RESEARCH
Dynamic Energy Budget Modeling of coral-algal symbioses
NSF DBI-PRFB 1400787
Dynamic Energy Budget (DEB) theory  describes the energy fluxes in living organisms as they are allocated to maintenance, growth, and reproduction. This powerful framework in theoretical ecology facilitates a quantitative, mechanistic understanding of organismal metabolism in dynamic abiotic environments. In collaboration with Dr. Ruth Gates at HIMB and Drs. Roger Nisbet and Erik Muller at the University of California Santa Barbara, I am developing dynamic models for coral-algal symbioses to better understand the mechanisms regulating their stability and breakdown under environmental stress. The first DEB model for a coral symbiosis, developed by Muller and colleagues, is available here .

Figure: Muller et al. 2009 J Theoretical Biol

Metacommunity dynamics of Symbiodinium in American Samoa
The algae that live in symbiosis with corals also exist free-living in the sediments and water column in coral reef environments. The free-living and symbiotic communities in different reef habitat compartments may interact as a metacommunity with emergent patterns that influence overall responses to environmental change. To evaluate metacommunity dynamics of Symbiodinium in American Samoa, we obtained over 1 million DNA sequences from these algae in the sediments, water, and corals of two backreef pools on Ofu Island using 454 pyrosequencing. I am working on new statistical analysis and visualization approaches for this large dataset to understand reef-scale patterns in Symbiodinium distribution and abundance. More information on this project is available here .
 
Cunning R, Yost DM, Guarinello ML, Putnam HM, Gates RD (2015) Variability of Symbiodinium communities in waters, sediments, and corals of thermally distinct reef pools in American Samoa. PLoS ONE 10(12):e0145099. doi:10.1371/journal.pone.0145099.    

Figure: Cunning et al. in prep.

Coral recovery from the 2014 bleaching event in Kaneohe Bay, Oahu
Kaneohe Bay experienced high seawater temperatures in the summers of 2014 and 2015, causing extensive coral bleaching - the loss of corals' symbiotic algae. We tagged affected colonies throughout the bay and have been continuously monitoring their performance through these back to back bleaching events. Using molecular techniques, I am analyzing how the diversity and abundance of Symbiodinium in these colonies changes over time throughout the bleaching and recovery process. This work will identify the natural rates and patterns of recovery on our local coral reefs and the community processes such as competition and succession that influence re-establishment of microbial symbioses after disturbance. This work has been supported by crowdfunding on Experiment.com - visit our project page there for more information, pictures, and video.
 

Photo: Raphael Ritson-Williams

Long-term dynamics of coral symbioses in St. John, U.S. Virgin Islands
Dr. Peter Edmunds at California State University Northridge has been monitoring the coral reefs of St. John since 1987 . In July 2015, I traveled to St. John with his group to collect corals, sediments, and seawater to analyze Symbiodinium metacommunities in the context of long-term data available from these reefs. Areas of low and high coral cover around St. John provide the opportunity to understand how coral community structure impacts Symbiodinium community structure, an important additional layer for understanding reef trajectories in response to local and global stressors. See my blog post describing this work for more information.
 

Photo: http://mcr.lternet.edu/vinp/overview/

Experimental manipulation of coral-algal symbioses
The factors that drive changes in the structure and function of microbial symbioses are critical to understanding how symbiotic organisms respond and acclimatize to dynamic environments. In a series of experiments at the University of Miami, we have shown that both the diversity and abundance of Symbiodinium in certain reef coral species change in predictable ways in response to the abiotic environment. In particular, the severity of bleaching and temperature during recovery determine which symbiont type comes to dominate the symbiosis in Orbicella faveolata, and the external light and temperature regimes determine the abundance of symbionts in Pocillopora damicornis.
 
   
Cunning R, Silverstein RN, Baker AC (2015) Investigating the causes and consequences of symbiont shuffling in a multi-partner reef coral symbiosis under environmental change. Proc R Soc B: doi: 10.1098/rspb.2014.1725
 
Cunning R, Vaughan N, Gillette P, Capo T, Maté J, Baker AC (2015) Dynamic regulation of partner abundance mediates response of reef coral symbioses to environmental change. Ecology 96:1411-1420.
 
Silverstein RN, Cunning R, Baker AC (2015) Change in algal symbiont communities after bleaching, not prior heat exposure, increases heat tolerance of reef corals. Global Change Biol 21:236-249.    
 

Figure: Cunning et al. 2015 Proc R Soc B