Professional Education


  • Master of Science, Unlisted School (2011)
  • Doctor of Philosophy, University of California Davis (2018)
  • Bachelor of Arts, Lawrence University (2008)

Stanford Advisors


All Publications


  • "Reference genome assembly of the sunburst anemone, Anthopleura sola". The Journal of heredity Cornwell, B. H., Beraut, E., Fairbairn, C., Nguyen, O., Marimuthu, M. P., Escalona, M., Toffelmier, E. 2022

    Abstract

    The sunburst anemone Anthopleura sola is an abundant species inhabiting the intertidal zone of coastal California. Historically, this species has extended from Baja California, Mexico to as far north as Monterey Bay, CA. However, recently the geographic range of this species has expanded to Bodega Bay, CA, possibly as far north as Salt Point, CA. This species also forms symbiotic partnerships with the dinoflagellate Breviolum muscatinei, a member of the family Symbiodiniaceae. These partnerships are analogous to those formed between tropical corals and dinoflagellate symbionts, making A. sola an excellent model system to explore how hosts will (co)evolve with novel symbiont populations they encounter as they expand northward. This assembly will serve as the foundation for identifying the population genomic patterns associated with range expansions, and will facilitate future work investigating how hosts and their symbiont partners will evolve to interact with one another as geographic ranges shift due to climate change.

    View details for DOI 10.1093/jhered/esac050

    View details for PubMedID 36074002

  • From coral reefs to Joshua trees: What ecological interactions teach us about the adaptive capacity of biodiversity in the Anthropocene. Philosophical transactions of the Royal Society of London. Series B, Biological sciences Lagerstrom, K. M., Vance, S., Cornwell, B. H., Ruffley, M., Bellagio, T., Exposito-Alonso, M., Palumbi, S. R., Hadly, E. A. 2022; 377 (1857): 20210389

    Abstract

    The pervasive loss of biodiversity in the Anthropocene necessitates rapid assessments of ecosystems to understand how they will respond to anthropogenic environmental change. Many studies have sought to describe the adaptive capacity (AC) of individual species, a measure that encompasses a species' ability to respond and adapt to change. Only those adaptive mechanisms that can be used over the next few decades (e.g. via novel interactions, behavioural changes, hybridization, migration, etc.) are relevant to the timescale set by the rapid changes of the Anthropocene. The impacts of species loss cascade through ecosystems, yet few studies integrate the capacity of ecological networks to adapt to change with the ACs of its species. Here, we discuss three ecosystems and how their ecological networks impact the AC of species and vice versa. A more holistic perspective that considers the AC of species with respect to their ecological interactions and functions will provide more predictive power and a deeper understanding of what factors are most important to a species' survival. We contend that the AC of a species, combined with its role in ecosystem function and stability, must guide decisions in assigning 'risk' and triaging biodiversity loss in the Anthropocene. This article is part of the theme issue 'Ecological complexity and the biosphere: the next 30 years'.

    View details for DOI 10.1098/rstb.2021.0389

    View details for PubMedID 35757872

  • Persistence of phenotypic responses to short-term heat stress in the tabletop coral Acropora hyacinthus. PloS one Walker, N. S., Cornwell, B. H., Nestor, V., Armstrong, K. C., Golbuu, Y., Palumbi, S. R. 2022; 17 (9): e0269206

    Abstract

    Widespread mapping of coral thermal resilience is essential for developing effective management strategies and requires replicable and rapid multi-location assays of heat resistance and recovery. One- or two-day short-term heat stress experiments have been previously employed to assess heat resistance, followed by single assays of bleaching condition. We tested the reliability of short-term heat stress resistance, and linked resistance and recovery assays, by monitoring the phenotypic response of fragments from 101 Acropora hyacinthus colonies located in Palau (Micronesia) to short-term heat stress. Following short-term heat stress, bleaching and mortality were recorded after 16 hours, daily for seven days, and after one and two months of recovery. To follow corals over time, we utilized a qualitative, non-destructive visual bleaching score metric that correlated with standard symbiont retention assays. The bleaching state of coral fragments 16 hours post-heat stress was highly indicative of their state over the next 7 days, suggesting that symbiont population sizes within corals may quickly stabilize post-heat stress. Bleaching 16 hours post-heat stress predicted likelihood of mortality over the subsequent 3-5 days, after which there was little additional mortality. Together, bleaching and mortality suggested that rapid assays of the phenotypic response following short-term heat stress were good metrics of the total heat treatment effect. Additionally, our data confirm geographic patterns of intraspecific variation in Palau and show that bleaching severity among colonies was highly correlated with mortality over the first week post-stress. We found high survival (98%) and visible recovery (100%) two months after heat stress among coral fragments that survived the first week post-stress. These findings help simplify rapid, widespread surveys of heat sensitivity in Acropora hyacinthus by showing that standardized short-term experiments can be confidently assayed after 16 hours, and that bleaching sensitivity may be linked to subsequent survival using experimental assessments.

