Project Overview

Summary:

In January 2018, Dr. Martin Grosell at University of Miami, Rosenstiel School of Marine and Atmospheric Science, was awarded an RFP-VI grant totaling $5,999,928 to lead the GoMRI project entitled “Relationship of Effects of Cardiac Outcomes in Fish for Validation of Ecological Risk II (RECOVER II)” which consisted of 6 collaborative institutions and approximately 38 research team members (including students).

The RECOVER II activities represented a unique and integrative approach encompassing studies at the molecular, cellular, organ, whole animal and population level placed in the context of the Gulf of Mexico (GOM) physical and chemical environment. The overarching objective was to gain what may be the most comprehensive understanding of oil impacts on any single organism, an objective that we pursued for a costal and a pelagic GOM fish species. This legacy will provide an exceptionally strong foundation for predicting biological endpoints most at risk during future oil spills in the context of relevant environmental factors (light, temperature, dissolved organic carbon, oxygen and currents). The RECOVER II team worked almost exclusively on two important GOM predatory fishes, the coastal red drum and the pelagic mahi-mahi (mahi). Notably, the RECOVER partner institutions have established facilities, brood stocks and expertise to produce and raise all life stages of mahi (University of Miami) and red drum (The University of Texas at Austin) and have extensive experience with experimental work on both species.

Outreach Highlights

As of June 30, 2020, RECOVER-2 research team members have participated in more than 120 outreach related activities including: school presentations, public events, invited talks, blogs, podcasts and other social media engagement, news articles and more.

Here are a few of our key outreach products and activities:

During the duration of RECOVER II, the outreach team has accomplished its goal of spreading awareness of our mission. The RECOVER Virtual (recovervirtuallab.com) successfully disseminated oil spill research and science to over 1,000 students throughout 56 different school within 30 states in the US, as well as into schools in 2 other countries: Australia and Canada. Through analysis of the content-based questions in the quizzes, students were receiving grades between 70-80%, which shows that these questions are challenging yet most students, where this is their first time being exposed to oil spill science, are able to receive a passing grade.

RECOVER created and further developed connections with collaborators.  We teamed up with the Miami Seaquarium to develop and display an interactive exhibit. This exhibit is currently on display within the main building of the aquarium and is seen by over 500,000 visitors annually.

Additionally, we collaborated with a Florida based magazine, Florida Sport Fishing, to write and publish an article on RECOVER research and the upcoming MAHI cruise.

Social media was an effective tool to increase the reach of RECOVER’s outreach, despite limited manpower. Initiatives included “Meet a Member Monday” and “Tuesday Tool Profile”. These weekly posts highlighted the many different people working within RECOVER and all the different areas, techniques and tools of marine and oil spill science that make up RECOVER .

Lastly, RECOVER outreach documented the MAHI cruise, the research cruise in June 2019, that was 5 years in the making. The end goal of documenting the cruise is to produce a short film focusing on the cruise and is near the end of production.

Research Highlights

As of June 30, 2020, this project’s research resulted in 27 peer-reviewed publications, 1 book, 5 book chapters, 95 scientific presentations, and 55 datasets being submitted to the GoMRI Information and Data Cooperative (GRIIDC), which are/will be made available to the public. The project also engaged 15 PhD and 5 Masters students over its award period. Significant outcomes of this project’s research are highlighted below.

Activities from RECOVER II revealed that adult fish show cardiovascular effects. Cardiovascular effects from developing embryos and larvae following oil exposure were well documented prior to the DWH oil spill. However, RECOVER II demonstrated that in addition to earlier reports of altered cardiovascular development and apparent reduction on heart rate and arrhythmia, larval fish show reduced stroke volume and thereby reduced cardiac output. Similar effects were seen for adult fish where reduced stroke volume and cardiac output was also demonstrated following oil exposure. Furthermore, isolated heart cells (cardio-myocytes) showed reduced sarcomere shortening caused by altered calcium cycling and explaining reduced stroke volume. Work also showed that these cardiovascular effects on juvenile and adult fish last for weeks after exposure is terminated.

Another novel outcome of RECOVER II’s work is the realization that sensory systems are impacted by oil exposure. Eye development and visual acquisition is severely impacted by oil exposure in early life stage fish. Genes related to pigmentation of the eye show reduced expression in oil exposed embryos and larvae. Olfaction, another important sensory system for fish, is also impacted by oil exposure. Juvenile damselfish and mahi-mahi both show altered olfactory performance after brief oil exposures. Damselfish exposed briefly to oil lose the ability to respond to an alarm cue released by conspecifics during predation events, an effect explained, at least in part, by a reduced response by the olfactory epithelium. Mahi-mahi exposed for just 24 hours, lose the ability to avoid oil but this effect was not explained by an inability to detect the oil at the level of the olfactory epithelium and therefore must be related to higher order effects in the central nervous system. Higher order central nervous system effects are also suggested by work on red drum. Red drum display reduced prey-capture after oil exposure which does not appear to be related to cardiovascular function suggesting that sensory function or central nervous system processing of sensory input is the reason for this reduced predatory efficiency. Social interactions between red drum conspecifics are also impacted by oil exposure, again suggesting central nervous system function as a target for oil exposure. Genome wide gene expression studies have revealed gene expression patterns in exposed fish also suggestive of altered nervous system function.

In sum, effects of oil exposure is a multi-organ syndrome and several subtle and sublethal effects likely add up to significantly reduced fitness in a natural environment.

Our studies of oil impacts revealed information about the basic biology of rarely studied fish resident to the Gulf of Mexico. One remarkable observation was that mahi embryos, early during development, shows avoidance behavior toward light in the ultraviolet range, which is harmful to early life stages of marine organism. Mahi embryos that are normally positively buoyant, alter specific gravity to become negatively buoyant when eliminated by natural light or by UV light. This behavioral response is adaptive because it serves embryos to sink to greater depths and thereby reduce UV exposure. Subsequent studies have revealed similar responses by Cobia, Red snapper and Yellowfin tuna indicating that it is a general mechanism present in many fish with buoyant embryos.

For adult mahi, two parallel studies have provided a more detailed understanding of thermal preference and thermal physiology. A study of wild mahi fitted with pop-up archival satellite tags showed that mahi show a strong preference for a narrow temperature range with a median of 27.5ºC despite access to a much wider range during their extensive horizontal migration of >100 km/day. Studies in captive mahi tested in swim tunnel respirometers at temperatures from 20 to 32 ºC showed that the maximal metabolic rate and the highest aerobic scope occurred at 28 ºC. The conclusion of these two studies is that mahi in the wild actively selects habitats with temperatures that maximize their metabolic performance and thereby fitness.         

 Proposal Abstract - RFP-VI PI Martin Grosell