Giant kelp (Macrocystis pyrifera) is the most widely distributed kelp species on the planet, constituting one of the richest and most productive ecosystems on Earth, but detailed information on its distribution is entirely missing in some marine ecoregions, especially in the high latitudes of the Southern Hemisphere. Here, we present an algorithm based on a series of filter thresholds to detect giant kelp employing Sentinel-2 imagery. Given the overlap between the reflectances of giant kelp and intertidal green algae (Ulvophyceae), the latter are also detected on shallow rocky intertidal areas. The kelp filter algorithm was applied separately to vegetation indices, the Floating Algae Index (FAI), the Normalised Difference Vegetation Index (NDVI), and a novel formula (the Kelp Difference, KD). Training data from previously surveyed kelp forests and other coastal and ocean features were used to identify reflectance threshold values. This procedure was validated with independent field data collected with UAV imagery at a high spatial resolution and point-georeferenced sites at a low spatial resolution. When comparing UAV with Sentinel data (high-resolution validation), an average overall accuracy ≥ 0.88 and Cohen’s kappa ≥ 0.64 coefficients were found in all three indices for canopies reaching the surface with extensions greater than 1 hectare, with the KD showing the highest average kappa score (0.66). Measurements between previously surveyed georeferenced points and remotely-sensed kelp grid cells (low-resolution validation) showed that 66% of the georeferenced points had grid cells indicating kelp presence within a linear distance of 300 m. We employed the KD in our kelp filter algorithm to estimate the global extent of giant kelp and intertidal green algae per marine ecoregion and province, producing a high-resolution global map of giant kelp and intertidal green algae, powered by Google Earth Engine.

In international fisheries management, scientific advice on the presence of "vulnerable marine ecosystems" (VMEs) per United Nations resolutions, has generally used qualitative assessments based on expert judgment of the occurrence of indicator taxa such as cold-water corals and sponges. Use of expert judgment alone can be criticized for inconsistency and sometimes a lack of transparency; therefore, development of robust and repeatable numeric methods to detect the presence of VMEs would be advantageous. Here, we present a multi-criteria assessment (MCA) method to evaluate how likely a given area of seafloor represents a VME. The MCA is a taxa-dependent spatial method that accounts for both the quantity and data quality available. This was applied to a database of records of VMEs built, held and compiled by the International Council for the Exploration of the Sea (ICES). A VME index was generated which ranged from 1.51 to 4.52, with 5.0 being reserved for confirmed VME habitats. An index of confidence was also computed that ranged from 0.0 to 0.75, with 1 being reserved for those confirmed VME habitats. Overall the MCA captured the important elements of the ICES VME database and provided a simplified, spatially aggregated, and weighted estimate of how likely a given area is to contain VMEs. The associated estimate of confidence gave an indication of how uncertain that assessment was for the same given area. This methodology provides a more systematic and standardized approach for assessing the likelihood of presence of VMEs in the NorthEast Atlantic.

In 2009 the NW and SE flanks of Anton Dohrn Seamount were surveyed using multibeam echosounder and video ground-truthing to characterise megabenthic biological assemblages (biotopes) and assess those which clearly adhere to the definition of Vulnerable Marine Ecosystems, for use in habitat mapping. A combination of multivariate analysis of still imagery and video ground-truthing defined 13 comprehensive descriptions of biotopes that function as mapping units in an applied context. The data reveals that the NW and SE sides of Anton Dohrn Seamount (ADS) are topographically complex and harbour diverse biological assemblages, some of which agree with current definitions of ‘listed’ habitats of conservation concern. Ten of these biotopes could easily be considered Vulnerable Marine Ecosystems; three coral gardens, four cold-water coral reefs, two xenophyophore communities and one sponge dominated community, with remaining biotopes requiring more detailed assessment. Coral gardens were only found on positive geomorphic features, namely parasitic cones and radial ridges, found both sides of the seamount over a depth of 1311–1740 m. Two cold-water coral reefs (equivalent to summit reef) were mapped on the NW side of the seamount; Lophelia pertusa reef associated with the cliff top mounds at a depth of 747–791 m and Solenosmilia variabilis reef on a radial ridge at a depth of 1318-1351 m. Xenophyophore communities were mapped from both sides of the seamount at a depth of 1099–1770 m and were either associated with geomorphic features or were in close proximity (< 100 m) to them. The sponge dominated community was found on the steep escarpment either side of the seamount over at a depth of 854-1345 m. Multivariate diversity revealed the xenophyophore biotopes to be the least diverse, and a hard substratum biotope characterised by serpulids and the sessile holothurian, Psolus squamatus, as the most diverse.

