scholarly journals Warming of water temperature in spring and nutrient release from sediment in a shallow eutrophic lake

2021 ◽  
Author(s):  
Ryuichiro Shinohara ◽  
Kenji Tsuchiya ◽  
Ayato Kohzu
Keyword(s):  
Water Temperature ◽  
Temperature Increase ◽  
Nonlinear Response ◽  
Nutrient Release ◽  
Eutrophic Lake ◽  
Lake Kasumigaura ◽  
Sediment Temperature ◽  
Shallow Eutrophic Lake ◽  
The Relationship ◽  
Temperature Water

Abstract We investigated whether recent springtime water temperature increases in a shallow eutrophic lake affected bottom sediment temperature and fluxes of ammonia (NH4+) and phosphate (PO43−) from the sediment. We conducted a lake-wide survey of Lake Kasumigaura, Japan, and analyzed the relationship between water temperature increases in spring and NH4+ and PO43− release fluxes. We also developed a numerical model to analyze how water temperature increase affects sediment temperature. Water temperature in May increased during 2010–2019 at a rate of 1.8–3.2 °C decade−1. The numerical simulation results showed that the water temperature increase was accompanied by a sediment temperature increase from a minimum of 18.3 °C in 2011 to a maximum of 21.6 °C in 2015. Despite the substantial difference in the observed sediment temperature (2.9 °C), no significant differences in NH4+ and PO43− fluxes in May between 2013/2014 and 2015 were found. These results suggest that both water and sediment temperatures are increasing in Lake Kasumigaura in spring, but it is unclear whether this warming has affected NH4+ and PO43− releases from the sediment. However, because a nonlinear response to sediment temperature was observed, future springtime warming may accelerate NH4+ and PO43− releases.

Characterization of natural organic matter in a shallow eutrophic lake

2002 ◽  
Vol 46 (11-12) ◽  
pp. 465-471 ◽  
Author(s):  
P.B. Thapa ◽  
F. Nakajima ◽  
H. Furumai
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Similarity Index ◽  
Eutrophic Lake ◽  
Lake Kasumigaura ◽  
Characterization Methods ◽  
Spatial Changes ◽  
Different Seasons ◽  
Shallow Eutrophic Lake ◽  
The Difference

Natural organic matter (NOM) from five sampling stations of a shallow, eutrophic lake, Lake Kasumigaura was analyzed in four different seasons of a year by several NOM characterization methods including GPC and pyrolysis GC/MS with the objective of elucidating its characteristics as well as studying its temporal and spatial changes. A comparison was also made among the characteristics of NOM from this and two other lakes. The study showed that NOM in Lake Kasumigaura had comparable DOC, UVA260, and THMFP with that of Lake Inbanuma, but much higher than that of Lake Tsukui. Both molecular weight and polydispersities remained similar among those three sources but these values were significantly smaller in comparison with Suwannee River NOM. The similarity index analysis based on pyrochromatograms was useful to evaluate spatial and seasonal changes in NOM characteristics. Distinctive characteristics of NOM at KS1 (station near the mouth of Sakura River) were better explained by the difference in pyro-chromatograms rather than in general water quality. Except for KS1, the change in NOM characteristics in the lake water was found to be more pronounced in different seasons than at different locations.

scholarly journals Effect of Climatic Factors and Habitat Characteristics on Anopheles Larval Density

2018 ◽  
Vol 13 (3) ◽  
pp. 345-355
Author(s):  
Noper Tulak ◽  
Handoko Handoko ◽  
Rini Hidayati ◽  
Upik Kesumawati ◽  
Lukman Hakim
Keyword(s):  
Water Temperature ◽  
Air Temperature ◽  
Brackish Water ◽  
Climatic Factors ◽  
Larval Density ◽  
Habitat Characteristics ◽  
Local Conditions ◽  
High Incidence ◽  
The Relationship ◽  
Temperature Water

Koya Barat village is one of the areas in Jayapura City which has high incidence of malaria. Malaria cases in this region are affected by local conditions, including the climate and environment of aquatic habitats.The purpose of this study was to analyze the effect of climatic factors and habitat characteristics on Anopheleslarval density in Koya Barat village. The method used is field observation with descriptive and statistical analysis approach.The results showed that there are four parameters that significantly affect on larval density, namely rainfall, air temperature, water temperature and salinity. The relationship between rainfall with the larval density in freshwater permanent habitat is negative linear. While in brackish water permanent habitat and semi permanent habitat is non-linear (2nd order polynomial). The relationship between air temperature, water temperature and salinity with the larval density in freshwater habitat are positive linear, while in brackish water habitat and semi permanent habitat are negative linear.

