Primer registro del pepino de mar nadador Enypniastes eximia Theel, 1882 (Echinodermata: Holothuroidea) en aguas peruanas

Enypniastes eximia Théel, 1882 (Echinodermata: Holothuroidea) a swimming sea cucumber is reported for the first time from Peru. The species was collected in the Continental rise (563-1,201 m) off Trujillo Department. Reference material has been deposited in the Coleccion Cientifica del Instituto del Mar del Peru (IMARPE), Lima, Peru.Se registra por primera vez para el Perú la especie pelágica de pepino de mar Enypniastes eximia Théel, 1882 (Echinodermata: Holothuroidea). La especie fue recolectada en el talud continental (563-1,201 m) frente al departamento de Trujillo. Material de referencia se encuentra depositado en la Colección Científica del Instituto del Mar del Perú (IMARPE), Lima, Perú

Asociaciones en la zona bentopelágica: el anfípodo Caprella subtilis (Amphipoda: Caprellidae) y la holoturia Ellipinion kumai (Elasipodida: Elpidiidae)

An association between the caprellid amphipod Caprella subtilis Mayer, 1903 and the elpidiid holothurian Ellipinion kumai (Mitsukuri, 1912) was confirmed through in situ submersible capture at 309 m depth in Sagami Bay, central Japan, and through shipboard observations. Information on this association, including behavioural and morphological data on both species, is presented. Information on the taxonomic standing of C. subtilis and related species is also introduced. Furthermore, we record swimming behaviour in the holothurian genus Ellipinion for the first time. We also introduce other biotic associations revealed during studies using submersible vehicles operated by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), including associations between benthopelagic holothurians and mysids, as well as hydrozoan polyps.Este trabajo confirma la asociación entre el anfípodo caprélido Caprella subtilis Mayer, 1903 y la holoturia elasipodida Ellipinion kumai (Mitsukuri, 1912), a partir de la captura in situ, a 309 m de profundidad, con un submarino, y a través de observaciones a bordo, en la Bahía Sagami, zona central de Japón. Se presenta información de esta asociación, incluyendo datos de comportamiento y morfológicos para ambas especies. También se incluye información del estado taxonómico de C. subtilis y especies relacionadas. Además, registramos por primera vez el comportamiento natatorio del género de holoturia Ellipinion. Asimismo, presentamos información de otras asociaciones bióticas reveladas durante estudios en los que se han utilizados vehículos sumergibles dirigidos por la Japan Agency for Marine-Earth Science and Technology (JAMSTEC), incluyendo asociaciones entre holoturias bentopelágicas y misidáceos, así como pólipos de hidrozoos

Light and Vision in the Deep-Sea Benthos: I. Bioluminescence at 500-1000 m Depth in the Bahamian Islands

Bioluminescence is common and well studied in mesopelagic species. However, the extent of bioluminescence in benthic sites of similar depths is far less studied, although the relatively large eyes of benthic fish, crustaceans and cephalopods at bathyal depths suggest the presence of significant biogenic light. Using the Johnson-Sea-Link submersible, we collected numerous species of cnidarians, echinoderms, crustaceans, cephalopods and sponges, as well as one annelid from three sites in the northern Bahamas (500–1000 m depth). Using mechanical and chemical stimulation, we tested the collected species for light emission, and photographed and measured the spectra of the emitted light. In addition, in situ intensified video and still photos were taken of different benthic habitats. Surprisingly, bioluminescence in benthic animals at these sites was far less common than in mesopelagic animals from similar depths, with less than 20% of the collected species emitting light. Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455 nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column

4. Wochenbericht SO199/2

Die F.S. Sonne-Expedition SO199 CHRISP (Merak Port/Indonesien - Singapur) findet vom 02.08. bis zum 22.09.2008 unter der Fahrtleitung von Prof. Kaj Hoernle (1. Fahrtabschnitt) und Dr. Reinhard Werner (2. Fahrtabschnitt) statt

Abyssal hills - hidden source of increased habitat heterogeneity, benthic megafaunal biomass and diversity in the deep sea

