Project title

Variation in the strength of coral-symbiont associations

Mentor name

Sean Connolly, ConnollyS@si.edu
Co-mentor name and position: Diana López, postdoctoral fellow, (dplopez@fsu.edu).

Location

Naos Marine Laboratory

Project summary and objectives

The strength of coral associations with Symbiodiniaceae can vary in response to environmental changes. Under stressful conditions such as heat and cold stress, increased sedimentation, nutrients, pollutants, or changes in salinity coral bleaching can occur (i.e., breakdown of the symbiosis). Less severe symptoms related to a weakened symbiotic relationship between corals and their accompanying Symbiodiniaceae include changes in symbiont density, chlorophyll concentration, protein biomass, colony coloration, among others. While it is widely accepted that many coral symbiotic associations are extremely sensitive to even moderate increases in mean temperature, less is known about the sensitivity of corals to changes in salinity. The Pacific coast of Panama is highly dynamic and drastic changes in temperature and salinity occur seasonally every year. In the Gulf of Panama, seasonal fluctuations in temperature occur between upwelling and non-upwelling seasons (i.e., January to May, June to December, respectively), while across the entire Panama Bight, rainfall and upwelling create a temporal change in sea surface salinity (i.e., upwelling salinity ~34 ppt, wet season salinity ~28 ppt). Across the TEP of Panama, shallow coral reefs are dominated by the species complex Pocillopora spp., and some evidence suggests reef populations from the Gulf of Panama are better able to endure bleaching than reefs from adjacent regions (i.e., Gulf of Chiriqui).  The aim of this study is to test whether the strength of the symbiosis between Pocillopora spp. and their Symbiodiniaceae vary according to seasonal changes in temperature and/or salinity across the Gulf of Panama and the Gulf of Chiriqui. Coral fragments will be sampled at three sites at each gulf during upwelling, non-upwelling, and wet seasons and physiological parameters will be assessed in the laboratory to determine the strength of the symbiotic relationship.

Mentorship goals

The intern will work closely with a large and diverse group of scientists at all career stages. The focus of the internship would be on sequencing of DNA for the coral microbiome, analysis of patterns of biodiversity (taxonomic richness, evenness, and biotic turnover) within and among colonies, sites, morphospecies, and regions, and evaluation of the extent to which these patterns correspond to differences in the environmental context of physiological performance of the colonies’ hosts and symbionts. There would also be opportunities to learn about the quantification of coral physiological parameters from an outdoor experimental system, and it is anticipated that there would be some opportunity to participate in fieldwork.

The intern will work ~40 hours per week and may be expected to work on weekends for field expeditions if needed. The product would be a poster presentation at the intern symposium if timing is appropriate. If the intern’s home institution requires a project report, mentorship will be provided for this stage as well (including, if necessary, after the intern returns to her or his home institution).

Advising/mentoring meetings would occur at least weekly, on average. Additional advice and support would be available from the senior mentor (Sean Connolly), as well as other team members both one-on-one and lab meetings (both the senior mentor and other senior collaborators on the project hold regular lab meetings). Additionally, the intern would be encouraged to attend STRI research seminars, including weekly Tupper seminars and approximately weekly informal science seminars at Naos Marine Laboratory.

List of suggested readings

Epstein HE, Smith HA, Cantin NE, Mocellin VJL, Torda G, van Oppen MJH. 2019 Temporal Variation in the Microbiome of Acropora Coral Species Does Not Reflect Seasonality. Front Microbiol 10. (doi:10.3389/fmicb.2019.01775)

Marangoni LF de B, Rottier C, Ferrier-Pagès C. 2021 Symbiont regulation in Stylophora pistillata during cold stress: an acclimation mechanism against oxidative stress and severe bleaching. Journal of Experimental Biology 224. (doi:10.1242/jeb.235275)

Hughes TP, Kerry JT, Simpson T. 2018 Large-scale bleaching of corals on the Great Barrier Reef. Ecology 99, 501–501. (doi:10.1002/ecy.2092)

Weis VM. 2008 Cellular mechanisms of Cnidarian bleaching: stress causes the collapse of symbiosis. Journal of Experimental Biology 211, 3059–3066. (doi:10.1242/jeb.009597)

Hoegh-Guldberg O, Bruno JF. 2010 The Impact of Climate Change on the World’s Marine Ecosystems. Science (1979) 328, 1523–1528. (doi:10.1126/science.1189930)

Hoegh-Guldbergl O, Smith GJ. 1989 The effect of sudden changes in temperature, light and salinity on the population density and export of zooxanthellae from the reef corals Stylophora pistillata Exper and Seriatopora hystrix Dana. Genetics and Ceff Biology 129, 279–303.

Dias M, Madeira C, Jogee N, Ferreira A, Gouveia R, Cabral H, Diniz M, Vinagre C. 2019 Oxidative stress on scleractinian coral fragments following exposure to high temperature and low salinity. Ecol Indic 107, 105586. (doi:10.1016/j.ecolind.2019.105586)

Randall CJ, Toth LT, Leichter JJ, Maté JL, Aronson RB. 2020 Upwelling buffers climate change impacts on coral reefs of the eastern tropical Pacific. Ecology 101. (doi:10.1002/ecy.2918)

Alory G, Maes C, Delcroix T, Reul N, Illig S. 2012 Seasonal dynamics of sea surface salinity off Panama: The far Eastern Pacific Fresh Pool. J Geophys Res Oceans 117, n/a-n/a. (doi:10.1029/2011JC007802)

Glynn P, Mate J, Baker A, Calderón M. 2001 Coral bleaching and mortality in Panama and Ecuador during the 1997-1998 El Niño-Southern Oscillation event: Spatial/temporal patterns and comparisons with the 1982-1983 event. Bull Mar Sci 69, 79–109.