Vertical distribution of zooplankton biomass in the Sea of Japan

Vertical distribution of total zooplankton biomass and major taxonomic groups are investigated by layers to depths of 2500-3400 m on the basis of three series of net plankton collections. Zooplankton is most abundant above 1500-2000 m. Since true deep-water species do not occur in the Sea of Japan, biomass drops much more sharply at greater depths than it does in the ocean. Since few carnivores inhabit the deep layers, abundant remains of planktonic organisms fall to the bottom, and carnivorous detritovores feeding on these remains are dominant in deep water bottom fauna.

Station characteristics and copepod fatty alcohol, fatty acid and lipid composition during MSM02/4 in Fram Strait

The biodiversity of pelagic deep-sea ecosystems has received growing scientific interest in the last decade, especially in the framework of international marine biodiversity initiatives, such as Census of Marine Life (CoML). While a growing number of deep-sea zooplankton species has been identified and genetically characterized, little information is available on the mechanisms minimizing inter-specific competition and thus allowing closely related species to co-occur in the deep-sea pelagic realm. Focussing on the two dominant calanoid copepod families Euchaetidae and Aetideidae in Fram Strait, Arctic Ocean, the present study strives to characterize ecological niches of co-occurring species, with regard to vertical distribution, dietary composition as derived from lipid biomarkers, and trophic level on the basis of stable isotope signatures. Closely related species were usually restricted to different depth layers, resulting in a multi-layered vertical distribution pattern. Thus, vertical partitioning was an important mechanism to avoid inter-specific competition. Species occurring in the same depth strata usually belonged to different genera. They differed in fatty acid composition and trophic level, indicating different food preferences. Herbivorous Calanus represent major prey items for many omnivorous and carnivorous species throughout the water column. The seasonal and ontogenetic vertical migration of Calanus acts as a short-cut in food supply for pelagic deep-sea ecosystems in the Arctic.

(Table 1) 100 m integrated temperature, chlorophyll a content and protist biomass during Leg 7 of Galathea 3 cruise (2006)

We present a study on the protozooplankton >5 µm and copepods larger than 50 µm at a series of contrasting stations across the Southern Indian Ocean (SIO). Numerically, over 80% of the copepod community across the transect was less than 650 µm in size, dominated by nauplii, and smaller copepods, while 80% of the biomass (as mg C/m**3) was larger than 1300 µm in body length. Predation by the carnivorous copepod Corycaeus sp. was estimated to be able to remove up to 2% /d of the copepods <1000 µm in size. By the help of grazing models we estimated that primary producers were mainly grazed upon by ciliates and heterotrophic dinoflagellates (40-80% /d combined) in temperate waters but appendicularians became increasingly important in the tropical waters grazing about 40% of the biomass per day. Despite their high abundance and biomass, copepods contributed less than 20% of the grazing at most stations. Secondary production was low (carbon specific egg production <0.14 /d) but typical for food limited oligotrophic oceans.

Nitrogen fuelling of the pelagic food web of the Tropical Atlantic

We estimated the relative contribution of atmospheric Nitrogen (N) input (wet and dry deposition and N fixation) to the epipelagic food web by measuring N isotopes of different functional groups of epipelagic zooplankton along 23°W (17°N-4°S) and 18°N (20-24°W) in the Eastern Tropical Atlantic. Results were related to water column observations of nutrient distribution and vertical diffusive flux as well as colony abundance of Trichodesmium obtained with an Underwater Vision Profiler (UVP5). The thickness and depth of the nitracline and phosphocline proved to be significant predictors of zooplankton stable N isotope values. Atmospheric N input was highest (61% of total N) in the strongly stratified and oligotrophic region between 3 and 7°N, which featured very high depth-integrated Trichodesmium abundance (up to 9.4×104 colonies m-2), strong thermohaline stratification and low zooplankton delta15N (~2 per mil). Relative atmospheric N input was lowest south of the equatorial upwelling between 3 and 5°S (27%). Values in the Guinea Dome region and north of Cape Verde ranged between 45 and 50%, respectively. The microstructure-derived estimate of the vertical diffusive N flux in the equatorial region was about one order of magnitude higher than in any other area (approximately 8 mmol m-2 d 1). At the same time, this region received considerable atmospheric N input (35% of total). In general, zooplankton delta15N and Trichodesmium abundance were closely correlated, indicating that N fixation is the major source of atmospheric N input. Although Trichodesmium is not the only N fixing organism, its abundance can be used with high confidence to estimate the relative atmospheric N input in the tropical Atlantic (r2 = 0.95). Estimates of absolute N fixation rates are two- to tenfold higher than incubation-derived rates reported for the same regions. Our approach integrates over large spatial and temporal scales and also quantifies fixed N released as dissolved inorganic and organic N. In a global analysis, it may thus help to close the gap in oceanic N budgets.

