Addressing grand ecological challenges in aquatic ecosystems: how can mesocosms be used to advance solutions?

Journal article

Rapid and drastic anthropogenic impacts are affecting global biogeochemical processes and driving biodiversity loss across Earth's ecosystems. In aquatic ecosystems, species distributions are shifting, abundances of many species have declined dramatically, and many are threatened with extinction. In addition to loss of diversity, the ecosystem functions, processes and services on which humans depend are also being heavily impacted. Addressing these challenges not only requires direct action to mitigate environmental impacts but also innovative approaches to identify, quantify and treat their effects in the environment. Mesocosms are valuable tools for achieving these goals as they provide controlled environments for evaluating effects of stressors and testing novel mitigation measures at multiple levels of biological organisation. Here, we summarise discussions from a survey of marine and freshwater researchers who use mesocosm systems to synthesise their opportunities and limitations for advancing solutions to grand ecological challenges in aquatic ecosystems. While most research utilising mesocosm systems in aquatic ecology has focused on quantifying the effects of environmental threats, there is a largely unexplored potential for using them to test solutions. To overcome spatio‐temporal constraints, there are opportunities to scale up the size and time‐scales of mesocosm studies, or alternatively, test the outcomes of habitat‐scale restoration at a smaller scale. Enhancing connectivity in future studies can help to overcome the limitation of isolation and test an important aspect of ecological recovery. Conducting ‘metacosm' studies: coordinated, distributed mesocosm experiments spanning wide climatic and environmental gradients and utilising more regression‐based experimental designs can help to tackle the challenge of context dependent results. Finally, collaboration of theoretical, experimental and applied ecologists and biogeochemists with environmental engineers and technological developers will be necessary to develop and test the tools required to advance solutions to the impacts of human activities on Earth's vulnerable aquatic ecosystems.

Authors: Macaulay, SJ; Jeppesen, E; Riebesell, U; Nejstgaard, JC; Berger, SA

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Oikos
• Article number: e11020
• Publication date: 2025-02-11
• Acceptance date: 2024-12-19
• DOI: 10.1111/oik.11020
• EISSN: 1600-0706
• ISSN: 0030-1299
• Language: English
• Keywords: marine; ecology; gradient designs; metacosm studies; freshwater; global change; connectivity; distributed experiments; restoration