Physics
Scientific paper
Dec 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011gecoa..75.7552s&link_type=abstract
Geochimica et Cosmochimica Acta, Volume 75, Issue 23, p. 7552-7565.
Physics
1
Scientific paper
Hydrogen isotope ratios of individual alkenones from haptophyte algae were measured in suspended particles and surface sediment from the Chesapeake Bay (CB) estuary, eastern USA, in order to determine their relationship to water δD values and salinity. δD values of four alkenones (MeC37:2, MeC37:3, EtC38:2, EtC38:3) from particles and sediments were between -165‰ and -221‰ and increased linearly (R2 = 0.7-0.9) with water δD values from the head to the mouth of the Bay. Individual alkenones were depleted in deuterium by 156-188‰ relative to water. The MeC37 alkenones were consistently enriched by ˜12‰ relative to the EtC38 alkenones, and the di-unsaturated alkenones of both varieties were consistently enriched by ˜20‰ relative to the tri-unsaturated alkenones. All of the increase in alkenone δD values could be accounted for by the water δD increase. Consequently, no net change in alkenone-water D/H fractionation occurred as a result of the salinity increase from 10 to 29. This observation is at odds with results from culture studies with alkenone-producing marine coccolithophorids, and from two field studies, one with a dinoflagellate sterol in the CB, and one with a wide variety of lipids in saline ponds on Christmas Island, that indicate a decline in D/H fractionation with increasing salinity. Why D/H fractionation in alkenones in the CB showed no dependence on salinity, while D/H fractionation in CB dinsoterol decreased by 1‰ per unit increase in salinity remains to be determined. Two hypotheses we consider to be valid are that (i) the assemblage of alkenone-producing haptophytes changes along the Bay and each species has a different sensitivity to salinity, such that no apparent trend in αalkenone-water occurs along the salinity gradient, and (ii) greater osmoregulation capacity in coastal haptophytes may result in a diminished sensitivity of alkenone-water D/H fractionation to salinity changes.
Sachs Julian P.
Schwab Valérie F.
No associations
LandOfFree
Hydrogen isotopes in individual alkenones from the Chesapeake Bay estuary does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Hydrogen isotopes in individual alkenones from the Chesapeake Bay estuary, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydrogen isotopes in individual alkenones from the Chesapeake Bay estuary will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1608142