THE BURGESS LAB
Florida State University, Department of Biological Science
Scott, Marília, and Jackson working on the seagrass beds near Dog Island (in the Florida “winter”)
Scott and Jackson collecting genetic samples on the fore reef in Moorea, French Polynesia
The crew (Erika, Danie, Scott, Jackson, and Erica) meeting up for their album cover photoshoot
Scott, Marília, and Jackson working on the seagrass beds near Dog Island (in the Florida “winter”)
Welcome to the Burgess Lab website. We are part of the Ecology and Evolution section of the Department of Biological Science at Florida State University. We are broadly interested in the connections between life history evolution, dispersal, population genetics, and quantitative genetics. We study coastal marine invertebrates, including bryozoans, corals, and mollusks, and typically use some combination of experimental (field and lab), molecular genetic, and theoretical approaches.
Check out our research, people, and publications pages for more details on our lab and our prospective students page to see if we are actively recruiting students.
Posts
January 10, 2024
2023, Zootaxa https://www.mapress.com/zt/article/view/zootaxa.5369.1.5
Erika Johnston, Scott Burgess
Abstract: Pocillopora tuahiniensis sp. nov. is described based on mitochondrial and nuclear genomic data, algal symbiont genetic data, geographic isolation, and its distribution pattern within reefs that is distinct from other sympatric Pocillopora species (Johnston et al. 2022a, b). Mitochondrial and nuclear genomic data reveal that P. tuahiniensis sp. nov. is a unique species, sister to P. verrucosa, and in a clade different from that of P. meandrina (Johnston et al. 2022a). However, the gross in situ colony appearance of P. tuahiniensis sp. nov. cannot easily be differentiated from that of P. verrucosa or P. meandrina at Mo’orea. By sequencing the mtORF region, P. tuahiniensis sp. nov. can be easily distinguished from other Pocillopora species. Pocillopora tuahiniensis sp. nov. has so far been sampled in French Polynesia, Ducie Island, and Rapa Nui (Armstrong et al. 2023; Edmunds et al. 2016; Forsman et al. 2013; Gélin et al. 2017; Mayfield et al. 2015; Oury et al. 2021; Voolstra et al. 2023). On the fore reefs of Mo’orea, P. tuahiniensis sp. nov. is very abundant ≥10 m and is one of the most common Pocillopora species at these depths (Johnston et al. 2022b). It can also be found at a much lower abundance at shallow depths on the fore reef and back reef lagoon. The holotype is deposited at the Smithsonian Institution as USNM-SI 1522390 and the mtORF Genbank accession number is OP418359.
January 06, 2023
2023, Nature Communications https://doi.org/10.1038/s41467-022-35550-5
ASJ Wyatt, JJ Leichter, L Washburn, L Kui, PJ Edmunds, SC Burgess
Abstract: The severity of marine heatwaves (MHWs) that are increasingly impacting ocean ecosystems, including vulnerable coral reefs, has primarily been assessed using remotely sensed sea-surface temperatures (SSTs), without information relevant to heating across ecosystem depths. Here, using a rare combination of SST, high-resolution in-situ temperatures, and sea level anomalies observed over 15 years near Moorea, French Polynesia, we document subsurface MHWs that have been paradoxical in comparison to SST metrics and associated with unexpected coral bleaching across depths. Variations in the depth range and severity of MHWs was driven by mesoscale (10s to 100s of km) eddies that altered sea levels and thermocline depths and decreased (2007, 2017 and 2019) or increased (2012, 2015, 2016) internal-wave cooling. Pronounced eddy-induced reductions in internal waves during early 2019 contributed to a prolonged subsurface MHW and unexpectedly severe coral bleaching, with subsequent mortality offsetting almost a decade of coral recovery. Variability in mesoscale eddy fields, and thus thermocline depths, is expected to increase with climate change, which, along with strengthening and deepening stratification, could increase the occurrence of subsurface MHWs over ecosystems historically insulated from surface ocean heating by the cooling effects of internal waves
December 20, 2022
2022, BioRxiv https://doi.org/10.1101/2022.12.19.521131
James H. Peniston, Scott C. Burgess
Abstract: Dispersal emerges as an outcome of organismal traits and external forcings. However, it remains unclear how the emergent dispersal kernel evolves as a by-product of selection on the underlying traits. This question is particularly compelling in coastal marine systems where dispersal is tied to development and reproduction, and where directional currents bias larval dispersal downstream causing selection for retention. We modelled the dynamics of a metapopulation along a finite coastline using an integral projection model and adaptive dynamics to understand how asymmetric coastal currents influence the evolution of larval (pelagic larval duration) and adult (spawning frequency) life history traits, which indirectly shape the evolution of dispersal kernels. Selection induced by unidirectional currents favors the release of larvae over multiple time periods, allowing long pelagic larval durations and long-distance dispersal to be maintained in marine life cycles in situations where they were previously predicted to be selected against. Two evolutionary stable strategies emerged: one with a long pelagic larval duration and many spawning events resulting in a dispersal kernel with a larger mean and variance, and another with a short pelagic larval duration and few spawning events resulting in a dispersal kernel with a smaller mean and variance. Our theory shows how the statistics of coastal ocean flows are important agents of selection that can generate multiple, often co-occurring, evolutionary outcomes for marine life history traits that affect dispersal.
