Reconstructing epilimnetic total phosphorus using diatoms: statistical and ecological constraints

Juggins, Steve; Anderson, Nicholas; Hobbs, Joy M. Ramstack; Heathcote, Adam J.

doi:10.1007/s10933-013-9678-x

Cited by 51 publications

(58 citation statements)

References 64 publications

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“…Aulacoseira subborealis) (Nygaard) Denys, Muylarert et Krammer, the most common diatom in MCR. The assumptions inherent in diatom-inferred reconstructions were not tested (Juggins et al 2013), but DI-TP is consistent with measured values (winter 2000-2003, p \ 0.05 Oneway ANOVA), most of the eligible taxa were planktonic, which better meets the inherent assumptions than benthic species (Juggins et al 2013), and for this study the trend in reconstructed values is more important than the absolute values. Shannon-Weiner diversity (H 0 ) was determined using PCORD software (McCune and Mefford 1999).…”

Section: Data and Statistical Analysismentioning

confidence: 68%

Diatom assemblages in a reservoir sediment core track land-use changes in the watershed

et al. 2015

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Diatom assemblages in a 144-cm sediment core reliably chronicled watershed changes and modifications of a riverine water-source reservoir in northeastern Ohio (USA) between 1932 and 2005. Non-metric Multidimensional Scaling segregated diatom assemblages into six groups that correspond to known anthropogenic modifications in the watershed and reservoir: zone I (filling, 1932-1936), zone II (high farming activity, [1937][1938][1939][1940][1941][1942][1943][1944][1945][1946][1947][1948][1949], zone III (declining farm activity and increased residential development, 1950-1976), zone IV (implementation of sewage bypass, 1977-1982), reduced development activity caused by economic recession, 1983-1993), zone VI (renewed population growth and construction of a dam extension, 1994-2005). Ten watershed and reservoir environmental variables (percent farmland, population, pH, total alkalinity, total hardness, transparency, surface area, air temperature, export of suspended solids, total phosphorus) were significantly correlated with diatom aggregate distribution in ordination space. Changes in species composition, in concert with watershed and reservoir changes, implicated light, alkalinity, and littoral macrophyte development as the primary drivers of diatom aggregate structure and function. Diatom productivity did not track nutrient loading (TP) and was likely driven by factors other than nutrients. Each zone was defined by a distinct set of environmental variables that differed from all other zones. Thus, diatom aggregate structure likely was determined by a dynamic suite of factors in the watershed and reservoir that had differential effects on diatom aggregate structure through time.

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Section: Data and Statistical Analysismentioning

confidence: 68%

Diatom assemblages in a reservoir sediment core track land-use changes in the watershed

et al. 2015

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“…A comparison of the relative TP optima between the dominant planktonic taxa in our dataset (Figure 3) with the dominant planktonic taxa from another large dataset from the Laurentian Great Lakes (Reavie et al, 2014), shows strong and significant correlation for the 17 planktonic taxa that are in common (r = 0.69, p = 0.002), whereas the correlation of the TP optima of the 11 benthic taxa in common is not significant (r = 0.15, p = 0.66). In an examination of eight relatively small regional datasets (each dataset between 42 and 152 lakes, median ∼68) Juggins et al (2013) found only 7 of 28 comparisons (or 25%) yielded significant, but weak correlations between the TP optima of benthic taxa, but 9 of 14 (or 64%) resulted in significant and much stronger correlations for planktonic taxa. These results are consistent with earlier observations of the weaker TP responses of benthic taxa that has been noted especially in shallow lakes (e.g., Bennion et al, 2001;Davidson and Jeppesen, 2013).…”

Section: Modern-day Calibration Datasetmentioning

confidence: 98%

“…Although changes in diatom assemblages in sediment cores, and the use of diatombased TP inferences have become widely accepted techniques for tracking trajectories associated with eutrophication (Hall and Smol, 2010), this approach may be misleading, especially if there have been violations made in the assumptions associated with the use of transfer functions (e.g., Juggins, 2013). As an example, there is particular concern over the confounding influence of secondary variables in the training sets, as well as poor or no spatial replicability in diatom optima to lake-water TP across different regional calibration datasets (Juggins, 2013;Juggins et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Tracking past changes in lake-water phosphorus with a 251-lake calibration dataset in British Columbia: tool development and application in a multiproxy assessment of eutrophication and recovery in Osoyoos Lake, a transboundary lake in Western North America

