Nitrogen-enriched discharges from a highly managed watershed intensify red tide (Karenia brevis) blooms in southwest Florida
Nitrogen-enriched discharges from a highly managed watershed intensify red tide (Karenia brevis) blooms in southwest Florida
复制标题
高度管理的流域排放的富氮物质加剧了佛罗里达州西南部赤潮（Karenia brevis）的爆发
DOI：
10.1016/j.scitotenv.2022.154149
复制
发表时间：
2022
影响因子：
9.8
通讯作者：
Angelini, Christine
中科院分区：
文献类型：
--
作者：
Medina, Miles;Kaplan, David;Milbrandt, Eric;Tomasko, David;Huffaker, Ray;Angelini, Christine
佛罗里达州墨西哥湾沿岸的短叶藻严重影响了区域生态系统、沿海经济和公众健康，制定有效的管理和政策策略来解决这些问题需要对驱动它们的过程有深入的了解。最近的研究表明，自然过程解释了近海水华的开始和海岸运输，而人为的营养输入可能会加剧沿海岸到达的水华。然而，过去的相关研究未能发现将沿海水华与指示人为输入的流域协变量联系起来的令人信服的证据。我们解释了为什么相关性既不是证明因果关系的必要条件，也不是充分条件。这是一种由确定性规则控制的持久的相互作用模式，并利用系统的时间模式可能揭示系统的因果关系这一事实进行实证调查。利用从现场样品数据中获得的时间序列，我们应用奇异谱分析-一种非参数谱分解方法-来恢复k动力学中的确定性信号。2012年至2021年间夏洛特港地区的短花和上游水质及排放协变量。其次，我们应用了基于混沌理论的因果分析方法，即：，收敛交叉映射和s映射-用于检测和量化沿海水华和流域协变量之间持续的，依赖于状态的相互作用机制。我们发现富含氮的卡卢萨哈奇河的排放一直在加剧。随着时间的推移，brevisa会有不同程度的开花。在华花的早期阶段，河流流量的影响最大，而总氮浓度在华花的生长/维持阶段的影响最大。这些结果表明，排放和氮输入通过不同但协同的因果机制影响开花。此外，我们将这种人为影响追溯到奥基乔比湖上游（流入卡卢萨哈奇河）和基西米河流域（流入奥基乔比湖），这表明流域尺度的营养管理和对奥基乔比湖排放协议的修改可能是必要的，以减轻沿海水华。
Karenia brevisblooms on Florida's Gulf Coast severely affect regional ecosystems, coastal economies, and public health, and formulating effective management and policy strategies to address these blooms requires an advanced understanding of the processes driving them. Recent research suggests that natural processes explain offshore bloom initiation and shoreward transport, while anthropogenic nutrient inputs may intensify blooms upon arrival along the coast. However, past correlation studies have failed to detect compelling evidence linking coastal blooms to watershed covariates indicative of anthropogenic inputs. We explain why correlation is neither necessary nor sufficient to demonstrate a causal relationship—i.e., a persistent pattern of interaction governed by deterministic rules—and pursue an empirical investigation leveraging the fact that systematic temporal patterns may reveal systematic cause-and-effect relationships. Using time series derived from in-situ sample data, we applied singular spectrum analysis—a non-parametric spectral decomposition method—to recover deterministic signals in the dynamics ofK. brevisblooms and upstream water quality and discharge covariates in the Charlotte Harbor region between 2012 and 2021. Next, we applied causal analysis methods based on chaos theory—i.e., convergent cross-mapping and S-mapping—to detect and quantify persistent, state-dependent interaction regimes between coastal blooms and watershed covariates. We discovered that nitrogen-enriched Caloosahatchee River discharges have consistently intensifiedK. brevisblooms to varying degrees over time. River discharge was typically most influential at the earliest stages of blooms, while total nitrogen concentrations exerted the strongest influence during blooms' growth/maintenance stages. These results indicate that discharges and nitrogen inputs influence blooms through distinct yet synergistic causal mechanisms. Additionally, we traced this anthropogenic influence upstream to Lake Okeechobee (which discharges to the Caloosahatchee River) and the Kissimmee River basin (which drains into Lake Okeechobee), suggesting that watershed-scale nutrient management and modifications to Lake Okeechobee discharge protocols will likely be necessary to mitigate coastal blooms.