Seasonal Variation of the Stable Isotopic Compositions of Coastal Marine Plankton from Woods Hole, Massachusetts and Georges Bank

Estuaries ◽  
1994 ◽  
Vol 17 (3) ◽  
pp. 552 ◽  
Author(s):  
Sam C. Wainright ◽  
Brian Fry
Keyword(s):  
Seasonal Variation ◽  
Georges Bank ◽  
Marine Plankton ◽  
Isotopic Compositions ◽  
Coastal Marine ◽  
Stable Isotopic

Long-term changes in the Georges Bank food web: trends in stable isotopic compositions of fish scales

1993 ◽  
Vol 115 (3) ◽  
pp. 481-493 ◽  
Author(s):  
S. C. Wainright ◽  
M. J. Fogarty ◽  
R. C. Greenfield ◽  
B. Fry
Keyword(s):  
Food Web ◽  
Fish Scales ◽  
Georges Bank ◽  
Isotopic Compositions ◽  
Stable Isotopic ◽  
Long Term Changes

Stable isotopes in planktonic and benthic foraminifera from Arctic Ocean surface sediments

1988 ◽  
Vol 25 (5) ◽  
pp. 701-709 ◽  
Author(s):  
A. E. Aksu ◽  
G. Vilks
Keyword(s):  
Surface Water ◽  
Arctic Ocean ◽  
Sea Water ◽  
Ocean Surface ◽  
The Arctic ◽  
Size Fractions ◽  
Isotopic Compositions ◽  
Isotopic Analyses ◽  
Stable Isotopic ◽  
Surface Water Salinity

Oxygen and carbon isotopic analyses have been performed on the tests of Planulina wuellerstorfi and three size fractions of sinistral Neogloboquadrina pachyderma recovered from 33 Arctic Ocean surface-sediment samples. Stable isotopic compositions of N. pachyderma are found to be dependent on the test size: larger specimens show considerable enrichment in both δ18O and δ18C. The difference between the isotopic compositions of the 63–125 and 125–250 μm size fractions in N. pachyderma can be explained by biogenic fractionation effects during foraminiferal test growth. Larger (250–500 μm) N. pachyderma displayed accretions of secondary calcite, i.e., the outermost shell contained significant amounts of inorganically precipitated magnesium calcite. Thus, larger foraminifera may not be suited for down-core stable isotopic studies. There is a difference of ~2‰ between δ18O values of surface samples from the eastern and western Arctic Ocean, reflecting large differences between surface-water salinity in these regions. Therefore, oxygen isotopic data may have limited use as a chronostratigraphic tool in down-core studies in the Arctic Ocean, but we can use them to infer past variations in surface-water salinities. Planulina wuellerstorfi also showed depletions of both δ18O and δ18C in its calcite tests relative to calcite precipitated in isotopic equilibrium with ambient sea water; these depletions ranged from −0.8 to −0.9‰ in δ18Oand −1.2 to −0.9‰ in δ18C. This taxon is found to deposit its shell very close to the δ18C of ΣCO2 of bottom waters.

scholarly journals Seasonal variations of triple oxygen isotopic compositions of atmospheric sulfate, nitrate and ozone at Dumont d'Urville, coastal Antarctica

2016 ◽  
Author(s):  
Sakiko Ishino ◽  
Shohei Hattori ◽  
Joel Savarino ◽  
Bruno Jourdain ◽  
Susanne Preunkert ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Ice Cores ◽  
Oxidative Capacity ◽  
So2 Oxidation ◽  
Mixing Ratios ◽  
Isotopic Compositions ◽  
Oxygen Isotopic ◽  
Low Sensitivity ◽  
Complex Chemistry ◽  
Oxidation Chemistry

Abstract. Reconstruction of the oxidative capacity of the atmosphere is of great importance to understanding climate change, because of its key role in determining the life times of trace gases. Triple oxygen isotopic compositions (Δ17O = δ17O − 0.52 × δ18O) of atmospheric sulfate (SO42−) and nitrate (NO3−) in the Antarctic ice cores have shown potential as stable proxies, because they reflect the oxidation chemistry involved in their formation processes. However, observations of Δ17O values of SO42−, NO3− and ozone in the present-day Antarctic atmosphere are very limited, and their complex chemistry is not fully understood in this region. We present the first simultaneous measurement of Δ17O values of atmospheric sulfate, nitrate, and ozone collected at Dumont d'Urville station (66°40' S, 140°01' E) throughout 2011. Δ17O values of sulfate and nitrate exhibited seasonal variation characterized by summer minima and winter maxima, within the ranges of 0.9–3.4 ‰ and 23.0–41.9 ‰, respectively. In contrast, Δ17O values of ozone showed no significant seasonal variation, with values of 26 ± 1 ‰ through the year. These contrasting seasonal trends suggest that Δ17O(O3) is not the major factor determining seasonal changes in Δ17O(SO42−) and Δ17O(NO3−) values. The summer/winter trends for Δ17O(SO42−) and Δ17O(NO3−) values are caused by sunlight-driven changes in O3/ROX ratios, which decrease in summer through ozone destruction and photo-oxidants production, resulting in co-variation between ozone mixing ratios and Δ17O(SO42−) and Δ17O(NO3−) values. However, despite similar ranges of ozone mixing ratios in spring (September to November) and fall (March to May), Δ17O(SO42−) values observed in spring were lower than in fall. The relatively low sensitivity of Δ17O(SO42−) values to the ozone mixing ratio in spring is possibly explained by (i) lower O3/ROX ratios caused by NOX emission from snowpack and/or (ii) SO2 oxidation by hypohalous acids (HOX = HOCl + HOBr) in the aqueous phase.

Stable isotopic compositions of hydrothermal vent organisms

1989 ◽  
Vol 102 (2) ◽  
pp. 257-263 ◽  
Author(s):  
C. L. Van Dover ◽  
B. Fry
Keyword(s):  
Hydrothermal Vent ◽  
Isotopic Compositions ◽  
Stable Isotopic
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