Abyssal hills are the most abundant landform on Earth, yet the ecological impact of the resulting habitat heterogeneity on the wider abyss is largely unexplored. Topographic features are known to influence food availability and the sedimentary environment in other deep-sea habitats, in turn affecting the species assemblage and biomass. To assess this spatial variation, benthic assemblages and environmental conditions were compared at four hill and four plain sites at the Porcupine Abyssal Plain. Here we show that differences in megabenthic communities on abyssal hills and the adjacent plain are related to environmental conditions, which may be caused by local topography and hydrodynamics. Although these hills may receive similar particulate organic carbon flux (food supply from the surface ocean) to the adjacent plain, they differ significantly in depth, slope, and sediment particle size distribution. We found that megafaunal biomass was significantly greater on the hills (mean 13.45 g m−2, 95% confidence interval 9.25–19.36 g m−2) than the plain (4.34 g m−2, 95% CI 2.08–8.27 g m−2; ANOVA F(1, 6) = 23.8, p < 0.01). Assemblage and trophic compositions by both density and biomass measures were significantly different between the hill and plain, and correlated with sediment particle size distributions. Hydrodynamic conditions responsible for the local sedimentary environment may be the mechanism driving these assemblage differences. Since the ecological heterogeneity provided by hills in the abyss has been underappreciated, regional assessments of abyssal biological heterogeneity and diversity may be considerably higher than previously thought

Characterization of Epibenthic and Demersal Megafauan at Mississippi Canyon 252 Following the Deepwater Horizon Oil Spill

Increased demand for new sources of oil and gas has resulted in an expansion of drilling into deeper waters. With this exploratory drilling come increased risks, which were realized on April 20, 2010 when the blow out preventer on the Macondo Well failed, resulting in the release of a large quantity of oil and gas into the Northern Gulf of Mexico from a bathypelagic source. This unprecedented environmental disaster was coined the Deepwater Horizon Oil Spill by the popular news media. In the months that followed the spill, the lack of knowledge about the pre-spill condition of deep-sea communities in this area of the Gulf of Mexico became apparent. This made it difficult to determine the effects of the spill on deep-water megafauna. The objective of this study was to characterize the epibenthic and demersal megafaunal community immediately following and one year after the spill. Remotely operated vehicles conducted a series of video surveys over an extended time series (11 surveys Aug 4 – Nov 1, 2010) of a site located 750 m to the Southwest of the Macondo Well and at five additional study sites during August and September 2010: 2000m north, west, south, and east, and 500m north of the Macondo well. The 750 m Southwest site was revisited in July of 2011 to determine what, if any, changes had occurred in the deep-water megafaunal community. These study sites were dominated by demersal fishes and mobile benthic invertebrates both in 2010 and 2011. The results indicate both diversity and densities of organisms declined over time in 2010, while densities appeared to increase in 2011 to levels similar to those observed immediately following the spill. The presence of carcasses of pyrosomes, salps, and crabs in 2010 indicated some short-term or acute mortality following the spill. It is hoped that these data will be used as a post-spill baseline against which future surveys of diversity and abundance of deep-water megafauna can be compared

Macro- and megafauna on the slopes of the Saya de Malha Bank of the Mascarene Plateau

A first characterization of the distribution and composition of benthic and demersal macro- and megafauna was derived based on video records sampled along five pre-determined transects up the slope on the western, northern and eastern sides of the Saya de Malha Bank on the Mascarene Plateau, starting at a maximum depth of 1000 m. Abundance was highest in the upper parts of eastern slope locations, primarily reflecting a relatively higher abundance of black corals (Antipatharia) than in other locations. A consistent feature of several transects, but most prominent in eastern and northern slopes, was the occurrence of patchy coral and sponge aggregations along the margin where the substrate was mostly hard. In some cases, these aggregations might be considered ‘gardens’ but reefs were not observed. Higher-level taxonomical composition of the fauna is presented. Demersal fish were widespread but not abundant, and within the depth range studied, there was a transition from a marginal shallow fish assemblage to a deepwater assemblage. Fishes were in most cases only assigned to family level, and 49 families were recorded. To thoroughly assess the biodiversity and abundance of fauna of the slopes of Saya de Malha Bank, further studies conducting more detailed video transects and sampling of specimens are warranted

Improving the estimation of deep-sea megabenthos biomass: dimension to wet weight conversions for abyssal invertebrates

Deep-sea megafaunal biomass has typically been assessed by sampling with benthic sledges and trawls, but non-destructive methods, particularly photography, are becoming increasingly common. Estimation of individual wet weight in seabed photographs has been achieved using equations obtained from measured trawl-caught specimens for a limited number of taxa. However, a lack of appropriate conversion factors has limited estimation across taxa encompassing whole communities. Here we compile relationships between measured body dimensions and preserved wet weights for a comprehensive catalogue of abyssal epibenthic megafauna, using ~47,000 specimens from the Porcupine Abyssal Plain (NE Atlantic) housed in the Discovery Collections. The practical application of the method is demonstrated using an extremely large dataset of specimen measurements from seabed photographs taken in the same location. We also collate corresponding field data on fresh wet weight, to estimate the impact of fixation in formalin and preservation in industrial denatured alcohol on the apparent biomass. Taxa with substantial proportions of soft tissues lose 35 to 60% of their wet weight during preservation, while those with greater proportions of hard tissues lose 10 to 20%. Our total estimated fresh wet weight biomass of holothurians and cnidarians in the photographic survey was ~20 times the previous estimates of total invertebrate biomass based on trawl catches. This dramatic uplift in megabenthic biomass has significant implications for studies of standing stocks, community metabolism, and numerical modelling of benthic carbon flows

