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The effects of cadmium pulse dosing on physiological traits and growth of the submerged macrophyte Vallisneria spinulosa and phytoplankton biomass: a mesocosm study

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  • Wuhan Botanical Garden, Chinese Academy of Sciences
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Pulse inputs of heavy metals are expected to increase with a higher frequency of extreme climate events (heavy rain), leading to stronger erosion of contaminated and fertilized farmland soils to freshwaters, with potentially adverse effects on lake ecosystems. We conducted a 5-month mesocosm study to elucidate the responses of the submerged macrophyte Vallisneria spinulosa and phytoplankton to four different doses of cadmium (Cd): 0 (control), 0.05, 0.5, and 5 g m(-2) (CK, I, II, and III, respectively) under mesotrophic conditions. We found that total phosphorus concentrations were larger in the three Cd pulse treatments, whereas total nitrogen concentrations did not differ among the four treatments. The contents of chlorophyll a and soluble sugar in macrophyte leaves decreased in III, and total biomass, ramet number, plant height, and total stolon length of macrophytes were lower in both II and III. In contrast, abundances of the three main phytoplankton taxa-Cyanophyta, Chlorophyta, and Bacillariophyta-did not differ among treatments. Total phytoplankton biomass was, however, marginally lower in CK than in the Cd treatments. We conclude that exposure to strong Cd pulses led to significantly reduced growth of macrophytes, while no obvious effect appeared for phytoplankton.
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RESEARCH ARTICLE
The effects of cadmium pulse dosing on physiological traits
and growth of the submerged macrophyte Vallisneria spinulosa
and phytoplankton biomass: a mesocosm study
Hui Liu
1,2
&Yu Cao
2,3
&Wei L i
3,4
&Zhao Zhang
5
&Erik Jeppesen
4,6
&Wei Wang
2,3
Received: 30 November 2016 /Accepted: 1 May 2017 /Published online: 13 May 2017
#Springer-Verlag Berlin Heidelberg 2017
Abstract Pulse inputs of heavy metals are expected to in-
crease with a higher frequency of extreme climate events
(heavy rain), leading to stronger erosion of contaminated
and fertilized farmland soils to freshwaters, with potentially
adverse effects on lake ecosystems. We conducted a 5-month
mesocosm study to elucidate the responses of the submerged
macrophyte Vallisneria spinulosa and phytoplankton to four
different doses of cadmium (Cd): 0 (control), 0.05, 0.5, and
5gm
2
(CK, I, II, and III, respectively) under mesotrophic
conditions. We found that total phosphorus concentrations
were larger in the three Cd pulse treatments, whereas total
nitrogen concentrations did not differ among the four treat-
ments. The contents of chlorophyll a and soluble sugar in
macrophyte leaves decreased in III, and total biomass, ramet
number, plant height, and total stolon length of macrophytes
were lower in both II and III. In contrast, abundances of the
three main phytoplankton taxaCyanophyta, Chlorophyta,
and Bacillariophytadid not differ among treatments. Total
phytoplankton biomass was, however, marginally lower in
CK than in the Cd treatments. We conclude that exposure to
strong Cd pulses led to significantly reduced growth of mac-
rophytes, while no obvious effect appeared for phytoplankton.
Keywords Extreme events .Cd .Submerged macrophyte .
Phytoplankton .Pulse loading .Heavy metal
Introduction
Cadmium (Cd) is known for its toxicity in animals and human
as it can induce dysfunction of the kidneys and interferes with
bone metabolism (Godt et al. 2006; Prozialeck and Edwards
2012). It is a typical heavy metal pollutant that is not easily
biodegradable and becomes enriched up through the food
chain. Thus, it continuously accumulates in the environment
and poses a potential threat to public health (Duc Phuc et al.
2016;Nawrotetal.2006; Wagner 1993).
Natural Cd release into waters and soil generally occurs
slowly from bedrocks or parent material (Jensen and Bro-
Rasmussen 1992; Kabata-Pendias 2010). However, Cd in
streams, rivers, and lakes has increased from pre-industrial
background concentrations of 0.00010.002 mg L
1
to an
average concentration in world rivers of 0.08 mg L
1
(Cullen and Maldonado 2013). Cd concentrations of 0.1
0.9 mg L
1
in lake water have been reported, and in some
heavy metal-polluted waters in China, as much as
4.5mgL
1
has been recorded (Deng et al. 2014,and
references herein). Meanwhile, according to the
Communique of the National Soil Pollution Survey (2014),
Responsible editor: Elena Maestri
*Wei Wa ng
wangwei@wbgcas.cn
1
Key Laboratory of Ecological Impacts of Hydraulic-Projects and
Restoration of Aquatic Ecosystem of Ministry of Water Resources,
Institute of Hydroecology, Ministry of Water Resources,
Chinese Academy of Sciences, Wuhan 430079, China
2
Key Laboratory of Aquatic Botany and Watershed Ecology,
Wuhan Botanical Garden, Chinese Academy of Sciences,
Wuhan, Hubei 430074, China
3
Hubei Key Laboratory of Wetland Evolution & Ecological
Restoration, Wuhan Botanical Garden, Chinese Academy of
Sciences, Wuhan 430074, China
4
Sino-Danish Centre for Education and Research (SDC),
Beijing, China
5
Xian Botanical Garden of Shaanxi Province, Institute of Botany of
Shaanxi Province, Xian, Shaanxi 710061, China
6
Lake Ecology Section, Department of Bioscience,
Aarhus University, 8600 Silkeborg, Denmark
Environ Sci Pollut Res (2017) 24:1530815314
DOI 10.1007/s11356-017-9155-6
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
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