Maggie Johnson

MarineGEO Postdoctoral Fellow

I am a MarineGEO postdoctoral fellow with the Smithsonian Tropical Research Institute and the Smithsonian Marine Station at Fort Pierce, Florida. I received my PhD in 2011 from Scripps Institution of Oceanography, where I studied the effects of anthropogenic change on coral reef primary producers. An ongoing theme of my research is understanding how local and global human impacts affect the structure and function of calcifier-dominated ecosystems. To do this, my research uses a combination of field and laboratory experiments to quantify how reef-builders, and the communities they create, are affected by increasing temperatures, decreasing pH (ocean acidification) and decreasing oxygen levels (hypoxia). I primarily use crustose coralline algae (CCA) and reef-building corals as model organisms, based on their essential ecological functions in coastal ecosystems across the planet, and their sensitivity to global change stressors. 

With MarineGEO, I use standardized monitoring procedures, including permanent benthic surveys and Calcification Accretion Units (CAUs), to quantify how coral and oyster reef structure and function changes over space and time. I have implemented this approach at three MarineGEO sites (Bocas del Toro, Panama; Carrie Bow Cay, Belize; Indian River Lagoon, Florida) and in Coiba on the Pacific coast of Panama. Additionally, I conduct field manipulations and targeted perturbation experiments in the lab to test the effects of ocean acidification on community structure and function and organismal biology. I am particularly interested in determining if organisms from highly variable habitats can acclimatize to stressful conditions and are thus more resilient to global change stressors such as warming and ocean acidification. My ongoing research will explore the combined effects of acidification, warming and hypoxia on reef-building corals in Florida, specifically focusing on tolerances and differential survival under stressful conditions. 

Project title: The life and breath of calcifying ecosystems in an acidifying ocean: Implications of ocean acidification for biodiversity and ecosystem function across the Tennenbaum Marine Observatory Network 

Advisors: Andrew Altieri, Valerie Paul, and Nancy Knowlton