Diversity

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28 pages, 4338 KiB

Open AccessArticle

Pan-Atlantic Comparison of Deep-Sea Macro- and Megabenthos

by Karlotta Kürzel, Saskia Brix, Angelika Brandt, Nils Brenke, Peter Enderlein, Huw J. Griffiths, Stefanie Kaiser, Jörundur Svavarsson, Anne-Nina Lörz, Inmaculada Frutos, James Taylor and Katrin Linse

Diversity 2023, 15(7), 814; https://doi.org/10.3390/d15070814 - 28 Jun 2023

Viewed by 1595

Abstract

Deep-sea benthic fauna is vital for a well-functioning marine ecosystem but is increasingly under threat from a changing environment. To monitor and conserve this fauna, an understanding of their large-scale spatial and bathymetric distribution and their environmental drivers is necessary. In this study, [...] Read more.

Deep-sea benthic fauna is vital for a well-functioning marine ecosystem but is increasingly under threat from a changing environment. To monitor and conserve this fauna, an understanding of their large-scale spatial and bathymetric distribution and their environmental drivers is necessary. In this study, we conduct a multivariate analysis on abundance benthic fauna data collected at the phylum and multitaxon levels using an epibenthic sledge (EBS) across the Atlantic, and identify the environmental factors that affect such data. Our findings show a decrease in abundance with depth in most of the Atlantic but find relatively heterogeneous abundances with depth within the Southern Ocean. Principal component analyses indicate differences in environmental conditions south of the Antarctic Polar Front (~52° S), outlining contrasts in the quantities of macronutrients and physical factors. Despite this, community composition seemed markedly similar throughout the Atlantic with the Antarctic Circumpolar Current seemingly not affecting benthic community composition for higher taxonomic levels. Those differences that did occur were largely caused by benthic chlorophyll, benthic iron, and surface silicate through a Bio-ENV. Overall, we argue that further large-scale spatial and bathymetric distribution studies are important amid environmental changes that are driving shifts in benthic community abundance and composition. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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21 pages, 40479 KiB

Open AccessArticle

Unciolidae of Deep-Sea Iceland (Amphipoda, Crustacea)

by Lauren E. Hughes and Anne-Nina Lörz

Diversity 2023, 15(4), 546; https://doi.org/10.3390/d15040546 - 11 Apr 2023

Viewed by 1628

Abstract

An overview of North Atlantic Unciola Say, 1818 is provided along with the description of two new species, U. conchicola sp. nov. and U. icelandica sp. nov. Both deep-sea species were collected living sympatrically at an almost 2000 m depth in the Iceland [...] Read more.

An overview of North Atlantic Unciola Say, 1818 is provided along with the description of two new species, U. conchicola sp. nov. and U. icelandica sp. nov. Both deep-sea species were collected living sympatrically at an almost 2000 m depth in the Iceland Basin, southwest of Iceland, each showing a vertical distribution of more than 1 km. In addition to the wide depth range, U. icelandica sp. nov. also shows a broad geographic distribution of more than 1000 km. Unciola conchicola sp. nov. was seen to attach its tubular domicile to the inner cavity of a gastropod shell; however, no specific lifestyle information is known for the species U. icelandica sp. nov. Both species present novel characters for the genus: in U. conchicola sp. nov., the epimeral plates 1–3 have acute projections angled ventrally, while in U. icelandica sp. nov., the male antenna 2 pedunclar article 2 is developed into a distinct phalange. The large amount of unciolid material allowed for ontogentic studies. The material of U. planipes Norman, 1867 was investigated. Changes from juvenile to adult specimens of Neohela monstrosa (Boeck, 1861) are discussed. A key is provided to the eight North East Atlantic species of Unciola. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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29 pages, 7027 KiB

Open AccessArticle

Benthic Foraminifera Diversity of the Abyssal Northwest Atlantic

by Michael Hesemann

Diversity 2023, 15(3), 381; https://doi.org/10.3390/d15030381 - 7 Mar 2023

Viewed by 2924

Abstract

The species diversity of benthic foraminifera at four abyssal working areas in the Labrador Sea, Labrador Basin, and Southwest of the Azores is documented. One hundred and fifty taxa (forty-three not assigned to a species) were found and their diversity was recorded. One [...] Read more.

