In November2012,the study site was uniformly divided into twenty sampling
points along the Island with adistance of about 200m between two consecutive
sampling points(Fig. 1). At each sampling point,three random samples of surface
sediment were collected by a rectangular sampler (10cmlong10 cm
wide15cmdeep).To analyze the pollution history of heavymetals in the
mangrove,three core sediments amples were collected by a PVC core(10cmin
diameter66cmdeep) in the unvegetated area at sampling points N5,N10 and
N15 to minimize the effect of root up take(Fig. 1). According to the previous results
of 210Pb dating,the sedimentation rate in Nansha mangrove is approximately
2 cmyr1 (Chen andLuo,1991). Thus,the sediment sample in each core was cut
into 33layersfromthetopat2cmdepthintervalbyaPVCknifetorepresentthe
pollution historyfrom1979to2011.
Roots,stems and leaves of the dominant plants,namely S. apetala and
C. malaccensis, were also collected from sampling points N5,N10 and N15.Stems
and leaves of S. apetala were collected by cutting.Rootsof S. apetala were collected
together with sediment using the PVC core,followed by washing away the sediment.
C. malaccensis was collected by carefully removing the whole individual from
sediment and each collected individual was then separated into roots and leaves.
At each sampling point,three individuals were collected for each plant species
In November2012,the study site was uniformly divided into twenty sampling
points along the Island with adistance of about 200m between two consecutive
sampling points(Fig. 1). At each sampling point,three random samples of surface
sediment were collected by a rectangular sampler (10cmlong10 cm
wide15cmdeep).To analyze the pollution history of heavymetals in the
mangrove,three core sediments amples were collected by a PVC core(10cmin
diameter66cmdeep) in the unvegetated area at sampling points N5,N10 and
N15 to minimize the effect of root up take(Fig. 1). According to the previous results
of 210Pb dating,the sedimentation rate in Nansha mangrove is approximately
2 cmyr1 (Chen andLuo,1991). Thus,the sediment sample in each core was cut
into 33layersfromthetopat2cmdepthintervalbyaPVCknifetorepresentthe
pollution historyfrom1979to2011.
Roots,stems and leaves of the dominant plants,namely S. apetala and
C. malaccensis, were also collected from sampling points N5,N10 and N15.Stems
and leaves of S. apetala were collected by cutting.Rootsof S. apetala were collected
together with sediment using the PVC core,followed by washing away the sediment.
C. malaccensis was collected by carefully removing the whole individual from
sediment and each collected individual was then separated into roots and leaves.
At each sampling point,three individuals were collected for each plant species
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