Histone underacetylation is an ancient component of mammalian X chromosome inactivation

Underacetylation of histone H4 is thought to be involved in the molecular mechanism of mammalian X chromosome inactivation, which is an important model system for large-scale genetic control in eukaryotes. However, it has not been established whether histone underacetylation plays a critical role in the multistep inactivation pathway. Here we demonstrate differential histone H4 acetylation between the X chromosomes of a female marsupial, Macropus eugenii. Histone underacetylation is the only molecular aspect of X inactivation known to be shared by marsupial and eutherian mammals. Its strong evolutionary conservation implies that, unlike DNA methylation, histone underacetylation was a feature of dosage compensation in a common mammalian ancestor, and is therefore likely to play a central role in X chromosome inactivation in all mammals.

High-precision 40Ar/39Ar geochronology and the advent of North America’s Late Cretaceous terrestrial fauna

A densely sampled, diverse new fauna from the uppermost Cedar Mountain Formation, Utah, indicates that the basic pattern of faunal composition for the Late Cretaceous of North America was already established by the Albian-Cenomanian boundary. Multiple, concordant 40Ar/39Ar determinations from a volcanic ash associated with the fauna have an average age of 98.39 ± 0.07 million years. The fauna of the Cedar Mountain Formation records the first global appearance of hadrosaurid dinosaurs, advanced lizard (e.g., Helodermatidae), and mammal (e.g., Marsupialia) groups, and the first North American appearance of other taxa such as tyrannosaurids, pachycephalosaurs, and snakes. Although the origin of many groups is unclear, combined biostratigraphic and phylogenetic evidence suggests an Old World, specifically Asian, origin for some of the taxa, an hypothesis that is consistent with existing evidence from tectonics and marine invertebrates. Large-bodied herbivores are mainly represented by low-level browsers, ornithopod dinosaurs, whose radiations have been hypothesized to be related to the initial diversification of angiosperm plants. Diversity at the largest body sizes (>106 g) is low, in contrast to both preceding and succeeding faunas; sauropods, which underwent demise in the Northern hemisphere coincident with the radiation of angiosperms, apparently went temporarily unreplaced by other megaherbivores. Morphologic and taxonomic diversity among small, omnivorous mammals, multituberculates, is also low. A later apparent increase in diversity occurred during the Campanian, coincident with the appearance of major fruit types among angiosperms, suggesting the possibility of adaptive response to new resources.

Amphipoda assemblages in a disturbed area (Alicante, Spain, Western Mediterranean)

The distribution and composition of Amphipoda assemblages were analysed off the coasts of Alicante (Spain, Western Mediterranean), a disturbed area affected by several co-occurring anthropogenic impacts. Although differences among sampled stations were mainly related to natural parameters, anthropogenic activities were linked with changes in amphipod assemblages. Expansion of the Port of Alicante, a sewage outfall and a high salinity brine discharge could be causing the disappearance of amphipods at stations closer to these disturbances. However, the completion of port enlargement works and mitigatory dilution of the brine discharge has led to the recovery of the amphipod assemblage. Among the natural parameters, depth determines the distribution of some of the species. While Siphonoecetes sabatieri was abundant at shallow stations, Ampelisca spp., Photis longipes, Pseudolirius kroyeri, Apherusa chiereghinii and Phtisica marina were more abundant at deeper stations. Grain size and percentage of organic matter also influenced amphipod distribution, resulting in changes in species composition and in the relative percentages of different trophic groups. Species such as Ampelisca brevicornis, Perioculodes longimanus, Urothoe hesperiae and Urothoe elegans were more abundant at stations with a high content of fine sand. Carnivorous species, mainly of the Oedicerotidae family, were more abundant at those stations with a low organic matter content, while detritivorous species were more abundant at stations with a higher mud content. Among 62 identified species, three were reported for the first time from the Spanish Mediterranean coast, two species were recorded for the second time and a new species of Siphonoecetes was found, Siphonoecetes (Centraloecetes) bulborostrum. These results confirm the need for further data on amphipods from the Mediterranean Spanish coast.

