Mapping Condor Seamount Seafloor Environment and Associated Biological Assemblages (Azores, NE Atlantic)

Tempera, Fernando; Giacomello, Eva; Mitchell, Neil C.; Campos, Aldino Santos de; Braga-Henriques, Andreia; Bashmachnikov, Igor; Martins, Ana; Mendonça, Ana; Morato, Telmo; Colaço, Ana; Porteiro, Filipe M.; Catarino, Diana; Gonçalves, João M.; Pinho, Mário A R; Isidro, Eduardo; Santos, Ricardo S.; Menezes, Gui

doi:10.1016/b978-0-12-385140-6.00059-1

Cited by 33 publications

(34 citation statements)

References 10 publications

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“…The nearest large seamount is at 39 km to the south, while the nearest small seamount (200 m ≤ height < 1000 m) is 23 km to the SSE (Morato et al, 2008a). Tempera et al (2012) describe in great detail the geomorphological structures on Condor seamount. Condor is characterized by peculiar multi-scale dynamics involving localized upwelling-downwelling patterns, enhanced mixing, and pronounced closed circulation structures over the seamount .…”

Section: Study Areamentioning

confidence: 97%

Persistent Enhancement of Micronekton Backscatter at the Summits of Seamounts in the Azores

et al. 2017

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Knowledge of the dynamics of micronekton at seamounts is critical to understanding the ecological role of these ecosystems. Active acoustic techniques are an effective tool to monitor the distribution and movements of pelagic organisms. We carried out several day-and nighttime active acoustic surveys over a 3-year period (2009)(2010)(2011) to characterize the spatial and temporal distribution of micronekton backscatter on two seamounts (Condor and Gigante) in the Azores and in the surrounding open-waters. The highest mean volume backscattering strength (MVBS) was consistently found in the water column over the seamount summits, regardless of the season and diel period. MVBS over the summits was 14-26 times higher than over the slopes, and 10 times higher than in open-waters. Diel variations in backscatter intensity were more pronounced in open-waters and in Gigante seamount, with higher values during the day in open-waters, and at night over the summits and slopes of Gigante. Over Condor seamount, diel changes in backscatter intensity were small, but MVBS was generally higher at night than during the day, as in Gigante. Persistence of strong acoustic backscatter over the summits of Condor and Gigante seamounts is a key finding of this study and may be explained by the presence of a seamount-associated micronekton community and by the retention of vertically migrating micronekton. The latter hypothesis is consistent with observed day-night differences in backscatter, suggesting that nocturnal migrants may be passively transported or actively swim above seamount summits and slopes. Possible physical mechanisms leading to the observed patterns in micronekton distribution are discussed. This study contributes to a better understanding of how seamounts may influence the spatial and temporal dynamics of micronekton assemblages.

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Section: Study Areamentioning

confidence: 97%

Persistent Enhancement of Micronekton Backscatter at the Summits of Seamounts in the Azores

et al. 2017

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“…Video surveys conducted in the Azores showed evidence of rich coral communities; however, these did not document new records or describe new species (e.g. BragaHenriques et al, 2012;Tempera et al, 2012). In addition, observations with the submersible Archimède in 1969 usually refer to common names such as gorgonians or antipatharians, and many recognized taxa are reported with question marks (CNEXO, 1972).…”

Section: Historical Reviewmentioning

confidence: 99%

“…Ongoing efforts to map, describe and catalogue benthic communities of the Azores using video surveys are contributing to the discovery of coral gardens Tempera et al, 2012), providing inputs to the EUNIS European hierarchical biotope classification system (Galparsoro et al, 2012) and to the OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR, 2010). However, this information is spatially restricted due to logistical constraints and the high costs associated with deep sampling.…”

Section: Introductionmentioning

confidence: 99%

Diversity, distribution and spatial structure of the cold-water coral fauna of the Azores (NE Atlantic)

et al. 2013

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Cold-water corals are widely considered as important structural components of benthic habitats, potentially enhancing local abundance in a variety of fish and invertebrate species. Yet, current knowledge of the taxonomic diversity and distribution patterns of these vulnerable, slow-growing organisms is scarce and fragmented, limiting the effectiveness of spatial management and conservation measures. We have conducted an exhaustive compilation of records of alcyonaceans, antipatharians, scleractinians and stylasterids available through present day to assess the diversity, distribution and spatial structure of coral assemblages in the Azores exclusive economic zone (EEZ). The resulting database comprises 2501 entries concerning historical oceanographic expeditions and other published sources, as well as unpublished data from bottom longline by-catch. Our taxonomic inventory appears to be fairly complete for the explored habitats, accounting for 164 species (79 alcyonaceans, 58 scleractinians, 18 antipatharians and 9 stylasterids), nine of which were documented for the first time. The Azores EEZ harbours a mixed coral fauna with several zoogeographic origins, showing the closest affinity with the Lusitanian–Mediterranean region. Very few apparent endemics were found (14%), and only in part supported by consistent sampling. Coral diversity is particularly high between 300 and 900 m depths, in areas recognized as traditional fishing grounds or exploitable fish habitat within the 100-mile limit of the EEZ. The composition of coral assemblages shows significant geographical structure among longitudinal sections of the study area at comparable depths (100–1500 m). There is no evidence of a possible role of the Mid-Atlantic Ridge or latitudinal effects underlying this pattern, which suggests that it may instead reflect assemblage variability among features. Stronger changes in species composition were found along the bathymetric gradient. Notwithstanding the mix of partially overlapping steno- and eurybathic species that characterize the vertical distribution of corals, there is a distinct transition from shallow (100–600 m) to intermediate (600–1000 m) depths. The analysis presented here constitutes a valuable contribution for efficient conservation policies of coral-associated vulnerable marine ecosystems and their sustainable use as fishing areas