et al. 2015

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Recently, there has been an active discussion about the potential and challenges of tracking past lake-water trophic state using paleolimnological methods. Herein, we present analyses of the relationship between modern-day diatom assemblages from the surface sediments of 251 fresh-water lakes from British Columbia and contemporary limnological variables. Total phosphorus (TP) was significantly related to the modern distribution of diatom assemblages. The large size of this new calibration dataset resulted in higher abundances and occurrences of many diatom taxa thereby allowing a more accurate quantification of the optima of diatom taxa to TP in comparison to previous smaller calibration datasets. Robust diatom-based TP inference models with a moderate predictive power were developed using weighted-averaging regression and calibration. Information from the calibration dataset was used to interpret changes in the diatom assemblages from the north and south basins of Osoyoos Lake, in conjunction with fossil pigment analyses. Osoyoos Lake is a large salmon-bearing lake that straddles the British Columbia-Washington border and has undergone cultural eutrophication followed by recovery due to substantial mitigation efforts in managing sources of nutrients. Both diatom assemblages and sedimentary pigments indicate that eutrophication began c. 1950 in the north basin and c. 1960 in the southern basin, reaching peak levels of production between 1960 and 1990, after which decreases in sedimentary pigments occurred, as well as decreases in the relative abundance and concentrations of diatom Cumming et al.Tracking eutrophication and recovery using Paleolimnology taxa inferred to have high TP optima. Post-1990 changes in the diatom assemblage suggests conditions have become less productive with a shift to taxa more indicative of lower TP optima in concert with measurements of declining TP, although two of these diatom taxa, Cyclotella comensis and Cyclotella gordonensis, that were previously rare are now abundant.

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“…However, several studies have highlighted the shortcomings of the transfer function technique in certain situations, and this is particularly well documented for shallow lakes where non-planktonic taxa dominate the diatom assemblages. Problems include the influence of factors such as light, substrate, and top-down factors in addition to water chemistry on the distribution of these taxa and their wide tolerance to nutrient concentrations, making them poor indicators of lake trophic status (e.g., Anderson et al, 1993;Bennion, 1995;Bennion et al, 2001;Sayer, 2001;Juggins et al, 2013). Nonetheless, in the absence of other techniques for hindcasting nutrient concentrations, inference models are likely to remain a valuable part of the lake manager's toolkit (SaulnierTalbot, 2015).…”

Section: Cyclotella Radiosa Cyclostephanos Dubiusmentioning

confidence: 99%

Assessing degradation and recovery pathways in lakes impacted by eutrophication using the sediment record

2015

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Efforts to restore enriched lakes have increased yet there remains uncertainty about whether restoration targets can be achieved and over what timescale. Paleoecological techniques, principally diatom analyses, were used to examine the degree of impact and recovery in 12 European lakes subject to eutrophication and subsequent reduction in nutrient loading. Dissimilarity scores showed that all sites experienced progressive deviation from the reference sample (core bottom) prior to nutrient reduction, and principal curves indicated gradual compositional change with enrichment. When additive models were applied to the latter, the changes were statistically significant in 9 of the 12 sites. Shifts in diatom composition following reduction in nutrient loading were more equivocal, with a reversal toward the reference flora seen only in four of the deep lakes and one of the shallow lakes. Of these, only two were significant (Lake Bled and Mjøsa). Alternative nutrient sources seem to explain the lack of apparent recovery in the other deep lakes. In three shallow lakes diatom assemblages were replaced by a community associated with lower productivity but not the one seen prior to enrichment. Internal loading and top down control may influence recovery in shallow lakes and climate change may have confounded recovery in several of the study sites. Hence, ecosystem recovery is not simply a reversal of the degradation pathway and may take several decades to complete or, for some lakes, may not take place at all. By assessing ecological change over a decadal to centennial timescale, the study highlights the important role that paleolimnology can play in establishing a benchmark against which managers can evaluate the degree to which their restoration efforts are successful.

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Reconstructing epilimnetic total phosphorus using diatoms: statistical and ecological constraints

Cited by 51 publications

References 64 publications

Diatom assemblages in a reservoir sediment core track land-use changes in the watershed

Diatom assemblages in a reservoir sediment core track land-use changes in the watershed

Tracking past changes in lake-water phosphorus with a 251-lake calibration dataset in British Columbia: tool development and application in a multiproxy assessment of eutrophication and recovery in Osoyoos Lake, a transboundary lake in Western North America

Assessing degradation and recovery pathways in lakes impacted by eutrophication using the sediment record

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