December 07, 2022
2022, Biology Letters https://doi.org/10.1098/rsbl.2022.0414
Peter J Edmunds, Kelly W Johnson, Scott C. Burgess
Abstract: For nearly 50 years, analyses of coral physiology have used small coral fragments (nubbins) to make inferences about larger colonies. However, scaling in corals shows that linear extrapolations from nubbins to whole colonies can be misleading, because polyps in nubbins are divorced of their morphologically complex and physiologically integrated corallum. We tested for the effects of integration among branches in determining size-dependent calcification of the coral Pocillopora spp. under elevated PCO2. Area-normalized net calcification was compared between branches (nubbins), aggregates of nubbins (complex morphologies without integration) and whole colonies (physiologically integrated) at 400 versus approximately 1000 µatm PCO2. Net calcification was unaffected by PCO2, but differed among colony types. Single nubbins grew faster than whole colonies, but when aggregated, nubbins changed calcification to match whole colonies even though they lacked integration among branches. Corallum morphology causes the phenotype of branching corals to differ from the summation of their branches.
August 10, 2022
2022, Molecular Ecology https://doi.org/10.1111/mec.16654
Erika C. Johnston, Ross Cunning, Scott C. Burgess
Abstract: The congruence between phylogenies of tightly associated groups of organisms (cophylogeny) reflects evolutionary links between ecologically important interactions. However, despite being a classic example of an obligate symbiosis, tests of cophylogeny between scleractinian corals and their photosynthetic algal symbionts have been hampered in the past because both corals and algae contain genetically unresolved and morphologically cryptic species. Here, we studied co-occurring, cryptic Pocillopora species from Mo’orea, French Polynesia, that differ in their relative abundance across depth. We constructed new phylogenies of the host Pocillopora (using complete mitochondrial genomes, genomic loci, and thousands of single nucleotide polymorphisms) and their Symbiodiniaceae symbionts (using ITS2 and psbAncr markers) and tested for cophylogeny. The analysis supported the presence of five Pocillopora species on the fore-reef at Mo’orea that mostly hosted either Cladocopium latusorum or C. pacificum. Only Pocillopora species hosting C. latusorum also hosted taxa from Symbiodinium and Durusdinium. In general, the Cladocopium phylogeny mirrored the Pocillopora phylogeny. Within Cladocopium species, lineages also differed in their associations with Pocillopora haplotypes, except those showing evidence of nuclear introgression, and with depth in the two most common Pocillopora species. We also found evidence for a new Pocillopora species (haplotype 10), that has so far only been sampled from French Polynesia, that warrants formal identification. The linked phylogenies of these Pocillopora and Cladocopium species and lineages suggest that symbiont speciation is driven by niche diversification in the host, but there is still evidence for symbiont flexibility in some cases.
