About

Professor Kaustuv Roy leads a research group at the University of California San Diego focused on understanding the processes that generate and maintain large-scale spatial gradients in biodiversity, how these gradients are impacted by climate change and anthropogenic effects such as human harvesting, and the ecological and evolutionary consequences of these changes. His lab employs an interdisciplinary approach, studying coastal marine invertebrates and their associated microbial taxa, or microbiomes, to address these questions. A central theme of the research is the latitudinal diversity gradient (LDG), a global pattern of increasing species richness from the poles to the tropics, which remains incompletely understood despite numerous hypotheses. Roy's work includes testing existing hypotheses and developing new models, such as the "Out of the Tropics" model that integrates evolutionary processes with biogeographical dynamics to provide insights into the origin and maintenance of the LDG. The lab also investigates molluscan microbiomes, recognizing microbes as the most diverse and abundant organisms that influence physiology, metabolism, ecological systems, and biogeochemical processes. Roy's group quantifies how marine mollusk microbiomes vary across spatial and environmental gradients, their functional consequences, evolutionary patterns, and responses to anthropogenic impacts like coastal eutrophication and climate change. Additionally, the lab studies the biotic effects of climate change, focusing on ecological and evolutionary responses such as species range shifts and community composition changes. Using data from glacial-interglacial cycles of the late Pleistocene, molecular markers, geochemical data, and phenotypic measurements, the research aims to identify species vulnerable or resilient to future warming. Further research explores the dynamics of extinctions, comparing anthropogenic extinctions with natural past events to understand how human-caused losses affect phenotypic diversity and evolutionary histories, using simulation models and empirical data from marine and terrestrial mollusks. The lab also addresses conservation issues related to the harvesting of coastal marine invertebrates, which is often size-selective and targets large individuals. This selective harvesting represents a novel evolutionary force, and the lab investigates its biological consequences, including impacts on life histories, phenotypic traits, local extinctions, population structures, macroecological relationships, and biogeographic patterns, using coastal marine mollusks as a model system.

Research topics

• Biology
• Ecology
• Computer Science
• Mineralogy
• Oceanography
• Computational biology
• Geology
• Genetics
• Evolutionary biology
• Environmental science
• Bioinformatics

Selected publications

• First Report of the Shell-Surface and Internal Microbiomes of the California Spiny Lobster, Panulirus interruptus

  Journal of Shellfish Research · 2025-01-01 · 1 citations

  articleSenior author

  Microbial communities associated with marine invertebrates play a key role in the health and functioning of their host. In decapod crustaceans, the microbiome is heavily implicated in both disease prevention and pathogenesis, among other functions. Despite this, the microbial communities of most decapod hosts remain largely unexamined, including those of the commercially and ecologically important California spiny lobster (Panulirus interruptus). This study uses 16S rRNA amplicon sequencing to investigate the composition and diversity of the microbial communities associated with internal tissues and external surfaces of California spiny lobsters from San Diego County, CA. Results show that P. interruptus harbors diverse, tissue-specific microbial communities, including many taxa not yet reported from other decapod crustaceans. Notably, members of the genus Aquimarina, a bacterial genus associated with lobster disease, were common on the surface of the carapace, though the functional role of this organism in the P. interruptus microbiome is unclear. Overall, these results act as a baseline for further investigation of the microbiomes of other populations of the California spiny lobster, especially given the presence of multiple clades known to harbor invertebrate pathogens.

  PublisherDOI

• Temporal trends in allometry of shell calcification in northeastern Pacific venerid bivalves: implications for predicting responses to climate change

  Biology Letters · 2025-08-01

  articleSenior authorCorresponding

  Despite literature spanning almost a century, how allometric relationships of phenotypic traits behave over evolutionary time remains poorly known for most marine species. In particular, the fossil record is seriously underutilized in this context despite harbouring a rich archive of traits. Here we use the late Pleistocene fossil record in San Diego, California, in conjunction with archival and field collected specimens, to quantify temporal changes in allometric relationships between shell size and calcification, two important functional traits, in five different species of marine bivalves. Our results reject the traditional hypothesis that allometric relationships are invariant over time. They also show that temporal changes in allometric relationships are species-specific, with closely related species showing divergent trends. Finally, we argue that information about the nature of long-term changes in allometric relationships of functionally important traits can provide a powerful yet underappreciated tool for understanding species and population responses to climate change.