habitats of conservation concern, 4 of which were classed as Vulnerable Marine Ecosystems. 24Some of the biotopes correspond to descriptions of communities from other megahabitat 25 features (for example the continental shelf and seamounts), although it appears that the 26 canyons host modified versions, possibly due to the inferred high rates of sedimentation in the 27 canyons. Other biotopes described appear to be unique to canyon features, particularly the sea 28 pen biotope consisting of Kophobelemnon stelliferum and cerianthids. of the region, thus canyons may be highly unstable environments subject to periodically 41 intense currents, debris transport, sediment slumps and turbidity flows (Shepard and Marshall, 42 1973; Inman et al. 1976; Gardner, 1989). 44Canyons may act as conduits, transporting sediment and organic matter from the continental 45 shelf to the deep sea (Shepard, 1951; Heezen et al. 1955; Monaco et al. 1990), and can be 46 areas of enhanced production and species diversity as a result of the accumulation of organic 47 matter and/or upwelling of nutrient rich waters (Hickey 1995). 49Submarine canyons have been suggested to play a role in generating areas of high 50 megabenthic biodiversity due to their complex topographies (Schlacher et al. 2007). Canyon 51 fauna flourish as a result of suspension feeding organisms benefiting from accelerated 52 currents within canyons (Rowe, 1971) as well as increased secondary production (Vetter et al. 53 2010) due to the exploitation of local increases in zooplankton during vertical migration 54 (Greene et al. 1988). In addition, detritivores benefit from enhanced sedimentation rates and 55 accumulated macrophytic detritus (Vetter, 1994; Harrold et al. 1998). However, a high 56 incidence of disturbance through sediment transport by intense tidal currents, turbidity 57 currents and detrital flows may be unfavourable to sessile invertebrate megafauna while 58 favouring highly motile species (Rowe, 1971; Vetter and Dayton, 1999; Vetter et al. 2010). Clark et al. 2010; Howell et al. 2010a; Rowden et al. 2010; Shank, 2010 The SW Approaches study area is located on the Celtic Margin and is an area characterised 158The upper reaches of three canyons were the target of this investigation. Two of those are 159 located in UK waters: Dangeard Canyon (also known as Dangaard Canyon), and Explorer 160Canyon (first in this special issue, see Stewart et al. (2014, this issue) 171(first named here) canyons, and were the target of this study. lasting between 0.5-1.5 hrs. Forty four transects were undertaken (see Table A1 The SIMPROF routine identified 43 clusters (p < 0.01) (see Table A2 In total 11 biotopes were identified from the cluster analysis ( Figure. 4) and related to 336 available environmental data to describe distinct biotopes (see Table 1 411This assemblage corresponds to the 'live Lophelia zone' as described by Mortensen et al. 412(1995) which is the main reef habitat found on the summit of the reef and consists of 413 predominantly live L. ...

Aim Marine habitats and their dynamics are difficult to systematically monitor, particularly those in remote locations. This is the case with the sub‐Antarctic ecosystem of the giant kelp Macrocystis pyrifera, which was already noted by Charles Darwin in his accounts on the Voyage of the Beagle and recorded on the nautical charts made during that expedition. We combined these and other nautical charts from the 19th and early 20th centuries with surveys conducted in the 1970s and 1980s and satellite detection algorithms from 1984 to 2019, to analyse kelp distribution through time and the factors that correlate with it. Location Marine ecoregions of Channels and Fjords of Southern Chile, Falkland Islands (Malvinas), and the island of South Georgia. Taxon Macrocystis pyrifera. Methods We characterised 309 giant kelp forests by their coastal geospatial attributes. Statistically significant variables were included in a conditional inference tree to predict kelp forest size. Sea surface temperature (SST) records were analysed to confirm temperature ranges over the last four decades. Nautical charts, historical surveys, aerial photogrammetry, unmanned aerial vehicle (UAV) surveys and satellite imagery were overlaid to assess spatial distribution of kelp forest canopies, spanning the period 1829–2020. Results Considering the extensive natural and human caused changes over the last two centuries, this diverse kelp ecosystem is remarkably persistent. We found that the ocean currents and wave exposure, combined with the geomorphological settings of the coastline are the most critical factors predicting the extent of the kelp forests. Main conclusions We have described the long‐term ecological persistence of the kelp forests in this vastly under‐studied region that offers a conceptual biogeographical model supporting the global importance proposed by Charles Darwin 200 years ago (Darwin, 1845). In the current context of global change, the need for conservation of this persistent and well‐preserved marine ecosystem has never been more important.

