Collaborative LTREB: Acidification in lowland Neotropical streams: building on a 25-year study of groundwater-surface water interactions

LTREB 合作：低地新热带溪流的酸化：基于 25 年地下水与地表水相互作用的研究

• 批准号: 1938843
• 负责人: Luis Ramirez-Ulate
• 金额: $ 24.4万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1938843&HistoricalAwards=false
• 关键词: Collaborative; LTREB; Acidification; lowland; Neotropical

Long-term studies in tropical streams in Costa Rica have documented the occurrence of rainfall-driven acidification events in lowland streams. Acidification events are short periods of time, from a few days to weeks, when the stream water becomes moderately acidic. These events result from the breakdown of forest organic material releasing carbon dioxide that moves with the water into streams, creating acid conditions in streams. Changes in acidification can affect the way streams function and their biodiversity. Research in lowland streams in Costa Rica suggest that stream invertebrates and algae, can withstand moderately acid conditions, but are negatively affected when acid conditions are extreme. This project investigates how periodic acidification affect streams in lowland Costa Rica. The research will take place at La Selva Biological Station, on the Caribbean slope of Costa Rica, where streams have been under study for more than 25 years. The main objective of this work is to understand the mechanisms and consequences of changing precipitation patterns on the acidity, biology and ecosystem functions of tropical streams. Acidification is a common phenomenon in streams wordwide, thus it is important to understand it in order to protect and sustain stream ecosystems. The research (1) will contribute to understanding how changing patterns of rainfall affect stream biodiversity and ecosystem function, (2) provide research training for graduate and undergraduate students, and (3) provide environmental outreach through a citizen science project using the iNaturalist mobile device application. The study will further ongoing long-term research on the consequences of changing patterns of precipitation on lowland tropical streams in Costa Rica. Ongoing LTREB research described the occurrence of episodic acidification events. It was hypothesized that an influx of soil-derived CO2 via subsurface flow paths contributes to those pH declines, signaling a tight coupling among rainfall, terrestrial, and aquatic ecosystems. Precipitation-driven acidification events are stronger and more common in solute-poor, poorly-buffered, streams than in solute-rich, well-buffered, streams - a characteristic of the study landscape. This project will evaluate and further develop this hypothesis by (1) assessing the relation among daily, seasonal, annual, and decadal patterns in stream water chemistry with major climate events (e.g., El Niño and La Niña - ENSO), by (2) assessing biotic responses to climate-driven acidification, and by (3) experimentally buffering a low-solute stream against acidification related to ENSO events. Climate trends and global circulation models predict changes in the frequency and intensity of weather extremes. For Central America, models predict greater seasonality, similar to patterns observed during ENSO years. In the Caribbean lowlands of Costa Rica, El Niño events result in abnormally low precipitation during the dry season, while La Niña results is high precipitation. Thus, the project will advance our understanding the consequences of extreme weather events on tropical lowland stream ecosystems.

在哥斯达黎加的热带流中的长期研究已经证明了低地流中降雨驱动的酸化事件的发生。酸化事件是短时间的短时间，从几天到几周，当水流变得适度酸性时。这些事件是由于森林有机材料的分解释放出二氧化碳，该二氧化碳与水一起流入溪流，从而在溪流中产生酸性条件。酸化的变化会影响流的功能及其生物多样性的方式。哥斯达黎加低地流的研究表明，溪流无脊椎动物和藻类可以承受适度的酸性条件，但在酸性条件极高时会受到负面影响。该项目研究了周期性酸化如何影响低地哥斯达黎加的流。这项研究将在哥斯达黎加加勒比海斜坡上的La Selva生物站进行，那里的流已经研究了25年以上。这项工作的主要目的是了解变化对热带流的酸度，生物学和生态系统功能的机制和后果。酸化是流动流中的一种常见现象，因此了解它以保护和维持流生态系统很重要。研究（1）将有助于了解降雨的变化方式如何影响流生物多样性和生态系统功能，（2）为研究生和本科生提供研究培训，（3）使用Inaturalist Mobile设备应用程序通过公民科学项目提供环境外展。这项研究将进一步持续进行有关哥斯达黎加低地热带热带降水模式的后果的长期研究。正在进行的LTREB研究描述了发作酸化事件的发生。据推测，通过地下流动路径的土壤衍生的二氧化碳的影响会导致这些pH值下降，这表明降雨，地面和水生生态系统之间的紧密耦合。降水驱动的酸化事件在可溶性贫困，延迟不佳的溪流中比在富含可溶性，延伸良好的溪流中更为常见，这是研究景观的特征。该项目将通过（1）评估流水化学中的每日，季节，年和十年模式之间的关系，并通过（例如，Elniño和LaNiña-enso）评估每日，季节性，年度和衰老模式之间的关系，（2）通过（2）评估对气候酸化的生物反应，以及（3）对气候酸化的抗酸性酸化。气候趋势和全球循环模型预测了极端天气的频率和强度的变化。对于中美洲而言，模型预测季节性更大，类似于ENSO年期间观察到的模式。在哥斯达黎加的加勒比海低地，厄尔尼诺事件在旱季中导致绝对低降水量，而拉尼娜的结果是很高的降水。这是该项目将促进我们理解热带低地流生态系统中极端天气事件的后果。

项目成果

Urban streams in Latin America: Current conditions and research needs

拉丁美洲的城市河流：现状和研究需求

• DOI: 10.15517/rbt.v68is2.44330
• 发表时间: 2020
• 期刊: Revista de Biología Tropical
• 作者: Walteros, Jeymmy M.;Ramírez, Alonso
• 通讯作者: Ramírez, Alonso

Freshwater research in Latin America: Current research topics, challenges, and opportunities

拉丁美洲的淡水研究：当前的研究主题、挑战和机遇

• DOI: 10.15517/rbt.v68is2.44328
• 发表时间: 2020
• 期刊: Revista de Biología Tropical
• 作者: Ramírez, Alonso;Gutiérrez-Fonseca, Pablo E.
• 通讯作者: Gutiérrez-Fonseca, Pablo E.

Mayfly emergence production and body length response to hydrology in a tropical lowland stream

热带低地溪流中蜉蝣的羽化量和体长对水文的响应

• DOI: 10.7717/peerj.9883
• 发表时间: 2020
• 期刊: PeerJ
• 影响因子: 2.7
• 作者: Gutiérrez-Fonseca, Pablo E.;Ramírez, Alonso
• 通讯作者: Ramírez, Alonso

Target species affects the duration of competitive interactions in the Neotropical dragonfly, Micrathyria atra (Odonata: Libellulidae)

目标物种影响新热带蜻蜓 Micrathyria atra（蜻蜓目：Libellulidae）竞争性相互作用的持续时间

• 发表时间: 2020
• 期刊: Notulae odonatologicae
• 作者: Peniston, James H;Gómez-Ruiz, Pilar A;Panwar, Pooja;Uno, Hiromi;Ramírez, Alonso
• 通讯作者: Ramírez, Alonso