ISSN:
1573-515X
Keywords:
Dissolved sulfur species
;
inorganic solid sulfur
;
pyrite
;
salt marshes
;
soluble iron
;
short term changes
;
210Pb
;
137Cs
;
7Be
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
Notes:
Abstract Porewater species and solid inorganic sulfur speciation were measured before and after the spring tide (which occurs over a 6–7 day period) during a portion of the summer seasons of 1987, 1988 and 1989 in Great Marsh, Delaware. Samples were taken from two locations in the marsh (near creek and mid-marsh) inhabited by the short form of Spartina alterniflora. In 1987, pyrite and thiosulfate decreased over the spring tide. Other porewater species also underwent large changes in concentration — in some cases order of magnitude. However, in 1988 and 1989, there was no evidence for short term changes of pyrite. In 1988, drought conditions were prevalent throughout the sampling whereas in 1989 wet conditions were prevalent. Porewater parameters demonstrated that oxidation was extensive during the sampling period in 1988 and related to dessication. Both climatic and spring tidal flooding conditions have a pronounced affect on the chemistry of the system. Data from atmospherically derived radionuclides (210Pb,137Cs,7Be) indicate that bioturbation is not as important at the mid-marsh site as at the near creek site. Porewater chloride and7Be data support infiltration of overlying waters at both sites. The decrease in pyrite over the spring tide in the 1987 samples is related to oxidation. The possible oxidants are discussed and Fe(III) is the favored direct oxidant based upon a review of field and laboratory data. Iron(III) was measured in several filtered porewater samples. However, we cannot indicate with certainty that the Fe(III) is always soluble. The Fe(III) measured may be colloidal or complexed. Pyrite oxidation is noted when the Fe(III) to Fe(II) ratio, pH and alkalinity are all low.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00000886
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