Microalgal interactions are fundamental contributors to large scale ecosystem processes including the ocean carbon pump, the duration of algal blooms, and the evolutionary success of coral reefs. Our research evaluates how environmental stressors elicit shifts in cellular crosstalk of microalgal symbioses and the resulting eco-physiological consequences. This research serves as a framework for how cellular interactions govern organismal physiology and cascade into shifts in functional ecology.
Below are brief overviews of a few ongoing research themes which fall into two major foci: 1) studying how changing ocean conditions alter trace metal exchanges in nutritional symbioses and 2) evaluating how biogeochemistry mediates cellular communication within microalgal -- bacteria interactions and, in turn, the vast array of outcomes (‘frenemies’). We are open to applying this framework to other microalgal symbioses. We are keen to explore other creative avenues of microalgal symbiosis research and welcome multidisciplinary collaborations.
A note to prospective graduate students – We are thrilled for you to use these vignettes as jumping off points as you think about what aspects of the unknown pique your interest (tangentially related blog post on choosing projects here). Hannah already has her graduate degrees, this thesis/dissertation is YOURS!
Below are brief overviews of a few ongoing research themes which fall into two major foci: 1) studying how changing ocean conditions alter trace metal exchanges in nutritional symbioses and 2) evaluating how biogeochemistry mediates cellular communication within microalgal -- bacteria interactions and, in turn, the vast array of outcomes (‘frenemies’). We are open to applying this framework to other microalgal symbioses. We are keen to explore other creative avenues of microalgal symbiosis research and welcome multidisciplinary collaborations.
A note to prospective graduate students – We are thrilled for you to use these vignettes as jumping off points as you think about what aspects of the unknown pique your interest (tangentially related blog post on choosing projects here). Hannah already has her graduate degrees, this thesis/dissertation is YOURS!
The iron economy of the coral holobiont
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Iron, and other trace metals, are ubiquitous components of cellular machinery needed for physiological acclimation to heat waves. As such, insufficient access to supplies of trace elements can accelerate coral dysbiosis and, in turn, bleaching outbreaks. Our recent (Symbiodiniaceae) cell culture research demonstrated metallome and gene expression indicators of Fe-deficiency. Further, Symbiodiniaceae with elevated metal contents were more resistant to heat stress. We are interested in continuing this line of research by evaluating how different trace metal sources mediate the success of partner pairing combinations (cnidarian, dinoflagellate, bacteria) when faced with environmental stressors.
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Bacterial interactions in the phycosphere
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Bacterial associations result in a range of antagonistic-protagonistic consequences for their microalgal (and animal) hosts. These contributions span nutrient acquisition, disease resistance, and secondary metabolite production. Despite the broad benefits conferred by microbial communities to aquatic holobionts, our understanding of the specific functions, mechanisms, and ecological roles of core bacterial taxa remains limited. We are interested in surveying for these interactions using via genomics and experimental approaches. We are system agnostic and always excited to expand our bacterial and microalgal cell culture collections.
We are grateful to the students and TAs of Haverford College’s FA22 Advanced Lab in Biology (#SiderophoreSuperLab) for their effort in isolating ~80 pure cultures of Symbiodiniaceae-associated bacteria & initial siderophore assays. |
Underwater nightlights: Dinoflagellate bioluminescence in Puerto Rico
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Pyrodinium bahamense var. bahamense is an iconic bioluminescent dinoflagellate that lights up shallow bay environments across the tropical and subtropical Atlantic, drawing ecotourism to places like Vieques, Puerto Rico. Following Hurricane Maria, P. bahamense bioluminescence was lost due to extensive disruption of mangrove and seagrass ecosystems and the collapse of water column populations, driven by high winds and salinity shock. Recovery was facilitated by sediment-based cyst seed banks, which reestablished motile populations. As the severity and frequency of hurricanes continues to rise, it is increasingly critical to understand the spatial distribution and environmental tolerances of both life stages, given the implicated role of seed banks in contributing to the residence and intensity of future blooms.
This research is embedded in ESF's Tropical Marine Ecology field course (EFB 496, co-taught with Josh Drew) |
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SOAP BUBBLE: Symbiotic Organisms Associate with Poriferans But our Understanding of Benthic Biodiversity is Limited in these Ecosystems
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Sponges are widespread in freshwater lakes, ponds, rivers and streams throughout North America. However, sponge sensitivity to water quality varies considerably. The distribution of some sponge species is restricted to pristine environments with low conductivity, making some lineages tractable indicators for water quality. However, the capacity of some sponges to form associations with endosymbiotic algae may confound the capacity of their hosts to serve as environmental indicators as the ecological success of freshwater might be mediated by different partner pairings. Improving our understanding of the molecular ecology of sponge-microalgal-bacterial symbioses will facilitate the inclusion of utilizing sponges monitoring in water quality and ecosystem health.
This work is in collaboration with the Ninokawa & Maresca Labs. |
