Standard Presentation (15 mins) Australian Marine Sciences Association 2022

Productivity, Fishes, Sediments and the Functioning of Future Coral Reefs (#15)

Sterling B Tebbett 1 , David R Bellwood 1
  1. James Cook University, Townsville City, QLD, Australia

Increasingly it is becoming apparent that many coral reefs in the Anthropocene will be characterised by lower coral cover, lower complexity, and an expansive covering of algal turfs. As such, the paradigms established on past reefs, and the functions we believed were critical in these systems, may no longer apply. This situation raises the question: how can we maintain the functioning of these highly altered coral reef assemblages and their ability to provide desired services to humanity? In this talk I will explore how part of the answer to this question lies in the intimate links and feedbacks between fishes, sediments, and algal turf productivity. Specifically, I will provide an overview of these feedbacks on coral reefs and outline how some are likely to intensify on future coral reefs. In addition, I will explore a case study where a 2100% increase in algal turf sediment loads appears to have underpinned a bottom-up functional collapse of a coral reef ecosystem, including a 50% decline in the productivity of the herbivorous fish assemblage. Similar declines could put the future of some reef-based fisheries in jeopardy, highlighting how the sustainable future of coral reefs is functionally intertwined with fishes, sediments, and productivity.