Replicability of an epibenthic sampler
ABSTRACT Hyperbenthos was sampled at six stations on the western slope of the Norwegian Trough. Four hauls, two day and two night replicates were taken at each station. The replicates were analyzed based on all sampled individuals of Mysidacea and Decapoda Natantia using Shannon diversity index, Spearman rank correlation, G-test, Bray-Curtis similarity index and Correspondence Analysis. The sampler provided samples of mysids and shrimps with an acceptable level of replicability based on number of individuals and diversity. In a cost-efficient context it is satisfactory to take only one sample at a station.
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ABSTRACT: Abyssal macrofaunal composition of 21 epibenthic sledge hauls from twelve stations taken in the Kuril-Kamchatka Trench (KKT) and at the adjacent abyssal plain, Northwest Pacific, is presented. Sampling with the fine meshed epibenthic sledge yielded higher abundances and species richness than was reported from previous expeditions from board of RV Vityaz. In total 84,651 invertebrates were sampled with RV Sonne between July and September of 2012 (31,854 invertebrates if standardised for 1000 m² trawled distances) from 41 taxa of different taxonomic ranks (15 phyla, 28 classes, 7 orders) were sampled from a trawled area of 53,708 m² and have been analyzed. Few taxa were frequent and most taxa were rare in the samples, twelve taxa occurred with more than 1% frequency. Of these, the Polychaeta were most abundant followed by the benthic Copepoda and Isopoda. Total numbers of individuals varied between stations and were highest with 4,238 individuals at station 2–10 close to the KKT in 4,865 m depth and lowest with 374 individuals at station 6–11 in 5,305 m depth. At this station also the lowest number of taxa occurred (18 taxa) while the highest number occurred with 31 taxa at station 3–9 in 4,991 m depth. Numbers of individuals decreased with increasing depth between 4,830 and 5,780 m. Crustaceans of the superorder Peracarida were one of the dominating taxa with four orders occurring frequently in most samples. In total, Isopoda were most important and occurred with 59% of all peracarid orders sampled, followed by Amphipoda with 21%, Tanaidacea with 11%, Cumacea with 9%, and Mysidacea with <1%. The communities of the stations (and hauls) of the KKT abyssal area differ in terms of taxon composition from each other. A cluster analysis (nMDS) performed for all sampled stations revealed no clear pattern of community similarity between stations or hauls. All hauls close to the trench (2–9 and 2–10 close to the eastern slope of the KKT; and 3–9 and 4-3 at the western slope) were most different to the other hauls. Hauls 8–9 and 8–12 as well as 5–10 and 7–10 in the approximate centre of the overall research area were most similar (88% similarity). The non-isolated KKT area is characterized by higher abundances and higher benthic species richness than the geographically isolated and young deep-sea basin of the Sea of Japan.Deep Sea Research Part II Topical Studies in Oceanography 11/2014; 111. DOI:10.1016/j.dsr2.2014.11.002 · 2.76 Impact Factor
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ABSTRACT: The abyssal macrobenthos of the Kuril-Kamchatka Trench (KKT) area was sampled for the first time using a fine-meshed camera-epibenthic sledge (C-EBS) during the German-Russian KuramBio expedition 2012 (RV Sonne, 223 cruise). Crustaceans of the order Isopoda were one of the dominant macrobenthic taxa, and the family Munnopsidae was the most abundant and diverse among 17 collected asellotan families, comprising about 48 % of all isopods. During the KuramBio expedition no less than 80 species of 28 genera and eight subfamilies of Munnopsidae were collected with 21 EBS hauls at 12 stations. About 80% species are new to science and half of the genera and the subfamily Lipomerinae are recorded for the first time in the Northwest Pacific. The most abundant and speciose subfamily was Eurycopinae (58% of all specimens and 29 % of species), followed by Ilyarachninae (12% and 16 %). Most species are rare and occur with low abundance at one or few stations. Ten most numerous species belonging to the genera Eurycope (5 species), Microcope (2), Disconectes (1), Ilyarachna (1) and Aspidarachna (1) comprised 68% of all munnopsids. The species Eurycope sp.1 and Microcope ovata ( Birstein, 1970) were the most abundant and frequent species, occurring at all stations. The highest abundance of Munnopsidae and high diversity, with 32 species, occurred at station 3–9 on the western slope of the KKT. The cluster analysis of the Bray-Curtis similarity shows a low similarity between stations. The least similar was station 1–10, with only 26% similarity with other stations. Low similarity also characterized station 3–9 (34%). The comparison with known data revealed differences in species composition of Munnopsidae of the abyssal plain of the KKT area and the fauna of adjacent bathyal and hadal zones. Similar ratios of the munnopsid subfamilies and genera and some similar species have been revealed for the KuramBio and ANDEEP areas.Deep Sea Research Part II Topical Studies in Oceanography 09/2014; 111. DOI:10.1016/j.dsr2.2014.08.016 · 2.76 Impact Factor
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ABSTRACT: Different techniques of species distribution modeling were applied to evaluate the distribution of eight benthic marine species in Icelandic waters. The species examined were Symplectoscyphus tricuspidatus, Stegopoma plicatile (both Hydrozoa), Prionospio cirrifera, Amphicteis gunneri (both Polychaeta), Desmosoma strombergi, Eurycope producta (both Isopoda), Andaniella pectinata and Harpinia crenulata (both Amphipoda). Information on 13 environmental variables (temperature mean, temperature mean SD, temperature minimum, temperature maximum, salinity mean, salinity mean SD, oxygen content, particulate organic carbon, seasonal variation index, bottom roughness, sediment thickness, acidification) and records of occurrences of these eight species was collated in an ArcGIS project. Modeling methods applied were MARS, TreeNet, and MaxENT. According to area under the receiver operating curve (AUC) model assessment values, models with moderate to outstanding discriminatory power were found for all species. There was a good overlap in the overall pattern of prediction for most species independent on the modeling technique. Among the three applied techniques MARS seemed to generalize most whereas TreeNet predictions very precisely reflected information from the training data set. The distribution of the selected benthic invertebrate species in Icelandic waters could be linked to a variety of environmental factors related to oceanography, seabed topography and human impact. Their multivariate interactions acted as a structuring force of species distribution, instead of just their one by one individual influence. The selected predictors varied between the different models for the same species. They substituted each other in different models. The expected distribution of the examined species was mapped for a seascape of known environmental settings. Such maps will serve as excellent references in future impact studies and enable the detection of changes in the distribution of benthic marine invertebrates.Journal of Sea Research 06/2013; DOI:10.1016/j.seares.2013.05.007 · 1.86 Impact Factor