643 research outputs found
Photometry of Irregular Satellites of Uranus and Neptune
We present BVR photometric colors of six Uranian and two Neptunian irregular
satellites, collected using the Magellan Observatory (Las Campanas, Chile) and
the Keck Observatory, (Manua Kea, Hawaii). The colors range from neutral to
light red, and like the Jovian and the Saturnian irregulars (Grav et al. 2003)
there is an apparent lack of the extremely red objects found among the Centaurs
and Kuiper belt objects.
The Uranian irregulars can be divided into three possible dynamical families,
but the colors collected show that two of these dynamical families, the Caliban
and Sycorax-clusters, have heterogeneous colors. Of the third possible family,
the 168-degree cluster containing two objects with similar average inclinations
but quite different average semi-major axis, only one object (U XXI Trinculo)
was observed. The heterogeneous colors and the large dispersion of the average
orbital elements leads us to doubt that they are collisional families. We favor
single captures as a more likely scenario. The two neptunians observed (N II
Nereid and S/2002 N1) both have very similar neutral, sun-like colors. Together
with the high collisional probability between these two objects over the age of
the solar system (Nesvorny et al. 2003, Holman et al. 2004), this suggests that
S/2002 N1 be a fragment of Nereid, broken loose during a collision or cratering
event with an undetermined impactor.Comment: 13 pages (including 3 figures and 2 tables). Submitted to ApJ Letter
Usage of Videomosaic for Computer Aided Analysis of North Sea Hard Bottom Underwater Video for Baseline Study of Offshore Windmill Park
Windmill park on the open North Sea coast at Hävsul area in Norway is one of the first in the world to be build on such extreme high-energy coast. To determine possible environmental impact of this project, baseline study was performed in 2010-2011. Two areas, impacted (area where windmill park is planned to be build) and reference were chosen. For hard bottoms work class ROV was used to take underwater video, as no traditional sampling methods are suitable for such environment and depths. The system was equipped with powerful (400 Watt) xenon lights, USBL navigation and HDTV color camera. For video analysis videomosaicing approach was used. Combining overlapping frames into a single picture allows include in the analysis all visual information, and avoid over counting due to the possible presence of the same feature in the number of differnt frames. Bottom fauna and flora in the area include highly heterogenic small patches of various red algae, encrusting algae and encrusting animals. For lesser depths kelp “forests” are common, some megabenthos species are also present. Due to extreme patchiness of the bottom views, it is difficult to process them manually. To overcome this problem computer aided analysis method was developed. Computer aided videomosaics analysis method used for this study is based on color differences of different bottom features. After manually creating training color pallets for different features, it is possible to process large amount of visual data obtaining repeatable and reliable quantitative estimations on the coverage. Additional benefits of videomosaickning are extended abilities to manipulate visual data, what allows more accurate manual estimation of certain features, such as counts of mega benthos species individuals. Although initial study was successful and color based features extraction approach proved to be robust and accurate, it can’t reliably separate certain features (for example, different red algae species). Additional researches on implementing textures and shapes based analysis are needed
Ecological risk assessment of invertebrates caught in Swedish west-coast fisheries
Ecological risk assessments are important as scientific support for the implementation of ecosystem-based fisheries management. Marine invertebrates are important to ecosystem structure and function and may be sensitive to fishing pressure. Some are also of increasing commercial value – but have hitherto not been paid much attention to in ecological risk assessments. Here, catches of invertebrates in Swedish west-coast fisheries with demersal trawls and creels are examined from an ecological risk assessment perspective. It is found that few non-commercial invertebrate species have been regularly recorded in onboard observer programs. Furthermore, for being a comparatively well-studied area, it is striking to find that out of the 93 species included, 56% could be classified as data deficient in terms of known attributes needed to perform basic ecological risk assessments. This implies that there is little or no available information on the basic life history traits important for estimating productivity. Additionally, onboard observer data for invertebrates are inadequate beyond targeted commercial species for robust statistical analysis on volumes generated over time and between fisheries. However, over 18% of the studied species are categorized as red-listed on the Swedish IUCN Red List. Combined with the few records available in observer data programs, the study illustrates the need to pay more attention to marine invertebrates in fisheries monitoring programs and research, especially bycaught and non-commercial invertebrate species
Abyssal fauna of polymetallic nodule exploration areas, eastern Clarion-Clipperton Zone, central Pacific Ocean: Annelida: Spionidae and Poecilochaetidae
