Revisiting generality in the global latitudinal gradient in species richness across ocean and land (and the 20°C effect)

Recent discoveries show that the global latitudinal gradient in marine species richness is bimodal, peaking in mid-latitudes (not at the equator as commonly believed). The dip at the equator has been getting deeper since the last glaciation and more so with recent global warming. This marine latitudinal gradient is explained by temperature: species richness peaks at 20°C in fossil and living species. This finding provides a signal at the ecosystem level for the fact that enzyme stability at the cellular level is most stable at 20°C across all Domains of life, and the thermal niche of most species across all environments overlaps 20°C. Our unpublished analyses find that latitudinal gradient in terrestrial species richness is similarly bimodal but its drivers are not so simple.

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 for 16 years, until joining Nord University in 2020.