Limits...
Industrial arsenic contamination causes catastrophic changes in freshwater ecosystems.

Chen G, Shi H, Tao J, Chen L, Liu Y, Lei G, Liu X, Smol JP - Sci Rep (2015)

Bottom Line: Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies.Concurrently, coherent responses in keystone biota signal pronounced ecosystem changes, with a >10-fold loss in crustacean zooplankton (important herbivores in the food webs of these lake systems) and a >5-fold increase in a highly metal-tolerant alga.Such fundamental ecological changes will cascade through the ecosystem, causing potentially catastrophic consequences for ecosystem services in contaminated regions.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Plateau Lake Ecology and Global Change, School of Tourism and Geography, Yunnan Normal University, Kunming, Yunnan, China.

ABSTRACT
Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies. Due to the frequent absence of long-term monitoring data, little is known of the long-tem ecological consequences of pollutants such as arsenic. Here, our dated sediment records from two contaminated lakes in China faithfully document a 13.9 and 21.4-fold increase of total arsenic relative to pre-1950 background levels. Concurrently, coherent responses in keystone biota signal pronounced ecosystem changes, with a >10-fold loss in crustacean zooplankton (important herbivores in the food webs of these lake systems) and a >5-fold increase in a highly metal-tolerant alga. Such fundamental ecological changes will cascade through the ecosystem, causing potentially catastrophic consequences for ecosystem services in contaminated regions.

No MeSH data available.


Related in: MedlinePlus

Multiple-proxy sediment records of the two study lakes from Yunnan, China, tracking limnological changes over the last century.(a,e) Total arsenic concentrations of sediment samples; (b,f) Fluxes of Bosmina (black) and Daphnia (brown, in Datun Lake the total cladoceran flux is shown as Daphnia was present in only six out of the 30 samples); (c,g) Gradient length of sediment diatom composition based on detrended correspondence analysis (DCA axis one score, black) and relative abundance of benthic diatom Achnanthidium minutissimum (red); (d,h) Stratigraphies of visible reflectance spectroscopy (VRS) chlorophyll a concentrations (black) and total nitrogen (TN) content (purple). The x-axis denotes sediment age in calendar years as estimated by 210Pb analysis (Supplementary Fig. 4) and the red dashed lines show the timings of significant industrial arsenic discharges at Yangzong Lake and Datun Lake.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4663503&req=5

f2: Multiple-proxy sediment records of the two study lakes from Yunnan, China, tracking limnological changes over the last century.(a,e) Total arsenic concentrations of sediment samples; (b,f) Fluxes of Bosmina (black) and Daphnia (brown, in Datun Lake the total cladoceran flux is shown as Daphnia was present in only six out of the 30 samples); (c,g) Gradient length of sediment diatom composition based on detrended correspondence analysis (DCA axis one score, black) and relative abundance of benthic diatom Achnanthidium minutissimum (red); (d,h) Stratigraphies of visible reflectance spectroscopy (VRS) chlorophyll a concentrations (black) and total nitrogen (TN) content (purple). The x-axis denotes sediment age in calendar years as estimated by 210Pb analysis (Supplementary Fig. 4) and the red dashed lines show the timings of significant industrial arsenic discharges at Yangzong Lake and Datun Lake.

Mentions: Geochemical analyses clearly identified significant enrichment of arsenic in the sediments of both contaminated lakes, a trend that parallels the water monitoring records (Figs 1b and 2). During the pre-1950 period, sediment arsenic levels have remained stable with a mean value of 34.4 ± 5.1 (±1 SD) μg g−1 dry weight at Yangzong Lake and of 44.2 ± 7.1 (±1 SD) μg g−1 dry weight at Datun Lake (Fig. 2a,e). Thereafter, at around 2007, total arsenic concentrations spiked with a peak value of 479 and 949 μg g−1 dry weight, respectively (i.e.13.9 and 21.4 times pre-1950 background levels). It is likely that even these striking increases are conservative estimates of arsenic pollution because sediment records likely underestimate the lakewater arsenic levels (Fig. 1b), as only about 40–90% of metal input are typically retained in lake sediments2223. A lack of a regional pattern of synchronous changes in arsenic among our study lakes and neighboring systems24 confirms that atmospheric inputs2526 could not explain the striking arsenic spikes in our affected lakes.


