Dan Sinclair

Dr Dan Sinclair profile picture

Senior Lecturer School of Geography, Environment and Earth Sciences

Courses

Teaching in 2020

Qualifications

  • PhD Australian National University (1999)
  • BSc with First Class Honours in Chemistry - University of Canterbury (1992)

Research Interests

I am an Environmental Geochemist with broad interests in the chemistry of earth surface processes. I work mostly with trace elements and stable isotopes in carbonate systems, combining environmental and analytical geochemistry with numerical and mathematical modelling to understand natural geochemical processes. My research focuses on developing methods and tools for reconstructing palaeoceanographic and palaeoenvironmental change on timescales of centuries to hundreds of millennia. To do this I use natural archives, such as corals and speleothems, which capture environmental processes in the varying composition of their layered structure.

I currently have funding to support a PhD project studying tropical Pacific paleoclimate.

Current Projects

Pacific Speleothems

I am using stalagmites from caves on several of the tropical South Pacific islands (e.g. Niue, Tonga) to study rapid changes in hydrology over the last 80,000 years. Stable isotopes of oxygen in speleothem calcite reflect the 18O of rainfall which, in turn, correlates to the amount of rain. I combine this with trace element measurements and dripwater studies. Recent results reveal that the tropical Pacific experienced sudden large changes in rainfall, possibly driven by the same ocean/atmosphere mechanisms responsible for the rapid warming intervals experienced by the Northern Hemisphere during the Glacial.

Deep-Sea Corals

I have been investigating the potential for long-lived deep-sea corals to provide information about the deep marine environment over hundreds to thousands of years. I am studying the application of stable isotopes and high-resolution trace element measurements in a variety of different corals, and have worked with sediment/coral cores from deep reefs in Scotland, and extremely long-lived organic-skeleton corals from the west African margin.

Marine Nutrient Proxies

I am presently working on reconstructing surface phosphate dynamics using P/Ca ratios in tropical corals from the western Indian Ocean and equatorial Pacific. Coral P/Ca shows promise as a direct proxy for ocean phosphate but the chemical system is not simple, and I am collaborating with researchers to study the phase and stability of P that is incorporated into the coral aragonite. I am also investigating the potential for 15N in corals to capture information about phytoplankton and nitrate dynamics in the surface ocean.

Biomineralization

Successfully interpreting proxy records in biological archives requires an understanding of the physiological and chemical processes affecting element incorporation into the biominerals. I have ongoing research interests in understanding and modelling the factors affecting element and isotope incorporation into calcifying organisms.

Ocean Acidification

One of the potentially major consequences of rising atmospheric CO2 levels is the decline in surface ocean pH as CO2 dissolves to form carbonic acid. This is predicted to affect calcifying marine organisms by making it harder to precipitate CaCO3 skeletons. I am working with a multidisciplinary team studying the impact on coral physiology and skeleton formation using analytical geochemistry and numerical models of coral biomineralization.

My current collaborations include Rob Sherrell, Jim Wright, Rick Mortlock and Yair Rosenthal (Rutgers University), Larry Edwards and Hai Cheng (University of Minnesota), Harry Rowe, Judson Partin, Fred Taylor and Jay Banner (University of Texas), Dave Mattey (Royal Holloway), John Hellstrom (University of Melbourne), Heather Stoll (University of Oviedo), Danny Sigman and Satish Myneni (Princeton).

Publications

Publications from 1998 - Current

Courses

Teaching in 2020