Field-based cultivation of Kappaphycus and Eucheuma seaweeds is widespread across the tropics and is largely done to extract the polysaccharide carrageenan, which is used in commercial applications. While such seaweed farming has been cited as a sustainable alternative livelihood to destructive fishing, there has not been a comprehensive review of its environmental impacts to assess its potential conservation benefit. We reviewed the peer-reviewed and industry gray literature to determine what is known about seaweed farming techniques and their impacts on local ecosystems, organisms, and ecosystem services. We identified 43 tropical or subtropical countries that are currently cultivating or have cultivated carrageenophytes. Ecosystem impacts of seaweed farming were measured directly in 33 publications with variable results. Placement of seaweed farms above seagrass beds led to reduced productivity and shoot density in 5 studies and reduced or altered meiofaunal abundance and diversity in 6 studies. On coral reefs, overgrowth of corals by farmed seaweed species was documented in 8 cases. Two studies showed changes to herbivorous fish communities in adjacent areas because seaweed farms changed the environment, whereas in 2 studies measures of overall abundance or diversity did not change. The impacts of seaweed farming may not be as destructive as some other human activities, but they should still be considered when establishing new farms or managing existing farm sites. Our findings are consistent with suggestions to mitigate impact on local ecosystems by shifting seaweed farms to deeper, sandy-bottom areas. However, some of these changes may adversely affect farmers and associated communities. Article impact statement: Tropical seaweed farming can negatively affect ecosystems, but shifting farms to deeper, sandy bottom areas can promote sustainability. This article is protected by copyright. All rights reserved.

中文翻译：

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热带角叉菜海藻养殖的环境影响和意义

Kappaphycus 和 Eucheuma 海藻的田间栽培在热带地区很普遍，主要用于提取用于商业应用的多糖角叉菜胶。虽然这种海藻养殖被认为是破坏性捕捞的可持续替代生计，但尚未对其环境影响进行全面审查，以评估其潜在的保护效益。我们回顾了同行评审和行业灰色文献，以确定有关海藻养殖技术的已知信息及其对当地生态系统、生物体和生态系统服务的影响。我们确定了 43 个目前正在种植或已经种植角叉菜植物的热带或亚热带国家。海藻养殖对生态系统的影响在 33 份出版物中直接进行了测量，结果各不相同。在 5 项研究中，将海藻养殖场放置在海草床上会导致生产力和芽密度降低，而在 6 项研究中导致小型动物丰度和多样性降低或改变。在珊瑚礁上，有 8 个案例记录了养殖海藻导致珊瑚过度生长。两项研究表明，由于海藻养殖场改变了环境，邻近地区的食草鱼类群落发生了变化，而在两项研究中，总体丰度或多样性的衡量标准没有改变。海藻养殖的影响可能不像其他一些人类活动那样具有破坏性，但在建立新养殖场或管理现有养殖场时仍应考虑到这些影响。我们的发现与通过将海藻养殖场转移到更深的沙底区域来减轻对当地生态系统影响的建议是一致的。然而，其中一些变化可能会对农民和相关社区产生不利影响。文章影响声明：热带海藻养殖会对生态系统产生负面影响，但将养殖场转移到更深的沙底区域可以促进可持续性。本文受版权保护。版权所有。