A research for the actual situation and mechanism of carbon flux between biosphere and environments in the urbanized artificial salt marsh

为了防止大坂南湖鸟类保护区北池发生绿色潮，进行了现场调查和实验室实验，并测量了二氧化碳排放量，这是有机物分解量的指标。最大优势种逐渐由孔石莼（Ulva pertusa）转变为大野石莼（Ulva ohnoi），这部分是由于生长季节温度升高和盐度降低所致。在35 ℃的空气中暴露6小时，再加上20 psu的低盐度，光合作用受到抑制。这些结果表明，在夏季低盐度的空气暴露相结合的控制绿色潮的石莼。在大坂南港鸟类保护区北池，当底质出现时，CO2通量随地下水位的下降而增加。沉水期的CO2通量为0.2- 1.2mgCO2/m2/min，小于出水期的1/5 ~ 1/40。

Field surveys and laboratory experiments were carried out to prevent the outbreak of green tides at the north pond of Osaka Nanko bird sanctuary and to measure the amount of discharge of carbon dioxide which is an index of the amount of organic matter decomposition. The most dominant species gradually changed from Ulva pertusa to Ulva ohnoi, which is partly due to temperature increase and low salinity at a growing season. Photosynthesis was inhibited when they were exposed to air for 6 hours at 35C followed by a low salinity of 20psu. These results suggest the possibility of controlling green tides of Ulva by a combination of exposure to air with low salinity in summer. CO2 flux increased with decrease of the groundwater level when the bottom sediment emerged at the north pond of Osaka Nanko bird sanctuary. The CO2 flux in the submerged period showed 0.2-1.2 mgCO2/m2/min which was less than 1/5 to 1/40 of the emerged period.