Research interests
- The relationship among community functional diversity, trophic structure, and dynamics
- Processes that dictate the biogeography and evolution of marine species
- Biomineralization of marine invertebrates
- The relationship between host functioning and resident microbiome composition
Ongoing projects
Reconstructing food web structure across the Richmondian Invasion
Biological invasion stands as a significant contributor to global biodiversity loss, with alien species in the United States alone causing up to $1 billion in environmental damages annually. The introduction of nonindigenous species often triggers adverse impacts on native species, leading to cascading effects and a decline in ecosystem functioning.
While our understanding of biological invasion largely stems from studies of modern ecosystems spanning human timescales, it's imperative to also examine these phenomena over longer, ecological, timescales. To address this gap, we employ the perspective of conservation paleobiology to investigate the response of marine community food web networks to an invasion event documented in the fossil record—the Richmondian Invasion during the Late Ordovician, recorded in the Cincinnati Series. Utilizing fossil occurrence data from collections and the Paleobiology Database, we reconstruct food web network models of marine paleocommunities from six third-order stratigraphic sequences that spanned periods before, during, and after the invasion. Through this exploration of invasion processes in pre-human ecosystems, we aim to establish an ecological baseline for understanding natural systems' responses to invasion over evolutionary timescales. Our investigation into Ordovician marine communities may serve as useful analogs for understanding similar dynamics in contemporary ecosystems, such as Palmer Deep in Antarctica, where the native benthic invertebrate community was recently devastated by the invading King Crab. By integrating network theory and concepts of conservation paleobiology, our research contributes important ecological insights into how natural systems may continue to respond to the myriad stressors generated by the ongoing climate crisis. Results from this work are forthcoming.
This work is supported by NSF-EAR 1848232. PI: Dr. Carrie L. Tyler
While our understanding of biological invasion largely stems from studies of modern ecosystems spanning human timescales, it's imperative to also examine these phenomena over longer, ecological, timescales. To address this gap, we employ the perspective of conservation paleobiology to investigate the response of marine community food web networks to an invasion event documented in the fossil record—the Richmondian Invasion during the Late Ordovician, recorded in the Cincinnati Series. Utilizing fossil occurrence data from collections and the Paleobiology Database, we reconstruct food web network models of marine paleocommunities from six third-order stratigraphic sequences that spanned periods before, during, and after the invasion. Through this exploration of invasion processes in pre-human ecosystems, we aim to establish an ecological baseline for understanding natural systems' responses to invasion over evolutionary timescales. Our investigation into Ordovician marine communities may serve as useful analogs for understanding similar dynamics in contemporary ecosystems, such as Palmer Deep in Antarctica, where the native benthic invertebrate community was recently devastated by the invading King Crab. By integrating network theory and concepts of conservation paleobiology, our research contributes important ecological insights into how natural systems may continue to respond to the myriad stressors generated by the ongoing climate crisis. Results from this work are forthcoming.
This work is supported by NSF-EAR 1848232. PI: Dr. Carrie L. Tyler
Food web structure of Mesozoic marine communities
The Mesozoic Marine Revolution describes a pattern of increased taxonomic diversity, ecospace utilization, predation intensity, and metabolic activity of marine taxa during the Mesozoic era (approximately 250 to 66 million years ago), indicating that there were likely concomitant changes to community trophic structure. Given that changes to trophic structure has important implications for community properties, such as geochemical cycling, community composition, and community stability.
We reconstructed trophic networks from various stages of the Mesozoic era (Anisian, Carnian, Bathonian, Aptian) to assess the effect of the Mesozoic Marine Revolution on ecosystem dynamics (Banker et al., 2022a). Networks were reconstructed using fossil data representing marine communities of the western Tethys sea and were also compared to an analogous modern Jamaican reef community. Findings reveal an expansion of trophic space over time, with variations in trophic position influenced by the presence of different functional guilds. Notably, the Bathonian stage displayed longer food chains and lower trophic omnivory compared to the Aptian stage, attributed to the presence of large predatory guilds. The study underscores the importance of understanding trophic position for effective restoration activities and suggests further research to elucidate the roles of top consumers in moderating network structure and community stability.
This work is supported by NSF-EAR 1629786 and 1629776. PIs: Drs. Peter D. Roopnarine and Carrie L. Tyler
We reconstructed trophic networks from various stages of the Mesozoic era (Anisian, Carnian, Bathonian, Aptian) to assess the effect of the Mesozoic Marine Revolution on ecosystem dynamics (Banker et al., 2022a). Networks were reconstructed using fossil data representing marine communities of the western Tethys sea and were also compared to an analogous modern Jamaican reef community. Findings reveal an expansion of trophic space over time, with variations in trophic position influenced by the presence of different functional guilds. Notably, the Bathonian stage displayed longer food chains and lower trophic omnivory compared to the Aptian stage, attributed to the presence of large predatory guilds. The study underscores the importance of understanding trophic position for effective restoration activities and suggests further research to elucidate the roles of top consumers in moderating network structure and community stability.