August 10, 2022
2022, Coral Reefs https://doi.org/10.1007/s00338-021-02107-9
Erika C. Johnston, Alex S.J Wyatt, James J. Leichter, Scott C. Burgess
Abstract: Cryptic species that are morphologically similar co-occur because either the rate of competitive exclusion is very slow, or because they are not, in fact, ecologically similar. The processes that maintain cryptic local diversity may, therefore, be particularly subtle and difficult to identify. Here, we uncover differences among several cryptic species in their relative abundance across a depth gradient within a dominant and ecologically important genus of hard coral, Pocillopora. From extensive sampling unbiased toward morphological characters, at multiple depths on the fore reef around the island of Mo’orea, French Polynesia, we genetically identified 673 colonies in the Pocillopora species complex. We identified 14 mitochondrial Open Reading Frame haplotypes (mtORFs, a well-studied and informative species marker used for pocilloporids), which included at least six nominal species, and uncovered differences among haplotypes in their relative abundance at 5, 10, and 20 m at four sites around the island. Differences in relative haplotype abundance across depths were greater than differences among sites separated by several kilometers. The four most abundant species are often visibly indistinguishable at the gross colony level, yet they exhibited stark differences in their associations with light irradiance and daily water temperature variance. The pattern of community composition was associated with frequent cooling in deeper versus shallower water more than warmer temperatures in shallow water. Our results indicate that these cryptic species are not all ecologically similar. The differential abundance of Pocillopora cryptic species across depth should promote their coexistence at the reef scale, as well as promote resilience through response diversity.
July 19, 2022
Scott C. Burgess, Jackson Powell, Marília Bueno.
2022, Ecology https://doi.org/10.1002/ecy.3858
Abstract: Dispersal has far-reaching implications for individuals, populations, and communities, especially in sessile organisms. Escaping competition with conspecifics and with kin are theorized to be key factors leading to dispersal as an adaptation. However, manipulative approaches in systems where adults are sessile but offspring have behaviors is required for a more complete understanding of how competition affects dispersal. Here, we integrate a series of experiments to study how dispersal affects the density and relatedness of neighbors, and how the density and relatedness of neighbors in turn affects fitness. In a marine bryozoan, we empirically estimated dispersal kernels and found that most larvae settled within ~1 m of the maternal colony, though some could potentially travel at least 10’s of meters. Larvae neither actively preferred or avoided conspecifics or kin at settlement. We experimentally determined the effects of spreading sibling larvae by manipulating the density and relatedness of settlers and measuring components of fitness in the field. We found that settler density reduced maternal fitness when settler neighbors were siblings compared to when neighbors were unrelated or absent. Genetic markers also identified very few half sibs (and no full sibs) in adults from the natural population, and rarely close enough to directly interact. In this system, dispersal occurs over short distances (meters) yet, in contrast to expectations, there appears to be limited kinship between adult neighbors. Our results suggest that the limited dispersal increases early offspring mortality when siblings settle next to each other, rather than next to unrelated conspecifics, potentially reducing kinship in adult populations. High offspring production and multiple paternity could further dilute kinship at settlement and reduce selection for dispersal beyond the scale of 10’s of meters.
July 19, 2022
Scott C. Burgess, Michael Bode, Jeffrey M. Leis, Luciano B. Mason
2022, Oikos https://doi.org/10.1111/oik.08896
Abstract: Dispersal emerges as a consequence of how an individual's phenotype interacts with the environment. Not all dispersing individuals have the same phenotype, and variation among individuals can generate complex variation in the distribution of dispersal distances and directions. While active locomotion performance is an obvious candidate for a dispersal phenotype, its effects on dispersal are difficult to measure or predict, especially in small organisms dispersing in wind or currents. Therefore, we analyzed the effects of larval swimming on dispersal and settlement of coral-reef fish larvae using a high-resolution biophysical model. The model is, to date, the only biophysical model of marine larval dispersal that has been statistically validated against genetic parentage estimates of larval origin and destination, and incorporates empirically-estimated larval behaviors and their ontogeny. Larval swimming, in combination with depth, orientation and navigation behaviors, actually reduced dispersal distances compared to those of passive larvae. Swimming had no consistent effects on long distance dispersal, but increased the spread of settlement locations. Swimming speed, in contrast, did not consistently affect median dispersal distances, but faster swimming larvae had greater mean and maximum dispersal distances than slower swimming larvae. Finally, faster larval swimming speeds consistently increased the probability of settlement. Our analysis shows how larval swimming differentially affects multiple properties of dispersal kernels. In doing so, it indicates how selection could favor faster larval swimming to increase settlement and local retention, which may actually result in longer dispersal distances as a by-product of larvae trying to locate habitat rather than to disperse greater distances.