CURRENT PROJECTS


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Physiological Thresholds

I am currently examining the physiological thresholds of corals and other marine invertebrates under local and global stressors using intermittent flow respirometry.


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Bleaching variation and susceptibility of corals

Why do some corals bleach and others do not? I am currently investigating the underlying traits that may be responsible for bleaching variation and susceptibility of corals to bleaching and ultimately climate change. 


The Proton Flux Hypothesis visual representation by K. Bahr.  All rights reserved.  As processes, photosynthesis and calcification compete for dissolved inorganic carbon (DIC). Corals uptake DIC as bicarbonate (HCO3-) to form calcium carbonate (CaCO3) with a proton (H+) as a waste product. This proton must then be removed from the coral to prevent acidosis inside the tissues. The protons are dissipated through the boundary layer into the bulk seawater by diffusion from high to low concentrations. Under ocean acidification (OA) conditions, more DIC is available however coral calcification is limited by the increasing concentration of protons in the bulk water due to OA. 

The Proton Flux Hypothesis visual representation by K. Bahr. 
All rights reserved. 
As processes, photosynthesis and calcification compete for dissolved inorganic carbon (DIC). Corals uptake DIC as bicarbonate (HCO3-) to form calcium carbonate (CaCO3) with a proton (H+) as a waste product. This proton must then be removed from the coral to prevent acidosis inside the tissues. The protons are dissipated through the boundary layer into the bulk seawater by diffusion from high to low concentrations. Under ocean acidification (OA) conditions, more DIC is available however coral calcification is limited by the increasing concentration of protons in the bulk water due to OA. 

The Proton Flux Hypothesis

Developed by the late Dr. Paul Jokiel, the Proton Flux Hypothesis explains that coral calcification is limited by diffusion of the calcification waste product, protons, out of the calcification compartment. The flux of protons across the biological coral membrane is diffusion limited by the net proton transport through the boundary layer, which is hindered by increasing proton concentration due to ocean acidification in the seawater.

In honor of Dr. Paul Jokiel, I will continue examining and testing his Proton Flux Hypothesis through experimental physiology and metabolic response of coral reefs in relation to ocean acidification and global warming.