Chemically mediated antifouling in the red alga Delisea pulchra

Using laboratory assays, we tested whether the secondary metabolites (furanones) on the surface of the red alga Delisea pulchra deter the settlement and growth of a range of ecologically relevant fouling organisms. D. pulchra and 4 other co-occurring seaweeds were almost exclusively fouled by other algae. Consequently, we carried out laboratory assays using propagules from 4 fouling algae (Ulva sp., Ceramium sp., Polysiphonia sp. and Ectocarpus siliculosis) representing the natural fouling community. The crude surface extract of D. pulchra at the same concentration as on the surface of the plant, the furanone fraction of this extract, and pure furnaones, deterred the settlement of fouling organisms in ecologically relevant assays. These data, coupled with knowledge of the surface concentration of furanones on D. pulchra and a mechanism by which furanones are sequestered onto the surface of the plant, provide a rigorous demonstration of chemically mediated antifouling

Knowledge gaps in the biology, ecology, and management of the Pacific crown-of-thorns sea star, Acanthaster sp., on Australia's Great Barrier Reef

Published online 17 November 2021Crown-of-thorns sea stars (Acanthaster sp.) are among the most studied coral reef organisms, owing to their propensity to undergo major population irruptions, which contribute to significant coral loss and reef degradation throughout the Indo-Pacific. However, there are still important knowledge gaps pertaining to the biology, ecology, and management of Acanthaster sp. Renewed efforts to advance understanding and management of Pacific crown-of-thorns sea stars (Acanthaster sp.) on Australia’s Great Barrier Reef require explicit consideration of relevant and tractable knowledge gaps. Drawing on established horizon scanning methodologies, this study identified contemporary knowledge gaps by asking active and/or established crown-of-thorns sea star researchers to pose critical research questions that they believe should be addressed to improve the understanding and management of crown-of-thorns sea stars on the Great Barrier Reef. A total of 38 participants proposed 246 independent research questions, organized into 7 themes: feeding ecology, demography, distribution and abundance, predation, settlement, management, and environmental change. Questions were further assigned to 48 specific topics nested within the 7 themes. During this process, redundant questions were removed, which reduced the total number of distinct research questions to 172. Research questions posed were mostly related to themes of demography (46 questions) and management (48 questions). The dominant topics, meanwhile, were the incidence of population irruptions (16 questions), feeding ecology of larval sea stars (15 questions), effects of elevated water temperature on crown-of-thorns sea stars (13 questions), and predation on juveniles (12 questions). While the breadth of questions suggests that there is considerable research needed to improve understanding and management of crown-of-thorns sea stars on the Great Barrier Reef, the predominance of certain themes and topics suggests a major focus for new research while also providing a roadmap to guide future research efforts.Morgan S. Pratchett … Camille Mellin … et al