Depth as a driver of evolution and diversification of ancient squat lobsters (Decapoda, Galatheoidea, Phylladiorhynchus).

The exceptional hidden diversity included in the squat lobster genus Phylladiorhynchus and its wide bathymetric and geographic range make it an interesting group to thoroughly study its evolutionary history. Here we have analyzed the entire currently known species diversity of Phylladiorhynchus using an integrative approach that includes morphological and molecular characters. The aim was to establish whether depth range (bathymetry) has played a role in their morphological and molecular evolution and in their diversification pathways. Phylogenetic analyses recovered the genus as monophyletic and as the sister group of Coralliogalathea, conforming with current systematic hypotheses, although their placement in a monophyletic Galatheidae is doubted. All the analyzed species represent well-supported lineages, structured in ten clades, correlated in most part with the morphological phylogeny. The reconstruction of ancestral habitat showed that the most recent common ancestor of Phylladiorhynchus most likely lived in shallow water environments. The divergence time estimation analyses dated the origin of the genus back to the Upper Jurassic, preceding the origin of all the other galatheoid lineages. Morphological analyses suggested that species from deeper waters exhibit greater morphological divergences and lower genetic divergences in comparison to species from shallower waters. In Phylladiorhynchus, the colonization of deeper waters has taken place independently multiple times since the Lower-Cretaceous. Our reconstruction of ancestral habitat suggests that shallow water ancestors might show an acceleration in the molecular rate of evolution and a slowdown in the rates of morphological evolution in comparison to deep sea lineages. However, although lineages from shallow and deep sea habitats show slight differences in diversification trends, bathymetry does not significantly affect the diversification rate in Phylladiorhynchus according to our diversification analyses.

The aquaculture supply chain in the time of covid-19 pandemic: Vulnerability, resilience, solutions and priorities at the global scale.

The COVID-19 global pandemic has had severe, unpredictable and synchronous impacts on all levels of perishable food supply chains (PFSC), across multiple sectors and spatial scales. Aquaculture plays a vital and rapidly expanding role in food security, in some cases overtaking wild caught fisheries in the production of high-quality animal protein in this PFSC. We performed a rapid global assessment to evaluate the effects of the COVID-19 pandemic and related emerging control measures on the aquaculture supply chain. Socio-economic effects of the pandemic were analysed by surveying the perceptions of stakeholders, who were asked to describe potential supply-side disruption, vulnerabilities and resilience patterns along the production pipeline with four main supply chain components: a) hatchery, b) production/processing, c) distribution/logistics and d) market. We also assessed different farming strategies, comparing land- vs. sea-based systems; extensive vs. intensive methods; and with and without integrated multi-trophic aquaculture, IMTA. In addition to evaluating levels and sources of economic distress, interviewees were asked to identify mitigation solutions adopted at local / internal (i.e., farm-site) scales, and to express their preference on national / external scale mitigation measures among a set of a priori options. Survey responses identified the potential causes of disruption, ripple effects, sources of food insecurity, and socio-economic conflicts. They also pointed to various levels of mitigation strategies. The collated evidence represents a first baseline useful to address future disaster-driven responses, to reinforce the resilience of the sector and to facilitate the design reconstruction plans and mitigation measures, such as financial aid strategies.

Indoor spectroradiometric characterization of plastic litters commonly polluting the Mediterranean Sea: toward the application of multispectral imagery.

Around 350 million tonnes of plastics are annually produced worldwide. A remarkable percentage of these products is dispersed in the environment, finally reaching and dispersed in the marine environment. Recent field surveys detected microplastics' concentrations in the Mediterranean Sea. The most commonly polymers found were polyethylene, polypropylene and viscose, ethylene vinyl acetate and polystyrene. In general, the in-situ monitoring of microplastic pollution is difficult and time consuming. The main goals of this work were to spectrally characterize the most commonly polymers and to quantify their spectral separability that may allow to determine optimal band combinations for imaging techniques monitoring. The spectral signatures of microplastics have been analysed in laboratory, both in dry condition and on water surface, using a full spectrum spectroradiometer. The theoretical use of operational satellite images for remote sensing monitoring was investigated by quantifying the spectral separability achievable by their sensors. The WorldView-3 sensor appears the most suitable for the monitoring but better average spectral separability are expected using the recently released PRISMA images. This research was preparatory to further outdoor experiments needed to better simulate the real acquisition condition.

