摘要
Dissolved oxygen(DO) and pH in the central part of the Bohai Sea were surveyed in late June and late August,2011.During the June cruise,the bottom DO was in the range of 215-290 μmol-O2 kg-1(i.e.85%-115% of the saturation level),and the bottom pH was in the range of 7.82-8.04 on the total-hydrogen-ion scale.In August,however,both the bottom DO and the pH had significantly declined in the northwestern-northern near-shore areas,where the water depth was no more than 35 m.The lowest bottom DO was 100-110 μmol-O2 kg-1(only 44%-47% of the June DO values) in the northern near-shore area,where the bottom pH was 7.64-7.68 on the total-hydrogen-ion scale(0.16-0.20 units lower than the June pH value).The largest decreases in DO and in pH were observed in the northwestern near-shore bottom waters,corresponding to declines of 170 μmol-O2 kg-1(as high as 59% of the June DO value) and 0.29 pH units,respectively.The greatest pH decline of 0.29 pH units meant that the total-hydrogen-ion concentration doubled in the bottom waters from June to August.Based on field measurements of bottom DO/pH combined with a simplified model simulation,we suggest that respiration/remineralization-derived CO2 increased the acidity in the bottom oxygen-depleted waters of northwestern-northern near-shore areas in the Bohai Sea as a result of coastal red tides and/or marine aquaculture.This aquatic chemistry is suggested to be partially responsible for scallop-breeding failures in the northwestern Bohai Sea in summer 2011.
Dissolved oxygen （DO） and pH in the central part of the Bohai Sea were surveyed in late June and late August, 2011. During the June cruise, the bottom DO was in the range of 215-290 μmol-O2 kg 1 （i.e. 85%-115% of the saturation level）, and the bottom pH was in the range of 7.82-8.04 on the total-hydrogen-ion scale. In August, however, both the bottom DO and the pH had signifi- candy declined in the northwestern-northern near-shore areas, where the water depth was no more than 35 m. The lowest bottom DO was 100-110 μmol-O2 kg-1 （only 44%--47% of the June DO values） in the northern near-shore area, where the bottom pH was 7.64-7.68 on the total-hydrogen-ion scale （0.164）.20 units lower than the June pH value）. The largest decreases in DO and in pH were observed in the northwestern near-shore bottom waters, corresponding to declines of 170 μmol-O2 kg〈 （as high as 59% of the June DO value） and 0.29 pH units, respectively. The greatest pH decline of 0.29 pH units meant that the total-hydrogen-ion concentration doubled in the bottom waters from June to August. Based on field measurements of bottom DO/pH combined with a simplified model simulation, we suggest that respiration/remineralization-derived CO2 increased the acidity in the bottom oxy- gen-depleted waters of northwestern-northern near-shore areas in the Bohai Sea as a result of coastal red tides and/or marine aq- uaculture. This aquatic chemistry is suggested to be partially responsible for scallop-breeding failures in the northwestern Bohai Sea in summer 2011.
基金
supported by the National Basic Research Program of China (2009CB421204)
the National Natural Science Foundation of China (NSFC) (41076044 and 40876040)
supported by the NSFC (41049901)
the State Oceanic Administration of China (contract DOMEP-MEA-01-10)
