Evaluating the influence of lake morphology, trophic status and diagenesis on geochemical profiles in lake sediments

Trolle, Dennis; Hamilton, David P.; Pilditch, Conrad A.

Evaluating the influence of lake morphology, trophic status and diagenesis on geochemical profiles in lake sediments

dc.contributor.author	Trolle, Dennis
dc.contributor.author	Hamilton, David P.
dc.contributor.author	Pilditch, Conrad A.
dc.date.accessioned	2010-03-15T23:41:37Z
dc.date.available	2010-03-15T23:41:37Z
dc.date.issued	2010
dc.description.abstract	Recent geochemical studies provide evidence that changes in vertical distributions of nutrients in lake sediments are driven by anthropogenic activities, based primarily on trends of increasing concentrations in upper sediment layers. However, we show that vertical concentration profiles of carbon (C), nitrogen (N) and phosphorus (P) in lake sediments can be higher in the upper, most recently deposited sediment strata, driven largely by natural diagenetic processes and not eutrophication alone. We examined sediment cores from 14 different lakes in New Zealand and China ranging from oligotrophic to highly eutrophic and shallow to deep, and found that the shape of vertical profiles of total P, a key nutrient for lake productivity, can be similar in sediments across gradients of widely differing trophic status. We derived and applied empirical and mechanistic diagenesis steady state profile models to describe the vertical distribution of C, N and P in the sediments. These models, which focus on large scale temporal (decades) and spatial (up to 35 cm in the vertical) processes, revealed that density-differentiated burial and biodiffusive mixing, were strongly correlated with vertical concentration gradients of sediment C, N and P content, whereas lake trophic status was not. A sensitivity analysis of parameters included in the diagenetic model further showed that the processes including flux of organic matter to the sediment-water interface, burial (net sedimentation), breakdown of organic matter and biodiffusion all significantly can influence the vertical distribution of sediment P content. We conclude that geochemical studies attempting to evaluate drivers of the vertical distribution of sediment C, N, and P content in lake sediments should also account for the natural diagenetic drivers of vertical concentration gradients, assisted with application of similar models to those presented in this study. This would include quantification of key sediment diagenesis model parameters to separate out the influence of anthropogenic activities.	en
dc.format.mimetype	application/pdf
dc.identifier.citation	Trolle, D., Hamilton, D. P. & Pilditch, C. (2010). Evaluating the influence of lake morphology, trophic status and diagenesis on geochemical profiles in lake sediments. Applied Geochemistry, 25(5), 621-632	en
dc.identifier.doi	10.1016/j.apgeochem.2010.01.003	en
dc.identifier.uri	https://hdl.handle.net/10289/3721
dc.language.iso	en
dc.publisher	Elsevier	en_NZ
dc.relation.isPartOf	Applied Geochemistry	en_NZ
dc.rights	This is an author’s accepted version of an article published in the journal: Applied Geochemistry. ©2010 Elsevier.	en
dc.subject	lake sediment	en
dc.subject	sediment	en
dc.subject	geochemical	en
dc.title	Evaluating the influence of lake morphology, trophic status and diagenesis on geochemical profiles in lake sediments	en
dc.type	Journal Article	en
pubs.begin-page	621	en_NZ
pubs.elements-id	34786
pubs.end-page	632	en_NZ
pubs.issue	5	en_NZ
pubs.volume	25	en_NZ