This work is supported by NSF-EAR 1629786 and 1629776. PIs: Drs. Peter D. Roopnarine and Carrie L. Tyler
Influence of seawater chemistry on Oyster shell formation, gene expression, and microbial community composition
Climate change-induced ocean acidification has already had severe consequences for marine organisms, and is will continue to disrupt the the shell-formation processes of marine organisms that build calcium carbonate shells.
Increasingly, results from research focused on evaluating the changing microbiomes of marine taxa indicates that there is an important nexus of interaction between the environment, host organisms, and their internal microbial communities (e.g., Banker and Vermeij, 2018, Banker and Coil 2020).
This study aims to investigate the role of environmental factors, including ocean acidification and microbial community composition, in shaping shell development in juveniles of the Pacific oyster. Through controlled environmental manipulations and detailed analyses of shell morphology, gene expression, and microbial communities, we aim to unravel the complex interplay between abiotic factors and biological processes underlying shell mineralization.
In the first phase of this work we manipulated experimental tanks in order to investigated the role of sulfate-reducing bacteria in shell formation of Pacific oysters (Magallana gigas) (Banker et al., 2022b). Contrary to expectations, attempting to inhibit these bacteria using sodium molybdate did not uniformly suppress sulfate-reducing bacteria; instead, oysters exposed to the inhibitor exhibited larger shell growth. Microbiome and gene expression analysis revealed distinct differences initially that converged over time. This suggests that oysters may regulate microbiome dysbiosis, which in turn lead to the differential growth of shell material between the two treatment groups. Overall, these results underscore that there is a complex relationship between microbiota and their host organisms that is important to host health (e.g. shell formation) that is susceptible to changing environmental conditions. Taken together with predicted trajectories for global change, these facts taken together point to a need to better understand this relationship to conserve marine species that are both ecologically and economically important.
This work is supported by the UC Davis Microbiome Special Research Program. Proposal co-written by myself and senior PIs, Drs. David Gold and Jay Stachowicz.
Increasingly, results from research focused on evaluating the changing microbiomes of marine taxa indicates that there is an important nexus of interaction between the environment, host organisms, and their internal microbial communities (e.g., Banker and Vermeij, 2018, Banker and Coil 2020).
This study aims to investigate the role of environmental factors, including ocean acidification and microbial community composition, in shaping shell development in juveniles of the Pacific oyster. Through controlled environmental manipulations and detailed analyses of shell morphology, gene expression, and microbial communities, we aim to unravel the complex interplay between abiotic factors and biological processes underlying shell mineralization.
In the first phase of this work we manipulated experimental tanks in order to investigated the role of sulfate-reducing bacteria in shell formation of Pacific oysters (Magallana gigas) (Banker et al., 2022b). Contrary to expectations, attempting to inhibit these bacteria using sodium molybdate did not uniformly suppress sulfate-reducing bacteria; instead, oysters exposed to the inhibitor exhibited larger shell growth. Microbiome and gene expression analysis revealed distinct differences initially that converged over time. This suggests that oysters may regulate microbiome dysbiosis, which in turn lead to the differential growth of shell material between the two treatment groups. Overall, these results underscore that there is a complex relationship between microbiota and their host organisms that is important to host health (e.g. shell formation) that is susceptible to changing environmental conditions. Taken together with predicted trajectories for global change, these facts taken together point to a need to better understand this relationship to conserve marine species that are both ecologically and economically important.
This work is supported by the UC Davis Microbiome Special Research Program. Proposal co-written by myself and senior PIs, Drs. David Gold and Jay Stachowicz.
Concluded projects
Formation and function of chalky calcite in the Pacific oyster shell |
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The molluscan shell is a generally external, calcium carbonate skeleton that is secreted by the animal. It has been hypothesized, however, that the soft, chalky deposits interspersed in oyster shells are the result of microbially-induced mineralization (Vermeij, 2014). Specifically, it is the result of bacterial sulfate-reduction affecting the carbonate chemistry within the calcifying space. The goal of my dissertation was to evaluate if, and to what extent, sulfate-reducing bacteria affect chalk formation in the Pacific oyster, and to better characterize the ecological function of chalk in oysters. I utilized next generation sequencing, x-ray computed tomography (CT) scans, and statistical tools to address these questions. Results from my dissertation did not support the hypothesis that sulfate-reducing bacteria are responsible for the unique morphology of chalk in oysters, however, my work indicated that internal microbial community composition does affect shell growth (Banker and Vermeij, 2018; Banker and Coil, 2020). Results from CT scan analysis (Banker and Sumner, 2020) provides novel insight into the functional morphology of chalk producing oysters and bivalves more generally, which will aid study of geochemical records from modern and fossil shells. Although outstanding questions remain, a better understanding of how host-microbiome affect host health is essential for fostering sustainable and economically successful aquaculture operations, particularly in the context of climate change.
This work was supported by funds from the Geological Society of America, the American Malacological Society, the Oceanography Society, and the University of California, Davis. |
Individual of the Pacific oyster, Magallana gigas (formerly Crassostrea gigas).
Mesh cages used to house juvenile Pacific oysters in Bodega Harbor, Bodega Bay, CA.
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