The Relationship between Concentration and Sensory Properties of 2-Methylisoborneol and Geosmin in Drinking Water

1988 ◽  
Vol 20 (8-9) ◽  
pp. 11-17 ◽  
Author(s):  
T. Ito ◽  
T. Okumura ◽  
M. Yamamoto
Keyword(s):  
Drinking Water ◽  
Water Temperature ◽  
Forced Choice ◽  
Residual Chlorine ◽  
Mixing Ratio ◽  
Consumer Panel ◽  
Triangle Method ◽  
Musty Odor ◽  
The Relationship ◽  
Mixed Samples

The study of the relations between the senses of smell and taste and odorant concentration is important for the solution of odor problems. The threshold concentrations of odor and taste (TOC, TTC) of 2-methylisoborneol (MIB) and geosmin were measured by the non-forced choice triangle method using 12-20 panelists. Both TOC and TTC were found to be functions of water temperature and the concentration of residual chlorine. The TOC and TTC of mixed samples were rather lower than the concentrations calculated from the mixing ratio. The sensitivities of the consumer panel and the number of musty odor complaints from consumers are related to MIB or geosmin concentration. The ratio of the number of complaints to MIB (or geosmin) concentration decreased after maximum complaint, but the sensitivity of the consumer panel remained the same.

Development of a water temperature-ecological model to stimulate global warming effects on lake ecosystem

1996 ◽  
Vol 34 (7-8) ◽  
pp. 237-244 ◽  
Author(s):  
Masaaki Hosomi ◽  
Tetsu Saigusa ◽  
Kenichi Yabunaka ◽  
Takuya Okubo ◽  
Akihiko Murakami
Keyword(s):  
Global Warming ◽  
Water Temperature ◽  
Thermal Stratification ◽  
Ecological Model ◽  
Nutrient Release ◽  
Eddy Diffusion ◽  
Nutrient Concentrations ◽  
Lake Ecosystem ◽  
Phytoplankton Species ◽  
Freezing And Thawing

This paper describes a newly developed combined water temperature-ecological (WT-ECO) model which is employed to simulate the effects of global warming on lake and reservoir ecosystems. The WT model includes (i) variations in the eddy diffusion coefficient based on the degree of thermal stratification and the velocity of wind, and (ii) a sub-model for simulating the freezing and thawing processes of surface water, water temperatures, and the mixing rates between two adjacent layers of water. The ECO model then uses these results to calculate the resultant effect on a lake's ecological dynamics, e.g., composition of phytoplankton species, their respective concentrations, and nutrient concentrations. When the model was benchmarked against Lake Yunoko, a dimictic lake, fairly good agreement was obtained over a 4-yr period; thereby indicating it is suitably calibrated. In addition, to assess the effects of global warming on a lake ecosystem, changes in Lake Yunoko's water temperature/quality were simulated in response to an increase in air temperature of 2 - 4°C. Results indicate that such an increase will (i) increase thermal stratification in summer, which increases the nutrient concentrations in bottom water due to nutrient release from bottom sediment, (ii) increase the concentration of phytoplankton at the beginning of the autumn circulation period, and (iii) change the composition of phytoplankton species.

scholarly journals Analyzing and Visualizing Spatiotemporal Patterns of El Niño Teleconnections Using Attribute Trajectories

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 414
Author(s):  
Long Zhang ◽  
Bert Van Schaeybroeck ◽  
Steven Caluwaerts ◽  
Piet Termonia ◽  
Nico Van de Weghe
Keyword(s):  
Data Structures ◽  
El Niño ◽  
Temperature Increase ◽  
El Nino ◽  
Global Climate ◽  
Spatiotemporal Patterns ◽  
New Method ◽  
Anomalous Temperature ◽  
General Dynamics ◽  
The Relationship

El Niño influences the global climate through teleconnections that are not constant in space and time. In order to study and visualize the spatiotemporal patterns of the El Niño teleconnections, a new method inspired by the concept of attribute trajectories is proposed. The coordinates of the trajectories are the normalized anomalies of the relevant meteorological variables in El Niño. The data structures called flocks are extracted from the trajectories to indicate the regions that are subject to the same type of El Niño teleconnection for a certain period. It is then shown how these structures can be used to get a detailed, spatiotemporal picture of the dynamics of the El Niño teleconnections. The comparison between the flocks of the same temporal scale reveals the general dynamics of the teleconnection, while the analysis among the flocks of different temporal scales indicates the relationship between the coverage and their duration. As an illustration of this method, the spatiotemporal patterns of the anomalous temperature increase caused by El Niño are presented and discussed at the monthly and seasonal scales. This study demonstrates the capability of the proposed method in analyzing and visualizing the spatiotemporal patterns of the teleconnections.

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