How Much Can Riverine Biogeochemical Fluxes Affect the Arctic Ocean Acidification?
How Much Can Riverine Biogeochemical Fluxes Affect the Arctic Ocean Acidification?
复制标题
DOI：
10.1029/2023jc020404
复制
发表时间：
2024-06-01
影响因子：
3.6
通讯作者：
Park，Hotaek
中科院分区：
文献类型：
--
作者：
Zhang，Yuanxin;Yamamoto-Kawai，Michiyo;Park，Hotaek
北极河流不仅携带大量的淡水，而且还携带大量的地球化学物质进入海洋，在北冰洋酸化（OA）中起着重要作用。本研究利用泛北极海冰-海洋模型，利用多年代际实验（1979-2018年）定量评估了河流生态地球化学通量（R-BGC;碳和营养盐）对北极海洋碳酸盐系统和OA的影响。采用改进的碳酸盐性质的初始和侧边界条件、基于观测的河流地球化学数据和基于陆地模型的年际变化的河流淡水排放，以实现更真实的实验。该模型模拟了北冰洋大部分地区的文石饱和状态（Ω）和pH值的负趋势，而不考虑R-BGC。增加河流淡水促进更多的OA通过更高的稀释效应。与只有淡水的河流排放实验相比，包含R-BGC导致Ω和pH值的正异常（在中央流域分别为0.14和0.03，在陆架海分别为0.15和0.06）。在中央盆地，这些异常主要是由R-BGC的碳（总碱度和溶解无机碳）引起的。在陆架海，营养盐（硝酸盐和硅酸盐）通量也贡献了0.14%和0.32%的异常，由于初级生产力的增强和海水pCO 2相应的减少。R-BGC缓解了河流淡水积累地区的OA（ΔΩ = −1.53 × 10− 3年− 1和ΔpH = −0.56 × 10− 3年−1）（即，加拿大海盆、楚科奇海帽、欧亚海盆和东西伯利亚海）。这项研究强调了将R-BGC纳入OA模型预测的重要性。
Arctic rivers carry not only large amounts of freshwater but also biogeochemical materials into the ocean and play important roles in Arctic ocean acidification (OA). This study quantitatively evaluated the effects of riverine biogeochemical fluxes (R‐BGC; carbon and nutrients) on the Arctic marine carbonate system and OA using multi‐decadal experiments (1979–2018) with a pan‐Arctic sea ice–ocean model. Improved initial and lateral boundary conditions of carbonate properties, observation‐based riverine biogeochemical data, and land model‐based interannually varying riverine freshwater discharge were adopted to enable more realistic experiments. The model simulated negative trends in aragonite saturation state (Ω) and pH in most regions of Arctic Ocean regardless of R‐BGC. The increased riverine freshwater promoted more OA through the higher dilution effect. Compared to the experiment with riverine discharge of only freshwater, the inclusion of R‐BGC caused positive anomalies in Ω and pH (by ∼0.14 and ∼0.03 in central basins, and by ∼0.15 and ∼0.06 in shelf seas, respectively). In the central basins, these anomalies were caused mostly by carbon (total alkalinity and dissolved inorganic carbon) of the R‐BGC. In the shelf seas, nutrient (nitrate and silicate) fluxes also contributed ∼14% and ∼32% of the anomalies owing to the enhanced primary production and a corresponding reduction in seawater pCO2. R‐BGC mitigated OA (ΔΩ = −1.53 × 10−3year−1and ΔpH = −0.56 × 10−3year−1) in regions where riverine freshwater was accumulated (i.e., the Canada Basin, Chukchi Cap, Eurasian Basin, and East Siberian Sea). This study stressed the importance of including R‐BGC for OA model projection.