Diatom response to heavy metal pollution and nutrient enrichment in an urban lake: evidence from paleolimnology

Abstract

-Diatoms and geochemical stratigraphy were studied in sediment core samples collected from a heavily polluted urban lake (SE China) in order to track the history of eutrophication and heavy metal contamination. The sediment profile covered ca. 60 years (from ca. 1951 to 2011) based on 137 Cs and Spheroidal carbonaceous particles (SCP) dating, and encompassed a period of rapid industrial development in this region. Diatoms experienced two visible shifts, including the replacement of benthic and epiphytic taxa by planktonic species (e.g., Cyclotella meneghiniana Ku¨tzing) in 1972, and the dominance of Cyclotella atomus Hustedt and Nitzschia palea (Ku¨tzing) W. Smith after 1999. Metals (i.e., Cd, Pb and Zn), total phosphorus, total nitrogen and total organic carbon all increased in the past 60 years. Redundancy analysis was used to correlate diatom with chemical change and explained 50.3-60% of total variation in diatom data for three periods (from 1951 to 1999, between 1951 and 2011 and from 1972 to 2011). The combined effects of nutrients and metals were the predominant factor, capturing 29.6-42.8% of the total variance. Nutrients alone accounted for little more variance than did metals alone for the first flora shift about 1972. The further shift after 1999 was more influenced by the sole effect of metals than that of nutrients. Increases in species (e.g., N. Palea) able to tolerate both nutrient-related and metal-related stressors were related to persistent nutrient and metal inputs. In addition, climate warming might exacerbate eutrophication and metal contamination in this lake.

The complete chloroplast and mitochondrial genomes of the diatomNitzschia palea(Bacillariophyceae) demonstrate high sequence similarity to the endosymbiont organelles of the dinotomDurinskia baltica

“…, Chen et al. ). All members of N. palea have lanceolate to linear‐lanceolate valves terminated with rostrate to subcapitate apices.…”

Sedimentary Evidence of Environmental Degradation in Sanliqi Lake, Daye City (A Typical Mining City, Central China)

“…The chronology was linearly extrapolated below 28 cm and so the mean sedimentation rate was the same as the above timespan . Detailed dating results are provided in Chen et al (2014).…”

“…Nitzschia palea, Cyclotella meneghiniana and Aulacoseira granulata) are displayed in this study. Detailed diatom results are shown in Chen et al (2014).…”

“…Between 1951 and 1993, high abundances (14 %-44 %) of A. granulata, a species preferring turbulent and mesoeutrophic conditions but relatively sensitive to heavy metals (Yang et al 2008;Chen et al 2014), reflected a well-mixed and nutrient-rich habitats. Meanwhile, percentages of C. meneghiniana and N. palea increased clearly (Fig.…”

Combined effects of nutrients and trace metals on chironomid composition and morphology in a heavily polluted lake in central China since the early 20th century

“…Daye Lake and its 15 sub-lakes 76 suffer from both eutrophication and metals pollution (Li & Zhang, 2010) and thus provide ideal sites 77 for studying the combined effects of nutrients and heavy metals on the lake biota. However, currently 78 available reports from these lakes are focused solely on metals, including their sources, distribution and 79 changes in concentration during the last decade (Lu et al, 2012;Mao et al, 2013), and few studies 80 have addressed the impacts of pollutants on organisms (Chen et al, , 2014. In the case of 81 paleolimnological studies of Daye Lake and its sub-lakes, only diatoms have been studied in order to 82 detect the relationships between pollutants and biota, and this work provides a reference for further 83 studies on the environmental reconstruction of these lakes (Chen et al, 2014).…”