نتایج جستجو برای: deep seawater

تعداد نتایج: 223348  

2000
Bryan E. Bemis Howard J. Spero David W. Lea Jelle Bijma

Laboratory experiments with the planktonic foraminifera Globigerina bulloides (nonsymbiotic) and Orbulina universa (symbiotic) were carried out to examine the effects of temperature, irradiance (symbiont photosynthesis), [CO 3 ], and ontogeny on shell δ13C values. In ambient seawater ([CO 3 ] D 171 μmol kg 1), the δ13C of G. bulloides shells decreases 0.11‰ oC , a pattern that likely results fr...

2004
TOBY TYRRELL RICHARD E. ZEEBE

Instead of having been more or less constant, as once assumed, it is now apparent that the major ion chemistry of the oceans has varied substantially over time. For instance, independent lines of evidence suggest that calcium concentration ([Ca ]) has approximately halved and magnesium concentration ([Mg ]) approximately doubled over the last 100 million years. On the other hand, the calcite co...

2004
HARUKO KURIHARA SHINJI SHIMODE YOSHIHISA SHIRAYAMA

Data concerning the effects of high CO2 concentrations on marine organisms are essential for both predicting future impacts of the increasing atmospheric CO2 concentration and assessing the effects of deep-sea CO2 sequestration. Here we review our recent studies evaluating the effects of elevated CO2 concentrations in seawater on the mortality and egg production of the marine planktonic copepod...

2017
Dewang Yang Jinjia Guo Chunhao Liu Qingsheng Liu Ronger Zheng

Raman spectroscopy has great potential as a tool in a variety of hydrothermal science applications. However, its low sensitivity has limited its use in common sea areas. In this paper, we develop a near-concentric cavity-enhanced Raman spectroscopy system to directly detect bicarbonate in seawater for the first time. With the aid of this near-concentric cavity-enhanced Raman spectroscopy system...

Journal: :Journal of environmental monitoring : JEM 2005
O Largiuni S Becagli M Innocenti A M Stortini R Traversi R Udisti

A sensitive spectrofluorimetric-FIA (flow injection analysis) method for formaldehyde (HCHO) determination was improved with the aim of analysing seawater samples. The fluorescence emission versus HCHO concentration shows a linear pattern from sub microg L(-1) to about 1000 microg L(-1). The reproducibility at 15 ppb level is about 2%. Interferences from other aldehydes were checked; only glyox...

1999
James C. Zachos Bradley N. Opdyke Terrence M. Quinn Charles E. Jones Alex N. Halliday

Stable and radiogenic isotopic and sedimentological data from sub-Antarctic deep sea sediment cores reveal a temporal link between changes in seawater SrrSr ratios and major episodes of late Eocene–early Oligocene climate change. The SrrSr records show two major inflections, one at 38–39 Ma near the middlerlate Eocene boundary, followed by another at 33.4 Ma. Similarly, the oxygen isotope, ice-...

Journal: :International Journal of Systematic and Evolutionary Microbiology 2015

2001
Daniel P. Schrag Jess F. Adkins Katherine McIntyre Jane L. Alexander David A. Hodell Christopher D. Charles Jerry F. McManus

High-resolution oxygen and hydrogen isotope measurements were made on pore fluids from deep-sea sediments from sites in the North and South Atlantic. The data provide direct measurements of changes in the isotopic composition of bottom waters during the Last Glacial Maximum (LGM). Results from Ocean Drilling Program (ODP) Site 981 in the North Atlantic, currently bathed in North Atlantic Deep W...

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