(Tables 1-3) Amphipod species observed under Antarctic pack ice during POLARSTERN cruises ANT-XXI/4, ANT-XXII/2 and ANT-XXIII/6

During three Antarctic expeditions (2004, ANT XXI-4 and XXII-2; 2006, ANT XXIII-6) with the German research icebreaker R/V Polarstern, six different amphipod species were recorded under the pack ice of the Weddell Sea and the Lazarev Sea. These cruises covered Austral autumn (April), summer (December) and winter (August) situations, respectively. Five of the amphipod species recorded here belong to the family Eusiridae (Eusirus antarcticus, E. laticarpus, E. microps, E. perdentatus and E. tridentatus), while the last belongs to the Lysianassidea, genus Cheirimedon (cf. femoratus). Sampling was performed by a specially designed under-ice trawl in the Lazarev Sea, whereas in the Weddell Sea sampling was done by scuba divers and deployment of baited traps. In the Weddell Sea, individuals of E. antarcticus and E. tridentatus were repeatedly observed in situ during under-ice dives, and single individuals were even found in the infiltration layer. Also in aquarium observations, individuals of E. antarcticus and E. tridentatus attached themselves readily to sea ice. Feeding experiments on E. antarcticus and E. tridentatus indicated a carnivorous diet. Individuals of the Lysianassoid Cheirimedon were only collected in baited traps there. Repeated conventional zooplankton hauls performed in parallel to this study did not record any of these amphipods from the water column. In the Lazarev Sea, E. microps, E. perdentatus and E. laticarpus were regularly found in under-ice trawls. We discuss the origin and possible sympagic life style of these amphipods.

Biological and environmental time series obtained from Point B, Bay of Villefranche

Ecological succession provides a widely accepted description of seasonal changes in phytoplankton and mesozooplankton assemblages in the natural environment, but concurrent changes in smaller (i.e. microbes) and larger (i.e. macroplankton) organisms are not included in the model because plankton ranging from bacteria to jellies are seldom sampled and analyzed simultaneously. Here we studied, for the first time in the aquatic literature, the succession of marine plankton in the whole-plankton assemblage that spanned 5 orders of magnitude in size from microbes to macroplankton predators (not including fish or fish larvae, for which no consistent data were available). Samples were collected in the northwestern Mediterranean Sea (Bay of Villefranche) weekly during 10 months. Simultaneously collected samples were analyzed by flow cytometry, inverse microscopy, FlowCam, and ZooScan. The whole-plankton assemblage underwent sharp reorganizations that corresponded to bottom-up events of vertical mixing in the water-column, and its development was top-down controlled by large gelatinous filter feeders and predators. Based on the results provided by our novel whole-plankton assemblage approach, we propose a new comprehensive conceptual model of the annual plankton succession (i.e. whole plankton model) characterized by both stepwise stacking of four broad trophic communities from early spring through summer, which is a new concept, and progressive replacement of ecological plankton categories within the different trophic communities, as recognised traditionally.

Reports of the Princeton University Expeditions to Patagonia, 1896-1899 : J.B. Hatcher in charge /

At head of title: J. Pierpont Morgan Publication Fund.

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"Production notes" at end of each no.

Catalogus mammalium tam viventium quam fossilium a doctore E.-L. Trouessart ...

Issued in VI fasciculi, each of which has special t.-p.