Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Andalucía, Spain.
Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Andalucía, Spain.
Sci Total Environ. 2022 Jan 20;805:150193. doi: 10.1016/j.scitotenv.2021.150193. Epub 2021 Sep 11.
The concentration of dissolved CH and NO, as well as the partial pressure of CO (pCO) were studied in the Guadalquivir estuary. Samples were taken in March and April 2018 and 2019, under different rainy and tidal conditions. The available database for summer 2017 (Sierra et al., 2020) was included in the interpretation of the factors that determine the variability of these gases in the Guadalquivir estuary. Two different types of samplings were carried out: a longitudinal transect across the river with salinity values close to zero and another one during two consecutive tidal cycles in the mouth of the estuary. The highest concentrations were found in the upper zone of the estuary and during the low tide. This distribution was related to 4 factors: temperature, salinity, exchange with the atmosphere, and biochemical processes together with the river inputs. Temperature is one of the factors that clearly seems to determine the distribution of gases and fluxes, showing the highest values in the upper zone during the summer of 2017. Intense rains cause a dilution effect of the gas in the water column, this provoked, during the season of spring 2018, an increase in the salinity factor in the distribution of gases in the middle zone. High concentrations of the gases have been linked to production processes in the water column, as well as to benthic production and lateral inputs. While the gases concentrations at the mouth presented values close to those of the equilibrium with the atmosphere, the fluxes in the upper zone of the estuary reached average values of 89.6 mmol m d, 121.7 μmol m d and 59.9 μmol m d for CO, CH and NO, respectively. Generally, water-atmosphere fluxes are positive through the whole study, which means that the estuary acts as a source of these gasses to the atmosphere.
本研究调查了瓜达尔基维尔河口水体中溶解态 CH 和 NO 的浓度以及 CO 的分压（pCO）。采样分别于 2018 年和 2019 年 3 月和 4 月进行，涵盖了不同的降雨和潮汐条件。2017 年夏季（Sierra 等人，2020）的可用数据库被纳入对决定瓜达尔基维尔河口水体中这些气体变化因素的解释中。共开展了两种类型的采样：在接近零盐度的河道纵剖面进行采样，以及在河口连续两个潮汐周期进行采样。在河口的上游区域和低潮时，检测到了最高的浓度。这种分布与 4 个因素有关：温度、盐度、与大气的交换以及生物化学过程与河流输入。温度是明显影响气体分布和通量的因素之一，在 2017 年夏季的上游区域显示出最高值。强降雨会导致水柱中气体的稀释效应，这在 2018 年春季期间导致气体在中间区域的分布中盐度因素增加。气体的高浓度与水柱中的产生过程以及底栖生物产生和侧向输入有关。虽然在河口处的气体浓度接近与大气平衡的值，但在河口的上游区域，通量达到了平均水平，分别为 CO、CH 和 NO 的 89.6 mmol m d、121.7 μmol m d 和 59.9 μmol m d。通常，整个研究期间水-气通量为正值，这意味着河口是这些气体向大气排放的源。
