Combined use of optical (satellite imagery), and acoustic (sidescan sonar) remote sensing techniques, as well as in situ methodologies (visual census; SCUBA diving, Towed Underwater Cameras, and Remotely Operated Vehicles) was employed to map the spatial distribution of seagrass habitats in the coastal waters of the Hellenic territory. Seagrass meadows were recorded at approximately 70% of the Hellenic coastline (Eastern Ionian, Aegean and Levantine Seas), and their surface area exceeded 2,673.1 km2. Posidonia oceanica is -by far- the dominant seagrass species of the Hellenic seas, covering the vast majority of seabed at depths between the shoreline and 25 – 30 m (or deeper in insular areas), followed by the species Cymodocea nodosa, Zostera noltei, and Halophila stipulacea, which, however, presenting local presence and limited areal extent. Habitat suitability in terms of the seabed spatial extent that is available for the growth of seagrass meadows (i.e., the spatial extent of coastal areas between the shoreline and the isobath of 20m) and the seawater clarity conditions are highlighted as the critical factors for the formation of well-structured and extensive meadows. The results of this study are of great importance and usefulness for the effective management and conservation of valuable marine ecosystems. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

Description of the coastal zone bank habitats of the Baltic Sea on Latvia-Lithuania border based on underwater video observation. Observation for National environmental status assessment, Maritime spatial planning, Marine Strategy Framework Directive. Underwater video observation was done by Latvian Institute of Aquatic Ecology. Open data policy.

Underwater imagery of Posidonia Oceanica area in Cala Santa Maria, Cabrera, Balearic Islands

Coralligenous and Rhodolith beds found in Oceana expeditons between 2006 and 2020

A geotechnical survey campaign was undertaken within the vicinity of the Westermost Rough Offshore Wind Farm. This was supported by a preliminary review of acoustic data and assessment for the presence of Annex I reefs to minimise the risk of potential damage to protected features. Following the review of existing data, a drop down video survey protocol was developed (EMU, 2011) and approved by the Marine Management Organisation (MMO). Part of this protocol identified that a number of proposed geotechnical sampling sites were likely to be in the vicinity of potential Annex I reefs and therefore warranted field ground-truthing by means of drop down video to verify the presence and status of these features. The video ground-truthing survey has now been completed. Drawing upon the findings of this survey, the 2012 EMU report present within this series provides an update of the assessment of the potential Annex I reefs present at the proposed geotechnical sample locations and fulfils condition 3.1.1 of the Marine Licence (Licence L/2011/001075). The aim of the 2013 Fugro EMU document also present within this series was to satisfy Marine Licence condition 31.22 and to address the responses from the MMO regarding the Annex I reef features (letter ref: REN024, dated 12th April 2013, and 21st June 2013). The objectives were to assess the impacts (direct and indirect) of the construction activities on the potential Annex I features. The objectives of this report were to: 1. Assess the direct impact (loss of habitat) of each of the construction activities; 2. Assess the associated indirect impacts (increase in sediment smothering, and suspended sediment concentrations. 3. Assess the cumulative impacts of all construction activities.

Photographs of marine biodiversity of unknown areas of high ecological value in the Andalusian Litoral, starting at Malaga, where the diving school is located. These studies are delivered to competent authorities for their knowledge and generation of protection figures.

Videoframe of seafloor displaying bedforms affecting sandy deposits in the continental slope of the Gulf of Cadiz, just downstream of the Strait of Gibraltar: A starved sand ribbon in a rocky area with superimposed smaller regular and asymmetric transverse ripples in centimetres. The sediment composition is mixed (biogenoeus and terrigenous) as is revealed by the different colours; the lighter colours comprise bioclastic debris located lee side of the ripples

Videoframe of seafloor displaying different bedforms affecting sandy deposits in the continental slope of the Gulf of Cadiz, just downstream of the Strait of Gibraltar. These bedforms are formed by the action of the Mediterranean Outflow Water which produces a complex patterns of bedforms from decametre to centimetre scales on the seafloor and remain poorly understood.

Videoframe of seafloor displaying bedforms affecting sandy deposits in the continental slope of the Gulf of Cadiz, just downstream of the Strait of Gibraltar: isolated rocky boulder on a gravelly seafloor. The boulder acts as an obstacle to the bottom current, favouring the formation of a longitudinal sandy ribbon superimposed on a small scale and transverse asymmetric ripples. Note the sandy accumulation lee side of the obstacle as well as the two ripple patterns drawing a fishbone feature produced by secondary flows formed on both sides of the boulder. Additionally, note the fast transport and armouring by the MOW toward the ROV

Videoframe of seafloor displaying bedforms affecting sandy deposits in the continental slope of the Gulf of Cadiz, just downstream of the Strait of Gibraltar: starved sand ribbons with superimposed ripples resting on the rocky surface that are also colonized by sponges. This image highlights obstacle marks formed by sponges.. Note that current direction is responsible for tails, bars and ripples formation and is coincident with suspended sediment transport direction.