Nutrient distribution and structure affect the acidification of eutrophic ocean margins: A case study in southwestern coast of the Laizhou Bay, China

Abstract

The effects of nutrient distribution and structure on the acidity of coastal waters were analyzed based on the data of 48 surface water samples collected in the southwestern coast of the Laizhou Bay and its adjacent rivers (SWLZB) which are heavily influenced by nutrient-laden discharges. The concentration and structure of nutrients varied considerably along the coast owing to different contributors. The studied inshore waters exhibited a sign of acidification. The pH was significantly negatively correlated with the concentration of NO 3 -N, NO 2 -N, NH 4 -N and DSi, but showed no obvious correlation with the concentration of PO 4 -P and the ratio of TDN/TDP, DSi/DIN and DSi/PO 4 -P, respectively. The results indicated that the distribution of nutrients might well be an important environmental factor affecting the acidification of the SWLZB in warmer months.

Removal Capacities and Environmental Constrains of Denitrification and Anammox Processes in Eutrophic Riverine Sediments

“…The total annual flux of DIN into Jiaozhou Bay from XQ was 59.0 Mmol N, as calculated by the data provided by the Chinese Ocean Environmental Quality Bulletin in 2012. The DIN fluxes from JL were estimated to be approximately one-fifth of XQ, according to the nutrient concentration and flow discharge ratio data for the two rivers (Zhang and Gao 2016;Zhang et al 2012). Thus, the denitrification and anammox both achieved 16.1% removal of the annual flux of the total nitrogen in XQ and JL.…”

Climate Change Information for Regional Impact and for Risk Assessment

“…Ocean warming and increased stratification decrease the oxygen content of the ocean (Griffiths et al, 2017;Schmidtko et al, 2017;Bindoff et al, 2019), lead to an expansion of oxygen minimum zones in the open ocean (Stramma et al, 2012;Zhang et al, 2013) and exacerbate the creation of anoxic 'dead zones' in the coastal oceans (Breitburg et al, 2018). Such a decline (characterized by successive dissolved oxygen concentration thresholds) could affect a wide range of marine organisms and reduce marine habitats (Chan et al, 2008;Vaquer-Sunyer and Duarte, 2008;Hoegh-Guldberg and Bruno, 2010;Altieri and Gedan, 2015;Breitburg et al, 2018) and can also lead to further local acidification (Zhang and Gao, 2016;Laurent et al, 2017).…”

Study on Total Control of Total Nitrogen in the Laizhou Bay

“…We collected relevant data from several studies and literature and found that there were relatively abundant measurements in September 2012. The mean values of the sampling sites at the estuaries of the Xiaoqinghe River (K-section, Figure 1) and the Yuhe River (H-section, Figure 1) were set as the concentration at these two estuaries, respectively [24]. The concentration of the sampling site at the tidal portion of the Jiaolaihe River was set [24].…”

“…The mean values of the sampling sites at the estuaries of the Xiaoqinghe River (K-section, Figure 1) and the Yuhe River (H-section, Figure 1) were set as the concentration at these two estuaries, respectively [24]. The concentration of the sampling site at the tidal portion of the Jiaolaihe River was set [24]. The concentration of TN at the Yellow River estuary referred to the sampling station data from the Lijin station in the lower Yellow River [25].…”

“…The seawater quality standard for dissolved inorganic nitrogen (DIN) was set by the Ministry of Ecology and Environment (MEE) [27]. Zhang and Gao indicated that the ratio of DIN to TN was around 1.6 in the Laizhou Bay [24]. Hence, the seawater quality standard for DIN and TN can be obtained (Table 2).…”