Coastal wetlands are hotspots for nitrogen(N)cycling,and crab burrowing is known to transform N in intertidal marsh soils.However,the underlying mechanisms remain unclear.This study conducted field experiments and use...Coastal wetlands are hotspots for nitrogen(N)cycling,and crab burrowing is known to transform N in intertidal marsh soils.However,the underlying mechanisms remain unclear.This study conducted field experiments and used indoor control test devices to investigate the seasonal response of nitrogen to crab disturbance at the sediment-water interface in coastal tidal flat wetlands.The results showed that crab disturbance exhibited significant seasonality with large seasonal differences in cave density and depth.Due to crab disturbance,nitrogen fuxes at the sediment-water interface were much greater in the box with crabs than in the box without crabs.In summer,NH-N showed a positive flux from the sediment to the overlying water,but NO2-N and NOg-N showed positive fluxes from the sediment to the overlying water only in early stages.In winter,NH-N showed a positive flux from the sediment to the overlying water,but NO-N and NO,-N both exhibited positive and negative fluxes.These results indicated that the presence of crab burrows can cause the aerobic layer to move downward by approximately 8-15 cm in summer and directly promote nitrification at the sediment surface.展开更多
From Nov. 2004 to Aug. 2005, based on macrobenthic samples collected seasonally from 12 intertidal stations in Qitou, Damen Island, Nanyue, Ximen Dock around the Yueqing Bay, the macrobenthic community and spatio-temp...From Nov. 2004 to Aug. 2005, based on macrobenthic samples collected seasonally from 12 intertidal stations in Qitou, Damen Island, Nanyue, Ximen Dock around the Yueqing Bay, the macrobenthic community and spatio-temporal variation of intertidal zone of the Yueqing Bay were analysized. We found a total of 65 species, belonging to 37 families, 9 classes and 7 phyla, most of them were arthropods and the mollusks. The density and biomass of four seasons including spring, summer, autumn and winter were 469.33±70.28 ind./m^2, 126.02±26.96 g/ m^2; 628±67.6 ind./m^2, 261.79±58.06 g/m^2; 494.67±72.62 ind./m^2, 103.90±23.25 g/m^2; 358.67±43.75 ind./m^2, 59.49±12.66 g/m^2. Densities were not significantly affected by tidal flats nor seasons (F=1.897 and F=1.057, P>0.05) but biomass differences were marked among seasons (F=3.695, P<0.05). The value of Margalef’s species richness index and Shannon-Wiener’s index was as follows: summer>spring>winter>autumn, the value of Pielou’s index was: spring>winter>summer>autumn, the value of Simpson’s index was: autumn>winter>summer>spring. The spatio-temporal variation of benthic community structure in Yueqing Bay was studied by hierarchical clustering and no-metric multidimension scaling. The results showed that location, the tidal flat and season were the three most important factors which greatly impact on spatio-temporal variation of benthic community structure in Yueqing Bay.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52271273)the Open Foundation of the Key Laboratory of Ministry of Education for Coastal Disaster and Protection(Grant No.Z202201)。
文摘Coastal wetlands are hotspots for nitrogen(N)cycling,and crab burrowing is known to transform N in intertidal marsh soils.However,the underlying mechanisms remain unclear.This study conducted field experiments and used indoor control test devices to investigate the seasonal response of nitrogen to crab disturbance at the sediment-water interface in coastal tidal flat wetlands.The results showed that crab disturbance exhibited significant seasonality with large seasonal differences in cave density and depth.Due to crab disturbance,nitrogen fuxes at the sediment-water interface were much greater in the box with crabs than in the box without crabs.In summer,NH-N showed a positive flux from the sediment to the overlying water,but NO2-N and NOg-N showed positive fluxes from the sediment to the overlying water only in early stages.In winter,NH-N showed a positive flux from the sediment to the overlying water,but NO-N and NO,-N both exhibited positive and negative fluxes.These results indicated that the presence of crab burrows can cause the aerobic layer to move downward by approximately 8-15 cm in summer and directly promote nitrification at the sediment surface.
文摘From Nov. 2004 to Aug. 2005, based on macrobenthic samples collected seasonally from 12 intertidal stations in Qitou, Damen Island, Nanyue, Ximen Dock around the Yueqing Bay, the macrobenthic community and spatio-temporal variation of intertidal zone of the Yueqing Bay were analysized. We found a total of 65 species, belonging to 37 families, 9 classes and 7 phyla, most of them were arthropods and the mollusks. The density and biomass of four seasons including spring, summer, autumn and winter were 469.33±70.28 ind./m^2, 126.02±26.96 g/ m^2; 628±67.6 ind./m^2, 261.79±58.06 g/m^2; 494.67±72.62 ind./m^2, 103.90±23.25 g/m^2; 358.67±43.75 ind./m^2, 59.49±12.66 g/m^2. Densities were not significantly affected by tidal flats nor seasons (F=1.897 and F=1.057, P>0.05) but biomass differences were marked among seasons (F=3.695, P<0.05). The value of Margalef’s species richness index and Shannon-Wiener’s index was as follows: summer>spring>winter>autumn, the value of Pielou’s index was: spring>winter>summer>autumn, the value of Simpson’s index was: autumn>winter>summer>spring. The spatio-temporal variation of benthic community structure in Yueqing Bay was studied by hierarchical clustering and no-metric multidimension scaling. The results showed that location, the tidal flat and season were the three most important factors which greatly impact on spatio-temporal variation of benthic community structure in Yueqing Bay.
