The concentration of methane (CH4) has doubled in the atmosphere over the last 200 yr, raising th... more The concentration of methane (CH4) has doubled in the atmosphere over the last 200 yr, raising the need to understand emissions of this potent greenhouse gas from inland waters. CH4 ebullition is the dominant pathway in shallow aquatic environments and is difficult to quantify due to its episodic nature and heterogeneous spatial distribution.We investigated the temporal and spatial variability of CH4 ebullition during 2013 in a shallow hypereutrophic urban reservoir, in Belo Horizonte City, Brazil. The average emission measured during summer was 780 mg CH4/m2/d, ranging from 1 to 3070 (n = 75). During winter, the average emission was 316 mg CH4/m2/d, ranging from 4 to 1253 (n = 75). A strong spatial variation (P < 0.001) was observed across the reservoir in both seasons. Several folds higher (39–58% of the total) emissions were recorded at the mouth of the main tributaries, which therefore was considered to be a hot spot ebullition zone. This was expected due to its shallow area (mean depth 1.30 m) with low hydrostatic pressure and 2 to 6 C (winter and summer, respectively) higher sediment temperatures, which is aggravated by the intense siltation process resulting from insufficient management of the sewage water entering the reservoir. In this article we demonstrate the consequence of siltation as an enhancing factor for CH4 emission from the hot spots ebullition zones.
The Ibirité reservoir is an urban and eutrophic environment, with regular occurrences of cyanobac... more The Ibirité reservoir is an urban and eutrophic environment, with regular occurrences of cyanobacteria blooms. The reservoir is warm monomict and remains stratified most of the year, circulating in the dry season (winter). During the hydrological cycle of October/07 to October/08 there were four scenarios with different environmental conditions, which influenced the structure of the zooplankton community, as confirmed in a previous study. Changes in the zooplankton community structure between the scenarios were studied, aiming at analyzing the stability and persistence of this community. The Spearman’s coefficient of correlation was used to measure the stability; the persistence was evaluated through a cluster analysis and changes in community composition were estimated by the “temporal” β diversity index. Considering the distribution patterns of abundance, the community was stable only in the transition between scenarios 1 and 2 (n = 30, r = 0.71, p = 0.00001), when there were no cyanobacteria blooms. The persistence of zooplankton between the scenarios was low, showing a distinct species composition for each scenario. The highest variations in species composition, observed by the values of temporal β diversity index, were the transitions between scenarios 3-0 (1.45) and 0-1 (1.05), and the lowest variations occurred in the transition between scenarios 1-2 (0.57). The results suggest that the cyanobacteria blooms at Ibirité reservoir are be acting as “selective filters”, and are, thus, disturbances with sufficient ability to change the structure of the zooplankton community.
The concentration of methane (CH4) has doubled in the atmosphere over the last 200 yr, raising th... more The concentration of methane (CH4) has doubled in the atmosphere over the last 200 yr, raising the need to understand emissions of this potent greenhouse gas from inland waters. CH4 ebullition is the dominant pathway in shallow aquatic environments and is difficult to quantify due to its episodic nature and heterogeneous spatial distribution.We investigated the temporal and spatial variability of CH4 ebullition during 2013 in a shallow hypereutrophic urban reservoir, in Belo Horizonte City, Brazil. The average emission measured during summer was 780 mg CH4/m2/d, ranging from 1 to 3070 (n = 75). During winter, the average emission was 316 mg CH4/m2/d, ranging from 4 to 1253 (n = 75). A strong spatial variation (P < 0.001) was observed across the reservoir in both seasons. Several folds higher (39–58% of the total) emissions were recorded at the mouth of the main tributaries, which therefore was considered to be a hot spot ebullition zone. This was expected due to its shallow area (mean depth 1.30 m) with low hydrostatic pressure and 2 to 6 C (winter and summer, respectively) higher sediment temperatures, which is aggravated by the intense siltation process resulting from insufficient management of the sewage water entering the reservoir. In this article we demonstrate the consequence of siltation as an enhancing factor for CH4 emission from the hot spots ebullition zones.
The Ibirité reservoir is an urban and eutrophic environment, with regular occurrences of cyanobac... more The Ibirité reservoir is an urban and eutrophic environment, with regular occurrences of cyanobacteria blooms. The reservoir is warm monomict and remains stratified most of the year, circulating in the dry season (winter). During the hydrological cycle of October/07 to October/08 there were four scenarios with different environmental conditions, which influenced the structure of the zooplankton community, as confirmed in a previous study. Changes in the zooplankton community structure between the scenarios were studied, aiming at analyzing the stability and persistence of this community. The Spearman’s coefficient of correlation was used to measure the stability; the persistence was evaluated through a cluster analysis and changes in community composition were estimated by the “temporal” β diversity index. Considering the distribution patterns of abundance, the community was stable only in the transition between scenarios 1 and 2 (n = 30, r = 0.71, p = 0.00001), when there were no cyanobacteria blooms. The persistence of zooplankton between the scenarios was low, showing a distinct species composition for each scenario. The highest variations in species composition, observed by the values of temporal β diversity index, were the transitions between scenarios 3-0 (1.45) and 0-1 (1.05), and the lowest variations occurred in the transition between scenarios 1-2 (0.57). The results suggest that the cyanobacteria blooms at Ibirité reservoir are be acting as “selective filters”, and are, thus, disturbances with sufficient ability to change the structure of the zooplankton community.
