这项研究考察了二氧化碳(CO2)的同时水-大气交换,加的斯湾大陆架上的甲烷(CH4)和一氧化二氮(N2O),以及它对大气辐射平衡的影响,2014年至2016年。实验数据库包括2016年CO2分压(pCO2)和N2O浓度的空间和季节分布的新测量值。pCO2显示出广泛的变化范围,主要受季节性热变化(8.0μatm0C-1)的影响,以及生物活性的相对强度。有实验证据表明,在过去的20年里,pCO2逐渐增加,估计梯度为4.2±0.7μatmy-1。在2016年,加的斯湾是大气中二氧化碳的轻微来源,平均通量为0.4±2.2mmolm-2d-1。对水柱浓度变化的分析表明,硝化是研究区N2O产生的主要过程,尽管在更沿海的地区,有迹象表明输入与大陆和沉积物的贡献有关,最有可能是由反硝化过程引起的。2016年,加的斯湾充当了大气N2O的弱汇,平均通量为-0.1±0.9μmolm-2d-1。从以前的研究来看,用类似的方法进行,CO2、CH4和N2O的水-大气通量年际数据库(2014-2016年),归一化为该地区的平均风速,已经产生了。考虑到它们各自的全球变暖潜能值(GWP)和联合温室气体(GHG)通量,以0.6±2.0mmolm-2d-1的CO2当量表示,已估计,扩展到研究区域,表明排放量约为67.9GgCO2y-1。然而,尽管与空间相关的不确定性很高,加的斯湾CO2,CH4和N2O通量的时间和年际变化,温室气体的交换可能会影响大气中的辐射强迫增加。在考虑当地和全球估计的现有信息时,温室气体联合交换对沿海海洋大气影响的不确定性显著增加。
This study examines the simultaneous water-atmosphere exchange of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) on the continental shelf of the Gulf of Cadiz, as well as the effect it has in terms of the radiative balance in the atmosphere, between 2014 and 2016. The experimental database consists of new measurements of the spatial and seasonal distribution of CO2 partial pressure (pCO2) and N2O concentration in 2016. pCO2 shows a wide range of variation influenced mainly by seasonal thermal variations (8.0 μatm 0C-1), as well as with the relative intensity of biological activity. There is experimental evidence of a progressive increase of pCO2 over the last 2 decades, with an estimated gradient of 4.2 ± 0.7 μatm y-1. During 2016, the Gulf of Cadiz acted as a slight source of CO2 to the atmosphere, with a mean flux of 0.4 ± 2.2 mmol m-2 d-1. The analysis of concentration variations in the water column shows that nitrification is the main N2O production process in the study area, although in the more coastal zone there are signs of inputs related to continental and sediment contributions, most probably induced by denitrification processes. In 2016, the Gulf of Cadiz acted as a weak sink of atmospheric N2O, with a mean flux of -0.1 ± 0.9 μmol m-2 d-1. From previous studies, performed with a similar methodology, an interannual database (2014-2016) of water-atmosphere fluxes of CO2, CH4 and N2O, normalized to the mean wind speed in the area, has been generated. Considering their respective Global Warming Potential (GWP) a joint greenhouse gasses (GHG) flux, expressed in CO2 equivalents of 0.6 ± 2.0 mmol m-2 d-1, has been estimated, which extended to the area of study indicates an approximate emission of 67.9 Gg CO2 y-1. However, although there is a high uncertainty associated with the spatial, temporal and interannual variations of CO2, CH4 and N2O fluxes in the Gulf of Cadiz, the exchange of greenhouse gasses could be influencing a radiative forcing increase in the atmosphere. When considering the available information on local and global estimates, the uncertainty about the effect of the joint exchange of GHGs to the atmosphere from the coastal seas increases significantly.