Industrial arsenic contamination causes catastrophic changes in freshwater ecosystems.

Chen G, Shi H, Tao J, Chen L, Liu Y, Lei G, Liu X, Smol JP - Sci Rep (2015)

Multiple-proxy sediment records of the two study lakes from Yunnan, China, tracking limnological changes over the last century.(a,e) Total arsenic concentrations of sediment samples; (b,f) Fluxes of Bosmina (black) and Daphnia (brown, in Datun Lake the total cladoceran flux is shown as Daphnia was present in only six out of the 30 samples); (c,g) Gradient length of sediment diatom composition based on detrended correspondence analysis (DCA axis one score, black) and relative abundance of benthic diatom Achnanthidium minutissimum (red); (d,h) Stratigraphies of visible reflectance spectroscopy (VRS) chlorophyll a concentrations (black) and total nitrogen (TN) content (purple). The x-axis denotes sediment age in calendar years as estimated by 210Pb analysis (Supplementary Fig. 4) and the red dashed lines show the timings of significant industrial arsenic discharges at Yangzong Lake and Datun Lake.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663503&req=5

f2: Multiple-proxy sediment records of the two study lakes from Yunnan, China, tracking limnological changes over the last century.(a,e) Total arsenic concentrations of sediment samples; (b,f) Fluxes of Bosmina (black) and Daphnia (brown, in Datun Lake the total cladoceran flux is shown as Daphnia was present in only six out of the 30 samples); (c,g) Gradient length of sediment diatom composition based on detrended correspondence analysis (DCA axis one score, black) and relative abundance of benthic diatom Achnanthidium minutissimum (red); (d,h) Stratigraphies of visible reflectance spectroscopy (VRS) chlorophyll a concentrations (black) and total nitrogen (TN) content (purple). The x-axis denotes sediment age in calendar years as estimated by 210Pb analysis (Supplementary Fig. 4) and the red dashed lines show the timings of significant industrial arsenic discharges at Yangzong Lake and Datun Lake.
Mentions: Geochemical analyses clearly identified significant enrichment of arsenic in the sediments of both contaminated lakes, a trend that parallels the water monitoring records (Figs 1b and 2). During the pre-1950 period, sediment arsenic levels have remained stable with a mean value of 34.4 ± 5.1 (±1 SD) μg g−1 dry weight at Yangzong Lake and of 44.2 ± 7.1 (±1 SD) μg g−1 dry weight at Datun Lake (Fig. 2a,e). Thereafter, at around 2007, total arsenic concentrations spiked with a peak value of 479 and 949 μg g−1 dry weight, respectively (i.e.13.9 and 21.4 times pre-1950 background levels). It is likely that even these striking increases are conservative estimates of arsenic pollution because sediment records likely underestimate the lakewater arsenic levels (Fig. 1b), as only about 40–90% of metal input are typically retained in lake sediments2223. A lack of a regional pattern of synchronous changes in arsenic among our study lakes and neighboring systems24 confirms that atmospheric inputs2526 could not explain the striking arsenic spikes in our affected lakes.

Bottom Line: Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies.Concurrently, coherent responses in keystone biota signal pronounced ecosystem changes, with a >10-fold loss in crustacean zooplankton (important herbivores in the food webs of these lake systems) and a >5-fold increase in a highly metal-tolerant alga.Such fundamental ecological changes will cascade through the ecosystem, causing potentially catastrophic consequences for ecosystem services in contaminated regions.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Plateau Lake Ecology and Global Change, School of Tourism and Geography, Yunnan Normal University, Kunming, Yunnan, China.

ABSTRACT
Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies. Due to the frequent absence of long-term monitoring data, little is known of the long-tem ecological consequences of pollutants such as arsenic. Here, our dated sediment records from two contaminated lakes in China faithfully document a 13.9 and 21.4-fold increase of total arsenic relative to pre-1950 background levels. Concurrently, coherent responses in keystone biota signal pronounced ecosystem changes, with a >10-fold loss in crustacean zooplankton (important herbivores in the food webs of these lake systems) and a >5-fold increase in a highly metal-tolerant alga. Such fundamental ecological changes will cascade through the ecosystem, causing potentially catastrophic consequences for ecosystem services in contaminated regions.

No MeSH data available.


Related in: MedlinePlus