| dc.description | Nutrient concentrations often vary seasonally due to influences of
anthropogenic inputs, hydrology, and the growing seasons of algae and
macrophytes. Major anthropogenic sources causing freshwater eutrophication are
animal farming, urban and agricultural runoff, sewage effluents and industrial
wastes. As a result, significant increases in the concentration of nutrients (e.g., N,
P) and the abundance of primary producers (e.g., phytoplankton, benthic algae
and macrophytes) have occurred around the worlds’ freshwater (Harper, 1992;
Biggs, 2000; Wetzel, 2001). In Korea, it is now a recognized problem of water
quality deterioration (Kim et al., 1998). Phosphorus and nitrogen are the most
important parameters that exhibit the current state of water quality. Elevated P
concentrations in rivers have been linked to increasing rates of plant growth,
changes in species composition and proliferation of planktonic and epiphytic and
epibenthic algae, resulting in shading of higher plants (Mainstone and Parr, 2002). | en_US |
| dc.description.abstract | The spatial and temporal distributions of phosphorus and nitrogen and a
number of physical, chemical and biological parameters were analyzed to in the
Youngsan and the Sumjin River systems, Korea. Substantial amount of P and N
was observed in both the rivers all the year round. Mean N:P ratios showed large
variations among the sampling sites; highest ratio was observed in most
sampling sites during summer. Relative proportions of DOP: TP were fairly
constant (0.08-0.09) in both the rivers. In the composition of nitrogen almost all
sampling sites of both the rivers were dominated with NO;-N followed by NH3-
N and NO>-N. Variations in dissolved nutrients tended to co-vary with
particulate forms (PON and POP), implying that dissolved nutrients are
primarily released from the decomposition of particulate forms or dissolved
forms are in equilibrium with particulate forms. Chlorophyll a levels in the
Sumjin River appear to be negatively correlated with the ammonia, implying
ammonia is absorbed by algae with preference. While chlorophyll a was
positively correlated with TP and DIP in the Sumjin River, negative correlations
of these parameters was observed in the Youngsan River. The pattern in
concentration of nutrients was found to be related with land use and domestic
sewage in the study area. Inter-parameter relationships may be strongly
influenced by geographical factors relative to temporal factors. | en_US |
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