This paper represents a continuation of taxonomic publications on the benthic fauna of polymetallic nodule fields in the eastern Clarion-Clipperton Zone (CCZ) using material collected during baseline environmental survey work targeting two exploration contract areas (“UK-1” and “OMS”) and one Area of Particular Environmental Interest, “APEI-6.” Families Poecilochaetidae Hannerz, 1956 and Spionidae Grube, 1850 of the annelid suborder Spioniformia were studied here. Taxonomic data are presented for 25 species from 98 records as identified by a combination of morphological and genetic approaches. Although sub-optimal morphological condition can prevent new species being formally described, it is essential that morphological, molecular, and voucher data are made available for future surveys. Descriptions of two new species—Poecilochaetus brenkei sp. nov. and Laonice shulseae sp. nov.—increase the number of formally described new annelid species from the areas targeted in this study to 15 and CCZ-wide to 46. We also discuss the commonly reported “cosmopolitan” deep-sea spionid Aurospio dibranchiata Maciolek, 1981, which we show represents several genetically distinct species (three of these from CCZ area alone) but without reliable morphological characters to separate them. Molecular data provide evidence that 15 out of 25 species reported here have a wide distribution within the eastern CCZ and that Aurospio sp. “NHM_2186” and the known species Prionospio amarsupiata Neal & Altamira in Paterson et al. 2016 may be cosmopolitan. Lastly, the molecular data provide insights into relationships within Spioniformia, suggesting that both Poecilochaetidae and Trochochaetidae belong within Spionidae.publishedVersio
Environmental DNA monitoring of pelagic fish fauna at the Hywind Scotland floating wind energy installation – A pilot study
Environmental impact assessment and regular environmental monitoring are prerequisites for the construction, operation, and decommissioning of offshore installations such as the Hywind Scotland wind park. Molecular approaches are increasingly being considered as a possible complement or alternative to currently used marine baseline and monitoring methods, both for pelagic and benthic organism studies. The following report is a proof-of-concept study where two molecular methods, metabarcoding and quantitative assays, have been used to characterize the pelagic environment at the Hywind Scotland wind park based on filtered water samples from the installation and a reference area. The purpose of the report is to showcase the use of molecular methodology in future studies of the pelagic ecosystem. Metabarcoding was employed for a community view of a) fish species specifically, using the MiFish primer set, and b) a universal eukaryote dataset based on 18S V1-V2 primers. Quantitative assays were employed for two commercially important pelagic fish species: mackerel and herring.publishedVersio
Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca
The file attached is the Published/publisher’s pdf version of the article. This is an OpenAccess article.Copyright Helena Wiklund et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Joint Written Testimony of Thomas C. Baxter and Sarah Dahlgren Before the Congressional Oversight Panel
Joint Written testimony of Thomas C. Baxter, Executive Vice President and General Counsel, and Sarah J. Dahlgren, Executive Vice President, Special Investments Management, Federal Reserve Bank of New York before the Congressional Oversight Panel regarding The Federal Reserve Bank of New York\u27s Involvement with AI
Quantification of eDNA to map the distribution of cold-water coral reefs
An effective management of vulnerable marine ecosystems is dependent on thorough knowledge of their location. Multibeam bathymetric mapping and targeted remotely operated vehicle (ROV) surveys are currently used to map areas impacted by industrial activities when vulnerable species are expected. However, multibeam bathymetric mapping is not always a possibility and surveying large areas using ROVs is expensive. Here, we developed a species-specific eDNA assay targeting a 178 bp fragment in the control region of the mitochondrial DNA of the cold-water coral (CWC) Lophelia pertusa. The aim was to test if concentrations of L. pertusa eDNA in seawater, determined using droplet digital PCR (ddPCR) technology, could be used to assess the broad scale distribution of CWCs in a region, to supplement multibeam mapping and direct targeted ROV surveys. Our assay successfully amplified L. pertusa DNA from seawater. In laboratory we documented an exponential decay rate of the targeted DNA fragment and a linear correlation between coral biomass and eDNA concentrations in flow through microcosms. The ability of the method to detect CWC reefs in situ was tested in the fjords south of Bergen, Norway, where such reefs are common. We tested five sites with, and five sites without, known reefs. Lophelia pertusa eDNA was detected in all 10 sites. However, concentrations were elevated by 5 to 10 times in water sampled off the two large reefs growing on vertical surfaces. Water sampled 10 m above CWC reefs growing on the flat seabed did not produce an equally clear eDNA signal, nor did single CWC colonies growing on vertical surfaces. Treating the eDNA as a passive particle with no active vertical or horizontal movement, we successfully modeled the dispersal of eDNA from the known CWC reefs in the region and achieved a good fit with measured eDNA concentrations. In all, our study demonstrated a great potential for eDNA measurements as a cost-efficient tool for a rapid screening of the broad scale distribution of CWC reefs growing on vertical surfaces (so called wall reefs) that cannot be imaged using traditional ship mounted downward looking multibeam echo-sounders and difficult to detect using ROVs alone.publishedVersio
Progress in systematics: from Siboglinidae to Pogonophora and Vestimentifera and back to Siboglinidae
Marin Overvåking Hordaland – Sammendragsrapport 2019–2022
Miljøovervåkningsprogrammet “Marin Overvåking Hordaland" omfatter ytre- og indre fjordsystemer i Hordaland. Overvåkingen inkluderer vannundersøkelser, bløtbunnundersøkelser og strandsoneundersøkelser. Formålet er å beskrive miljøtilstander basert på biologiske og fysisk-kjemiske parametere. Vannundersøkelsene ble gjennomført på 14 prøvestasjoner fordelt på 11 ulike kystvannforekomster i Hordaland. Undersøkelsen inkluderer målinger og analyser av siktedyp, næringssalter, planteplankton, salinitet, temperatur og oksygen. Bløtbunnundersøkelser ble gjennomført på 7 utvalgte stasjoner i 7 ulike kystvannsforekomster. Bunnundersøkelsene omfatter sedimentprøver for analyser av geologi, kjemi og biologi. Strandsoneundersøkelsene ble i 2022 gjennomført på 12 utvalgte prøvestasjoner i 12 ulike kystvannsforekomster. Undersøkelsene viser generelt gode eller svært gode tilstander med noen unntak. To stasjoner har lave oksygenkonsentrasjoner i bunnvannet. En makroalgestasjon viser moderat tilstand. Forhøyede nivåer av TOC og sink på enkelte bunnstasjoner.Marin Overvåking Hordaland – Sammendragsrapport 2019–2022publishedVersio
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