  PublisherDOI

• Author response for "Temporal trends in allometry of shell calcification in northeastern Pacific venerid bivalves: implications for predicting responses to climate change"

  2025-06-26

  peer-reviewSenior author
  PublisherDOI

• Education, "Artificial" Intelligence, and Cognition

  2025-01-01

  bookOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Microbiome divergence of marine gastropod species separated by the Isthmus of Panama

  Applied and Environmental Microbiology · 2024-10-31

  articleOpen accessSenior author

  ABSTRACT The rise of the Isthmus of Panama separated the populations of many marine organisms, which then diverged into new geminate sister species currently living in the Eastern Pacific Ocean and the Caribbean Sea. However, we know very little about how such evolutionary divergences of host species have shaped the compositions of their microbiomes. Here, we compared the microbiomes of whole-body and shell-surface samples of geminate species of marine gastropods in the genera Cerithium and Cerithideopsis to those of congeneric outgroups. Our results suggest that the effects of ~3 million years of separation and isolation on microbiome composition varied among host genera and between sample types within the same hosts. In the whole-body samples, microbiome compositions of geminate species pairs tended to be similar, likely due to host filtering, although the strength of this relationship varied among the two groups and across similarity metrics. Shell-surface microbiomes show contrasting patterns, with co-divergence between the host taxa and a small number of microbial clades evident in Cerithideopsis but not Cerithium . These results suggest that (i) isolation of host populations after the rise of the Isthmus of Panama affected microbiomes of geminate hosts in a complex and host-specific manner, and (ii) host-associated microbial taxa respond differently to vicariance events than the hosts themselves. IMPORTANCE While considerable work has been done on evolutionary divergences of marine species in response to the rise of the Isthmus of Panama, which separated two previously connected oceans, how this event shaped the microbiomes of these marine hosts remains poorly known. Using whole-body and shell-surface microbiomes of closely related gastropod species from opposite sides of the Isthmus, we show that divergences of microbial taxa after the formation of the Isthmus are often not concordant with those of their gastropod hosts. Our results show that evolutionary responses of marine gastropod-associated microbiomes to major environmental perturbations are complex and are shaped more by local environments than host evolutionary history.

  PublisherOA PDFDOI

• Populism and the Death of Imagination

  2024-01-01

  book-chapter1st authorCorresponding
  PublisherDOI

• Diversity, distribution and intrinsic extinction vulnerability of exploited marine bivalves

  Nature Communications · 2023-08-15 · 31 citations

  articleOpen access

  Marine bivalves are important components of ecosystems and exploited by humans for food across the world, but the intrinsic vulnerability of exploited bivalve species to global changes is poorly known. Here, we expand the list of shallow-marine bivalves known to be exploited worldwide, with 720 exploited bivalve species added beyond the 81 in the United Nations FAO Production Database, and investigate their diversity, distribution and extinction vulnerability using a metric based on ecological traits and evolutionary history. The added species shift the richness hotspot of exploited species from the northeast Atlantic to the west Pacific, with 55% of bivalve families being exploited, concentrated mostly in two major clades but all major body plans. We find that exploited species tend to be larger in size, occur in shallower waters, and have larger geographic and thermal ranges-the last two traits are known to confer extinction-resistance in marine bivalves. However, exploited bivalve species in certain regions such as the tropical east Atlantic and the temperate northeast and southeast Pacific, are among those with high intrinsic vulnerability and are a large fraction of regional faunal diversity. Our results pinpoint regional faunas and specific taxa of likely concern for management and conservation.

  PublisherOA PDFDOI

• Steps to the Magicology of Art

  2023-01-01

  book-chapter1st authorCorresponding
  PublisherDOI

• Secrets of Color, Secrets of Form

  2023-01-01

  book-chapter1st authorCorresponding
  PublisherDOI

• Ghosts of Uncertainty and the Spirit of Art

  2023-01-01

  book-chapter1st authorCorresponding
  PublisherDOI

Frequent coauthors

• David Jablonski

  University of Chicago

  89 shared

• M Zevenbergen

  University of Notre Dame

  64 shared

• Dmitri E. Nikonov

  Intel (United States)

  64 shared

• Wiliot Ltd

  Intel (United Kingdom)

  64 shared

• Kenji Endo

  64 shared

• Paolo Crovetti

  Polytechnic University of Turin

  64 shared

• Yi Shao

  Oklahoma City University

  64 shared

• A Yehezkely

  University of Notre Dame

  64 shared