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OASIS Thriving Cold-Water Coral Reefs in the Mediterranean Sea

OASIS Cruise Report

Scientific Discipline: Geology, New technologies, Marine Biology, Physical Oceanography

Work Area: SE Alboran Sea (W Mediterranean)

Research Vessel/Marine Equipment: RV Pelagia & ROV Max Rover

PI Name and Affiliation: Dr Claudio Lo Iacono, Spanish National Research Council

Date: 31st March - 12th April 2023

Links to OASIS post-cruise news item and social media channels below:

OASIS Post-Cruise NEWS ITEM

OASIS Instagram

OASIS Twitter

Cruise Objectives:

  1. Assess the real extent of the living Cabliers Cold Water Coral (CWC) reefs, quantify their biodiversity and groundtruth the exceptional (bio)morphologic features evident on the available fine-scale maps.
  2. Quantify, across multiple spatial scales, the oceanographic and hydrodynamic processes maintaining the northern Cabliers reefs in thriving conditions and evaluate the retroactive mechanisms with the small-scale seafloor complexity, being these processes responsible for CWC functioning.
  3. Apply and test the efficiency of smart automatic survey strategies on the reefs, contributing to define new management procedures for deep-sea ecosystems.
Figure 1 a Blue squares: OASIS areas of work. Yellow squares: northern and southern sectors already visited with ROV. CCM: Cabliers Coral Mound province; vo: volcanic outcrop. Red circle of the inset: location of the CCM; white circle: Almeria (Al). GS: Gibraltar Strait. b, c: AUV-MB maps of the CCM (yellow sectors in a); red X: proposed deployment sites of seafloor observatories. d, e: ROV images of northern and southern Cabliers reefs; d: 3 m wide L. pertusa colony; f: dead M. oculata frameworks hosting the gorgonian Acanthogorgia hirsuta; white bar: 30 cm. f, g: AUV-MB of complex bioconstructions that will be visited during OASIS.

To fulfill the objectives, we propose the collection of ROV and AUV video footage throughout the mound; the deployment of multiple seafloor observatories (landers, moorings, moored dynamic CTD) to measure hydrographic and oceanographic data throughout the water column and in-situ, on the thriving (northern) and, for comparison, on the dead (southern) Cabliers reefs; the application of cutting-edge photogrammetric techniques for high-resolution 3D image reconstructions of Cabliers reefs and the development of machine-learning routines for AUV adaptive sampling methods.

Figure 2: OASIS activities on the Cabliers area. The regions previously visited exclusively correspond to part of the Dive 1 (Cabliers north) and Dive 2 (Cabliers south).
ROV Images captured during OASIS

During the oceanographic cruise OASIS a Co-PI project 'UNSEEN' (UNveiling microplaStic abundancE pattErNs on a pristine Cold Water Coral reef) will also take place. UNSEEN project proposes the collection of sediment, water and fauna samples across different sectors of the Cabliers Coral Mound Province to assess microplastic occurrence in different environmental compartments. The ultimate goal of the project will be pursued following an integrated approach aimed at:

a) understanding the influence of oceanographic and sedimentary processes on the transport and emplacement of microplastics in deep-sea environments b) assessing potential impacts on CWCs species.

Examining microplastic occurrence and distribution patterns will provide significant insights into our understanding of transfer and accumulation pathways of microplastic across different aquatic compartments, including impacts on deep-sea ecosystem engineering species.