Hay Bernward J.

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Hay
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Bernward J.
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  • Technical Report
    Particle fluxes, south central Black Sea : 1982-1985
    (Woods Hole Oceanographic Institution, 1987-05) Honjo, Susumu ; Manganini, Steven J. ; Asper, Vernon L. ; Hay, Bernward J. ; Karowe, Amy
    Annual particle fluxes were measured by sediment traps deployed at a station about 40 km north of Amasra, Southern Black Sea, by an international team of oceanographers from Germany, Turkey, and the United States. This experiment continuously monitored oceanic particle flux for two and a half years from October 28, 1982 to April 6, 1985 at approximately two-week intervals at 250 m and 1200 m below the surface using 1.2 m2 Mark 5-12 time-series sediment traps. The water depth at this station was about 2,200 m and both traps were situated within the anoxic layer of the Black Sea. The collected flux samples were analyzed at the Woods Hole Oceanographic Institution to document the basic sedimentary characteristics using a quarter of each sample split. In the first data file from this experiment, total mass, carbonate, noncombustible, combustible, opal (biogenic silica), organic carbon, and organic nitrogen fluxes data are presented in bar graphs and detailed tables, in unit samples covering a two-week period at each depth. The Black Sea Sedimentation Data File is intended to provide source data on particle fluxes from this unique ocean environment for further investigation and for planning advanced research programs.
  • Technical Report
    Temporal and spatial variability in sedimentation in the Black Sea : cruise report R/V Knorr 134-8, Black Sea Leg 1, April 16-May 7, 1988
    (Woods Hole Oceanographic Institution, 1988-10) Honjo, Susumu ; Hay, Bernward J. ; Members of the Scientific Shipboard Party
    This document represents the cruise report of the highly successful Leg 1 of the R/V Knorr cruise to the Black Sea (Cruise 134-8) as a joint Turkish-American Oceanographic Expedition (Izmir to Istanbul, April 16 to May 7,1988). The focus of Leg 1 was to study the biogeohemical variability in sedimentation in the present and throughout the anoxic history of the Black Sea with high spatial and temporal resolution. In particular, this study involved the integrated study of water column fluxes (sediment traps, suspended sediment investigations, etc.), benthic boundary layer ("fluff layer"), and laminated bottom sediments (box cores, giant gravity cores). Highlights of the cruise include the collection of 62 giant gravity cores, and 30 box cores with perfectly laminated sediment and, for the first time ever, with the intact fluff layer. Three moorings with time-series sediment traps were deployed in the abyssal regions of the eastern, central, and western Black Sea to collect continuous samples over a time period of about 1 year and 3 months. Summarized in the cruise report are logistics of the cruise, sample collections and descriptions, and preliminary discussions of observations and first measurements.
  • Thesis
    Particle flux in the Western Black Sea in the present and over the last 5,000 years : temporal variability, sources, transport mechanisms
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1987-09) Hay, Bernward J.
    The particle flux in the present and over the last 5,000 years was investigated in the Black Sea in a comparative study with samples from time-series sediment traps and laminated core sediments. The sediment trap samples were collected in the southwestern Black Sea over 2 1/2 years at sampling intervals of about two weeks. Sediment core samples were derived from the central part of the western Black Sea, deposited throughout the last 5,000 years during which the Black Sea was anoxic. Conclusions from this study shed important light on temporal and regional variability of the particle flux in the Black Sea, dominant particle sources, and particle transport mechanisms. Dominant particle sources are biogenic matter (coccolithophorids of the species Emiliania huxleyi, diatoms, and silicoflagellates) and terrigenous matter from the Danube and nearby local rivers. The relative importance in the supply of these particles varies annually and can be grouped into three phases: Phase I (June-October) coccolithophorid production, Phase II (November-January) - resuspension of coccoliths and terrigenous matter, and Phase III (February-May) river input of terrigenous matter and production of diatoms and silicoflagellates. Once removed from the surface water, particles settle rapidly at a rate of 115 ±70 m/day. Regionally, the particle flux varies considerably. Throughout the last 1,000 years (sediment unit I), the particle flux (paleoflux) was more than 5 times larger in the central part of the western Black Sea than at present in the southwestern Black Sea, mostly because of the 11 times larger supply of coccoliths. The coccoliths were probably largely produced on or adjacent to the Danube shelf in the northwestern Black Sea and subsequently resuspended and transported offshelf by the fall storms. Terrigenous matter in the central part of the western Black Sea is higher by a factor of 3 compared to the southwestern Black Sea. The coccoliths are concentrated in the white laminae (>93 % CaCO3), and if the seasonal dynamics in the particle supply at the sediment trap site is taken as a standard, the white laminae would be deposited between about June and January. The black laminae contain largely terrigenous matter and form during the peak river discharge period between about February and May. Compared to the last 1,000 years (unit I), the particle flux in the central part of the western Black Sea between 1,000 and 5,000 years B.P. was smaller by a factor of three, because the salinity was still too low during this time period for the coccolithophorid Emiliania huxleyi to exist. The Black Sea was a fresh water environment before more than 5,000 years ago and gradually became brackish; Emiliania huxleyi became established after the salinity exceeded 11%. The terrigenous matter supply remained about constant over the last 5,000 years. The western Black Sea is dominated by terrigenous input from the Danube as revealed by the illite/montmorillonite ratio. Seasonally, the terrigenous matter from the Danube appears to be traceable in the southwestern Black Sea, as seen by the Ti/Al and illite/montmorillonite ratios in the sediment trap samples.