The extent of marine biodiversity is best understood in the context of knowing the geographic barriers to species dispersal and environmental gradients that limit species richness; i.e., biogeography. Trends in the discovery of species on Earth, including the ocean, indicate about two thirds of species have been named. Thus, we have a representative sample of ocean life. Maps of environmental variation and habitat explain why coastal seas have far greater species endemicity and richness than the deep-sea. Analyses of latitudinal gradients show how temperature is the primary driver of marine species richness globally. This gradient is increasingly bimodal due to climate range shifts of species away from the equator, leading to a doubling of fish species richness in parts of the Arctic. Moreover, cell biochemistry energetics, across all Domains of life, shows that the optimal (most energetically stable and efficient) temperature for life is 20°C. There is evidence for this “20°C Effect” on biodiversity at ecosystem levels in the ocean. This suggests fundamental biochemical constraints to life being able to evolve to adapt to a warmer planet.
My interests are in biodiversity, biogeography and ecology, especially in the ocean, with applications in relation to nature conservation, climate change, invasive species, and aquaculture. I am from Kildare in Ireland. I studied in Galway (BSc Hon. Zoology NUIG) and Cork (PhD UCC), followed by postdoc's at the Marine Biological Association Plymouth, and jointly with the Marine Laboratory Aberdeen and Napier University Edinburgh (where I was based at Poolewe, a remote field station on the west coast). After being a lecturer in Trinity College Dublin for 6 years my group set up a research and consulting company called EcoServe (Ecological Consultancy Services Ltd) of which I was Managing Director. I was Executive Director of the Huntsman Marine Science Centre in St Andrews, New Brunswick, Canada for almost 4 years, and then became a professor at the University of Auckland, New Zealand until joining Nord University in 2020.