Debora Benjamen at field work in Tanzania

30/06/2023 | In the frame of the Climate Protection Fellowship for prospective leaders of the prestigious Alexander von Humboldt Foundation Debora Benjamen aims at providing the scientific basis for a community-based Blue Carbon project in her home country Tanzania during a one-year stay in the workgroup "Ecological Biogeochemistry" of Dr. Tim Jennerjahn at the Leibniz Centre for Tropical Marine Research (ZMT). She holds a Master in Marine and Lacustrine Sciences and Management from the Free University of Brussels and works as a Blue Carbon consultant at the NGO Aqua Farms Organization (AFO,

The AFO aims to ensure development and food security through environmentally friendly aquaculture and sustainable fisheries. In Tanzania, as in many other countries, mangrove forests are threatened by deforestation, conversion to aquaculture ponds and overfishing. However, in the meantime, the multitude of ecosystem functions and services of the mangroves, which are important for humans and nature, have been recognized and efforts are being intensified to protect them and to use them more sustainably. In response, the organization secured a partnership with the Ocean Risk and Resilience Action Alliance (ORRA) to establish a Blue Carbon project in Tanzania, with the aim to restore mangroves and support local communities.

Of central importance is the function of mangroves as one of the most efficient natural carbon sinks on earth. More than many other ecosystems, they can absorb carbon dioxide (CO2) released by humans and store it in their sediments for centuries or millennia. In this way, they contribute significantly to mitigating the effects of climate change. In the meantime, policy and society have recognized this important function and develop it as a market-based financial instrument in climate policy in so-called "Blue Carbon" projects.

Blue Carbon is CO2 sequestered and stored in biomass and sediments of vegetated coastal ecosystems like mangrove forests, tidal marshes and seagrass beds. In Blue Carbon projects human interventions aim at conserving the ecosystem in order to avoid further CO2 emissions upon degradation of the ecosystem and increasing the carbon storage by, for example, planting of mangrove trees. Through the increased CO2 storage such a project creates so-called carbon credits which can be sold. The buyer in their aim to reach carbon neutrality can then use these credits to offset their own emissions.

In order to develop a credible and attractive Blue Carbon project for the voluntary carbon market it is important to follow internationally acknowledged standards. This, in turn, requires a robust scientific basis. In their Blue Carbon project, Debora Benjamen and the AFO want to protect and restore mangrove forests in Buyuni, Mbweni and Kunduchi, around Tanzania's business capital Dar es Salaam, in order to increase the carbon storage of the ecosystem and to sustain the livelihoods of the local population. Therefore, the plants and sediments in both regions were sampled and will now be analyzed for their carbon content and biogeochemical composition in the ZMT laboratories. Carbon stocks and accumulation rates will then be calculated and used as a basis for developing a carbon trading scheme for the voluntary carbon market.