region was 64.8 kg N ha
À1 year
À1 (range, 59.1–70.5 kg N ha
À1 year
À1 ). On an
annual basis, the ratio of reduced to oxidized N deposition was 1.7, suggesting that
the reduced form of N dominates N deposition. Of the annual N deposition, 45.5%
was deposited via precipitation, with the remaining via dry deposition. The total
gaseous and particulate N deposition was 24.9 and 10.4 kg N ha
À1 year
À1 , respectively. The high N loading in this region has resulted in the reduction of water quality
in Lake Taihu. Atmospheric N deposition accounted for 33.3 and 27.5% of the total
N loading in Lake Taihu and in water bodies in the region, respectively. This study
confirmed that atmospheric deposition of N is one of the most important sources of
surface water pollution and should be taken into account when developing strategies
for mitigating water pollution.
Decreases in riverine N inputs from watersheds are expected to continue into the
future as China aims to lower the N inputs from reusing reclaimed water and urban
stormwater (Water pollution control action plan 2015). Current projections of
increasing NH 3 emissions (Sutton et al. 2013), meanwhile, suggest that N deposition
levels, especially reduced N, will increase and form a larger fraction of total N
loading to the lake in the future. We note that reduced N (as NH 4
+
) is the preferred N
source for bloom-forming cyanobacteria, including Microcystis spp. (Paerl et al.
2015). Compared to Lake Dianchi, the contribution made by atmospheric N depositions may be even greater in other eutrophic lakes in East and North China which
are experiencing extremely poor air quality (Xu et al. 2015). Although China’s
central government has issued regulatory policies for cleaner air and water (Water
pollution control action plan, Zhang et al. 2012), local administrators still face
challenges in coordinating the reductions of atmospheric deposition and riverine
inputs, given limited financial resources. In addition to implementing a
Fig. 12.15 Comparison between monthly streamflow and groundwater discharge from April 2010
to March 2011. (This figure was adapted from Zhan et al. (2017) with permission by the American
Chemical Society)
290
F. Zhou et al.
À1 year
À1 (range, 59.1–70.5 kg N ha
À1 year
À1 ). On an
annual basis, the ratio of reduced to oxidized N deposition was 1.7, suggesting that
the reduced form of N dominates N deposition. Of the annual N deposition, 45.5%
was deposited via precipitation, with the remaining via dry deposition. The total
gaseous and particulate N deposition was 24.9 and 10.4 kg N ha
À1 year
À1 , respectively. The high N loading in this region has resulted in the reduction of water quality
in Lake Taihu. Atmospheric N deposition accounted for 33.3 and 27.5% of the total
N loading in Lake Taihu and in water bodies in the region, respectively. This study
confirmed that atmospheric deposition of N is one of the most important sources of
surface water pollution and should be taken into account when developing strategies
for mitigating water pollution.
Decreases in riverine N inputs from watersheds are expected to continue into the
future as China aims to lower the N inputs from reusing reclaimed water and urban
stormwater (Water pollution control action plan 2015). Current projections of
increasing NH 3 emissions (Sutton et al. 2013), meanwhile, suggest that N deposition
levels, especially reduced N, will increase and form a larger fraction of total N
loading to the lake in the future. We note that reduced N (as NH 4
+
) is the preferred N
source for bloom-forming cyanobacteria, including Microcystis spp. (Paerl et al.
2015). Compared to Lake Dianchi, the contribution made by atmospheric N depositions may be even greater in other eutrophic lakes in East and North China which
are experiencing extremely poor air quality (Xu et al. 2015). Although China’s
central government has issued regulatory policies for cleaner air and water (Water
pollution control action plan, Zhang et al. 2012), local administrators still face
challenges in coordinating the reductions of atmospheric deposition and riverine
inputs, given limited financial resources. In addition to implementing a
Fig. 12.15 Comparison between monthly streamflow and groundwater discharge from April 2010
to March 2011. (This figure was adapted from Zhan et al. (2017) with permission by the American
Chemical Society)
290
F. Zhou et al.