桑沟湾表层水pCO2的季节变化及影响因素分析

Seasonal variation of pCO_2 and its potential influencing factors in aquaculture areas of Sanggou Bay

根据2011年4、8、10月和2012年1月在桑沟湾获得的表层海水总碱度(TA)和pH值,结合现场水文、化学、生物和养殖等参数,探讨了桑沟湾海域CO2体系各参数的空间分布特征、季节变化情况及其影响因素。调查结果显示,10月和翌年1月,CO2体系各参数主要受温度和盐度的影响;8月,pH和pCO2分别与初级生产力和溶解氧显著相关;4月与水文、化学生物因子无显著相关性。8月各参数的空间差异最大,其次是10月,1月最小。4个航次的平均表层pCO2都低于大气pCO2,为表观碳汇区;季节变化趋势是8月<4月<1月<10月。pCO2总体的空间分布趋势都是湾内向湾外递增,即贝类养殖区<贝藻混养区<藻类养殖区<非养殖区。8月,桑沟湾较低的pCO2可能与赤潮有关,而4月可能是物理、生物及大规模贝藻养殖的综合结果。桑沟湾较低的pCO2是由于受沿岸区高初级生产力的影响,还是受大规模的贝藻养殖的影响,尚需进一步的研究。

Based on four investigations of total alkalinity and pH,and combined with other chemical,biological factors and mariculture activities,the distribution characteristics,seasonal variation of seawater CO2 parameters and the major influencing factors were discussed in this research.The results showed that in October and January,the CO2 system parameters were primarily influenced by temperature and salinity ;while in August,the pCO2 and pH were controlled by dissolved oxygen and primary productivity,respectively.While in April,no significant correlation was found between CO2 system parameters and hydrological,chemical or biological factors.The maximum differences in spatial distribution of pCO2 were in August,fol-lowed by October,April and January.Average pCO2 in the four investigations were below the atmospheric CO2 pressure ;seasonal trend in pCO2 was AugustAprilJanuaryOctober.Overall spatial distribution trend of pCO2 was shellfish mono-culture zoneshellfish and seaweed polyculture zoneseaweed mono-culture zonenon-culture zone.In August,the low pCO2 may be related to the red tide in Sanggou Bay.However,in April it might be the integrated influence of physical,biological factors and mariculture activity.Whether the lower pCO2 in Sanggou Bay is due to the relatively high primary productivity or the influence of large-scale mariculture in the Bay requires further study.