An improved taxonomic sampling is a necessary but not sufficient condition for resolving inter-families relationships in Caridean decapods.

During the past decade, a large number of multi-gene analyses aimed at resolving the phylogenetic relationships within Decapoda. However relationships among families, and even among sub-families, remain poorly defined. Most analyses used an incomplete and opportunistic sampling of species, but also an incomplete and opportunistic gene selection among those available for Decapoda. Here we test in the Caridea if improving the taxonomic coverage following the hierarchical scheme of the classification, as it is currently accepted, provides a better phylogenetic resolution for the inter-families relationships. The rich collections of the Muséum National d'Histoire Naturelle de Paris are used for sampling as far as possible at least two species of two different genera for each family or subfamily. All potential markers are tested over this sampling. For some coding genes the amplification success varies greatly among taxa and the phylogenetic signal is highly saturated. This result probably explains the taxon-heterogeneity among previously published studies. The analysis is thus restricted to the genes homogeneously amplified over the whole sampling. Thanks to the taxonomic sampling scheme the monophyly of most families is confirmed. However the genes commonly used in Decapoda appear non-adapted for clarifying inter-families relationships, which remain poorly resolved. Genome-wide analyses, like transcriptome-based exon capture facilitated by the new generation sequencing methods might provide a sounder approach to resolve deep and rapid radiations like the Caridea.

New taxonomy and old collections: integrating DNA barcoding into the collection curation process.

Because they house large biodiversity collections and are also research centres with sequencing facilities, natural history museums are well placed to develop DNA barcoding best practices. The main difficulty is generally the vouchering system: it must ensure that all data produced remain attached to the corresponding specimen, from the field to publication in articles and online databases. The Museum National d'Histoire Naturelle in Paris is one of the leading laboratories in the Marine Barcode of Life (MarBOL) project, which was used as a pilot programme to include barcode collections for marine molluscs and crustaceans. The system is based on two relational databases. The first one classically records the data (locality and identification) attached to the specimens. In the second one, tissue-clippings, DNA extractions (both preserved in 2D barcode tubes) and PCR data (including primers) are linked to the corresponding specimen. All the steps of the process [sampling event, specimen identification, molecular processing, data submission to Barcode Of Life Database (BOLD) and GenBank] are thus linked together. Furthermore, we have developed several web-based tools to automatically upload data into the system, control the quality of the sequences produced and facilitate the submission to online databases. This work is the result of a joint effort from several teams in the Museum National d'Histoire Naturelle (MNHN), but also from a collaborative network of taxonomists and molecular systematists outside the museum, resulting in the vouchering so far of ∼41,000 sequences and the production of ∼11,000 COI sequences.

Biotic and abiotic controls on iron oxyhydroxide formation in the gill chamber of the hydrothermal vent shrimp Rimicaris exoculata.

A unique feature of the shrimp, Rimicaris exoculata, from the Rainbow hydrothermal vent field is the abundance of iron oxyhydroxides in its branchial chamber. These minerals accumulate throughout the molting cycle and are intimately associated with the shrimps' epibiotic microflora. In this study, an enhancement of the iron oxidation rate through shrimp swarms in the vicinity of vents is highlighted. This process is sustained by the high molting frequency of the shrimp, and potentially has large biogeochemical and ecological consequences for the associated hydrothermal ecosystem. The calculated rate for abiotic (homogeneous and heterogeneous) iron oxidation suggests that autocatalytic oxidation is the predominant reaction pathway leading to the accumulation of iron oxyhydroxides throughout the molting cycle. The occurrence of iron-oxidizing bacteria is not excluded, but their growth is most probably restricted to the first molting stage when competition with the abiotic iron oxidation is low. The influence of epibiont activity on local oxygen conditions and on the surface properties of the formed mineral, combined with the position of the shrimp in the hydrothermal mixing gradient, is expected to drive the relative contribution of abiogenic and biogenic iron oxidation.