The species diversity of benthic foraminifera at four abyssal working areas in the Labrador Sea, Labrador Basin, and Southwest of the Azores is documented. One hundred and fifty taxa (forty-three not assigned to a species) were found and their diversity was recorded. One hundred and twenty-four taxa (fifteen not assigned to a species) were illustrated with optical and/or SEM (Scanning Electron Microscope) images on twelve plates. The material was sampled during RV Sonne cruise SO286 as part of IceDivA2 (Icelandic marine Animals meets Diversity along latitudinal gradients in the deep sea of the Atlantic Ocean 2). IceDivA2 investigated the biodiversity within key groups of the marine benthic abyssal habitats of the North Atlantic. Thirty-two samples from four sliced and three full cores, from six stations sampled with a MUC (Multiple corer), were analyzed. Given low sedimentation rates in such environments the material is assumed to be of Holocene to late Pleistocene age. Due to the scarcity of living specimens this study was based on total assemblages. Four species-based clusters are identified, which correspond to the four working areas. The samples of each cluster show specific characteristics markedly different from those of the samples of the other clusters. It indicates that abyssal faunas are heterogeneous. Three clusters are dominated by Epistominella exigua (Brady, 1884), which is recorded as not rare to dominant in many abyssal plains worldwide. The faunal differences are manifested in the long tail of less important species and differing abundances of E. exigua. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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22 pages, 3642 KiB

Open AccessArticle

Deep-Sea Epibenthic Megafaunal Assemblages of the Falkland Islands, Southwest Atlantic

by T. R. R. Pearman, Paul E. Brewin, Alastair M. M. Baylis and Paul Brickle

Diversity 2022, 14(8), 637; https://doi.org/10.3390/d14080637 - 10 Aug 2022

Cited by 4 | Viewed by 2358

Abstract

Deep-sea environments face increasing pressure from anthropogenic exploitation and climate change, but remain poorly studied. Hence, there is an urgent need to compile quantitative baseline data on faunal assemblages, and improve our understanding of the processes that drive faunal assemblage composition in deep-sea [...] Read more.

Deep-sea environments face increasing pressure from anthropogenic exploitation and climate change, but remain poorly studied. Hence, there is an urgent need to compile quantitative baseline data on faunal assemblages, and improve our understanding of the processes that drive faunal assemblage composition in deep-sea environments. The Southwest Atlantic deep sea is an undersampled region that hosts unique and globally important faunal assemblages. To date, our knowledge of these assemblages has been predominantly based on ex situ analysis of scientific trawl and fisheries bycatch specimens, limiting our ability to characterise faunal assemblages. Incidental sampling and fisheries bycatch data indicate that the Falkland Islands deep sea hosts a diversity of fauna, including vulnerable marine ecosystem (VME) indicator taxa. To increase our knowledge of Southwest Atlantic deep-sea epibenthic megafauna assemblages, benthic imagery, comprising 696 images collected along the upper slope (1070–1880 m) of the Falkland Islands conservation zones (FCZs) in 2014, was annotated, with epibenthic megafauna and substrata recorded. A suite of terrain derivatives were also calculated from GEBCO bathymetry and oceanographic variables extracted from global models. The environmental conditions coincident with annotated image locations were calculated, and multivariate analysis was undertaken using 288 ‘sample’ images to characterize faunal assemblages and discern their environmental drivers. Three main faunal assemblages representing two different sea pen and cup coral assemblages, and an assemblage characterised by sponges and Stylasteridae, were identified. Subvariants driven by varying dominance of sponges, Stylasteridae, and the stony coral, Bathelia candida, were also observed. The fauna observed are consistent with that recorded for the wider southern Patagonian Slope. Several faunal assemblages had attributes of VMEs. Faunal assemblages appear to be influenced by the interaction between topography and the Falkland Current, which, in turn, likely influences substrata and food availability. Our quantitative analyses provide a baseline for the southern Patagonian shelf/slope environment of the FCZs, against which to compare other assemblages and assess environmental drivers and anthropogenic impacts. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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27 pages, 3543 KiB

Open AccessArticle

The Biodiversity of Calcaxonian Octocorals from the Irish Continental Slope Inferred from Multilocus Mitochondrial Barcoding

by Declan Morrissey, Candice B. Untiedt, Karen Croke, Aisling Robinson, Eva Turley and A. Louise Allcock

Diversity 2022, 14(7), 576; https://doi.org/10.3390/d14070576 - 18 Jul 2022

Cited by 4 | Viewed by 2279

Abstract

Deep-sea corals are important benthic inhabitants that support the biodiversity and function of the wider faunal community; however, their taxonomy is underdeveloped and their accurate identification is often difficult. In our study, we investigated the utility of a superextended (>3000 bp) barcode and [...] Read more.

