forests in several regions of the world. In this study, we examined how changes in ocean temperature and associated nitrate concentrations driven by the strengthening of the East Australian Current (EAC) will influence the morphology, reproduction and development of the widespread kelp Ecklonia radiata in southeastern Australia. E. radiata morphology and reproduction were examined at sites in New South Wales (NSW) and Tasmania, where sea surface temperature differs by ~5°C, and a laboratory experiment was conducted to test the interactive effects of temperature and nutrients on E. radiata development. E. radiata size and amount of reproductive tissue were generally greater in the cooler waters of Tasmania compared to NSW. Importantly, one morphological trait (lamina length) was a strong predictor of the amount of reproductive tissue, suggesting that morphological changes in response to increased temperature may influence reproductive capacity in E. radiata. Growth of gametophytes was optimum between 15 and 22°C and decreased by >50% above 22°C. Microscopic sporophytes were also largest between 15 and 22°C, but no sporophytes developed above 22°C, highlighting a potentially critical upper temperature threshold for E. radiata in Tasmania. Lower nitrate concentration had no effect on E. radiata gametophytes and sporophytes. Given forecast increases in ocean temperature of between 2 and 3°C in southeastern Australia by 2100, these findings suggest that E. radiata is likely to be affected by a strengthening EAC and highlight the susceptibility of the development and growth of early life-cycle stages to these changes. KEY WORDS: Ecklonia radiata · East Australian Current · Climate change · Morphology · Reproduction Full text in pdf format PreviousNextCite this article as: Mabin CJT, Gribben PE, Fischer A, Wright JT (2013) Variation in the morphology, reproduction and development of the habitat-forming kelp Ecklonia radiata with changing temperature and nutrients. Mar Ecol Prog Ser 483:117-131. https://doi.org/10.3354/meps10261 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 483. Online publication date: May 30, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.