The tale of an endemic shrimp's exceptional osmoregulation and the ancient Athalassic mangrove oasis.

The hyperarid mangrove in the Middle East is characterised by the absence of rivers or freshwater inputs and is one of the most extreme settings of this ecosystem on Earth. Endemic to Qatar's hyperarid mangroves, a Palaemon shrimp is uniquely confined to a sole mangrove site in the Arabian Gulf. Within these mangrove channels, we unveiled brine groundwater sources exceeding 70 ppt salinity, contrasting the local marine standard of 42 ppt. Concurrently, a mysid species typically linked to salt pans and groundwater coexists. Stable isotopic analysis implied the existence of a predator-prey dynamic between this mysid species and the studied shrimp. Then, investigating the endemic shrimp's adaptation to extreme salinity, we conducted osmolarity experiments and phylogenetic studies. Our findings demonstrate that this shrimp transitions from hypo- to hyper-osmoregulation, tolerating salinities from 18 to 68 ppt-an unprecedented osmoregulatory capacity among caridean shrimps. This speciation pattern likely arises from the species osmolarity adaptation, as suggested for other Palaemon congeners. Phylogenetic analysis of the studied Palaemon, along with the mangrove's geological history, suggests a profound evolutionary interplay between the ecosystem and the shrimp since the Eocene. This study proposes the hyperarid mangrove enclave as an Athalassic mangrove oasis-a distinctive, isolated ecosystem within the desert landscape.

Expanding ocean protection and peace: a window for science diplomacy in the Gulf.

The ecological state of the Persian or Arabian Gulf (hereafter 'Gulf') is in sharp decline. Calls for comprehensive ecosystem-based management approaches and transboundary conservation have gone largely unanswered, despite mounting marine threats made worse by climate change. The region's long-standing political tensions add additional complexity, especially now as some Gulf countries will soon adopt ambitious goals to protect their marine environments as part of new global environmental commitments. The recent interest in global commitments comes at a time when diplomatic relations among all Gulf countries are improving. There is a window of opportunity for Gulf countries to meet global marine biodiversity conservation commitments, but only if scientists engage in peer-to-peer diplomacy to build trust, share knowledge and strategize marine conservation options across boundaries. The Gulf region needs more ocean diplomacy and coordination; just as critically, it needs actors at its science-policy interface to find better ways of adapting cooperative models to fit its unique marine environment, political context and culture. We propose a practical agenda for scientist-led diplomacy in the short term and lines of research from which to draw (e.g. co-production, knowledge exchange) to better design future science diplomacy practices and processes suited to the Gulf's setting.

Whole genome sequencing of marine organisms by Oxford Nanopore Technologies: Assessment and optimization of HMW-DNA extraction protocols.

Marine habitats are Earth's largest aquatic ecosystems, yet little is known about marine organism's genomes. Molecular studies can unravel their genetics print, thus shedding light on specie's adaptation and speciation with precise authentication. However, extracting high molecular weight DNA from marine organisms and subsequent DNA library preparation for whole genome sequencing is challenging. The challenges can be explained by excessive metabolites secretion that co-precipitates with DNA and barricades their sequencing. In this work, we sought to resolve this issue by describing an optimized isolation method and comparing its performance with the most commonly reported protocols or commercial kits: SDS/phenol-chloroform method, Qiagen Genomic Tips kit, Qiagen DNeasy Plant mini kit, a modified protocol of Qiagen DNeasy Plant kit, Qiagen DNeasy Blood and Tissue kit, and Qiagen Qiamp DNA Stool mini kit. Our method proved to work significantly better for different marine species regardless of their shape, consistency, and sample preservation, improving Oxford Nanopore Technologies sequencing yield by 39 folds for Spirobranchus sp. and enabling generation of almost 10 GB data per flow cell/run for Chrysaora sp. and Palaemon sp. samples.

Lysmata arvoredensis nov. sp. a new species of shrimp from the south coast of Brazil with a key to species of Lysmata (Caridea: Lysmatidae) recorded in the southwestern Atlantic.

Lysmata arvoredensis sp. nov. inhabits temperate waters in the south coast of Brazil and is named in tribute to the Marine Protected Area REBIO Arvoredo. This is the fourth species belonging to the genus Lysmata recorded for the region and the ninth for Brazil. L. arvoredensis sp. nov. can be distinguished from other species of Lysmata by the presence of a nearly completely fused accessory branch with a single free unguiform segment on the outer antennular flagellum; a rostrum with seven dorsal (2+5) and three ventral teeth; a stylocerite with a pointed tip bearing mesial setae; a second pereiopod with 22-24 carpal subsegments and 14-16 subsegments in the merus; a merus of the third pereiopod with five ventrolateral and 12 ventral spines on the propodus; and its color pattern, with red bands and patches in pleonites 2-3 that resemble a mask in dorsal view. Molecular characters demonstrate that L. arvoredensis sp. nov. is most closely related to other species of Lysmata belonging to the Neotropical and Cleaner clades. To support future ecological studies in the region, identification keys to the species of Lysmata recorded in the southwestern Atlantic Ocean are provided.