    View details for DOI 10.1371/journal.pone.0269206

    View details for PubMedID 36084033

  • Widespread variation in heat tolerance and symbiont load are associated with growth tradeoffs in the coral Acropora hyacinthus in Palau. eLife Cornwell, B., Armstrong, K., Walker, N. S., Lippert, M., Nestor, V., Golbuu, Y., Palumbi, S. R. 2021; 10

    Abstract

    Climate change is dramatically changing ecosystem composition and productivity, leading scientists to consider the best approaches to map natural resistance and foster ecosystem resilience in the face of these changes. Here we present results from a large-scale experimental assessment of coral bleaching resistance, a critical trait for coral population persistence as oceans warm, in 221 colonies of the coral Acropora hyacinthus across 37 reefs in Palau. We find that bleaching resistant individuals inhabit most reefs but are found more often in warmer microhabitats. Our survey also found wide variation in symbiont concentration among colonies, and that colonies with lower symbiont load tended to be more bleaching resistant. By contrast, our data show that low symbiont load comes at the cost of lower growth rate, a tradeoff that may operate widely among corals across environments. Corals with high bleaching resistance have been suggested as a source for habitat restoration or selective breeding in order to increase coral reef resilience to climate change. Our maps show where these resilience corals can be found, but the existence of tradeoffs with heat resistance may suggest caution in unilateral use of this one trait in restoration.

    View details for DOI 10.7554/eLife.64790

    View details for PubMedID 34387190

  • Genetic structure in the endosymbiont Breviolum 'muscatinei' is correlated with geographical location, environment and host species PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Cornwell, B. H., Hernandez, L. 2021; 288 (1946): 20202896

    Abstract

    Corals and cnidarians form symbioses with dinoflagellates across a wide range of habitats from the tropics to temperate zones. Notably, these partnerships create the foundation of coral reef ecosystems and are at risk of breaking down due to climate change. This symbiosis couples the fitness of the partners, where adaptations in one species can benefit the holobiont. However, the scales over which each partner can match their current-and future-environment are largely unknown. We investigated population genetic patterns of temperate anemones (Anthopleura spp.) and their endosymbiont Breviolum 'muscatinei', across an extensive geographical range to identify the spatial scales over which local adaptation is possible. Similar to previously published results, two solitary host species exhibited isolation by distance across hundreds of kilometres. However, symbionts exhibited genetic structure across multiple spatial scales, from geographical location to depth in the intertidal zone, and host species, suggesting that symbiont populations are more likely than their hosts to adaptively mitigate the impact of increasing temperatures.

    View details for DOI 10.1098/rspb.2020.2896

    View details for Web of Science ID 000627840400012

    View details for PubMedID 33715441

    View details for PubMedCentralID PMC7944108

  • Investing in Blue Natural Capital to Secure a Future for the Red Sea Ecosystems FRONTIERS IN MARINE SCIENCE Cziesielski, M. J., Duarte, C. M., Aalismail, N., Al-Hafedh, Y., Anton, A., Baalkhuyur, F., Baker, A. C., Balke, T., Baums, I. B., Berumen, M., Chalastani, V. I., Cornwell, B., Daffonchio, D., Diele, K., Farooq, E., Gattuso, J., He, S., Lovelock, C. E., McLeod, E., Macreadie, P. I., Marba, N., Martin, C., Muniz-Barreto, M., Kadinijappali, K. P., Prihartato, P., Rabaoui, L., Saderne, V., Schmidt-Roach, S., Suggett, D. J., Sweet, M., Statton, J., Teicher, S., Trevathan-Tackett, S. M., Joydas, T. V., Yahya, R., Aranda, M. 2021; 7
  • Gene flow in the anemone Anthopleura elegantissima limits signatures of local adaptation across an extensive geographic range. Molecular ecology Cornwell, B. H. 2020

    Abstract

    Species inhabiting marine environments face a wide range of environmental conditions that vary spatially across several orders of magnitude. The selective pressures that these conditions impose on marine organisms, in combination with potentially high rates of gene flow between distant populations, make it difficult to predict the extent to which these populations can locally adapt. Here, I identify how selection and gene flow influence the population genetic structure of the anemone Anthopleura elegantissima along the Pacific coast of North America. Isolation-by-distance is the dominant pattern across the range of this species, with a genetic break near Pt. Conception, CA. Furthermore, demographic modeling suggests that this species was historically confined to southerly latitudes before expanding northward. Outlier analyses identify 24 loci under selection (out of ~1,100), but the same analysis on simulated genetic data generated using the most likely demographic model erroneously identified the same number of loci under selection, if not more. Taken together, these results suggest that demographic processes are the dominant force shaping population genetic patterns in A. elegantissima along the Pacific coast of North America. I discuss these patterns in terms of the evolutionary history of A. elegantissima, the potential for local adaptation, and their consequences with respect to interactions with the endosymbiont Breviolum muscatinei across their geographic range.

    View details for DOI 10.1111/mec.15506

    View details for PubMedID 32525589