Marine predators as ecosystem sentinels
Marine environments are under siege via concurrent anthropogenic stressors including pollution, climate change, over-harvesting, industrial development, and ship traffic. Marine organisms can serve as early indicators of ecosystem disruption with changes in their distribution, behavior, body condition, reproduction, and other measurable traits. Monitoring these species can inform recovery and proactive conservation of ecosystems, food webs, and species. My work has focused on the ability of marine predators to help us understand and protect marine environments under threat. Doing so will help us meet the growing sustainability challenges of the Anthropocene.
Marine environments are under siege via concurrent anthropogenic stressors including pollution, climate change, over-harvesting, industrial development, and ship traffic. Marine organisms can serve as early indicators of ecosystem disruption with changes in their distribution, behavior, body condition, reproduction, and other measurable traits. Monitoring these species can inform recovery and proactive conservation of ecosystems, food webs, and species. My work has focused on the ability of marine predators to help us understand and protect marine environments under threat. Doing so will help us meet the growing sustainability challenges of the Anthropocene.
Relevant publications:
- Savoca, M.S.... and J. Lynch. 2022. Towards a North Pacific Ocean long-term monitoring program for plastic pollution: A review and recommendation for plastic ingestion bioindicators. Environmental Pollution 310: 119861
- Savoca, M.S., McInturf, A.G. and E.L. Hazen. 2021. Plastic ingestion by marine fish is widespread and increasing. Global Change Biology 27(10): 2188-2199.
- Goldbogen, J.A.... Savoca, M.S.... et al. 2019. Why whales are big but not bigger: Physiological drivers and ecological limits in the age of ocean giants. Science 366(6471): 1367-1372.
- Hazen, E.L., Abrahms, B., Brodie, S., Carroll, G., Jacox, M., Savoca, M.S., Scales, K.L., Sydeman, W.J. and S.J. Bograd. 2019. Marine top predators as climate and ecosystem sentinels. Frontiers in Ecology and the Environment
Nutrient recycling by top predators
Marine predators augment nutrient transport from sea to land, but there is less research demonstrating how these ecosystem engineers may benefit primary productivity by recycling nutrients at sea. Procellariiform seabirds recruited en masse by phytoplankton-produced dimethyl sulfide (DMS) have the potential to recycle significant quantities of soluble iron via their guano to the iron-limited polar oceans. During my postdoctoral work, I used field data to inform estimates on the quantity of nutrients baleen whales recycle in past as present oceans. Extending these findings to future scenarios of ecosystem collapse or recovery, we have begun to quantify the carbon benefits of rebuilding ocean ecosystems. Our findings are of broad interest to community and marine ecologists, and to climate scientists interested in fertilizing iron-limited marine regions (e.g., the Southern Ocean) to sequester atmospheric carbon and mitigate climate change.
Nutrient recycling by top predators
Marine predators augment nutrient transport from sea to land, but there is less research demonstrating how these ecosystem engineers may benefit primary productivity by recycling nutrients at sea. Procellariiform seabirds recruited en masse by phytoplankton-produced dimethyl sulfide (DMS) have the potential to recycle significant quantities of soluble iron via their guano to the iron-limited polar oceans. During my postdoctoral work, I used field data to inform estimates on the quantity of nutrients baleen whales recycle in past as present oceans. Extending these findings to future scenarios of ecosystem collapse or recovery, we have begun to quantify the carbon benefits of rebuilding ocean ecosystems. Our findings are of broad interest to community and marine ecologists, and to climate scientists interested in fertilizing iron-limited marine regions (e.g., the Southern Ocean) to sequester atmospheric carbon and mitigate climate change.
Relevant publications:
- Pearson, H.C., Savoca, M.S., Costa, D.P., Lomas, M.W., Molina, R., Pershing, A.J., Smith, C.R., Villaseñor-Derbez, J.C., Wing, S.R. and J. Roman. 2023. Whales in the carbon cycle: Can recovery remove carbon dioxide? Trends in Ecology & Evolution 38(3): 238-249
- Savoca, M.S., Czapanskiy, M.F., Kahane-Rapport, S.R., Gough, W.T., Fahlbusch, J.A., Bierlich, K.C., Segre, P.S., Di Clemente, J., Penry, G.S., Wiley, D.N., Calambokidis, J., Nowacek, D.P., Johnston, D.W., Pyenson, N.D., Friedlaender, A.S., Hazen, E.L. and J.A. Goldbogen. 2021. Baleen whale prey consumption based on high-resolution foraging measurements. Nature 599: 85-90.
- Savoca, M.S. 2018. Chemoattraction to dimethyl sulfide links the sulfur, iron, and carbon cycles in high-latitude oceans. Biogeochemistry 138(1): 1-21.
