Interactions of Deep-Sea Vent Invertebrates with Their Environment: The Case of Rimicaris exoculata

The vent shrimp Rimicaris exoculata thrives around many hydrothermal vent sites along the Mid-Atlantic Ridge (MAR), where it aggregates into dense swarms. In contrast to hydrothermal vent fields at the East Pacific Rise (EPR), where the biomass is dominated by tubeworms, clams, and mussels, this shrimp is one of the major animal species at MAR vents. These animals are found in the dynamic mixing interface between cold oxygenated seawater and hot, reduced hydrothermal vent fluid. The adaptation of this shrimp to the hostile deep-sea hydrothermal environment and its survival strategy has been investigated since their discovery at the TAG site in the late 1980s. Rimicaris exoculata is now known to colonize black smoker complexes along the MAR in the depth-range of 2,300-3,900 in (Rainbow, Broken Spur, TAG, Snake Pit, Logatchev, 5 degrees S (Rimicaris of exoculata). Although the presence of the Rimicaris genus was first believed to be restricted to the MAR, a related species, Rimicaris kairei, was found recently at the Central Indian Ridge (CIA) (Edmonds and Kairei vent field). This review summarizes the current knowledge of Rimicaris shrimp, focusing on their spatial and temporal distribution, chemical and thermal environment, as well as on possible nutrition strategies and behavioral aspects. Recent studies suggested that iron oxide encrusted bacteria hosted in the branchial chamber of R. exoculata from the Rainbow vent field (MAR) might rely on iron oxidation. Striking results on the occurrence and morphology of iron precipitates, as well as on bacterial-mineral interaction in the gill chamber, have lead to the hypothesis of an iron-based symbiosis between bacteria and the shrimp. Special attention is called to these issues

Co-constructing knowledge with the International Panel for Ocean Sustainability

UIDB/04666/2020 UIDP/04666/2020The efficacy of global environmental assessments in informing and shaping ocean and coastal management is hampered by recognized gaps in global science endeavours. In order to bridge these gaps, and secure inclusive and equitable knowledge co-construction by ocean stakeholders, the International Panel for Ocean Sustainability (IPOS) is emerging. Here we present the outcomes of the “Bridging Shades of Blue Workshop” held in Spain 2023. A diverse group of Ocean knowledge holders, including policymakers, small-scale fishers, marine social scientists and ocean lawyers gathered to reflect on the key features, challenges, strategies, actors to be involved, as well as pathways to balance power for advancing an inclusive and equitable IPOS. As a result, six foundational dimensions of IPOS’s institutional identity were proposed as IPOS ID cards: 1) Diversifying Ocean Knowledge Systems, 2) Widening the Range of Methods for Ocean Knowledge Production, 3) Informing Decision-making, 4) Engaging at the Interfaces of Knowledge with Decision-making, 5) Communicating, Learning, and Sharing Knowledge, 6) Measuring Progress and Evaluating Success. We conclude by emphasizing IPOS’s potential role as a beacon for inclusive, equitable, and sustainable ocean governance.publishersversionpublishe

Molecular characterization of bacteria associated with the trophosome and the tube of Lamellibrachia sp., a siboglinid annelid from cold seeps in the eastern Mediterranean

Specimens of Lamellibrachia (Annelida: Siboglinidae) were recently discovered at cold seeps in the eastern Mediterranean. In this study, we have investigated the phylogeny and function of intracellular bacterial symbionts inhabiting the trophosome of specimens of Lamellibrachia sp. from the Amon mud volcano, as well as the bacterial assemblages associated with their tube. The dominant intracellular symbiont of Lamellibrachia sp. is a gammaproteobacterium closely related to other sulfide-oxidizing tubeworm symbionts. In vivo uptake experiments show that the tubeworm relies on sulfide for its metabolism, and does not utilize methane. Bacterial communities associated with the tube form biofilms and occur from the anterior to the posterior end of the tube. The diversity of 16S rRNA gene phylotypes includes representatives from the same divisions previously identified from the tube of the vent species Riftia pachyptila, and others commonly found at seeps and vents

Textures And Traction: How Tube-Dwelling Polychaetes Get A Leg Up

By controlling the traction between its body and the tube wall, a tube-dwelling polychaete can move efficiently from one end of its tube to the other, brace its body during normal functions (e.g., ventilation and feeding), and anchor within its tube avoiding removal by predators. To examine the potential physical interaction between worms and the tubes they live in, scanning electron microscopy was used to reveal and quantify the morphology of worm bodies and the tubes they produce for species representing 13 families of tube-dwelling polychaetes. In the tubes of most species there were macroscopic or nearly macroscopic (~10 μm–1 mm) bumps or ridges that protruded slightly into the lumen of the tube; these could provide purchase as a worm moves or anchors. At this scale (~10 μm-1 mm), the surfaces of the chaetal heads that interact with the tube wall were typically small enough to fit within spaces between these bumps (created by the inward projection of exogenous materials incorporated into the tube wall) or ridges (made by secretions on the interior surface of the tube). At a finer scale (0.01–10 μm), there was a second overlap in size, usually between the dentition on the surfaces of chaetae that interact with the tube walls and the texture provided by the secreted strands or microscopic inclusions of the inner linings. These linings had a surprising diversity of micro-textures. The most common micro-texture was a “fabric” of secreted threads, but there were also orderly micro-ridges, wrinkles, and rugose surfaces provided by microorganisms incorporated into the inner tube lining. Understanding the fine structures of tubes in conjunction with the morphologies of the worms that build them gives insight into how tubes are constructed and how worms live within them

Mineralization of Alvinella polychaete tubes at hydrothermal vents

© 2014 The Authors. Geobiology Published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License [4.0], which permits use, distribution and reproduction in any medium, provided the original work is properly cited. The attached file is the published version of the article

Tomography of bacteria–mineral associations within the deep-sea hydrothermal vent shrimp <i>Rimicaris exoculata</i>

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