Biology subjects

Paz-Garcia, D. A.

Publications and source records attributed to Paz-Garcia, D. A..

5 recordsLinked to original sources

bioRxiv2026

Within-colony microbial response of three species with different susceptibility to Stony Coral Tissue Loss Disease

Stony coral tissue loss disease (SCTLD), a coral pathology with rapid tissue loss and high mortality rate has affected nearly 30 species with a variable degree of susceptibility across species. It has been suggested that SCTLD has a systemic effect within coral colonies, but little is known about within-colony changes of the microbial communities associated with this disease. Here we evaluate the microbial shifts within coral colonies: apparently healthy tissue and SCTLD tissue. The study was done in three species following a gradient of susceptibility to the disease: Dendrogyra cylindrus (Dcyl, n = 11) and Pseudodiploria strigosa (Pstr, n = 6) two highly susceptible species; and Orbicella faveolata (Ofav, n = 8), a moderately affected species. 16S rRNA Illumina sequences analysis showed differential microbial community structure within two species (Dcyl, p = 0.01, Pstr, p = 0.01) but not for Ofav (p = 0.28). Taxonomic profiles of bacterial groups were species-specific in SCTLD tissue, but healthy tissue shared similarities between species including Pirelullales, NB1-J and SAR324. Our results reveal that the microbial communities effects associated to the disease follow a similar pattern to the species susceptibility to SCTLD, providing new insights into the disease dynamics in the Mexican Caribbean.

microbiology↗

bioRxiv2026

Diversity, host-specificity, and environmental drivers of the coral reef eukaryome

Coral reefs are among the most diverse ecosystems on Earth, yet the diversity and structure of their associated microeukaryotic communities remain poorly resolved. We characterized reef-associated eukaryomes across 113 reefs spanning the Pacific Ocean using more than 6,300 samples from corals, seawater, and sediments during the Tara Pacific expedition. We identified [~]121,000 eukaryotic ASVs, revealing one of Earths largest undocumented reservoirs of eukaryotic diversity; over 80% of the recovered diversity was previously undetected in global ocean surveys and fewer than 2% of sequences matched reference databases. Reef habitats supported highly distinct communities, with sediments and seawater harboring 20-40-fold higher richness than corals. Unexpectedly, coral-associated communities across 29 host lineages were consistently dominated by small metazoans, particularly demosponges and maxillopods, identifying these taxa as pervasive and previously unrecognized components of coral eukaryomes alongside Apicomplexa. Across the Pacific, eukaryome composition was strongly structured by environmental gradients, with thermal stress emerging as the primary driver of community turnover. Together, these results identify coral reefs as a globally important reservoir of hidden eukaryotic diversity and reveal the reef eukaryome as a sensitive indicator of ecosystem reorganization under climate change.

systems biology↗

bioRxiv2025

Tropicalisation of rocky shore gastropod communities along the Baja California Peninsula

Tropicalisation is rapidly restructuring marine communities globally. Despite extensive research in subtidal habitats, the extent of tropicalisation and its impact on rocky intertidal communities remains poorly understood. Here we integrated contemporary field surveys with genetic barcoding, historic surveys, museum collections, and fossil records to document changes in the rocky shore gastropod communities along 8 degrees of latitude (approximately 3,120 km of coastline) of the Baja California Peninsula. We detected poleward range expansions of 30 tropical and subtropical species, and trailing-edge retractions of 13 temperate species, with some range shifts occurring across long-standing biogeographic boundaries. Fossil evidence reveals that several range-extending species previously occupied latitudes beyond their modern distributions during Pleistocene warm periods, suggesting that contemporary expansions echo historical responses to climatic warming, albeit under accelerated rates. Using Lottia gigantea as a case study, we demonstrated early range retractions can be marked by shifts in size-frequency distributions demonstrating declines in abundance, and loss of small individuals suggestive of reduced recruitment. We showed that rocky intertidal systems are sensitive to climate-driven range shifts, and highlighted the importance of integrating historical, palaeontological and contemporary data to detect early ecological and evolutionary consequences of tropicalisation. Continued monitoring combined with molecular approaches is crucial for predicting and managing biodiversity responses under ongoing climate change.

ecology↗

bioRxiv2024

Microbiomes of three coral species in the Mexican Caribbean and their shifts associated with the Stony Coral Tissue Loss Disease

Stony Coral Tissue Loss Disease (SCTLD) has caused widespread coral mortality in the Caribbean Region. However, how the disease presence alters the microbiome community, their structure, composition, and metabolic functionality is still poorly understood. In this study, we characterized the microbial communities of the tissues of apparently healthy and diseased SCTLD colonies of the species Siderastrea siderea, Orbicella faveolata, and Montastraea cavernosa to explore putative changes related to the presence of SCTLD. Gammaproteobacteria, Alphaproteobacteria, and Bacteroidia were the best represented classes in the healthy tissues of all coral species, and alpha diversity did not show significant differences among the species. The microbial community structure between coral species was significantly different (PERMANOVA: F=3.46, p=0.001), and enriched genera were detected for each species: Vibrio and Photobacterium in S. siderea, Spirochaeta2 and Marivivens in O. faveolata and SAR202_clade and Nitrospira in M. cavernosa. Evidence of SCTLD in the microbial communities was more substantial in S. siderea, where differences in alpha diversity, beta diversity, and functional profiles were observed. In O. faveolata, differences were detected only in the community structure, while M. cavernosa samples showed no significant difference. Several microbial groups were found to have enriched abundances in tissue from SCTLD lesions from S. siderea and O. faveolata, but no dominant bacterial group was detected. Our results contribute to understanding microbial diversity associated with three scleractinian coral species and the shifts in their microbiomes associated with SCTLD in the Mexican Caribbean.

microbiology↗

bioRxiv2022

Disparate patterns of genetic divergence in three widespread corals across a pan-Pacific environmental gradient highlights species-specific adaptation trajectories.

Tropical coral reefs are among the worst affected ecosystems by climate change with predictions ranging between a 70-90% loss of reefs in the coming decades. Effective conservation strategies that maximize ecosystem resilience, and potential for recovery, must be informed by the accurate characterization of extant genetic diversity and population structure together with an understanding of the adaptive potential of keystone species. Here, we analyzed samples from the Tara Pacific Expedition (2016 to 2018) that completed an 18,000 km longitudinal transect of the Pacific Ocean sampling three widespread corals - Pocillopora meandrina, Porites lobata, and Millepora cf. platyphylla - across 33 sites from 11 islands. Using deep metagenomic sequencing of 269 colonies in conjunction with morphological analyses and climate variability data we can show that the sampled transect encompasses multiple morphologically cryptic species that exhibit disparate biogeographic patterns, and most importantly, distinct evolutionary patterns, despite exposure to identical environmental regimes. Our findings demonstrate on a basin-scale that evolutionary trajectories are species-specific and complex, and can only in part be predicted from the environment. This highlights that conservation strategies must integrate multi-species investigations to consider the distinct genomic footprints shaped by selection as well as the genetic potential for adaptive change.

genetics↗