莱州湾沉积有机碳储量及海洋健康评估

CARBON STOCK IN THE LAIZHOU BAY AND EVALUATION OF ITS OCEAN HEALTH

海洋沉积碳储量在全球碳循环中发挥着重要作用,而海湾作为海洋的重要组成部分,近几十年来由于受人类活动影响有机碳循环发生了明显变化,对碳储备能力的响应同样不可忽视,但却鲜有报道。研究区域位于莱州湾(37°~38°N,118.9°~120.3°E),是渤海三大海湾之一。利用39个表层沉积物和其6根沉积箱式柱状样(站位为6154、6174、6184、6194、7211和7214,柱长在17~39 cm之间)对海湾有机碳储量进行评估。同时,通过计算海洋健康指数(OHI)十个目标之一的碳储(carbon storage)来评估海洋健康状况。结果表明,莱州湾表层沉积物1 cm的有机碳储量平均为0.3 t/ha,在研究区域的中部、东部和北部偏高,莱州湾东南部、区域西北部以及黄河口处有机碳储量偏低。莱州湾0~20 cm有机碳储量为20.6 t/ha,低于我国表层土壤0~20 cm有机碳储量29.7 t/ha以及浙江、云南、海南和重庆等省市。莱州湾碳储(carbon storage)得分为37,远低于中国平均值51以及世界平均水平75。

The ocean plays an important role in the global carbon cycle.The carbon stock in bays was especially essential because bays were influenced by human activities and the organic carbon accumulations have changed during the past decades.The study area is the Laizhou Bay(37° ~ 38°N,118.9° ~ 120.3°E),one of the three major bays in the Bohai Sea,China.39 surface sediments and 6 boxing cores(including stations 6154,6174,6184,6194,7211 and 7214,length of 17 ~ 39 cm) obtained from the Laizhou Bay were used to assess the carbon stock.Meanwhile,the carbon storage,one of the ten goals of the Ocean Health Index(OHI) was calculated to evaluate the ocean health.Our results showed that the average value of carbon stock in surface sediments was 0.3 t/ha.The relatively high values of carbon stock were found in the middle,eastern and northern parts of the Laizhou Bay,while low values were in the southeastern and northwestern parts of the Laizhou Bay and near the Yellow River Estuary.The average value of carbon stock in the top 20 cm of sediments in the Laizhou Bay was 20.6 t/ha,which was lower than that in soil in China(29.7 t/ha),as well as that in Zhejiang,Yunnan,Hainan and Chongqing provinces.The carbon storage is score of 37 in the Laizhou Bay,which was far lower than the average score of 51 in China and the world average score of 75.