Predicting Ectotherm Response to Environmental Variation

My research operates on three axes, integrating fundamental organism biology for predicting biological and ecological patterns across scales

Develop Organismal Models of How Ectotherms Work: How do synergistic and antagonistic processes like thermal injury and repair drive performance and mortality in variable environments?
Scale Individual Performance Ecologically: Build forecasting tools to predict marine ectotherm mortality and population dynamics in the environment.
Evolutionary Basis of Thermal Performance: How do organisms in variable environments evolve?

A Stommel diagram, indicating my research reach across spatial and temporal scales.

Applications

In an era of ecological, climatological, and social uncertainty and change, it is imperative that biological and ecological theory is developed and bent to the applied needs of resource management. To that end, my research aims

Current Research

Forecasting Organismal Responses to Heatwaves

The interactive widget above displays a thermal tolerance landscape of the Eastern oyster Crassostrea virginica displaying population survival probability as a function of temperature magnitude and exposure duration. I use these models to forecast individual and population-level responses to heatwave events. Why predict over heatwaves?

Heatwaves, rather than gradual warming about the meteorological mean, are the driving abiotic factor behind marine invertebrate physiological stress. Because they highly variable in duration, magnitude and return time, it is difficult to predict organismal responses using traditional physiological exposure experiments.

I use experiments to parameterize these thermal death time models, but primarily am using a simulation approach to understand how heatwaves of varying magnitude, duration, and return time affect organismal survivorship and metapopulation dynamics. I currently focus on the eastern Oyster Crassostrea virginica, and am expanding work into the Mediterranean gorgonian coral Paramuricea clavata. I am also interested in how these models can be used to optimize aquaculture and management activities under an increasingly unstable future climate.

Fine-scale temperature variation in the intertidal

An Electricblue temperature logger and intertidal oysters in Great Bay, NH

The ocean is really hard to measure. The intertidal zone is a dynamic environment, and the temperature of the water and air can vary widely over short distances and time scales. I am interested in understanding how these fine-scale temperature variations affect the physiology of marine organisms, particularly in the context of climate change. My efforts are both descriptive (our Madagascar thermal environments project) and predictive (oyster mortality work in New Hampshire). Mismatches in the scales at which we measure the environment (often, in oceans, tens of kilometers) and at which we measure indvidual response (often single populations) can lead to inaccuracies in how we predict organismal responses to climate change.

I use wavelet analysis to understand periodicities within the thermal environment. Here, we see the impacts of tidal (8 hour) and solar (24 hour) cycles on a reef in Madagascar.

Previous Research

Marine Local Adaptation - Master’s Research

As ecologists attempting to understand the impacts of climate change on marine organisms, we often neglect to consider how evolution may play a role in making organisms either more or less susceptible to climate change impacts. Organisms often have a plastic ability to change their physiology or behavior when subjected to different environmental conditions, but environmental changes that last for longer periods of time may drive evolutionary events, manifesting as a shift in genotypes. Countergradient variation is a type of local adaptation where organisms in cooler environments show comparatively higher growth rates than populations in warmer environments . This may result because of shorter growing seasons at high latitudes, where organisms must exploit small windows of ideal growing conditions. Therefore, if an evolutionary event were to drive a cool genotype organism to a warm genotype as a result of climate change, we can expect to see an overall decrease in organismal growth rates. This is an implication that is not fully appreciated in the field.

Through my Master’s research, I sought to better understand how populations of a single species may react differently to climate change. A common assumption of ecological niche models is trait homogeneity across a species, while in fact populations may inhabit diverse environments and be locally adapted to those conditions. The implication of this locally adapted reality is that some populations will be more resilient to climate change than others. I used the predatory marine snail Urosalpinx cinerea to ask these questions about intraspecific variation, specifically quantifying thermal tolerance and growth rates. This snail species is native to the Atlantic coast of the US and is an invasive species on the Pacific coast. In addition, it is a common marine predator on wild and cultured Eastern (Crassostrea virginica) and Pacific (C. gigas) oysters. My results will therefore not only inform coastal managers of projected U. cinerea sensitivity to climate change, but contribute to the growing body of knowledge surrounding how we predict organisms will react to climate change.

This research was recently published in Conservation Physiology (thermal tolerance and plasticity) and Proceedings of the Royal Society: B (growth rates, environmental drivers of adaptation). Research was supported by the American Malacological Society and the PADI Foundation.

This research provided pilot data for a successful NSF-funded grant by my Master’s advisor, Brian Cheng. Research continues at UMass with Project Uro!

Tropical Aquatic Ecology

Tagged Nerite snails to track migration rate

In the summer of 2017 I served as the Aquatic Ecologist for Operation Wallacea at their Dominica field site. In addition to working with high school students performing macroinvertebrate surveys, I developed a research program tracking the migration rates of a species of amphidromous freshwater snail, Nereina punctulata, across altitude and river flow rate. These hyper-abundant snails are likely extremely important for the transport of nutrients into oligotrophic headwaters of tropical streams. We found snails increase their migration rate low in the watershed, likely to avoid being swept downstream by freshets and to avoid large predators. Further, large snails were found more often in upstream areas, but smaller snails tended to exploit high flow environments once they had reached a few kilometers upstream. Antillean streams provide a unique opportunity to ask further questions on energy acquisition and predator avoidance. Research on Nereina migration is published in Aquatic Ecology.

Chameleon habitat use

The world’s second smallest lizard, *Brookesia micra*

In the spring of 2015, I performed research on the remote island of Nosy Hara, Madagascar, quantifying population density and habitat use of the cryptic leaf chameleon Brookesia micra. I was able to demonstrate novel habitat use by this primarily leaf-litter dwelling genus by showing the presence of this species on limestone outcroppings. Further, I performed the first intensive survey of the island for the species. Findings delivered to MNP, Nosy Hara National Park. See my Herpetological Conservation and Biology article for more!

Field Work

2023. Northwest and Southwest Madagascar. Intertidal biodiversity surveying and temperature logger deployment.
2019, 2022. East Coast of the United States, Urosalpinx cinerea broodstock collection.
2019. Gloucester, Massachusetts. Gloucester Marine Station, University of Massachusetts. Local adaptation in a marine snail.
2018. Hurricane Island, Maine. Hurricane Island Center for Science and Leadership. Scallop aquaculture.
2017. Rosalie, Dominica. Operation Wallacea. Macroinvertebrate diversity and freshwater snail migration.
2016. Curaçao, Netherlands Antilles. Smithsonian Institute, National Museum of Natural History. Cryptic reef biodiversity project support.
2016. El Dorado and Stanislaus National Forests, California. The Wilderness Society. Wilderness land cataloging and mapping.
2015. Nosy Hara, Madagascar. School for International Training. Brookesia chameleon habitat use.
2014. Kent Island, New Brunswick, Canada. Bowdoin Science Station. Intertidal biodiversity and invasive species cataloging.
2012. Deep Creek, Eleuthera, The Bahamas. Cape Eleuthera Institute. Cage aquaculture and lionfish surveying.