Sedimentary Pigments

Leavitt, Peter R.; Hodgson, Dominic A.

doi:10.1007/0-306-47668-1_15

Cited by 165 publications

(246 citation statements)

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“…The lowest r values were obtained for pairwise comparisons between GSR at the shallowest and deepest locations, underlining the discrepancy of sedimentological processes in these zones. On the other hand, the seasonal covariance in POM-normalized content of photopigments in different traps was rather high, and r was higher for b-car, which is less degradable than Chl a (Leavitt and Hodgson 2001). This finding suggests similar seasonal dynamics of settling POM, especially algal-based organic particles, across the water body and confirms lateral uniformity of temporally averaged distributions of algae in the upper productive stratum.…”

Section: Discussionmentioning

confidence: 56%

“…We used Chl a and b-car to characterize the entire phytoplankton community, as these pigments are harbored by all oxygenic photosynthetic organisms, with the exception of cryptophytes, which lack b-car (Rowan 1989). To characterize the fate of newly produced algal material as a whole, we used the difference in degradability of these most common algal pigments (Leavitt and Hodgson 2001) as the basis for comparing euphotic zone pigment composition to that of recently settled material, as previously suggested by Yacobi and Ostrovsky (2008). First, for sake of comparison of pigment abundance in the water column and in the traps, the following pigment indices (PI) were calculated:…”

Section: Methodsmentioning

confidence: 99%

“…Trap performance with respect to POM-b-car is the least degradable photopigment (Leavitt and Hodgson 2001); therefore, FI b-car seems an appropriate index of trap sampling efficiency of algae-associated particles in comparison to A up and can also indicate particle overtrapping with values . 1.…”

Section: Sedimentation In the Bbl Vs The Hypolimnion Interior-mentioning

confidence: 99%

“…Further, we studied the seasonal dynamics and composition of POM accumulated in traps, with special emphasis on the most common thylakoid-bound pigments as markers of algal biomass. We used the difference in degradability of Chl a and b-carotene (b-car) (Leavitt and Hodgson 2001) to follow the fate of newly produced algal material on sinking. Finally, we quantified the proportion of new POM exported from the upper productive layer by sedimentation and discuss the factors affecting material sedimentation over the annual cycle.…”

mentioning

confidence: 99%

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Sedimentation flux in a large subtropical lake: Spatiotemporal variations and relation to primary productivity

Ostrovsky

Yacobi

2010

Limnology & Oceanography

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Spatial and temporal heterogeneity in sedimentation of particulate organic material (POM) was studied in a large subtropical lake, and its export from the upper mixed layer was quantified. Sedimentation fluxes were measured over 4 yr with traps deployed in pelagic and littoral areas, the benthic boundary layer (BBL), and the lake interior. Analysis of fluxes and composition of collected material showed that traps deployed at the lake periphery and in the BBL notably overestimate the export flux of newly produced POM. The best estimation of the primary production (PP) export from the upper mixed layer was achieved when traps were deployed in the quiescent hypolimnion, where the effect of lake boundaries is negligible. The proportion and composition of POM exported from the upper productive stratum was dependent on lake thermal and chemical structure and on the dominant phytoplankton species. The dynamics of photopigments (chlorophyll and b-carotene) collected in hypolimnetic traps reflected the composition and abundance of phytoplankton in the upper mixed stratum. Despite large variation in algal community composition, the ratio of POM sedimentation flux to PP (export ratio) changed only slightly (average , 20%) throughout the stratified period. The observed temporal and spatial variability of sedimentation flux in response to ambient conditions was influenced by secondary processes (resuspension at the lake boundaries and oversampling under turbulent conditions) as intensely as by the actual export of POM.

