Phosphorus dynamics in Danish lakes and the implications for diatom ecology and palaeoecology

Abstract

SUMMARY 1. Seasonal phosphorus variability may be considerable in eutrophic lakes and patterns are influenced by internal, as well as external, nutrient loading. The strong seasonality of planktonic diatoms, with main growth periods in the spring and also in the autumn in meso‐ to eutrophic lakes, means that the measure of total phosphorus (TP) that is most relevant for diatom ecology may not be adequately assessed by single or few measurements during the year. 2. The diatom species assemblage of surface sediments can be used to infer in‐lake nutrient concentrations. Weighted averaging (WA) and weighted averaging partial least squares (WAPLS) regression and calibration models for diatoms and annual mean TP were developed for a 29‐site data set of Danish lakes based on (a) all diatom species and (b) planktonic species only. Jack‐knifed error statistics were: =0.37, root mean squared error of prediction (RMSEP)=0.28 log10μg TP L−1 and mean bias=0.04 log10μg TP L−1 for the WAPLS 2‐component model based on all species; =0.23, RMSEP= 0.32log10μg TP L−1 and mean bias=0.07 log10μg TP L−1 for the WA model with tolerance downweighting based on planktonic species only. These are comparable with similar, published data sets. 3. A subset of 23 sites was used to develop models based on seasonal TP measurements. Mean spring TP concentrations gave only slightly improved RMSEP values for models based on all species and plankton‐only (0.24 log10μg TP L−1 and 0.29 log10μg TP L−1, respectively). 4. Weighted averaging models derive environmental optima, for individual species, which are not necessarily of ecological relevance. However, good water chemistry data are required to model species' responses adequately and to develop calibration data sets.

Diatoms from Lake Kushu: A pilot study to test the potential of a Late Quaternary palaeoenvironmental archive from Rebun Island (Hokkaido Region, Japan)

“…Krammer and Lange-Bertalot (2000) mentioned the difficulty of the named-by-synonym Fragilaria pinnata-taxon (see also Morales et al, 2013) and suggest S. pinnata to be a very tolerant species concerning pH (<7 up to 9.3) and trophic level (oligo-to eutrophic; Van Dam et al, 1994). B. berolinensis is a planktonic colonial form associated with alkaline, eutrophic (Van Dam et al, 1994) unless hypereutrophic conditions (Bradshaw et al, 2002) which fits very well with the measured water parameters.…”

“…9a). In comparison to the modern Lake Kushu samples, mesotraphentic A. ambigua (Reynolds, 1998;Poister et al, 2012) is replaced by highly eutraphentic N. palea and B. berolinensis (Bradshaw et al, 2002;Trobajo et al, 2009) indicating an increase in nutrient concentrations within the last 300 yr BP.…”

Environmental change over the last millennium recorded in two contrasting crater lakes in western Uganda, eastern Africa (Lakes Kasenda and Wandakara)

“…Cyclotella meneghiniana is found in the plankton in nutrient-enriched lakes in diverse landscapes (e.g. Bradshaw et al, 2002;Dong et al, 2008), and so may be more indicative of higher productivity rather than increased salinity. Inputs of nutrients from the catchment, and/or increased availability within the water column (from cyanophyte decomposition or recycling from profundal sediments), together with lower salinity (a wetter period) may have provided ideal conditions for a short period when this diatom could bloom.…”

Seasonal Diatom Variability and Paleolimnological Inferences – A Case Study

“…Therefore, knowledge of the responses of the organisms to environmental variability at finer temporal scales is necessary for more refined interpretations of the paleolimnological record (Reynolds 1990). Although Smol (1990) stressed the need for more communication between ecologists and paleoecologists, few researchers have established this link between neoand paleolimnological studies (Siver and Hamer 1992;Bradbury and Dieterich-Rurup 1993;Bennion and Smith 2000;Lotter and Bigler 2000;Pienitz and Vincent 2000;Bradshaw et al 2002;Chu et al 2005).…”