The unusual occurrence of green algal balls of Chaetomorpha linum on a beach in Sydney, Australia

Julia Cooke, Robert Lanfear 1 , Alison Downing 1 , Michael R. Gillings 1 , Alistair G.B. Poore 3 , Ian D. Goodwin 1 , Liette S. Waldron 1 , Aaron Phillips 1 , Yola Metti 4  and Matthew W. Bulbert 1
  • 1 Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
  • 2 Department of Environment, Earth and Ecosystems, The Open University, Milton Keynes, MK7 6AA, UK
  • 3 Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
  • 4 The National Herbarium of New South Wales, Royal Botanic Gardens and Domain Trust, Sydney, NSW 2000, Australia
Julia CookeORCID iD:
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  • Julia Cooke is a lecturer in Ecology at the Open University, UK. She was awarded a PhD from Macquarie University, Sydney for her work on the functional ecology of plant silicon. Over the last 10 years, Julia has used plants trait analysis as a tool to study the ecological strategies of plants, including quantifying plant responses to climate change, understanding invasiveness, characterising growth strategies and global patterns in traits, and the use of silicon by plants.
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, Robert Lanfear, Alison Downing, Michael R. Gillings, Alistair G.B. Poore
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  • Alistair G.B. Poore is an Associate Professor at the University of New South Wales, Australia. He was awarded a PhD in Marine Ecology from the University of New South Wales for research into the ecology of evolution of marine plant-herbivore interactions. His recent research has focused on the impacts of herbivores on marine macroalgae and seagrasses, the evolution of herbivory in the Crustacea, understanding the impacts of human stressors on marine communities and the likelihood of adaptation by marine invertebrates and algae to changing ocean conditions.
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, Ian D. Goodwin, Liette S. Waldron, Aaron Phillips, Yola Metti
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  • Yola Metti was awarded a PhD in Phycology by the University of New South Wales, Sydney, Australia. She is a post-doctoral Research Fellow at the National Herbarium of New South Wales (Sydney) and is currently working on the Australian Laurencia complex for the Algae of Australia project (ABRS). Her research interests focus on understanding evolutionary relationships of marine algae (primarily Rhodophyta) through algal molecular systematics and traditional morphological studies.
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and Matthew W. Bulbert
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  • Matthew W. Bulbert is a lecturer in Animal Behaviour at Macquarie University. His PhD investigated the behavioural ecology of the feather-legged assassin bug – an obligate ant-eater that uses a luring strategy to capture its ant-prey. His research programme focuses on the behavioural and ecological solutions that organisms adopt to mitigate the cost of conflict, with a strong interest in understanding the underlying mechanisms and evolutionary drivers responsible for predator-prey dynamics. He is also a keen natural historian with a broad interest in both fauna and flora with a bias towards to the rare, the unknown, and the exceptionally weird.
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In spring 2014, thousands of green algal balls were washed up at Dee Why Beach, Sydney, New South Wales, Australia. Reports of algal balls are uncommon in marine systems, and mass strandings on beaches are even more rare, sparking both public and scientific interest. We identified the algal masses as Chaetomorpha linum by using light microscopy and DNA sequencing. We characterize the size and composition of the balls from Dee Why Beach and compare them to previous records of marine algal balls. We describe the environmental conditions that could explain their appearance, given the ecophysiology of C. linum.

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Botanica Marina publishes high-quality contributions from all of the disciplines of marine botany at all levels of biological organisation from subcellular to ecosystem: chemistry and applications, genomics, physiology and ecology, phylogeny and biogeography. Research involving global or interdisciplinary interest is especially welcome as well as applied science papers dealing with emerging conceptual issues or developing technologies.