The occurrence of pigments in marine sediments

Qualitative and quantitative studies of pigments in marine sediments, using chromatographic and spectrophotometric methods, showed the presence of degradation products of chlorophylls; some of their optical properties are given. It is concluded that pigments decompose rapidly in aerated, coarse-grained sediment whereas in deeper layers of the same sediment, under anaerobic conditions, decomposition is slow...

Soluble iron in coastal waters

Soluble iron, defined as the amount of the element found in a unit volume of millipore-filtered sea water, after oxidation of organic matter, has been determined on samples collected in insh!Jre waters of the State of Washington. After filtration the samples were oxidized. The particulate matter and its iron content were also determined. Bathophenanthrolene was the reagent used...

Determination and occurrence of cobalt in sea water

Methods have been investigated to ascertain the most desirable procedure for determining the trace concentrations of cobalt in sea water. The nitroso-R-salt method of Sandell was adopted and modified for sea water analysis. Samples of water were secured with the nonmetallic water sampler of Thompson and Chow. Preliminary studies of the waters of the San Juan Archipelago and of Puget Sound showed cobalt concentrations ranging from 0.0039 to 0.0054 µg-at Co/I

Shorewards Upslope of the Layer of Minimum Oxygen Off Bombay: Its Influence on Marine Biology, Especially Fisheries

Shorewards Upslope of the Layer of Minimum Oxygen Off Bombay: Its Influence on Marine Biology, Especially Fisherie

Linking spatial pattern of bottom fish assemblages with water masses in the North Sea

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75155/1/j.1365-2419.2008.00495.x.pd

Tracking seasonal changes in North Sea zooplankton trophic dynamics using stable isotopes

Trophodynamics of meso-zooplankton in the North Sea (NS) were assessed at a site in the southern NS, and at a shallow and a deep site in the central NS. Offshore and neritic species from different ecological niches, including Calanus spp., Temora spp. and Sagitta spp., were collected during seven cruises over 14 months from 2007 to 2008. Bulk stable isotope (SI) analysis, phospholipid-derived fatty acid (PLFA) compositions, and δ 13CPLFA data of meso-zooplankton and particulate organic matter (POM) were used to describe changes in zooplankton relative trophic positions (RTPs) and trophodynamics. The aim of the study was to test the hypothesis that the RTPs of zooplankton in the North Sea vary spatially and seasonally, in response to hydrographic variability, with the microbial food web playing an important role at times. Zooplankton RTPs tended to be higher during winter and lower during the phytoplankton bloom in spring. RTPs were highest for predators such as Sagitta sp. and Calanus helgolandicus and lowest for small copepods such as Pseudocalanus elongatus and zoea larvae (Brachyura). δ 15NPOM-based RTPs were only moderate surrogates for animals’ ecological niches, because of the plasticity in source materials from the herbivorous and the microbial loop food web. Common (16:0) and essential (eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA) structural lipids showed relatively constant abundances. This could be explained by incorporation of PLFAs with δ 13C signatures which followed seasonal changes in bulk δ 13CPOM and PLFA δ 13CPOM signatures. This study highlighted the complementarity of three biogeochemical approaches for trophodynamic studies and substantiated conceptual views of size-based food web analysis, in which small individuals of large species may be functionally equivalent to large individuals of small species. Seasonal and spatial variability was also important in altering the relative importance of the herbivorous and microbial food webs