Institute of the Environment and Sustainability, University of California Los Angeles, Los Angeles, California, United States of America.
Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada B.C. Mexico.
PLoS One. 2021 Apr 22;16(4):e0236218. doi: 10.1371/journal.pone.0236218. eCollection 2021.
Ocean acidification is one the biggest threats to marine ecosystems worldwide, but its ecosystem wide responses are still poorly understood. This study integrates field and experimental data into a mass balance food web model of a temperate coastal ecosystem to determine the impacts of specific OA forcing mechanisms as well as how they interact with one another. Specifically, we forced a food web model of a kelp forest ecosystem near its southern distribution limit in the California large marine ecosystem to a 0.5 pH drop over the course of 50 years. This study utilizes a modeling approach to determine the impacts of specific OA forcing mechanisms as well as how they interact. Isolating OA impacts on growth (Production), mortality (Other Mortality), and predation interactions (Vulnerability) or combining all three mechanisms together leads to a variety of ecosystem responses, with some taxa increasing in abundance and other decreasing. Results suggest that carbonate mineralizing groups such as coralline algae, abalone, snails, and lobsters display the largest decreases in biomass while macroalgae, urchins, and some larger fish species display the largest increases. Low trophic level groups such as giant kelp and brown algae increase in biomass by 16% and 71%, respectively. Due to the diverse way in which OA stress manifests at both individual and population levels, ecosystem-level effects can vary and display nonlinear patterns. Combined OA forcing leads to initial increases in ecosystem and commercial biomasses followed by a decrease in commercial biomass below initial values over time, while ecosystem biomass remains high. Both biodiversity and average trophic level decrease over time. These projections indicate that the kelp forest community would maintain high productivity with a 0.5 drop in pH, but with a substantially different community structure characterized by lower biodiversity and relatively greater dominance by lower trophic level organisms.
海洋酸化是全球海洋生态系统面临的最大威胁之一，但人们对其生态系统的整体响应仍知之甚少。本研究将野外和实验数据整合到一个温带沿海生态系统的质量平衡食物网模型中，以确定特定 OA 强迫机制的影响，以及它们如何相互作用。具体来说，我们将加利福尼亚大海洋生态系统南部分布极限附近的海带林生态系统的食物网模型在 50 年内强迫降低 0.5 pH 值。本研究利用建模方法来确定特定 OA 强迫机制的影响以及它们如何相互作用。将 OA 对生长（生产力）、死亡（其他死亡率）和捕食相互作用（易损性）的影响孤立起来，或者将这三种机制结合起来，会导致各种生态系统响应，一些分类群的丰度增加，而另一些则减少。结果表明，碳酸钙矿化群如珊瑚藻、鲍鱼、蜗牛和龙虾的生物量减少最大，而大型藻类、海胆和一些大型鱼类的生物量增加最大。低营养级群体如巨藻和褐藻的生物量分别增加了 16%和 71%。由于 OA 胁迫在个体和种群水平上表现出多种多样的方式，生态系统水平的影响可能会有所不同，并呈现出非线性模式。综合 OA 强迫导致生态系统和商业生物量最初增加，然后随着时间的推移商业生物量下降到初始值以下，而生态系统生物量仍然很高。生物多样性和平均营养水平随时间下降。这些预测表明，海带林群落将保持高生产力，pH 值下降 0.5，但群落结构发生显著变化，生物多样性降低，低营养级生物相对占主导地位。
