Organic carbon losses measured by heterotrophic activity of mesozooplankton and CaCO3 flux in the bathypelagic zone of the Arabian Sea

Organic carbon requirements for metabolisms of mesozooplankton in the bathypelagic zone were calculated for two stations (Western Arabian Sea Sediment Trap, WAST, 16°N 60°E, and Central Arabian Sea Sediment Trap, CAST, 14°N 64°E) and two different intermonsoonal periods (October 1995 and April 1997) in the Arabian Sea. These requirements were compared with inputs of particulate organic carbon (POC) measured from sediment traps. The temporal variability of POC flux is compared to the CaCO3 flux made up by planktic foraminiferans and coccolithophorids. The potential oxygen requirement of mesozooplankton was measured by the electron transport system (ETS) activity and the organic carbon demand calculated using conversion factors from the literature. Particulate CaCO3 flux was calculated from multinet hauls and sediment trap samples. Mesozooplankton organic carbon demand in the zone between 1050 and 3000 m differed locally and seasonally. At WAST, the mesozooplankton required 1778 μg C m−2 d−1 in October and only 484 μg C m−2 d−1 in April. At CAST, the respective values were 997 and 211 μg C m−2 d−1. No differences between the stations and time periods were discernible for the zone between 3000 and 3900 m at CAST and between 3000 and 4000 m at WAST; the values ranged between 73 and 98 μg C m−2 d−1. The input measured by sediment traps was sufficient to cover the calculated requirements of the mesozooplankton. The flux of calcareous particles and the mesozooplankton carbon requirements showed a similar pattern of temporal variability. At CAST the planktic foraminiferal shell flux was 33.2 mg CaCO3 m−2 d−1 in October and only 5.9 mg CaCO3 m−2 d−1 at 3000 m depth in April. Flux data derived from multinet hauls are of the same order of magnitude as the sediment trap data and, as multinet data yield a high temporal and spatial resolution, they could serve as a measure for open-ocean particulate flux

Medin aggregation causes cerebrovascular dysfunction in aging wild-type mice

Medin is the most common amyloid known in humans, as it can be found in blood vessels of the upper body in virtually everybody over 50 years of age. However, it remains unknown whether deposition of Medin plays a causal role in age-related vascular dysfunction. We now report that aggregates of Medin also develop in the aorta and brain vasculature of wild-type mice in an age-dependent manner. Strikingly, genetic deficiency of the Medin precursor protein, MFG-E8, eliminates not only vascular aggregates but also prevents age-associated decline of cerebrovascular function in mice. Given the prevalence of Medin aggregates in the general population and its role in vascular dysfunction with aging, targeting Medin may become a novel approach to sustain healthy aging

Taxonomic diversity and identification problems of oncaeid microcopepods in the Mediterranean Sea

The species diversity of the pelagic microcopepod family Oncaeidae collected with nets of 0.1-mm mesh size was studied at 6 stations along a west-to-east transect in the Mediterranean Sea down to a maximum depth of 1,000 m. A total of 27 species and two form variants have been identified, including three new records for the Mediterranean. In addition, about 20, as yet undescribed, new morphospecies were found (mainly from the genera Epicalymma and Triconia) which need to be examined further. The total number of identified oncaeid species was similar in the Western and Eastern Basins, but for some cooccurring sibling species, the estimated numerical dominance changed. The deep-sea fauna of Oncaeidae, studied at selected depth layers between 400 m and the near-bottom layer at >4,200 m depth in the eastern Mediterranean (Levantine Sea), showed rather constant species numbers down to ∼3,000 m depth. In the near-bottom layers, the diversity of oncaeids declined and species of Epicalymma strongly increased in numerical importance. The taxonomic status of all oncaeid species recorded earlier in the Mediterranean Sea is evaluated: 19 out of the 46 known valid oncaeid species are insufficiently described, and most of the taxonomically unresolved species (13 species) have originally been described from this area (type locality). The deficiencies in the species identification of oncaeids cast into doubt the allegedly cosmopolitan distribution of some species, in particular those of Mediterranean origin. The existing identification problems even of well-described oncaeid species are exemplified for the Oncaea mediacomplex, including O. media Giesbrecht, O. scottodicarloi Heron & Bradford-Grieve, and O. waldemari Bersano & Boxshall, which are often erroneously identified as a single species (O. media). The inadequacy in the species identification of Oncaeidae, in particular those from the Atlantic and Mediterranean, is mainly due to the lack of reliable identification keys for Oncaeidae in warm-temperate and/or tropical seas. Future efforts should be directed to the construction of identification keys that can be updated according to the latest taxonomic findings, which can be used by the non-expert as well as by the specialist. The adequate consideration of the numerous, as yet undescribed, microcopepod species in the world oceans, in particular the Oncaeidae, is a challenge for the study of the structure and function of plankton communities as well as for global biodiversity estimates

Large deep-sea zooplankton biomass mirrors primary production in the global ocean

The biological pump transports organic carbon produced by photosynthesis to the meso- and bathypelagic zones, the latter removing carbon from exchanging with the atmosphere over centennial time scales. Organisms living in both zones are supported by a passive flux of particles, and carbon transported to the deep-sea through vertical zooplankton migrations. Here we report globally-coherent positive relationships between zooplankton biomass in the epi-, meso-, and bathypelagic layers and average net primary production (NPP). We do so based on a global assessment of available deep-sea zooplankton biomass data and large-scale estimates of average NPP. The relationships obtained imply that increased NPP leads to enhanced transference of organic carbon to the deep ocean. Estimated remineralization from respiration rates by deep-sea zooplankton requires a minimum supply of 0.44 Pg C y(-1) transported into the bathypelagic ocean, comparable to the passive carbon sequestration. We suggest that the global coupling between NPP and bathypelagic zooplankton biomass must be also supported by an active transport mechanism associated to vertical zooplankton migration

Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific

Intensive observations using hydrographical cruises and moored sediment trap deployments during 2010 and 2012 at station K2 in the North Pacific western subarctic gyre (WSG) revealed seasonal changes in δ15N of both suspended and settling particles. Suspended particles (SUS) were collected from depths between the surface and 200 m; settling particles by drifting traps (DST; 100-200 m) and moored traps (MST; 200 and 500 m). All particles showed higher δ15N values in winter and lower in summer, contrary to the expected by isotopic fractionation during phytoplankton nitrate consumption. We suggest that these observed isotopic patterns are due to ammonium consumption via light-controlled nitrification, which could induce variations in δ15N(SUS) of 0.4-3.1 ‰ in the euphotic zone (EZ). The δ15N(SUS) signature was reflected by δ15 N(DST) despite modifications during biogenic transformation from suspended particles in the EZ. δ15 N enrichment (average: 3.6 ‰) and the increase in C:N ratio (by 1.6) in settling particles suggests year-round contributions of metabolites from herbivorous zooplankton as well as TEPs produced by diatoms. Accordingly, seasonal δ15 N(DST) variations of 2.4-7.0 ‰ showed a significant correlation with primary productivity (PP) at K2. By applying the observed δ15 N(DST) vs. PP regression to δ15 N(MST) of 1.9-8.0 ‰, we constructed the first annual time-series of PP changes in the WSG. Moreover, the monthly export ratio at 500 m was calculated using both estimated PP and measured organic carbon fluxes. Results suggest a 1.6 to 1.8 times more efficient transport of photosynthetically-fixed carbon to the intermediate layers occurs in summer/autumn rather than winter/spring

European and multi-ancestry genome-wide association meta-analysis of atopic dermatitis highlights importance of systemic immune regulation.

Atopic dermatitis (AD) is a common inflammatory skin condition and prior genome-wide association studies (GWAS) have identified 71 associated loci. In the current study we conducted the largest AD GWAS to date (discovery N = 1,086,394, replication N = 3,604,027), combining previously reported cohorts with additional available data. We identified 81 loci (29 novel) in the European-only analysis (which all replicated in a separate European analysis) and 10 additional loci in the multi-ancestry analysis (3 novel). Eight variants from the multi-ancestry analysis replicated in at least one of the populations tested (European, Latino or African), while two may be specific to individuals of Japanese ancestry. AD loci showed enrichment for DNAse I hypersensitivity and eQTL associations in blood. At each locus we prioritised candidate genes by integrating multi-omic data. The implicated genes are predominantly in immune pathways of relevance to atopic inflammation and some offer drug repurposing opportunities

Horizontal and Vertical Distribution of Mesopelagic Fishes with special reference to Vinciguerria lucetia (Phosichthyidae:Pisces) in the Humboldt Current Region Off Peru

The horizontal and vertical distribution of adult mesopelagic fishes is described from acoustic-trawls sampling over the full-depth of 500 m at 169 stations on a longitudinal transect between 50 to 200 nautical miles crossing the Humboldt Current off Peru coast (03°45\u27S, 81°76\u27W and 18°23\u27S, 71°13\u27W) during austral spring (october-november) of 2001, 2002 and 2003. A total of 2952 kg of fishes were collected and included 28 species belonging to 23 genera. The mesopelagic community is dominated by the fish families Phosichthyidae (Vinciguerria lucetia ), Myctophidae (Diogenichthys laternatus and Lampanyctus idostigma) and Bathylagidae (Leuroglossus urotranus), corresponding respectively 84.48 %, 7.19 %, 2.18 % and 1.06 % of the total abundance. Based on horizontal distribution patterns these species were categorized into three groups, i.e. Humboldt north-central group (Leuroglossus urotranus, Nemichthys fronto and Scopelarchoides nicholsi ), Humboldt south group (Hygophum reinhardti, Myctophum nitidulum, Paralepis sp and Scopeloberyx sp.)and Pan-Humboldt group (Vinciguerria lucetia, Diogenichthys laternatus, Lampanyctus(Nannobrachium) idostigma, L. omostigma, M. aurolaternatum, Triphoturus oculeus, Melanolagus berycoides, Leuroglossus stilbius, Argyropelecus affinis, Sternoptyx obscura, Melamphaes sp., Stomias sp., Scopelosaurus sp). Night-time vertical distribution was characterized by single abundance peak in the upper 50 m. Day-time patterns showed 3 peaks of abundance, an upper abundance peak, occurring in the upper 100 m, a midwater abundance peak, over a wider depth range (200-400 m), coinciding with oxygen mimimum zone and a near-bottom abundance peak, occurring between 400-500 m. (Vinciguerria lucetia ) was dominant in upper and midwater peaks while myctophids, other planctivores and piscivorous fishes were distributed in the midwater and deeper peaks. Backscattered energy (Sa) were ubiquitous in the region. Maximum Sa was mainly located between 11 and 18S during day-night time. (Vinciguerria lucetia ) is significant in the oceanic pelagic ecosystem as a major component of fish biomass in deep scattering layer in the Humboldt Current region off Peru and probably of transitional waters in the southeastern Pacific. Keywords: Mesopelagic fishes, (Vinciguerria lucetia) , Humboldt current, Peru, vertical and horizontal distribution, Backscattering energ