- Savoca, M.S. and G.A. Nevitt. 2014. Evidence that dimethyl sulfide facilitates a tritrophic mutualism between primary producers and top predators. PNAS 111(11): 4157-4161.
Mechanistic basis of plastic ingestion
Plastic debris is a pernicious anthropogenic addition to marine ecosystems. Over one thousand species ingest plastic debris, but our knowledge of why animals mistake plastic for prey remains incomplete. As part of my dissertation research, I investigated chemical cues associated with marine plastic debris to ascertain whether plastic debris could be chemically attractive to marine wildlife. My research found appreciable concentrations of dimethyl sulfide (DMS; a foraging infochemical) on ocean plastics. We also discovered that tube-nosed seabird species, which use DMS to locate foraging sites, more likely to ingest plastic than those species not attracted to DMS. To examine an organism's behavioral response to the chemical signature of plastic debris, I conducted an experiment on a known plastic consumer - the Northern Anchovy (Engraulis mordax) - at the Aquarium of the Bay. Later, we tested the same hypothesis on young loggerhead sea turtles. Results from these experiments indicated that the chemical signature of ocean plastic can induce foraging behaviors in marine consumers. My postdoctoral work has investigated a separate pathway of ingestion and uncovered that baleen whales ingest the majority of their microplastics via trophic transfer and not from polluted water they filter. These results can help inform risk assessments and guide mitigation strategies of this mounting threat.
Relevant publications:
- Kahane-Rapport S.R., Czapanskiy, M.F., Fahlbusch J.A, Friedlaender, A.S., Calambokidis, J., Goldbogen, J.A. and M.S. Savoca. 2022. Field measurements reveal exposure risk to microplastic ingestion by marine megafauna. Nature Communications 13: 6327
- Pfaller, J.B. Goforth, K., Gil, M.A, Savoca, M.S. and K.J. Lohmann. 2020. Odors from marine plastic debris elicit foraging behaviors in sea turtles. Current Biology 30(5): R213-R214.
- Savoca, M.S., Tyson, C.W., McGill, M., and C.J. Slager. 2017. Odours from marine plastic debris induce food search behaviours in a forage fish. Proceedings of the Royal Society B 284: 20171000.
- Savoca, M.S., Wohlfeil, M.E., Ebeler, S.E. and G.A. Nevitt. 2016. Marine plastic debris emits a keystone infochemical for olfactory foraging seabirds. Science Advances 2(11): e1600395.
Past research projects and themes
Analysis of bycatch in United States fisheries to support management
As the main project for my Sea Grant Fellowship, I amalgamated data from the NMFS’ National Bycatch Reports, augmented by several other data sources, to evaluate bycatch patterns in 100 federal fisheries. In addition to a continental-scale fisheries analysis, my goal is to make publicly available national bycatch data more accessible to managers, fishers, students, and the general public. We have secured additional funding through the National Observer Program to continue to improve the availability and communication of bycatch data to facilitate conservation and management that ensures U.S. fisheries sustainability in the 21st century and beyond.
Relevant publications:
- Savoca, M.S., Brodie, S., Welch, H., Hoover, A., Benaka, L.R., Bograd, S.J., and E.L. Hazen. 2020. Comprehensive bycatch assessment in U.S. fisheries for prioritizing management. Nature Sustainability 3(4)
Seabird breeding biology
I had my first crack at independent research in the summers of 2008 and 2009 at the Shoals Marine Laboratory. While there, I studied the behavior and life history of the resident populations of Great Black-backed (Larus marinus) and Herring Gulls (L. argentatus). This is also where I fell in love with marine science, ignited by a passion for these raucous and fascinating seabirds. In early 2017, I had the opportunity of a lifetime when I volunteered as a researcher on the New Zealand Storm-Petrel Project, led by the Northern New Zealand Seabird Trust. The New Zealand Storm-Petrel (Fregetta maoriana) is a bird of legend, thought to be extinct for over a century prior to its rediscovery in 2003. In 2011, researchers located the only known breeding colony of this species and I was delighted to work on that particular island, as part of the first mark-recapture analysis for this species, with the aim of determining a rigorous estimate of population size and trajectory.
Relevant publications:
- Savoca, M.S., Bonter, D.N., Zuckerberg, B., Dickinson, J.L. and J.C. Ellis. 2011. Nesting density is an important factor affecting chick growth and survival in the Herring Gull. The Condor 113(3): 565-571.
- Savoca, M.S. Introduced mammals on seabird breeding islands. First published on Wikipedia 11 May 2011.
- Savoca, M.S. Seabird breeding behavior. First published on Wikipedia 5 May 2011.
Pictures of me working on several different projects over the last decade of research.