Dataset: Persistence in a tropical transition zone? Sargassum forests maintain productivity in warming waters at the expense of reduced annual biomass

This data set is part of the published manuscript titled "Persistence in a tropical transition zone? Sargassum forests maintain productivity in warming waters at the expense of reduced annual biomass". DOI: 10.1016/j.scitotenv.2022.158154
It provides all calculations used to develop the manuscript. The abstract is below

Macroalgal forests provide productivity and biomass that underpins the function of many coastal ecosystems globally. The phenology of forests is seasonally driven by environmental conditions, with the environment-productivity relationship understood for most coastlines of the world. Climatic transition zones, however, have characteristics of temperate and tropical regions, creating large fluctuations in environmental conditions, and potentially limiting productivity and the persistence of macroalgal forests. The response of a forest-forming, dimorphic seaweed (Sargassum hemiphyllum) to seasonal temperature and light conditions in a rapidly warming tropical-temperate transitional zone (Hong Kong) was quantified by measuring in situ growth, net primary productivity (NPP), respiration, and photosynthetic potential. These physiological responses of S. hemiphyllum were then experimentally tested in response to changing temperatures (16.5 - 27°C) and irradiances (20, 110, and 300 μmol m-2 s-1) in laboratory mesocosms. In contrast to predictions, S. hemiphyllum demonstrated asynchronous NPP and growth patterns, with growth maximized in cooler conditions but, counter-intuitively, highest photosynthetic rates in summer after annual senescence and dormancy were established. This discrepancy between peak photosynthetic rates and growth may provide regional populations of S. hemiphyllum the ability to survive higher temperatures in the near future, resisting the predicted range shifts under ocean warming. In contrast, warming is likely to drive a shorter growth season, longer dormancy, and reduced annual biomass production in bi-phasic seaweeds inhabiting climatic transition zones, potentially reducing system-wide productivity of these algal forests.

本数据集收录于已发表的手稿《热带过渡区中的持久性？马尾藻森林在变暖水域中维持生产力以牺牲年度生物量减少为代价》。DOI: 10.1016/j.scitotenv.2022.158154

该数据集提供了用于开发手稿的所有计算。摘要如下

大型藻类森林为全球众多海岸生态系统的功能提供了生产力和生物量。森林的物候学受季节性环境条件驱动，对于世界大多数海岸的环境与生产力关系已有明确认识。然而，气候过渡区兼具温带和热带地区的特征，导致环境条件发生大幅波动，并可能限制生产力以及大型藻类森林的持久性。通过对在香港这个快速变暖的热带-温带过渡区中形成的二态海藻（Sargassum hemiphyllum）在季节性温度和光照条件下的生长、净初级生产力（NPP）、呼吸作用和光合潜力进行量化测量，研究了该海藻对季节性温度和光照条件的响应。随后，在实验室中构建的中生境中，对这些生理响应进行了实验测试，以检验在不同温度（16.5 - 27°C）和辐照度（20、110和300 μmol m-2 s-1）下的变化。与预期相反，S. hemiphyllum 表现出非同步的NPP和生长模式，生长在较冷条件下达到最大值，但出人意料的是，在年度衰老和休眠建立之后的夏季光合速率最高。这种光合速率峰值与生长之间的差异，可能使得S. hemiphyllum的区域种群在未来能够适应更高的温度，抵抗海洋变暖预测的物种范围变动。相比之下，变暖可能促使双相海藻的生长期缩短、休眠期延长，以及年度生物量生产减少，这可能会降低这些藻类森林的系统整体生产力。