Introduction:Seasonal and tidal variations in nutrient concentration and water quality were investigated in the western Sundarbans of Bangladesh during the post-monsoon,winter and monsoon seasons during 2010–2011.Met...Introduction:Seasonal and tidal variations in nutrient concentration and water quality were investigated in the western Sundarbans of Bangladesh during the post-monsoon,winter and monsoon seasons during 2010–2011.Methods:Water collected from the surface,middle and bottom layers at six locations of the Kholpetua-Arpangashia river system during high and low tides was analyzed for temperature,salinity,pH,dissolved oxygen(DO),total dissolved solids(TDS),electrical conductivity(EC)and dissolved nutrients(NO3–N,PO4–P,SO4 and NH3–N).Results:The study revealed that nutrient concentrations were influenced by seasonal changes.Mean nutrient levels during post-monsoon,winter and monsoon seasons,respectively,were in the following ranges:nitrate(0.06–0.40,0.06–0.46 and 0.08–0.46 mg/L);phosphate(0.09–0.18,0.05–0.42 and 0.10–0.16 mg/L);sulphate(58.71–86.14,68.68–119.01 and 78.15–136.47 mg/L)and ammonia(0.02–0.08,0.02–0.04 and 0.26–0.38 mg/L).Increased levels of PO4–P,SO4 and NH3–N and lower DO and salinity were recorded during the monsoon period.Most of the experimental sites showed higher NO3–N content during monsoon,whereas few elevated concentrations were observed during post-monsoon and winter periods.High and low tidal waters contained mean nutrient levels in the following ranges:nitrate(0.05–0.46 and 0.04–0.40 mg/L);phosphate(0.05–0.42 and 0.07–0.18 mg/L);sulphate(63.63–125.36 and 58.71–136.47 mg/L)and ammonia(0.02–0.38 and 0.02–0.37 mg/L)without following any distinct fluctuation patterns.The western part of the Sundarbans receives less freshwater input during the monsoon season than other areas of the ecosystem,which reduces the variability of nutrient levels and water quality components.Conclusions:This study provides considerable advances in understanding the seasonality of nutrient distribution with possible tidal influence.The data generated from this study will guide continuing efforts to support a sound management for coastal mangrove ecosystems.展开更多
基金Ministry of Education,Government of the Peoples’Republic of Bangladesh provided the necessary financial support under the Grants for Advanced Research in Science to carry out the present study.The authors would like to acknowledge the support of the laboratory staff of the Fisheries and Marine Resource Technology Discipline and Environmental Science Discipline of Khulna University during sample analysis in the laboratory.Thanks are due to the graduate and undergraduate students for their generous cooperation during field observation,in-situ measurement and laboratory analysis.Support of the authorities of the Forest Department of Bangladesh are appreciated.The authors would like to thank two anonymous reviewers for their valuable comments and suggestions that helped improve the manuscript.
文摘Introduction:Seasonal and tidal variations in nutrient concentration and water quality were investigated in the western Sundarbans of Bangladesh during the post-monsoon,winter and monsoon seasons during 2010–2011.Methods:Water collected from the surface,middle and bottom layers at six locations of the Kholpetua-Arpangashia river system during high and low tides was analyzed for temperature,salinity,pH,dissolved oxygen(DO),total dissolved solids(TDS),electrical conductivity(EC)and dissolved nutrients(NO3–N,PO4–P,SO4 and NH3–N).Results:The study revealed that nutrient concentrations were influenced by seasonal changes.Mean nutrient levels during post-monsoon,winter and monsoon seasons,respectively,were in the following ranges:nitrate(0.06–0.40,0.06–0.46 and 0.08–0.46 mg/L);phosphate(0.09–0.18,0.05–0.42 and 0.10–0.16 mg/L);sulphate(58.71–86.14,68.68–119.01 and 78.15–136.47 mg/L)and ammonia(0.02–0.08,0.02–0.04 and 0.26–0.38 mg/L).Increased levels of PO4–P,SO4 and NH3–N and lower DO and salinity were recorded during the monsoon period.Most of the experimental sites showed higher NO3–N content during monsoon,whereas few elevated concentrations were observed during post-monsoon and winter periods.High and low tidal waters contained mean nutrient levels in the following ranges:nitrate(0.05–0.46 and 0.04–0.40 mg/L);phosphate(0.05–0.42 and 0.07–0.18 mg/L);sulphate(63.63–125.36 and 58.71–136.47 mg/L)and ammonia(0.02–0.38 and 0.02–0.37 mg/L)without following any distinct fluctuation patterns.The western part of the Sundarbans receives less freshwater input during the monsoon season than other areas of the ecosystem,which reduces the variability of nutrient levels and water quality components.Conclusions:This study provides considerable advances in understanding the seasonality of nutrient distribution with possible tidal influence.The data generated from this study will guide continuing efforts to support a sound management for coastal mangrove ecosystems.
