About Relab

The “Building Resilience of Lake Bosumtwi to Climate Change” (RELAB) Project is a multidisciplinary development research initiative aimed at investigating the impact of climate change on Lake Bosumtwi, its fisheries resources and the resultant socioeconomic impacts of fisheries resource constraints on local communities. The project is being funded by the Ministry of Foreign Affairs, Denmark through Danish International Development Agency (DANIDA) for a period of 5-years (2018-2022) with a grant amount of 10 million DKK or 1.5 million US Dollars. The project is an international and multidisciplinary research composed of an elaborate team of scientists, researchers and students from University of Energy and Natural Resources (UENR), Ghana as the host institution and University of Ghana, Legon, Aarhus University, Denmark and the Helmholtz Centre for Environmental Research (UFZ), Department of Lake Research, Germany as partners.

Project Description

Natural systems show variability on all time scales and freshwater lakes are sensitive to changes in climatic forcing, which drives their physical dynamics and influence a wide range of biogeochemical processes.

Ongoing climate warming is directly influencing the functioning of Lake Bosumtwi which is undermining its ecological, socioeconomic and cultural importance. Lake Bosumtwi is a climate-sensitive lake (Talbot and Johannessen, 1992) that has been recognized by UNESCO as a World Heritage Site for its natural and cultural significance. It is the only natural lake in Ghana, and it is the oldest (1.07 million years) and deepest (~78 m) in West Africa.

Lake Bosumtwi was formed by a meteorite impact, which formed a nearly circular crater with diameter 10.5 km (±0.5; watershed surface area = 103 km2, including the lake surface), lake surface area of 52 km², and lake-surface diameter of 8 to 8.5 km (Koeberl et al. 1997a; 2007). The crater walls are steep and elevated well above the lake surface (210 m), which greatly reduces wind speed and energy at the lake’s surface. The water budget is mainly controlled by the balance between precipitation and evaporation (Turner et al., 1996).

The lake is sacred to the Ashanti people and is at the center of their cultural identity. The fisheries resources currently support a local population of over fifty thousand people. Additionally, the lake is highly important for tourism and contributes significantly to the country’s GDP.

The lake is valuable to climate science as it contains one of the best preserved and informative records of past climate change in the world.

It is also one of the few records of climatic and ecological change in terrestrial regions of tropical West Africa (Beuning et al., 2003; Shanahan et al., 2009). Preservation of the lake’s ecological integrity is therefore critical to maintaining its local and global significance.

Fish productivity in Lake Bosumtwi is strongly affected by climatic variations via their control of lake physical structure and biogeochemical processes (Otu, 2010).

Though fish catches are reported to have declined dramatically in recent years, the causes and mechanisms are unknown. Climate warming  is increasing thermal stability of the lake and reducing vertical flux of nutrients to the surface waters and reducing fish productivity (Almond and Hecky, 2002).

Recent developments suggest Lake Bosumtwi may be turning from a holomictic (i.e. regularly mixed) lake into a meromictic lake (incomplete mixing, e.g. Boehrer and Schultze, 2008, Boehrer et al., 2017) due to warming (Turner et al., 1996; Puchniak et al., 2009).

Meromixis may be interfering with the lake’s productivity and may also have consequences for human health (e.g. by outgassing bursts). New livelihoods are beginning to emerge from various adaptations to the decline in fish harvest. These adaptive responses have the potential to alter land use patterns within the watershed (e.g. clearing of forest) with implications for the ecological health of the lake and its ability to rebound from climate impacts.

The combined and potentially synergistic effect of climate change and human activities in the watershed on the ecological functioning of the lake is unknown.

New scientific tools therefore are required to link climate forcing with lake hydrodynamics, fish productivity and human activities in the watershed.

Our project will quantify the impact of changes in climate and watershed use by humans on hydrodynamics, primary productivity and fisheries of the lake by combining a state-of-the-art modeling framework with detailed monitoring efforts (e.g. Moreira et al., 2016, Weber et al., 2017). We will test the hypothesis that climate and watershed dynamics may act individually and/or synergistically to undermine the ecological integrity of the lake by inducing multiple stressors that affect the resilience of the lake ecosystem to climate change.

Figure 1Meteorological pattern and water column thermal (degree celsius) variability of Lake Bosumtwi from 2004 to 2006 showing stratification and mixing periods during the NSERC/LBRP project (Puchniak et al., 2009). Climatic seasons; RS (rainy), H (harmattan, long dry), SD (short dry).

Relevance of Relab Project

This project responds to the Resilience to Climate Change (Theme 4) of the Ministry of Foreign Affairs, Denmark research collaboration projects in Danida priority countries (Window 1 2017) and consistent with the UN Millennium Development goals on environmental sustainability, eradicating extreme poverty and hunger, Sustainable Development Goals (SDG’s) 11 – sustainable cities and communities, 13 – climate action, 14 –life below water, 15 – life on land; DANIDA’s ‘Right to a Better Life’ enshrined in the Denmark-Ghana Partnership Policy 2014-2018; Ghana’s Shared Growth and Development Agenda II, the Ghana National Climate Change Policy and the National Climate Change Adaptation Strategy.

Project Objectives

Sustainability of fishery resources of Lake Bosumtwi is under the influence of two main stressors namely climate change and anthropogenic activities in the watershed with unknown individual and synergistic effects on ecosystem functioning and fish productivity.

We aim to resolve the individual pathways that climatic and anthropogenic factors impact the lake environment as well as their combined effects on water quality and fish productivity.

