Biology subjects

Gomez-Gras, D.

Publications and source records attributed to Gomez-Gras, D..

3 recordsLinked to original sources

bioRxiv2024

Recurrent extreme climatic events are driving gorgonian populations to local extinction: low adaptive potential to marine heatwaves.

Extreme climatic events (ECEs), such as marine heatwaves (MHWs), are a major threat to biodiversity. Understanding the variability in ecological responses to recurrent ECEs within species and underlying drivers arise as a key issue owing to their implications for conservation and restoration. Yet, our knowledge on such ecological responses is limited since it has been mostly gathered following "single-event approaches" focused on one particular event. These approaches provide snapshots of ecological responses but fall short of capturing heterogeneity patterns that may occur among recurrent ECEs, questioning current predictions regarding biodiversity trends. Here, we adopt a "multi-event" perspective to characterize the effects of recurrent ECEs and the ecological responses in Paramuricea clavata, a Mediterranean temperate coral threatened by MHWs. Through a common-garden experiment repeated three consecutive years with the same individuals from three populations, we assessed the respective roles of environmental (year effect), genetic (population effect) and phenotypic (population-by-environment interactions effect) components in the ecological response to recurrent heat stress. The environmental component (year) was the main driver underlying the responses of P. clavata colonies across experiments. To build on this result, we showed that: i) the ecological responses were not related to population (genetic isolation) and individual (multilocus heterozygosity) genetic make-up, ii) while all the individuals were characterized by a high environmental sensitivity (genotype-by-environment interactions) likely driven by in-situ summer thermal regime. We confront our experimental results to in situ monitoring of the same individuals conducted in 2022 following two MHWs (2018, 2022). This confirms that the targeted populations harbor limited adaptive and plastic capacities to on-going recurrent ECEs and that P. clavata might face unavoidable population collapses in shallow Mediterranean waters. Overall, we suggest that biodiversity forecasts based on "single event" experiments may be overly optimistic and underscore the need to consider the recurrence of ECEs in assessing threats to biodiversity.

ecology↗

bioRxiv2022

Apicomplexans predict thermal stress mortality in the Mediterranean coral Paramuricea clavata

The octocoral Paramuricea clavata is an ecosystem architect of the Mediterranean temperate reefs that is currently threatened by episodic mass mortality events related to global warming. Local average thermal regimes nor recent thermal history have been shown to play a significant role in population thermotolerance in this species. The microbiome, however, may play an active role in the thermal stress susceptibility of corals, potentially holding the answer as to why corals show differential sensitivity to heat-stress. To investigate this, the prokaryotic and eukaryotic microbiome of P. clavata collected from around the Mediterranean was characterized before experimental heat-stress to determine if its microbial composition influences the thermal response of the holobiont. We found that the prokaryotic community was not informative in predicting the thermal susceptibility of P. clavata. On the other hand, members of P. clavatas microeukaryotic community were significantly correlated with thermal stress sensitivity. Syndiniales from the Dino-Group I Clade 1 were significantly enriched in thermally resistant corals, while the apicomplexan corallicolids were significantly enriched in thermally susceptible corals. Corallicolids are associated with 70% of coral genera around the world, yet the ecological role of this general anthozoan symbiont has yet to be determined. We hypothesize that P. clavata mortality following heat-stress may be caused by a shift from apparent commensalism to parasitism in the corallicolid-coral host relationship driven by the added stress. Our results show the potential importance of corallicolids and the rest of the microeukaryotic community of corals to understanding thermal stress response in corals and provides a useful tool to guide conservation efforts and future research into coral-associated microeukaryotes.

microbiology↗

bioRxiv2019

The genome sequence of the octocoral Paramuricea clavata - a key resource to study the impact of climate change in the Mediterranean

The octocoral, Paramuricea clavata, is a habitat-forming anthozoan with a key ecological role in rocky benthic and biodiversity-rich communities in the Mediterranean and Eastern Atlantic. Shallow populations of P. clavata in the North-Western Mediterranean are severely affected by warming-induced mass mortality events (MMEs). These MMEs have differentially impacted individuals and populations of P. clavata (i.e. varied levels of tissue necrosis and mortality rates) over thousands of kilometers of coastal areas. The eco-evolutionary processes and genetic factors contributing to these differential responses remain to be characterized. Here, we sequenced a P. clavata individual with short and long read technologies, producing 169.98 Gb of Illumina paired-end and 3.55 Gb of Oxford Nanopore Technologies (ONT) reads. We obtained a de novo hybrid assembly accounting for 712.4 Mb and 107,682 scaffolds. The contig and scaffold N50 are 15.85 Kb and 17.01 Kb, respectively. Despite of the low contiguity of the assembly, the gene completeness was relatively high, including 86% of the 978 metazoan genes contained in the metazoa_odb9 database. A total of 76,508 protein-coding genes and 85,763 transcripts have been annotated. This assembly is one of the few octocoral genomes currently available. This is undoubtedly a valuable resource for characterizing the genetic bases of the differential responses to thermal stress and for the identification of thermo-resistant individuals and populations. Overall, the genome of P. clavata will help to understand various aspects of its evolutionary ecology and to elaborate effective conservation plans such as active restoration actions to overcome the threats of global change.

genomics↗