Toxic algae silence physiological responses to multiple climate drivers in a tropical marine food chain

Research output: Contribution to journalArticle


Research on the effects of climate change in the marine environment continues to accelerate, yet we know little about the effects of multiple climate drivers in more complex, ecologically relevant settings - especially in sub-tropical and tropical systems. In marine ecosystems, climate change (warming and freshening from land run-off) will increase water column stratification which is favorable for toxin producing dinoflagellates. This can increase the prevalence of toxic microalgal species, leading to bioaccumulation of toxins by filter feeders, such as bivalves, with resultant negative impacts on physiological performance. In this study we manipulated multiple climate drivers (warming, freshening, and acidification), and the availability of toxic microalgae, to determine their impact on the physiological health, and toxin load of the tropical filter-feeding clam, Meretrix meretrix. Using a structural equation modeling (SEM) approach, we found that exposure to projected marine climates resulted in direct negative effects on metabolic and immunological function and, that these effects were often more pronounced in clams exposed to multiple, rather than single climate drivers. Furthermore, our study showed that these physiological responses were modified by indirect effects mediated through the food chain. Specifically, we found that when bivalves were fed with a toxin-producing dinoflagellate (Alexandrium minutum) the physiological responses, and toxin load changed differently and in a non-predictable way compared to clams exposed to projected marine climates only. Specifically, oxygen consumption data revealed that these clams did not respond physiologically to climate warming or the combined effects of warming, freshening and acidification. Our results highlight the importance of quantifying both direct and, indirect food chain effects of climate drivers on a key tropical food species, and have important implications for shellfish production and food safety in tropical regions.


  • Lucy M. Turner
  • Jonathan N. Havenhand
  • Christian Alsterberg
  • Andrew D. Turner
  • S. K. Girisha
  • Ashwin Rai
  • M. N. Venugopal
  • Indrani Karunasagar
  • Anna Godhe
External organisations
  • University of Gothenburg
  • Plymouth University
  • Centre for Environment, Fisheries and Aquaculture Science (CEFAS)
  • Karnataka Veterinary, Animal and Fisheries Sciences University
  • NITTE University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Microbiology
  • Ecology


  • Arabian Sea, Climate change, Indirect effects, Meretrix, Multiple drivers, PSP, Structural equation modeling, Trophic/food chain
Original languageEnglish
Article number00373
JournalFrontiers in Physiology
Issue numberAPR
Publication statusPublished - 2019
Publication categoryResearch