Paul's Research

Research Interests

In the Lab we study the geological and geomorphological development of Holocene and late Pleistocene coral reefs. Obviously we're interested in the basic details: why are reefs located in some areas and not others? When did they start growing, and how do they develop? But we also look at the bigger picture: what types of reefs exist today and where do they develop? And what happened to them as sea-level and climate changed through time?

So far we've discovered some surprising things. Instead of building frameworks, we found that reefs in hurricane-prone areas are composed of stabilized coral gravels, and that they've migrated along and inshore since the mid-Holocene. We've also found that reefs have drowned and backstepped upslope several times in response to abrupt accelerations in postglacial sea-level rise. We discovered a similar backstepping during the last interglacial some 125 ka ago, and linked this to an unstable ice-sheet at that time. And even further back in time, we solved a long-standing puzzle about how Pacific reefs transform from simple fringing reefs into large-scale Barrier reefs and Atolls during glacial sea-level cycles.

We're now back in the Caribbean looking at all breakwater reefs to figure out what other reef types exist, and how they develop both locally and regionally in response to environmental variations. 

Teaching Philosophy

I train my graduate students to become scientists, critical thinkers, and collaborators in that order. I want them to understand science as both a philosophical and social activity. Few start with an understanding of how to identify scientific problems and formulate hypotheses. Most have no idea of the cognitive traps and biases that exist along the way, nor the importance of credibility upon which their careers will rely.

But once these lessons are understood, I want them to question authority, accept nothing that isn't nailed down, whilst acknowledging their own ignorance. They need to distinguish good from bad, accurate from precise, and claims from conjecture. They need to qualify what they have found and give credit where it's due. They need to see the wood from the trees and grasp the importance of what they find, then pledge to disseminate it ensuring equality of access.

Above all I want them to apply their critical-thinking skills not only in advancing science, but in their everyday lives, so they can contribute to both societal and planetary needs. If you want a modern society with an ability to discern truth from falsehood, then training students to think critically is of national importance.

The Origin of Darwin's Reef Types

This video describes our research on IODP reef cores drilled off the South-Pacific island of Tahiti. Here we looked at how reefs evolved during the postglacial rise in sea level. We showed how a fringing reef that grew during the glacial lowstand migrated upslope and became a barrier reef upon reaching a fossil reef-flat that formed during the last Interglacial highstand. The model we outline to explain all this finally solves the puzzle of how reefs change from Fringing to Barrier to Atoll types during Glacial sea-level cycles. (Yes, Darwin was wrong about how this happens)

Retrograde Reef Accretion

This video explores the anatomy of a Yucatan fringing reef and outlines a model explaining how reefs develop in areas commonly hit by hurricanes. The reef's anatomy is dominated by coral gravels that represent multiple episodes of reef destruction and recovery over the last 6000 year. The model proposes that each cycle of coral gravel is tossed further inshore as sea-level rises, producing a structure that retreats over its back-reef through time. It shows two things: what you see on the reef surface is not what you get inside, and that not all reefs are equal and can develop in fundamentally different ways.

The classification of Caribbean Coral Reefs

This video describes our recent paper in PLoS One, which reports that, instead of Darwin’s one reef-type with three stages of development, Caribbean reefs actually consist of two distinct types with different morphologies, geographic distributions and internal structures. The first type, called Flat-Type reefs, have wide flat intertidal back-reef zones, are found predominantly in the southern Caribbean, and have an internal structure of stacked interlocking coral skeletons, features which are also found in their Pacific cousins. The second type called Crest-Type reefs, have sloping subtidal back-reefs instead of flats, are found predominantly in the northern Caribbean, and have an internal structure composed not of stacked colonies but of large fragmented pieces of their skeletons.

CV in English

CV in Español