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CH4 ebullition during 2013 in a shallow hypereutrophic urban reservoir, in Belo Horizonte City, Brazil. The average emission measured during summer was 780 mg CH4/m2/d, ranging from 1 to 3070 (n = 75). During winter, the average emission was 316 mg CH4/m2/d, ranging from 4 to 1253 (n = 75). A strong spatial variation (P < 0.001) was observed across the reservoir in both seasons. Several folds higher (39–58% of the total) emissions were recorded at the mouth of the main tributaries, which
therefore was considered to be a hot spot ebullition zone. This was expected due to its shallow area (mean depth 1.30 m) with low hydrostatic pressure and 2 to 6 C (winter and summer, respectively)
higher sediment temperatures, which is aggravated by the intense siltation process resulting from insufficient management of the sewage water entering the reservoir. In this article we demonstrate the consequence of siltation as an enhancing factor for CH4 emission from the hot spots ebullition zones.
reservoir is warm monomict and remains stratified most of the year, circulating in the dry season (winter). During the
hydrological cycle of October/07 to October/08 there were four scenarios with different environmental conditions, which
influenced the structure of the zooplankton community, as confirmed in a previous study. Changes in the zooplankton
community structure between the scenarios were studied, aiming at analyzing the stability and persistence of this
community. The Spearman’s coefficient of correlation was used to measure the stability; the persistence was evaluated
through a cluster analysis and changes in community composition were estimated by the “temporal” β diversity index.
Considering the distribution patterns of abundance, the community was stable only in the transition between scenarios
1 and 2 (n = 30, r = 0.71, p = 0.00001), when there were no cyanobacteria blooms. The persistence of zooplankton
between the scenarios was low, showing a distinct species composition for each scenario. The highest variations in
species composition, observed by the values of temporal β diversity index, were the transitions between scenarios 3-0
(1.45) and 0-1 (1.05), and the lowest variations occurred in the transition between scenarios 1-2 (0.57). The results
suggest that the cyanobacteria blooms at Ibirité reservoir are be acting as “selective filters”, and are, thus, disturbances
with sufficient ability to change the structure of the zooplankton community.
CH4 ebullition during 2013 in a shallow hypereutrophic urban reservoir, in Belo Horizonte City, Brazil. The average emission measured during summer was 780 mg CH4/m2/d, ranging from 1 to 3070 (n = 75). During winter, the average emission was 316 mg CH4/m2/d, ranging from 4 to 1253 (n = 75). A strong spatial variation (P < 0.001) was observed across the reservoir in both seasons. Several folds higher (39–58% of the total) emissions were recorded at the mouth of the main tributaries, which
therefore was considered to be a hot spot ebullition zone. This was expected due to its shallow area (mean depth 1.30 m) with low hydrostatic pressure and 2 to 6 C (winter and summer, respectively)
higher sediment temperatures, which is aggravated by the intense siltation process resulting from insufficient management of the sewage water entering the reservoir. In this article we demonstrate the consequence of siltation as an enhancing factor for CH4 emission from the hot spots ebullition zones.
reservoir is warm monomict and remains stratified most of the year, circulating in the dry season (winter). During the
hydrological cycle of October/07 to October/08 there were four scenarios with different environmental conditions, which
influenced the structure of the zooplankton community, as confirmed in a previous study. Changes in the zooplankton
community structure between the scenarios were studied, aiming at analyzing the stability and persistence of this
community. The Spearman’s coefficient of correlation was used to measure the stability; the persistence was evaluated
through a cluster analysis and changes in community composition were estimated by the “temporal” β diversity index.
Considering the distribution patterns of abundance, the community was stable only in the transition between scenarios
1 and 2 (n = 30, r = 0.71, p = 0.00001), when there were no cyanobacteria blooms. The persistence of zooplankton
between the scenarios was low, showing a distinct species composition for each scenario. The highest variations in
species composition, observed by the values of temporal β diversity index, were the transitions between scenarios 3-0
(1.45) and 0-1 (1.05), and the lowest variations occurred in the transition between scenarios 1-2 (0.57). The results
suggest that the cyanobacteria blooms at Ibirité reservoir are be acting as “selective filters”, and are, thus, disturbances
with sufficient ability to change the structure of the zooplankton community.