Palynological investigations of profile Cergowa in Poland

The decomposition rate of organic, Compounds, following the death of a plant, is dependent on several external factors. Assimilatory pigments generally undergo a rapid degradation. In certain condition, however, their decomposition may be considerably retarded; e.g. compounds similar to chlorophyll and some carotenoids, as a and ß-carotene, lutein and others, may persist several thousand years in marine and lake Sediments (Vallentyne 1960). Derivatives of chlorophyll were also found in the surface layer of wood soil (Gorham 1959). In this connection the question arises, in what a way a still different environment, namely peat, influences the decomposition rate of pigments. The starting point in these investigations was the fact observed by one of the co-authors, that many subfossil fir needles from various depths of the peat bog in Cergowa Gora were bright yellow green pigmented. Macroscopic otoservations have already suggested that, at least, a part of the pigments did not undergo decomposition. A study was undertaken with the aim to determine the quantitative and qualitative changes in assimilatory pigments, occurring in fir needles in dependence on the pexiod of time they were lying in the peat bog.

Abundance and biomass of planktic ciliates at time series station DYNAPROC

The composition and vertical distribution of planktonic ciliates within the surface layer was monitored over four diel cycles in May 95, during the JGOFS-France DYNAPROC cruise in the Ligurian Sea (NW Mediterranean). Ciliates were placed into size and trophic categories: micro- and nano-heterotrophic ciliates, mixotrophic ciliates, tintinnids and the autotrophic Mesodinium rubrum. Mixotrophic ciliates (micro and nano) represented an average of 46% of oligotrich abundance and 39% of oligotrich biomass; nano-ciliates (hetero and mixotrophic) were abundant, representing about 60 and 17% of oligotrich abundance and biomass, respectively. Tintinnid ciliates were a minor part of heterotrophic ciliates. The estimated contribution of mixotrophs to chlorophyll a concentration was modest, never exceeding 9% in discrete samples. Vertical profiles of ciliates showed that chlorophyll-containing ciliates (mixotrophs and autotrophs) were mainly concentrated and remained at the chlorophyll a maximum depth. In contrast, among heterotrophic ciliates, a portion of the population appeared to migrate from 20-30 m depth during the day to the surface at night or in the early morning. Correlation analyses of ciliate groups and phytoplankton pigments showed a strong relationship between nano-ciliates and zeaxanthin, and between chlorophyll-containing ciliates and chlorophyll a, as well as other pigments that were maximal at the chlorophyll a maximum depth. Total surface layer concentrations showed minima of ciliates during nightime/early morning hours.

Hydrocarbons in particulate matter and bottom sediments from the north Caspian Sea shelf

Data are presented on content and composition of hydrocarbons (HC) (aliphatic AHC and polyaromatic PAH) in filtered particulate matter and in the surface layer of bottom sediments from the northern shelf of the Caspian Sea and related to data on their contents in the Volga River estuary. Because of transformation and precipitation of anthropogenic and natural compounds, HC composition in particulate matter and bottom sediments undergoes transformations caused by mixing of fresh and saline waters (in bottom sediments, within concentration ranges 70.4-4557.9 µg/g for AHC and 3.8-4800 ng/g for PAH). It was found that the greatest concentrating of HC proceeds in the region of the avalanche sedimentation, and their contents are independent of grain-size types of bottom sediments. Anthropogenic HC (oil and pyrogenous) do not get over the marginal filter of the Volga River and do not pass to the open part of the sea.

Middle Miocene stable carbon and oxygen isotope record of foraminifera of ODP Hole 120-747A

Paleoceanographic variability at southern high latitude Ocean Drilling Program (ODP) Site 747 was investigated in this study through the interval which spans the Middle Miocene Climate Transition (MMCT). Between 15.0 and 12.2 million years ago (Ma), foraminiferal d18O records derived from both benthic (Cibicidoides spp.) and planktonic taxa (Globorotalia praescitula and Globigerina bulloides) reveal a history of changes in water column thermal and salinity structure and a strong imprint of seasonality. Prior to the MMCT, in the interval between 14.35 and 13.9 Ma, G. bulloides displays relatively high d18O values similar to those of G. praescitula, interpreted to indicate weakening of the thermocline and/or increased seasonality with cooler early-spring and/or late-fall temperatures. Following this interval, G. bulloidesd18O values diverge significantly from benthic and G. praescitula values, with G. bulloides values remaining relatively low for at least 600 kyr following the benthic foraminiferal d18O shift during the MMCT at ~13.9 Ma. This divergence in d18O records occurs in direct association with the Mi3 cooling and glaciation event and may suggest: (1) a strengthening of the vertical temperature gradient, with greater cooling of deep waters than surface waters, (2) changes in the depth habitat of G. bulloides, (3) changes in the dominant season of G. bulloides calcification, (4) modification of surface-water d18O values in association with enhanced sea-ice formation, (5) increased surface-water carbonate ion concentration, and/or (6) a significant decrease in surface-water salinity across the MMCT. The first of these possible scenarios is not likely, particularly in light of recent Mg/Ca evidence for significant surface-water cooling in the Southern Ocean associated with the MMCT. Of the remaining possibilities, we favor a change in surface salinity to explain the observed trends in d18O values and hypothesize that surface salinity may have decreased by up to 2 salinity units at ~13.9 Ma. In this scenario, the development of a lower-salinity Antarctic surface layer coincided with regional cooling of both surface and deep waters of the Southern Ocean during the Mi3 glaciation of East Antarctica, and contributed into the dominance of Neogloboquadrina spp. between 13.8 and 13.2 Ma. Additionally, the distinct patterns observed in planktonic foraminiferal d18O records spanning the MMCT correspond with changes in the vertical d13C gradient between planktonic and benthic foraminiferal records and major changes in planktonic foraminiferal assemblages at Site 747, providing further evidence of the environmental significance of this climatic transition.