We will examine the various pathways through which fisheries decline has triggered alternative livelihood actions and assess the degree of counter productivity of these actions on the lake.

Specific Objectives

  • Elucidate lake physical structure and climate-regulating mechanisms of lake productivity, degree of climate change impacts on the functioning of the lake and fish productivity with historical and instrumental data.
  • Obtain requisite data for development of lake ecosystem model and apply the model to assess the risk of persistent meromixis in Lake Bosumtwi under future climate scenarios.
  • Obtain requisite data for development of appropriate watershed model and apply model to quantify hydrology and sediment erosion under future climate scenarios.
  • Investigate fisheries productivity and fisheries management aimed at development of fisheries management plan.
  • Understand the role of fishery decline in livelihood vulnerability and adaptation strategies and resultant watershed changes and feedback on lake ecology.
  • Build capacity for sustainable watershed and fisheries management.

Expected Outcomes and Outputs

  • Collection of historical data and new data records through field monitoring for elucidation of climate change effects on the physical dynamics, biogeochemical fluxes, primary productivity and fisheries production in Lake Bosumtwi.
  • Development and application of models for watershed hydrology and lake ecosystem to enhance our ability to accurately predict future climate events on fishery productivity.
  • Training of Ghanaian staff, students and interested stakeholders in state-of-the-art hydrological and lake ecological modelling.
  • Understanding how socioeconomic responses to fishery decline is stimulating activities in the watershed that is counterproductive to lake ecosystem integrity and health. Livelihood pathways for adaptation will be assessed to help balance resource utilization with conservation.
  • Policy briefs on impacts of changing lake conditions and current fishing practices for effective management plans and strategies.

Working Groups

The project will be structured into six Work Packages (WP); WP1-4 deal with lake functioning, climate variability and fisheries management. WP5 will resolve linkages between alternative livelihood patterns, watershed degradation and ecosystem health. WP6 seeks to translate scientific information to community action plans and institutionalized management strategies.

Project Organization and Management

Ghanaian partners: The RELAB Project is spearheaded by the University of Energy and Natural Resources (UENR), Sunyani through its Department of Fisheries and Water Resources (DFWR) which has a strong focus on limnology and fisheries. UENR is collaborating with the Department of Marine and Fisheries Science and Institute of Environment and Sanitation Studies (IESS) of the University of Ghana, Legon, Accra. The involved scientists and researchers have considerable teaching and research experience in limnology and fisheries science and participated in the ICDP/NSERC/LBRP, FAO projects and other international agencies.

Danish Partners: The Danish partners represent the Department of Biosciences, Aarhus University, Denmark. They are highly ranked internationally with vast experience in limnology, development and application of hydrodynamic-ecological lake models (HELM) and watershed models for understanding land use and climate change impacts on lake systems within large international collaborative research projects. They have vast experiences from related work sponsored by Danish Ministry of Foreign Affairs (MFA) on Lake Tanganyika in East Africa and Lake Volta in Ghana.

German Partners: The Department of Lake Research, Helmholtz Centre for Environmental Research – UFZ, Magdeburg-Germany will contribute their great expertise on lake physics, meromixis, ionic balance  and modelling. UFZ in Magdeburg is also a distinguished international research institution of aquatic scientists with a track record of cutting-edge research. UFZ have a past history of succesful collaborations with both the Ghanaian and Danish partner.

Capacity Strengthening

The project will support the training and strengthening of indigenous capacities in the following ways;

  • Four (4) PhD students will be supported through contributions to to WP1 (Limnology), WP3 (Fisheries Productivity and Management) and WP4 (Watershed Modelling, Land Use and Sedimentation Rates)
  • Four (4) MPhil students will conduct research within WP1 (Limnology) and WP5 (Socioecological/Livelihood Dynamics).
  • Provision of field and laboratory equipment and resources.
  • Training of Ghanaian field and laboratory Technicians by Danish Technicians
  • Knowledge improvement and skills enhancement of Ghanaian, Danish and German scientists in tropical limnology.
  • Tailor-made project training workshops for students, senior researchers, technicians, government agencies and resource managers.
  • Increased proficiency of local scientists in lake monitoring, field sampling, analyses and interpretation of data and application of models for decision making on lake and fisheries management.


The project will benefit from experiences of past projects and ongoing Ministry of Foreign Affairs, Denmark (MFA) sponsored projects on tropical lakes including the CLEAT project (Lake Tanganyika) and the VOLTRES project (Lake Volta) to maximize synergy between projects (e.g., potential joint scientific papers). Scientists involved in the previous NSERC/LBRP project on Lake Bosumtwi will participate actively in integration of historical data with data from RELAB to enhance analysis and interpretation of research results. They will be involved in a number of joint scientific publications.

Publication and Dissemination Strategy

The strategy covers both internal and external communication and dissemination to promote the project activities and disseminate the project results and outcomes to a multitude of audiences. The internal strategy will manage the interactions among the project team members of scientists and students on project activities and outcomes and capacity building via a diversity of channels. Other dissemination outlets include project reports, scientific journal articles and conference presentations, academic audiences, with the active involvement of the lead scientists and students on the projects. Both local and international conferences will be opportunities to networking with wider academic stakeholders and to receive feedback on our scientific research. We will use policy briefs, media communications (radio interviews and a documentary), community durbars, workshops and social media to engage with stakeholders and interact with the Ghanaian public and international scientific and development community.