Deep-sea corals are important benthic inhabitants that support the biodiversity and function of the wider faunal community; however, their taxonomy is underdeveloped and their accurate identification is often difficult. In our study, we investigated the utility of a superextended (>3000 bp) barcode and explored the effectiveness of various molecular species delimitation techniques with an aim to put upper and lower bounds on the estimated number of calcaxonian species in Irish waters. We collected 112 calcaxonians (70 Keratoisididae, 22 Primnoidae, 20 Chrysogorgiidae) and one chelidonisid from the Irish continental slope and sequenced a 3390 bp DNA barcode comprising four mitochondrial regions (mtMutS, COI + igr1, 16S rRNA-ND2, and igr4), recovering 38 haplotypes. Individuals that shared a haplotype were often morphologically distinct, and we thus undertook detailed morphological work, including SEM of sclerites, on one representative of each morphotype within each haplotype. GMYC, bGMYC, and mPTP returned incongruent estimates of species numbers. In total, there are between 25 and 40 species, although no definitive number could be assigned, primarily due to poorly defined keratoisidid species boundaries. As expected, the superextended barcode provided greater discrimination power than single markers; bGMYC appeared to be the most effective delimiter. Among the identified species were Chelidonisis aurantiaca, collected deeper than previously known at 1507 m, and Calyptrophora clinata, recorded for the second time from the Northeast Atlantic. A full understanding of the diversity and distribution of calcaxonians requires substantial taxonomic work, but we highlight the Irish continental slope as harbouring significant diversity. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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62 pages, 33236 KiB

Open AccessArticle

The Eurycope producta Sars, 1868 Species Complex (Isopoda, Munnopsidae) at the Transition of the Northern North Atlantic and the Nordic Seas—Including Descriptions of Six New Species and a Key

by Sarah M. Schnurr, Marina V. Malyutina and Saskia Brix

Diversity 2022, 14(7), 545; https://doi.org/10.3390/d14070545 - 7 Jul 2022

Viewed by 1399

Abstract

Eurycope producta Sars, 1868 is a highly abundant and widely distributed munnopsid species complex within Icelandic waters. The complex differs from all other Eurycope Sars, 1864 species by having a broad and long rostrum with serrated margins, which is subequal in length and [...] Read more.

Eurycope producta Sars, 1868 is a highly abundant and widely distributed munnopsid species complex within Icelandic waters. The complex differs from all other Eurycope Sars, 1864 species by having a broad and long rostrum with serrated margins, which is subequal in length and width to article 1 of antenna I. Previous molecular evidence to disentangle the E. producta species complex forms the base for the herein-presented taxonomic description of six new species belonging to the genus Eurycope. Additionally, descriptions of specimens of E. producta sensu stricto and E. dahli Svavarsson, 1987, which were included in the analyses, are presented herein for morphological comparison with the new species. The studied species can be divided in two subgroups: (1) E. producta sensu stricto, E. dahli, E. mishkai sp. nov., and E. nikitai sp. nov. and (2) E. gordeyi sp. nov., E. emmae sp. nov., E. jakobi sp. nov., and E. mathiasi sp. nov. Additionally, a key to the eight studied species of the complex is presented. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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15 pages, 4826 KiB

Open AccessArticle

DNA Barcoding of Cold-Water Coral-Associated Ophiuroid Fauna from the North Atlantic

by Angelina Eichsteller, James Taylor, Sabine Stöhr, Saskia Brix and Pedro Martìnez Arbizu

Diversity 2022, 14(5), 358; https://doi.org/10.3390/d14050358 - 3 May 2022

Cited by 2 | Viewed by 2760

Abstract

In this study we focus on the ophiuroid species associated with cold-water corals south of Iceland. The specimens were sampled with the ROV Phoca (GEOMAR) in three different areas, during the recent expedition MSM75 connected to the IceAGE_RR (Icelandic marine Animals: Genetics and [...] Read more.