Prevalence, Faunal Composition, and Vertical Distribution of Bioluminescence in the Pelagic Gulf of Mexico: Fishes, Crustaceans, Cephalopods and Gelatinous Megaplankton

Bioluminescence is the phenomenon of light emission by living organisms. It occurs through a chemical reaction within an organism and serves various purposes. The diversity of bioluminescent capabilities and occurrence in unrelated taxa suggest that bioluminescence has evolved independently numerous times amongst taxa thriving in certain environments. One such environment is the deep ocean, where little to no sunlight penetrates the water column, specifically in the mesopelagic (200-1000 m depth) and bathypelagic (\u3e 1000 m) zones. The mesopelagic and bathypelagic zones have been extensively sampled and well documented in the Gulf of Mexico (GoM), one of the few places globally where this has occurred. Currently, no detailed faunal inventory of bioluminescence for the deep-pelagic GoM exists. This study is the first to quantitatively characterize the prevalence (both taxonomic and numerical), faunal composition, and vertical distribution of bioluminescence among major taxonomic groups at intermediate trophic levels. This large cumulative dataset of fishes, crustaceans, and cephalopods (micronekton hereafter) provides the basis for the current study with the following aims: (1) create an inventory of the bioluminescent micronekton and net-caught gelatinous megaplankton in the “upper mile” (0-1500 m depth) of the northern and eastern GoM; (2) quantitatively assess the vertical partitioning of bioluminescence as a function of taxonomic composition and organismal abundance; and (3) investigate variability in the vertical partitioning of bioluminescence as a function of diel cycle. Additionally, these topics will provide insight for discussing the relationship between the distribution of bioluminescence and the overall vertical ecology of a low-latitude, oceanic ecosystem. Quantification of abundance amongst bioluminescent organisms within the GoM revealed that approximately 75.5% of all captured individuals were capable of bioluminescence. The expression of bioluminescence was found to be most prominent vertically between 200-1000 m, representing the upper and lower mesopelagic zones, with ~87% of all individuals capable of bioluminescence. The mesopelagic also contained the largest percentages of bioluminescent fishes in this study. In the upper mesopelagic (200 to 600 m) ~67% of fish taxa in this depth interval were bioluminescent during daytime, while at night time values decreased to approximately 54%. Day and nighttime percentages of bioluminescent individuals in this depth zone were very similar and very high (97-98%). The most numerically abundant bioluminescent taxon was fishes, notably the Order Stomiiformes (genus Cyclothone). Alone, Cyclothone comprised approximately 72% of all bioluminescent fishes. Regarding crustaceans, a vertical ‘gradient’ of bioluminescent was exhibited, reaching a maximum 93.4% in the 200-1600 m depth stratum. Below this depth, the percentage of bioluminescent individuals decreased. While pelagic cephalopods are characterized by rapid swimming speeds and avoidance behavior, making sampling quite difficult, this study found that approximate 94% of all individuals collected were bioluminescent, with these distributed evenly throughout the water column. Finally, as predicted, there was a profound shift in bioluminescent organisms from deeper zones towards the epipelagic zone at night, highlighting the tight connections between diel vertical migration and bioluminescence in Earth’s largest ecosystem type

Vanishing Horizontal Sea Surface Temperature Gradients at Low Wind Speeds

Sea surface temperature (SST) is a result of multiple interactions in air-sea processes. During days with strong insolation and low wind speed, there may be uneven net heating of the water layer near the surface of the ocean, when there are horizontal temperature gradients at the sea surface. Cooling of the water caused by evaporation, sensible, or longwave radiative, heat loss would be greater from warm water compared to that from relatively cold water. As a result, under low wind speed conditions and clear skies, the horizontal SST discontinuities, occurring at fronts, eddies, or in storm wakes, may diminish or even vanish. This phenomenon is illustrated here with some field and modelling results. The dependence on latitude and mean environmental conditions of the difference in warming on the cold and warm side of SST discontinuities is explored. The time dependence is important for the impact on remote sensing of SST, and it is found to be short enough that substantial masking of SST gradients can occur during the first six hours of the diurnal heating cycle, but the effect would continue to grow if calm and solar heating persist for several subsequent days. An integrated effect of this uneven net heating is seen in the seasonal masking of subsurface temperature gradients in the Gulf of Mexico and Florida Straits