R-codes, and coral abundance, water temperature and transect characteristics of nearshore reefs in Belize

Coral reefs are increasingly threatened by global and local anthropogenic stressors, such as rising seawater temperature and nutrient enrichment. These two stressors vary widely across the reef face and parsing out their influence on coral communities at reef system scales has been particularly challenging. Here, we investigate the influence of temperature and nutrients on coral community traits and life history strategies on lagoonal reefs across the Belize Mesoamerican Barrier Reef System (MBRS). A novel metric was developed using ultra-high-resolution sea surface temperatures (SST) to classify reefs as enduring low (lowTP), moderate (modTP), or extreme (extTP) temperature parameters over 10 years (2003 to 2012). Chlorophyll-a (chl a) records obtained for the same interval were employed as a proxy for bulk nutrients and these records were complemented with in situ measurements to "sea truth" nutrient content across the three reef types. Chl a concentrations were highest at extTP sites, medial at modTP sites and lowest at lowTP sites. Coral species richness, abundance, diversity, density, and percent cover were lower at extTP sites compared to lowTP and modTP sites, but these reef community traits did not differ between lowTP and modTP sites. Coral life history strategy analyses showed that extTP sites were dominated by hardy stress-tolerant and fast-growing weedy coral species, while lowTP and modTP sites consisted of competitive, generalist, weedy, and stress-tolerant coral species. These results suggest that differences in coral community traits and life history strategies between extTP and lowTP/modTP sites were driven primarily by temperature differences with differences in nutrients across site types playing a lesser role. Dominance of weedy and stress-tolerant genera at extTP sites suggests that corals utilizing these two life history strategies may be better suited to cope with warmer oceans and thus may warrant further protective status during this climate change interval.

Data associated with this project are archived here, including:
-SST data
-Satellite Chl a data
-Nutrient measurements
-Raw coral community survey data

For questions contact Justin Baumann (j.baumann3 <at> gmail.com)

珊瑚礁正日益受到全球与局地人为压力源的威胁，例如海水温度上升与营养盐富集。这两类压力源在礁体表面的差异显著，而厘清它们在礁系统尺度上对珊瑚群落的影响一直是一项极具挑战性的工作。
本研究针对伯利兹中美洲堡礁系统（Mesoamerican Barrier Reef System, MBRS）的潟湖礁，探究温度与营养盐对珊瑚群落特征及生活史策略的影响。研究团队开发了一项全新指标，基于2003至2012年共10年的超高分辨率海表温度（SST）数据，将礁体划分为持续低（lowTP）、中等（modTP）及极端（extTP）温度等级。
研究采用同期获取的叶绿素a（chl a）数据作为整体营养盐水平的代用指标，并结合原位测量数据对三类礁体的营养盐含量进行“实地验证”。结果显示，叶绿素a浓度在extTP位点最高，modTP位点次之，lowTP位点最低。
相较于lowTP与modTP位点，extTP位点的珊瑚物种丰富度、丰度、多样性、密度及盖度均更低，但lowTP与modTP位点的珊瑚群落特征并无显著差异。珊瑚生活史策略分析表明，extTP位点以耐受胁迫能力强且生长迅速的杂草型珊瑚物种为主，而lowTP与modTP位点则包含竞争型、泛化型、杂草型及耐胁迫型珊瑚物种。
上述结果表明，extTP与lowTP/modTP位点间的珊瑚群落特征及生活史策略差异主要由温度差异驱动，不同位点间的营养盐差异仅起到次要作用。extTP位点杂草型与耐胁迫型属的主导地位提示，采用这两类生活史策略的珊瑚或更适应海洋暖化环境，因此在当前气候变化阶段或许应获得进一步的保护地位。

本项目关联数据已在此归档，包括：
- 海表温度（SST）数据
- 卫星遥感叶绿素a（chl a）数据
- 营养盐测量数据
- 原始珊瑚群落调查数据

如有疑问，请联系Justin Baumann（邮箱：j.baumann3 <at> gmail.com）