Highly localized concentrations of elasmobranch egg capsules of the deep-water skate Bathyraja richardsoni were discovered during the first remotely operated vehicle (ROV) survey of the Hebrides Terrace Seamount in the Rockall Trough, north-east Atlantic Ocean. Conductivity-temperature-depth profiling indicated that the eggs were bathed in a specific environmental niche of well-oxygenated waters between 4·20 and 4·55 ∘ C, and salinity 34·95-35·06, on a coarse to fine-grained sandy seabed on the seamount's eastern flank, whereas a second type of egg capsule (possibly belonging to the skate Dipturus sp.) was recorded exclusively amongst the reef-building stony coral Solenosmilia variabilis. The depths of both egg-laying habitats (1489-1580 m) provide a de facto refuge from fisheries mortality for younger life stages of these skates. Key words: deep sea; elasmobranch; environment; habitat; reproduction.Global conservation of sharks, skates and rays is hampered by the stark lack of knowledge of deep-sea elasmobranchs in waters beyond the continental shelf (Kyne & Simpfendorfer, 2010), with 57·6% of deep-sea chondrichthyans listed by the IUCN as Data Deficient (Dulvy et al., 2014). Seamounts in the deep sea are often thought of as megafaunal hotspots, attracting animals such as sharks, tuna and cetaceans that forage, refuge and mate in the area (Morato et al., 2010). As technology such as baited photo-landers, remotely operated vehicles (ROV) and autonomous underwater vehicles (AUV) become standard tools, seamount exploration offers new opportunities for observing deep-sea elasmobranch behaviours in situ that can deepen understanding of habitat associations.There are three seamounts in the Rockall Trough west of the British Isles. The first ROV investigation of the southernmost seamount, the Hebrides Terrace Seamount

The Croker Carbonate Slabs, in the UK sector of the Irish Sea, has shallow (70 to 100 m) water, strong (> 2 knot) tidal currents, coarse mobile surficial sediments and the most extensive methane-derived authigenic carbonate (MDAC) known in European waters. Multi-disciplinary studies (2004 to 2015) were commissioned specifically to document the benthic habitat, and have resulted in the designation of this site as a Marine Protected Area (MPA) under the European Commission’s Habitats Directive as an example of “Submarine structures formed by leaking gases”. However, this paper is focussed on the geoscience aspects of the site: the mineralogy and isotopic composition of the MDAC, its formation and age. It considers the implications of these findings with respect to the timing of the deglaciation of the area since the Last Glacial Maximum (LGM), and the environmental implications of the seepage of methane from the site over a period of at least 17,000 years. Carbon isotope ratios (δ13 C − 34 to − 54‰) confirm that the carbonate minerals (high-Mg calcite and aragonite) result from the anaerobic oxidation of methane. Widespread shallow gas within post-glacial sediments is sourced from underlying coal-bearing Carboniferous strata. Geophysical (side-scan sonar and multi-beam echo sounder) and visual surveys show that the MDAC occurs as isolated lumps, continuous pavements, and cliffs < 6 m tall, which post-date the post-glacial sediments, but are in places covered by a veneer of coarse mobile surficial sediments. U-Th dates (17,000 ± 5500 to 4000 ± 200 BP) suggest continual MDAC formation since the last glacial maximum, and constrain the postglacial sea level rise in this part of the Irish Sea; the site must have been submarine before MDAC formation started, whether or not methane was escaping. Visual and acoustic evidence of gas seepage is limited, but methane concentrations in the water are high (< 21.4 nmol l−1) and suggest present-day export to the atmosphere. It is also implied that significant methane release to the atmosphere occurred immediately after the retreat of the ice that covered the site during the LGM until 21.9 to 20.7 ka BP.

Kelp forests provide many important ecosystem services to people, including mitigating storm damage, cycling nutrients, and providing commercially-harvestable resources. However, kelp forests’ ability to sequester carbon dioxide, and therefore help regulate the climate, has until recently, been overlooked in assessments of the beneficial services they provide. In this study we incorporate updated knowledge on the potential of kelp to sequester ‘blue carbon’, and use the extensive kelp forests of the Falkland Islands as a case study to assess the value of kelp forest to society through multiple associated ecosystem services. Our analysis shows kelp forests provide a highly valuable range of direct and indirect services, which if managed correctly, will continue to benefit people, both now and in the future. The total estimated value of the Falkland Islands’ kelp system is currently equivalent to ~ £2.69 billion per year (or £3.24 million km-2 year-1). However, the true value of the kelp forest surrounding the Falkland Islands is likely to be higher still, given that our estimate does not account for elements such as associated scientific research, tourism, and cultural services, due to the necessary data currently being unavailable. Similarly, the full value of these highly biodiverse ecosystems in supplying habitat and food to a large range of associated species is crucial, yet extremely difficult to fully quantify. This study illustrates the importance of maintaining kelp ecosystems in a healthy state to ensure they continue to supply valuable ecological processes, functional roles, and ecosystem services, including their overlooked role as significant long-term carbon sinks.