In this study we focus on the ophiuroid species associated with cold-water corals south of Iceland. The specimens were sampled with the ROV Phoca (GEOMAR) in three different areas, during the recent expedition MSM75 connected to the IceAGE_RR (Icelandic marine Animals: Genetics and Ecology_Reykjanes Ridge hydrothermal vent activity) project. In each area, several corals were sampled and the ophiuroid specimens identified to the species level. The integrative taxonomic approach, based on morphological characters and DNA barcoding with COI of the collected ophiuroids, revealed five species that live on corals: Ophiomitrella clavigera (Ljungman, 1865); Ophiomyxa serpentaria (Lyman, 1883); Ophiacantha cuspidata (Lyman, 1879); Ophiactis abyssicola (M. Sars, 1861); and Ophiolebes bacata Koehler, 1921. Some of the sampled deep-sea corals exclusively host the species O.clavigera. The collected species are therefore associated with different corals but do not demonstrate a species-specific distribution. The video data support the integrative taxonomy and confirm the ecological evidence. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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13 pages, 1922 KiB

Open AccessArticle

Changes in the Abundance and Taxonomic Composition of Benthic Heterotrophic Protists from Atlantic Sublittoral to Deep-Sea Sediments

by Manon Hohlfeld and Hartmut Arndt

Diversity 2022, 14(3), 164; https://doi.org/10.3390/d14030164 - 25 Feb 2022

Cited by 4 | Viewed by 2197

Abstract

Protists are the most diverse eukaryotes on our planet and metabarcoding has revealed an enormous diversity even from deep-sea environments. A range of different species has also been isolated from the deep sea and some have proven able to survive and even grow [...] Read more.

Protists are the most diverse eukaryotes on our planet and metabarcoding has revealed an enormous diversity even from deep-sea environments. A range of different species has also been isolated from the deep sea and some have proven able to survive and even grow under deep-sea conditions. However, little is known about how the community structure of benthic protists changes from sublittoral down to abyssal depths. This is especially important regarding island and seamount communities which are surrounded by deep-sea areas potentially isolating them. Using a combination of live-counting and cultivation techniques, we investigated the abundance and taxonomic composition of benthic protist communities in sediments from sublittoral to abyssal depths around three islands and two seamounts of the Azores’ archipelago in the North Atlantic. Protist abundance decreased significantly and community composition changed with increasing depth. While some species were found at all depths, others were only detected in sublittoral or lower bathyal depths, indicating that some benthic taxa are limited in their distribution to a certain depth, whereas others are also present at the deep-sea floor. The proportion of unidentified specimens increased with depths pointing towards a high number of so far undetected species in the deep-sea realm. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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23 pages, 11037 KiB

Open AccessArticle

Bivalve Diversity on the Continental Shelf and Deep Sea of the Perdido Fold Belt, Northwest Gulf of Mexico, Mexico

by Nancy Yolimar Suárez-Mozo, Victor Manuel Vidal-Martínez, M. Leopoldina Aguirre-Macedo, Daniel Pech, Edlin Guerra-Castro and Nuno Simões

Diversity 2021, 13(4), 166; https://doi.org/10.3390/d13040166 - 12 Apr 2021

Cited by 4 | Viewed by 3915

Abstract

Mollusk diversity in coastal areas of the Gulf of Mexico (GOM) has been studied extensively, but this is not the case for deep-water habitats. We present the first quantitative characterization of mollusks in shallow and deep waters of the Perdido Fold Belt. The [...] Read more.

Mollusk diversity in coastal areas of the Gulf of Mexico (GOM) has been studied extensively, but this is not the case for deep-water habitats. We present the first quantitative characterization of mollusks in shallow and deep waters of the Perdido Fold Belt. The data came from two research cruises completed in 2017. Sediment samples were collected from 56 sites using a 0.25-m² box corer. We tested hypotheses about spatial patterns of α, β, and γ-diversity of bivalves in two water-depth zones, the continental shelf (43–200 m) and bathyal zone (375–3563 m). A total of 301 bivalves belonging to 39 species were identified. The two zones display similar levels of γ-diversity, but host different bivalve assemblages. In general, α-diversity was higher on the continental shelf, whereas β-diversity was higher in the bathyal zone. These patterns can be explained by the higher input of carbon (energy) to the near-coast shelf zone, as well as by the greater topographic complexity of habitats in the bathyal zone. These results enabled us to propose redirection of sampling efforts for environmental characterization from continental zones to the deep-water zone, especially in the context of environmental assessments during oil and gas exploration and production. Full article

(This article belongs to the Special Issue Deep Atlantic Biodiversity)

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