scholarly journals Relationship between dissolved oxygen concentration of bottom water and macrophyte biomass in the southern basin of Lake Biwa, Japan

2006 ◽  
Vol 67 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Hiroki HAGA ◽  
Minako ASHIYA ◽  
Taisuke OHTSUKA ◽  
Masanari MATSUDA ◽  
Akihiro TUJI ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Bottom Water ◽  
Lake Biwa ◽  
Dissolved Oxygen Concentration ◽  
Southern Basin ◽  
Macrophyte Biomass

scholarly journals Influence of climatic warming on the amount of snow cover and water quality of Lake Biwa, Japan

1993 ◽  
Vol 18 ◽  
pp. 257-260
Author(s):  
Hiroji Fushimi
Keyword(s):  
Dissolved Oxygen ◽  
Snow Cover ◽  
Oxygen Concentration ◽  
Catchment Area ◽  
Lake Biwa ◽  
Deep Layer ◽  
Climatic Warming ◽  
Dissolved Oxygen Concentration ◽  
Average Amount

The amount of snow cover in the Lake Biwa catchment area has changed significantly from 1.9 × 1012kg in 1974 to 0.3 × 1012kg in 1979. The amount of snow cover was less in the warmer winter and when the amount of snow cover was less than 1012 kg, the average amount of snow cover in recent years, the lowest dissolved-oxygen concentration in the deep layer rapidly decreases. Climatic warming will significantly decrease the amount of snow cover in Lake Biwa catchment area and the dissolved-oxygen concentration in the deep layer of the lake, which may further enhance eutrophication of the lake.

scholarly journals Influence of climatic warming on the amount of snow cover and water quality of Lake Biwa, Japan

1993 ◽  
Vol 18 ◽  
pp. 257-260 ◽  
Author(s):  
Hiroji Fushimi
Keyword(s):  
Dissolved Oxygen ◽  
Snow Cover ◽  
Oxygen Concentration ◽  
Catchment Area ◽  
Lake Biwa ◽  
Deep Layer ◽  
Climatic Warming ◽  
Dissolved Oxygen Concentration ◽  
Average Amount

The amount of snow cover in the Lake Biwa catchment area has changed significantly from 1.9 × 1012kg in 1974 to 0.3 × 1012kg in 1979. The amount of snow cover was less in the warmer winter and when the amount of snow cover was less than 1012 kg, the average amount of snow cover in recent years, the lowest dissolved-oxygen concentration in the deep layer rapidly decreases. Climatic warming will significantly decrease the amount of snow cover in Lake Biwa catchment area and the dissolved-oxygen concentration in the deep layer of the lake, which may further enhance eutrophication of the lake.

scholarly journals Detection of low bottom water oxygen concentrations in the North Sea; implications for monitoring and assessment of ecosystem health

2009 ◽  
Vol 6 (4) ◽  
pp. 8411-8453 ◽  
Author(s):  
N. Greenwood ◽  
E. R. Parker ◽  
L. Fernand ◽  
D. B. Sivyer ◽  
K. Weston ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
North Sea ◽  
Mixed Layer ◽  
Ecosystem Health ◽  
Bottom Water ◽  
Dissolved Oxygen Concentration ◽  
The North ◽  
The North Sea ◽  
Oxygen Concentrations

Abstract. This paper presents new results from high temporal resolution observations over two years (2007 and 2008) from instrumented moorings deployed in the central North Sea, at the Oyster Grounds and on the northern slope of Dogger Bank (North Dogger). The water column was stratified in the summer at both sites, leading to limited exchange of the water in the bottom mixed layer. Data from these moorings revealed the variable nature of summer oxygen depletion at the Oyster Grounds. The combination of in situ and ship-based measurements allowed the physical and biological conditions leading to decreasing dissolved oxygen concentrations in bottom water to be examined. The concentration of dissolved oxygen in the bottom water at both sites was observed to decrease throughout the summer period after the onset of stratification. Depleted dissolved oxygen concentration (6.5 mg l−1, 71% saturation) was measured at the North Dogger, a site which is not significantly influenced by anthropogenic nutrient inputs. Lower oxygen saturation (5.2 mg l−1, 60% saturation) was measured for short durations at the Oyster Grounds. Increasing bottom water temperature accounted for 55% of the decrease in dissolved oxygen concentration at the Oyster Grounds compared to 10% at North Dogger. Dissolved oxygen concentration in bottom water at the Oyster Grounds was shown to be strongly influenced by short term events including storm events and pulses of biomass input. In contrast, dissolved oxygen concentration in bottom water at the North Dogger reflected longer seasonal processes such as gradual temperature increases and a more steady supply of biomass to the bottom mixed layer. The differences between the study sites shows the need for an improved understanding of the mechanisms driving these processes if the use of oxygen in marine management and ensuring ecosystem health is to be meaningful and successful in the future. These observations provide greater understanding of the nature of the depletion in bottom oxygen concentration in the North Sea.

scholarly journals Detection of low bottom water oxygen concentrations in the North Sea; implications for monitoring and assessment of ecosystem health

2010 ◽  
Vol 7 (4) ◽  
pp. 1357-1373 ◽  
Author(s):  
N. Greenwood ◽  
E. R. Parker ◽  
L. Fernand ◽  
D. B. Sivyer ◽  
K. Weston ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
North Sea ◽  
Particulate Organic Matter ◽  
Ecosystem Health ◽  
Bottom Water ◽  
Dissolved Oxygen Concentration ◽  
The North ◽  
The North Sea

Abstract. This paper presents new results from high temporal resolution observations over two years (2007 and 2008) from instrumented moorings deployed in the central North Sea, at the Oyster Grounds and on the northern slope of Dogger Bank (North Dogger). The water column was stratified in the summer at both sites, leading to limited exchange of the water in the bottom mixed layer. Data from these moorings revealed the variable nature of summer oxygen depletion at the Oyster Grounds. The combination of in situ and ship-based measurements allowed the physical and biological conditions leading to decreasing dissolved oxygen concentrations in bottom water to be examined. In 2007 and 2008, the concentration of dissolved oxygen in the bottom water at both sites was observed to decrease throughout the summer period after the onset of stratification. Depleted dissolved oxygen concentration (6.5 mg l−1, 71% saturation) was measured at the North Dogger, a site which is not significantly influenced by anthropogenic nutrient inputs. Lower oxygen saturation (5.2 mg l−1, 60% saturation) was measured for short durations at the Oyster Grounds. The seasonal increase in bottom water temperature accounted for 55% of the decrease in dissolved oxygen concentration at the Oyster Grounds compared to 10% at North Dogger. Dissolved oxygen concentration in bottom water at the Oyster Grounds was shown to be strongly influenced by short term events including storms and pulses of particulate organic matter input. In contrast, dissolved oxygen concentration in bottom water at the North Dogger reflected longer seasonal processes such as a gradual temperature increase over the summer and a more steady supply of particulate organic matter to the bottom mixed layer. The differences between the study sites shows the need for an improved understanding of the mechanisms driving these processes if the use of oxygen in marine management and ensuring ecosystem health is to be meaningful and successful in the future. These high frequency observations provide greater understanding of the nature of the depletion in bottom oxygen concentration in the North Sea.

Dissolved oxygen concentration in river sediment of the Lake Biwa tributaries, Japan

Limnology ◽  
2011 ◽  
Vol 13 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Yoshihiro Yamada ◽  
Yugo Mito ◽  
Akitake Igeta ◽  
Eitaro Wada
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
River Sediment ◽  
Lake Biwa ◽  
Dissolved Oxygen Concentration
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