Research

Current Research

Grottoli’s research focuses on three areas of research: 1- determining what drives resilience in corals in the face of climate change, 2- reconstructing oceanographic conditions in the past based on coral skeletal isotope and trace metal records, and 3- the impact of land-use on the delivery of carbon to small tropical and temperate rivers. Grottoli currently has two funded projects through the Division of Oceanography at the National Science Foundation that focus on her first area of research interest.

1) Will corals recover from bleaching under ocean acidification conditions?

Following the second hottest month on record since the 1940s, water temperatures in the main Hawaiian Islands reached 30°C in October 2014. The result of this ~2°C increase above normal summer temperatures has been a severe bleaching event across the entire length of the Hawaiian Archipelago.  Bleaching is a stress response in corals whereby they lose their symbiotic algal partners and turn white. Prolonged bleaching can lead to disease and death. By the end of this century, bleaching events are expected to become annual events and the oceans are predicted to be twice as acidic as today.  Ocean acidification is caused by the dissolution of excess atmospheric CO2 into the surface ocean and has been linked to decreases in coral calcification and reduced health.  My team is conducting research in Hawaii in collaboration with Dr. Rob Toonen and Dr. Peter Marko at the University of Hawaii to determine if ocean acidification slows down recovery rates of corals following bleaching.   We are also determining if feeding can offset any negative effects of ocean acidification following bleaching.  This year-long project is funded by the National Science Foundation – RAPID program.  Bleached and non-bleached corals were collected from the field following the peak of the natural bleaching event in the fall of 2014 and have been cultured in flow-through tanks with either ambient or acidic pH seawater (among which half of the corals are fed zooplankton and have are not) at the Hawaii Institute of Marine Biology ever since.  We made our first assessments of the coral health in <a href=”https://u.osu.edu/grottoli.1/fieldwork/”>December 2014</a> and return in May and December 2015 to repeat the assessments and determine recovery rates.  Results of this research would inform coral reef managers as to which species or reef regions are more resilient to global change conditions and better targets for protection.

 2) Phenotype and genotype of coral adaptation and acclimatization to global change

Coral reefs are among the most diverse ecosystems on the planet, housing an estimated 25% of marine species. Global climate models predict that by the end of this century, tropical seawater temperatures are expected to be up to 3°C warmer than they are today and at least twice as acidic, which threatens the long-term survival of coral reef ecosystems. Elevated temperature and ocean acidification have been shown to cause reduced coral growth rates and increased coral disease and mortality rates. To date, the assumption has been that corals will not be able to adapt because the rates of anthropogenically driven ocean acidification and climate change are too high. My team is conducting a two-year long experiment in Hawaii in collaboration with Dr. Rob Toonen to determine if coral adapt or acclimatize to global change conditions expected at the end of this century. If they can adapt, how fast is the adaptation rate? How do adaptation rates differ among species and geographic locations? Answers to these questions are key to developing strategic coral conservation and management plans. To address these questions, eight species of Hawaiian corals are being studied using a two-part approach: 1) a survey of natural corals found across natural temperature and acidity gradients and 2) a two-year long mesocosm study which will expose corals collected in part 1 to temperature and acidity conditions expected at the end of this century.

 

Past Research

Past research have included the following:

  1. the interactive effect of elevated temperature and ocean acidification on corals
  2. the effect of repeat bleaching on Caribbean coral adaptation and  acclimation
  3. the effect of bleaching on the acquisition, allocation, and utilization of carbon in bleached and recovering corals
  4. the effect of land-use on the concentration and isotopic character of organic and inorganic carbon in tropical and temperature streams
  5. the history of land-use change in tropical streams as recorded in coral skeletal records
  6. paleoceanography of the western tropical Pacific using coral, sclerosponge, and gorgonian isotope and elemental records
  7. coral skeletal cadmium-based paleoceanography of upwelling in the eastern tropical Pacific

Results from past research are published and can be viewed through the Publications link on the right-hand toolbar.