Lignin geochemistry of a Late Quaternary sediment core from Lake Washington

Hedges, John I.; Ertel, John R.; Leopold, Estella B.

doi:10.1016/0016-7037(82)90125-9

Cited by 141 publications

(49 citation statements)

References 25 publications

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“…2009). The extent of oxygenic diagenetic alteration of lignin phenols can be examined from the ratios of vanillic acid to vanillin (Ac : Al) v and syringic acid to syringealdehyde (Ac : Al) s (Hedges et al 1982;Ertel and Hedges 1985). In core M98-1P these ratios are relatively constant throughout the past 23 kyr B.P., with values falling within a range that indicates the lignin is well-preserved (Castañ eda et al.…”

Section: Discussionmentioning

confidence: 99%

Influence of climate change on algal community structure and primary productivity of Lake Malawi (East Africa) from the Last Glacial Maximum to present

Castañeda

Werne

Johnsona

2009

Limnology & Oceanography

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Biomarkers of aquatic algae and compound-specific carbon isotopes are used to examine past variations in algal community composition and primary productivity in Lake Malawi. We note major changes at the Pleistocene-Holocene boundary. From the Last Glacial Maximum until ,11.8 calendar years before present (kyr B.P.), Lake Malawi was characterized by either low rates of primary productivity or algal productivity that was dominated by a group other than diatoms. At the onset of the Holocene, conditions similar to those of modern Lake Malawi were initiated, with diatoms and nitrogen-fixing cyanobacteria becoming more important contributors to primary productivity. The transition at ,11.8 kyr B.P. is likely related to a shift in the dominant wind direction over Lake Malawi, resulting from a southward shift in the mean latitudinal position of the Intertropical Convergence Zone during the last glacial. Throughout the 23-kyr B.P. record, the effects of windinduced upwelling are important and may be the main control on the carbon isotopic composition of algal lipids through delivery of 13 C-depleted CO 2 , derived from organic matter decomposition in deeper waters, to the photic zone. Relationships are also suggested between thermal stratification and primary productivity, with cool conditions at ,12 and 8 kyr B.P. resulting in weaker thermal stratification and increased primary productivity. The opposite situation occurs at 4.9 kyr B.P., when significantly warmer temperatures and decreased algal productivity are observed. Thus, in lentic systems such as Lake Malawi the major influence of climate on algal ecology appears to be through feedbacks in physical circulation mechanisms.

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Section: Discussionmentioning

confidence: 99%

Influence of climate change on algal community structure and primary productivity of Lake Malawi (East Africa) from the Last Glacial Maximum to present

Castañeda

Werne

Johnsona

2009

Limnology & Oceanography

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“…British Council grant JRP472. Taylor et al (1992), Francis (1984Francis ( , 1986, Ash and Creber (1992), Francis et al (1994), Jefferson and Taylor (1983), Yadav and Bhattacharyya (1996), Poole and Francis (1999), 5 Morgans et al (1999), Francis (1986), 6 Francis and Poole (2002), Hunt and Poole (2003), Poole et al (2005), 7 Hedges et al (1982), Gon˜i (1997), Kuder and Kruge (1998), 8 van Aarssen et al (2000), Otto et al (1994), 9 Jones (1994), Hesselbo et al (2000), Gro¨cke et al (1999), van Bergen and Poole (2002), Poole et al 2004, 10 Spike andHatcher (1987), Loader et al (2003), 11 Spiker and Hatcher (1987), Bates and Spiker (1992), Lu¨cke et al (1999), 12 Anderson et al (1998), Sauer et al (2000, 13 Lipp et al (1996), Mayr et al (2003), 14 Poole et al (2004). Solid grey line indicates certain applicability of each methodology, dotted grey line indicates the possible applicability if all caveats are acknowledged and discussed (authors' opinion).…”

Section: Resultsmentioning

confidence: 99%

“…Lignin-derived markers have been used to evaluate changes in vegetation composition which in turn were believed to be climate driven (Hedges et al 1982;Gon˜i 1997;Sheng Hu et al 1999). However, the use of molecular markers only indirectly reflects climate changes.…”

Section: Climate Induced Vegetation Changesmentioning

confidence: 99%

Physiognomic and chemical characters in wood as palaeoclimate proxies

Poole

Bergen

2006

Plant Ecol

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Fossil wood is both abundant and ubiquitous through geological time and space. During growth the parent plant was directly influenced by the biotic and abiotic (including climatic-) factors in the surrounding environment. The climate affects wood production in a number of ways and it is the resulting physiognomic and chemical characters that can help retrodict palaeoclimate. Physiognomic characters include those morphological and anatomical characters that in turn have enabled the use of wood characters, tree ring characters and statistical parameters (Mean Sensitivity) to determine seasonality, length and favourability of growing season, growth rates and forest productivity. Potential chemical characters discussed include (i) the preservation of wood-derived compounds (e.g. guaiacyl, syringyl p-hydroxyphenyl and resins); (ii) degree of lignin degradation to determine climate induced environmental changes; and (iii) stable isotopes (dD, d13 C and d 18 O) to help determine aspects of past climates as derived from environmental changes. The feasibility and methodology of these characters, in both angiosperm and conifer wood, are reviewed in order to establish certain safe guards, or prerequisites, such that interpretations of palaeoclimate can be as unbiased, and thus as reliable, as possible.

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“…CuO oxidation, but not alkaline nitrobenzene oxidation, is widely applied to investigate aromatic moieties of lignin in the field of geochemistry, palaeogeography and so on 5,14,15,29,45,46,48 , to avoid production of by-products from nitrobenzene 14 . Alkaline CuO oxidation gives significant amount of p-hydroxyacetophenones such as acetovanillon and acetosyringone 14,15,46 , and total yield of monomeric oxidation products is considerably lower than that by alkaline nitrobenzene oxidation because of different reaction mechanism between both the procedures 6,22 .…”

Section: Introductionmentioning

confidence: 99%

“…Alkaline CuO oxidation gives significant amount of p-hydroxyacetophenones such as acetovanillon and acetosyringone 14,15,46 , and total yield of monomeric oxidation products is considerably lower than that by alkaline nitrobenzene oxidation because of different reaction mechanism between both the procedures 6,22 . In this study, peat samples collected from tropical peat swamps at Narathiwat Province, southern Thailand, were characterised by analytical methods used in plant cell wall science instead of procedures used in soil organic chemistry.…”

Section: Introductionmentioning

confidence: 99%