Sedimentary lipids as indicators of depositional conditions in the coastal Peruvian upwelling regime

McCaffrey, Mark A.

doi:10.1575/1912/5428

Cited by 15 publications

(8 citation statements)

References 51 publications

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“…The most intense zone of sulfate reduction and the degradation of alkenones in present-day anoxic sediments is in the upper few centimeters of the sediment column (c.f. Kennedy and Brassell, 1992;McCaffrey, 1990;Sun and Wakeham, 1994). The data of Sun and Wakeham (1994) establishes that alkenones are in fact relatively resistant to degradation in the anoxic setting of Black Sea sediments.…”

Section: Discussionmentioning

confidence: 88%

“…The data of Sun and Wakeham (1994) establishes that alkenones are in fact relatively resistant to degradation in the anoxic setting of Black Sea sediments. No offset in alkenone unsaturation indices within the sediment zone of rapid organic matter recycling has been observed to date; instead, alkenone paleotemperature results give very plausible SST's over the historical period at such active sulfate reduction environments as Santa Barbara Basin (Kennedy and Brassell, 1992) and the Peruvian margin (McCaffrey, 1990).…”

Section: Discussionmentioning

confidence: 89%

“…Lipids were extracted following the method of Kennedy (1992) and compound classes isolated for gas chromatography following the procedure of McCaffrey (1990). Two to 5 g of wet sediment were extracted by ultrasonication using a sequence of three solvents: 100% methanol, 2:1 methylene chloride:methanol (twice), and 100% methylene chloride.…”

Section: Methodsmentioning

confidence: 99%

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Glacial-Interglacial Sea-Surface Temperature Record Inferred from Alkenone Unsaturation indices, Site 893, Santa Barbara Basin

Herbert¹,

Yasuda²,

Burnett³

1995

Proceedings of the Ocean Drilling Program

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Samples from Ocean Drilling Program Hole 893A were analyzed for paleotemperatures by determining the "U k , 7 " unsaturation index at about 3 k.y. resolution over the past 162 ka. Values of the unsaturation index at Hole 893A range from 0.415 to 0.696, corresponding to a total range in estimated paleotemperature of 8°C. Most of the variance is paced by the 41 k.y. obliquity cycle, although 100 k.y. eccentricity and 21 k.y. precessional components are present as well. The pattern of alkenone unsaturation indices over time is quite different from that produced by planktonic foraminiferal paleoclimatic proxies. We conclude that the alkenone record approximates the history of sea-surface temperature in the Santa Barbara Basin over the time period studied. Alkenone data suggest that Santa Barbara Basin sea-surface temperatures exceeded present values by about 4°d uring oxygen isotope Stage 5e. The Younger Dryas event may be represented as a 3° cooling that spanned several k.y. The predominance of the obliquity cycle in inferred glacial-interglacial changes in sea-surface temperature most likely reflects a real divergence of North Pacific sea-surface temperature from the classical picture of glacial-interglacial change based on oxygen isotope analyses. Alkenone abundances in the sediment vary by nearly two orders of magnitude. High abundances coincide with laminated facies, suggesting that oxygen content of basinal waters plays an important role in the preservation of these compounds.

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Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 89%

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Glacial-Interglacial Sea-Surface Temperature Record Inferred from Alkenone Unsaturation indices, Site 893, Santa Barbara Basin

Herbert¹,

Yasuda²,

Burnett³

1995

Proceedings of the Ocean Drilling Program

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“…Despite being considered a specific marker to assess the contamination caused by domestic sludge and presenting good resistance to degradation by microbial communities, especially in anoxic environments, a few authors such as Grimalt et al (1990) and McCaffrey (1990) pointed out some limitations to the exclusive use of coprostanol, due to two main factors: (1) lack of a quantitative criterion involving a certain level of coprostanol due to the presence of fecal contamination, (2) possible production of coprostanol in situ in anoxic sediments, which would be an independent source of coprostanol. Therefore, the analysis of coprostanol alone is not enough to evaluate whether an environment is contaminated by sewage or not, thus it is necessary to consider the ratios and concentrations among other sterols and ketones.…”

Section: Resultsmentioning

confidence: 99%

“…If the treatment of sludge takes a long time, epicoprostanol can form from cholesterol and relative proportions of those compounds may be used as an indicator of the presence of untreated sewage in the sediments. It can also be formed by bacterial action on the coprostanol (McCaffrey 1990) because it is structurally more stable.…”

Section: Resultsmentioning

confidence: 99%

Assessment of fecal sterols in Barigui River sediments in Curitiba, Brazil

Froehner

Martins

Errera

2008

Environ Monit Assess

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The Barigui River watershed is located in the metropolitan region of Curitiba, southern Brazil, passing through several neighboring counties. In recent years, due to growth and disorderly occupation along the river, in addition to lack of sanitation, the Basin suffered a very large inflow of untreated domestic sewage. Current programs to monitor the watershed use traditional physical-chemical parameters and generally the analysis is performed only with water samples. This study analyzes the presence of fecal sterols in sediment samples. Sediment samples were collected from six points along the river and the stanols were extracted, purified and analyzed by GC-MS. Eight compounds were analyzed, among sterols and ketones. The presence of coprostanol was also identified. Coprostanol is a stanol containing a large amount in human feces. It is found near sources of pollution and can be associated with contamination by domestic sewage. The results showed high concentrations of coprostanol, ranging from 0.25 to 196 mug g( - 1). The ratio of coprostanol and epicoprostanol, was below 0.20 at most stations, indicating that the sewage discharged into the river does not undergo prior treatment. Contamination by untreated sewage was also confirmed by ratios of isomeric forms of sterols and ketones 5beta/(5beta + 5alpha).

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Degradation and Preservation of Organic Matter in Marine Sediments

Wakeham

Canuel

The Handbook of Environmental Chemistry

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Sedimentary lipids as indicators of depositional conditions in the coastal Peruvian upwelling regime

Cited by 15 publications

References 51 publications

Glacial-Interglacial Sea-Surface Temperature Record Inferred from Alkenone Unsaturation indices, Site 893, Santa Barbara Basin

Glacial-Interglacial Sea-Surface Temperature Record Inferred from Alkenone Unsaturation indices, Site 893, Santa Barbara Basin

Assessment of fecal sterols in Barigui River sediments in Curitiba, Brazil

Degradation and Preservation of Organic Matter in Marine Sediments

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