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Asia Center of The Academy of Natural Sciences

Biogeochemistry and Water Quality

Puntsag Tamiraa

Research Objectives:

  • Measure and describe water chemistry characteristics and conditions for each of the six Lake Hövsgöl study rivers
  • Define how climate change and permafrost thaw affects the water quality of tributary rivers of Lake Hövsgöl
  • Evaluate impacts of human activities on streams
  • Describe importance of wintertime regime of water quality
  • Define long term chemical trends for the rivers of Lake Hövsgöl

Research activities:

Monitoring

  • Stream water quality conditions (pH, conductivity, temperature, dissolved oxygen) and inorganic minerals (anion, cation and biogenic elements) are measured in each river valley and the near shore water of Lake Hövsgöl
  • Stream organic matter (DOC, CDOM, Chl a) are measured in each river valley and in Lake Hövsgöl
  • Perform graphical and statistical analysis of all data, following the guidance of specialists to analyze monitoring data, and relate to soil chemical, meteorological and hydrological data at Lake Hövsgöl and Selenge river basin.
  • Relate present day monitoring data with acceptable available chemical records from prior years, and help correlate all data with other studies of the Lake basin.

Preliminary Results

Water of the rivers belongs to hydrocarbonium class, calcium group and I-II kinds, according to O. A. Alekin’s classification. Hardness ranges from very soft to slightly hard by E. V. Posoknov’s classification. The salinity content for each stream differs, and appears to result from grazing by domestic livestock that causes serious changes in the riparian zones and affects the water quality of the stream (p<0.01). Salinity content is highly correlated with the livestock number, i.e., grazing by domestic livestock causes serious damage to riparian zones, affecting the water quality of the stream. (p<0.01, r2=0.95).

Nitrate and ammonia levels in July and August (high water level) were higher than in June, 2003. The main source in open-channel flow, apart from the discharge from inflowing streams, is the runoff from soil.

Turag and Shagnuul Rivers are higher than other rivers in regard to the chloride ion. Chloride ion originates from the natural weathering of rock and from atmospheric transport of oceanic inputs and from a wide variety of anthropogenic sources. In the Borsog River, chloride concentrations are the lowest in six tributaries. In our tributaries the increased chloride ion content depends on anthropogenic sources, most likely resulting from overgrazing in Turag and Shagnuul.

Lake Hövsgöl and its tributary streams have ultra-oligotrophic conditions. However, the Chloride trend is increasing (r2=0.11), Ammonia is increasing (r2=0.15), and the dissolved oxygen saturation is decreasing (r2=0.41) in the six rivers.

The relationship between chloride and dissolved oxygen is significantly different (p< 0.05). The correlation coefficient is r2=-0.63. When chloride increases, dissolved oxygen decreases, most likely because of the erosion of organic materials, including dung, into the streams.

We measured chlorophyll “a” in vivo and colored dissolved organic matter with a Fluorometer. Chlorophyll “a” ranges from 27µg/ to 343µg/l. Colored dissolved organic matter (CDOM) ranges from 0.03 to 2.6 mg/l. The Dalbay lower site had the highest CDOM and the lake had the lowest.

Organic Matter in Streams

In 2004, we measured in vivo Chlorophyll a and Colored Dissolved Organic Matter (CDOM). Chlorophyll a ranges from 27µg/ to 343µg/l. CDOM ranges from 0.03 to 2.6 mg/l. The Dalbay lower site had the highest CDOM and the lake had the lowest. We also measure dissolved organic carbon (DOC) at each site, for the lake and the lake outlet. In Summary, the Shagnuul mid-stream DOC concentrations suggest that much of the runoff in this catchment has had significant contact with high-organic content soils. This may be associated with runoff from the active layer over permafrost on north-facing slopes. The high DOC in June suggests that there is a build up of DOC in the late summer and fall (due to microbial activity), and the low DOC concentrations in June suggest that the DOC water that forms in summer is flushed from soils.

stream organic matter

Salinity changes

The salinity content for each stream differs, and appears to depend on grazing by domestic livestock that causes serious changes in the riparian zones affecting the water quality of the stream (p<0.01). Salinity content is highly correlated with the livestock number, i.e., grazing by domestic livestock causes serious changes in the riparian zones affecting the water quality of the stream. (p<0.01, r2=0.95).

salinity changes

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