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Section: Discussionmentioning

confidence: 56%

Section: Methodsmentioning

confidence: 99%

Section: Sedimentation In the Bbl Vs The Hypolimnion Interior-mentioning

confidence: 99%

mentioning

confidence: 99%

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Sedimentation flux in a large subtropical lake: Spatiotemporal variations and relation to primary productivity

Ostrovsky

Yacobi

2010

Limnology & Oceanography

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“…Further, because algal sedimentation is known to be the main mechanism removing N from these lakes (Patoine et al 2006), we hypothesized that urban effects would decline rapidly because of sequestration of urban N in lake sediments. When combined with paleolimnological reconstructions of lake production using chemically stable fossil pigments (reviewed in Leavitt and Hodgson 2001), our isotopic analysis sought to demonstrate both that lake eutrophication could arise from N pollution and that such P-sufficient lakes had substantial capabilities to ameliorate degradation of downstream ecosystems, such as has been suggested for wetlands and storm-water retention ponds (e.g., Gerke et al 2001). …”

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confidence: 99%

Landscape-scale effects of urban nitrogen on a chain of freshwater lakes in central North America

et al. 2006

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We measured nitrogen (N) transport to and storage in nine lakes linked by the Qu'Appelle River, Saskatchewan, Canada, to quantify the unique effects of N on the eutrophication of phosphorus (P)-replete lakes. Stable isotope content (d 15 N) was measured for dissolved N, periphyton, particulate organic matter (POM), and sediment samples collected at 10 stations along Wascana Creek and the Qu'Appelle River, lotic ecosystems that receive wastewaters from the City of Regina and that drain into Pasqua Lake. Urban effluent (d 15 N ,16 6 2%) enriched dissolved N isotope ratios of river water by up to 15% but was not stored in lotic sediments. Instead, urban N increased d 15 N signatures of lotic periphyton and POM by 10-15% and was transported to Pasqua Lake, where sedimentary d 15 N values increased from ,6.5% during the 19th century to 14.0% by the 1990s. This increase was linearly correlated both to the mass of dissolved N released from Regina (r 2 5 0.84, p , 0.0001) and to a 300% increase in the production of Pasqua Lake (as fossil pigments) since ca. 1880 (r 2 5 0.69, p , 0.0001). Similar isotopic enrichment was recorded in five downstream lakes, but not three reference ecosystems, although the degree of downstream enrichment declined rapidly, mainly as a result of sequestration of urban N in lake sediments. Together, these patterns demonstrate that urban N can directly degrade surface waters of P-sufficient lakes, but that these ecosystems can eliminate urban effects through permanent storage of wastewater N in their sediments.

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Melanosomes and ancient coloration re‐examined: A response to Vinther 2015 (DOI 10.1002/bies.201500018)

Schweitzer¹,

Moyer²

2015

BioEssays

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Round to elongate microbodies associated with fossil vertebrate soft tissues were interpreted as microbial traces until 2008, when they were re-described as remnant melanosomes -intracellular, pigment-containing eukaryotic organelles. Since then, multiple claims for melanosome preservation and inferences of organismal color, behavior, and physiology have been advanced, based upon the shape and size of these microstructures. Here, we re-examine evidence for ancient melanosomes in light of information reviewed in Vinther (2015), and literature regarding the preservation potential of microorganisms and their exopolymeric secretions. We: (i) address statements in Vinther's recent (2015) review that are incorrect or which misrepresent published data; (ii) discuss the need for caution in interpreting ''voids'' and microbodies associated with degraded fossil soft tissues; (iii) present evidence that microorganisms are in many cases an equally parsimonious source for these ''voids'' as are remnant melanosomes; and (iv) suggest methods/criteria for differentiating melanosomes from microbial traces in the fossil record.

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Sedimentary Pigments

Cited by 165 publications

References 91 publications

Sedimentation flux in a large subtropical lake: Spatiotemporal variations and relation to primary productivity

Sedimentation flux in a large subtropical lake: Spatiotemporal variations and relation to primary productivity

Landscape-scale effects of urban nitrogen on a chain of freshwater lakes in central North America

Melanosomes and ancient coloration re‐examined: A response to Vinther 2015 (DOI 10.1002/bies.201500018)

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