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“…The more general term "multi-scale" is used in this paper to refer to both types of analysis as well as geomorphometric analysis using data of different resolutions. (Lundblad et al, 2006;Lanier et al, 2007;Micallef et al, 2012a;Dolan and Lucieer, 2014) Aspect (Galparsoro et al, 2009), northness/northerness and eastness/easterness (Monk et al, 2011) Mean curvature (Dolan et al, 2008); profile curvature (Guinan et al, 2009); plan/planimetric curvature (Ross et al, 2015); Bathymetric Position Index (BPI) (Monk et al, 2010;Pirtle et al, 2015) Rugosity (Dunn and Halpin, 2009); vector ruggedness measure (VRM) (Tempera et al, 2012); relative relief (Elvenes, 2013); fractal dimension (Wilson et al, 2007) Commonly used terrain attribute and software (algorithm reference)…”

Section: General Geomorphometry (Terrain Attributes)mentioning

confidence: 99%

“…Geomorphometry is equally useful for both these approaches and those that combine both aspects (e.g. Tempera et al, 2012) and this discussion is relevant to an all-encompassing definition of habitat mapping (Lecours et al, 2015b). Figure 6 illustrates how terrain attributes are typically used in the production of predictive seabed habitat maps, providing an invaluable suite of full coverage predictor variables, which are used together with point samples of observed habitat as the input data to modelling.…”

Section: Marine Habitat Mapping Biogeography and Ecologymentioning

confidence: 99%

A review of marine geomorphometry, the quantitative study of the seafloor

Lecours

Dolan

Micallef

et al. 2016

Hydrol. Earth Syst. Sci.

183

120

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Abstract. Geomorphometry, the science of quantitative terrain characterization, has traditionally focused on the investigation of terrestrial landscapes. However, the dramatic increase in the availability of digital bathymetric data and the increasing ease by which geomorphometry can be investigated using geographic information systems (GISs) and spatial analysis software has prompted interest in employing geomorphometric techniques to investigate the marine environment. Over the last decade or so, a multitude of geomorphometric techniques (e.g. terrain attributes, feature extraction, automated classification) have been applied to characterize seabed terrain from the coastal zone to the deep sea. Geomorphometric techniques are, however, not as varied, nor as extensively applied, in marine as they are in terrestrial environments. This is at least partly due to difficulties associated with capturing, classifying, and validating terrain characteristics underwater. There is, nevertheless, much common ground between terrestrial and marine geomorphometry applications and it is important that, in developing marine geomorphometry, we learn from experiences in terrestrial studies. However, not all terrestrial solutions can be adopted by marine geomorphometric studies since the dynamic, fourdimensional (4-D) nature of the marine environment causes its own issues throughout the geomorphometry workflow. For instance, issues with underwater positioning, variations in sound velocity in the water column affecting acousticbased mapping, and our inability to directly observe and measure depth and morphological features on the seafloor are all issues specific to the application of geomorphometry in the marine environment. Such issues fuel the need for a dedicated scientific effort in marine geomorphometry.This review aims to highlight the relatively recent growth of marine geomorphometry as a distinct discipline, and offers the first comprehensive overview of marine geomorphometry to date. We address all the five main steps of geomorphometry, from data collection to the application of terrain attributes and features. We focus on how these steps are relevant to marine geomorphometry and also highlight differences and similarities from terrestrial geomorphometry. We conclude with recommendations and reflections on the future of marine geomorphometry. To ensure that geomorphometry is used and developed to its full potential, there is a need to increase awareness of (1) marine geomorphometry amongst scientists already engaged in terrestrial geomorphometry, and of (2) geomorphometry as a science amongst marine scientists with a wide range of backgrounds and experiences.

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Mapping Condor Seamount Seafloor Environment and Associated Biological Assemblages (Azores, NE Atlantic)

Cited by 33 publications

References 10 publications

Persistent Enhancement of Micronekton Backscatter at the Summits of Seamounts in the Azores

Persistent Enhancement of Micronekton Backscatter at the Summits of Seamounts in the Azores

Diversity, distribution and spatial structure of the cold-water coral fauna of the Azores (NE Atlantic)

A review of marine geomorphometry, the quantitative study of the seafloor

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