In light of the global increase of greenhouse gases, blue carbon habitats been shown to play a crucial role in sequestering carbon dioxide, with experts stating that the most efficient carbon–storing habitats are coastal environments that support continuous plant production.
Mozambique’s coastline boasts a rich variety of blue carbon stocks, including the largest mangrove forest in Southern Africa. This extensive mangrove forest stretches approximately from Beira to Pemba, covering three-fourths of the country’s total coastline. The West Indian Ocean region features substantial expanses of seagrasses, with higher concentrations in island nations like Madagascar, the Comoros, Seychelles, and Mauritius. It is estimated is that Mozambique is home to around 44 thousand hectares of seagrass, with 2,500 hectares located in Inhassoro and on Bazaruto Island (source). Northwest Benguerra island, the location of the BCSS field station, also hosts a significant seagrass habitat (source).
What is blue carbon?
Blue carbon is carbon dioxide stored within oceanic and coastal ecosystems, for example, mangrove forests, seagrass beds, and coral reefs. Carbon storage is a phenomenon observed in all plant ecosystems – carbon becomes integrated into soils through the accumulation of organic matter, primarily facilitated by plant growth. The carbon is then absorbed into the sediment or biomass of the ecosystem. To distinguish between carbon storied in terrestrial ecosystems and that stored in oceanic and coastal environments, the term ‘blue carbon’ was introduced. It is a subset of ‘green carbon’: a concept primarily focused on land-based carbon absorption.
Two years ago, BCSS supported the Master’s thesis of Sara Forsberg (Stockholm University, Sweden) and the Ph.D. of Manuela Amone (Eduardo Mondlane University, Mozambique). BCSS facilitated fieldwork for their dissertations and Ph.D. chapters, aiming to assess organic and inorganic carbon stocks in sediments of seagrass meadows and mangrove forests. The research findings contributed to the IUCN report “Coastal Blue Carbon Stocks in Tanzania and Mozambique: Support for Climate Adaptation and Mitigation Actions”.
BCSS facilitated fieldwork for the Master’s thesis of Sara Forsberg (Stockholm University, Sweden) and the Ph.D. of Manuela Amone (Eduardo Mondlane University, Mozambique)
Mozambique’s coastline boasts a rich variety of blue carbon stocks, including the largest mangrove forest in Southern Africa. This extensive mangrove forest stretches approximately from Beira to Pemba, covering three-fourths of the country’s total coastline.
Seagrass habitat
Seagrasses have multiple functions and play an important role in larger ecosystems. The meadows provide protection against erosion and storms by reducing the impact, filter seawater, and form an important food source for a variety of animals. For example, in the Bazaruto Archipelago, seagrass forms the primary food source of the 300-individuals large subpopulation of dugongs. Furthermore, this habitat also supports numerous invertebrates and fish species and forms an important nursery ground for juveniles. Globally, the habitat covers a mere 0.1% of the seafloor but seagrass habitats are estimated to be accountable for holding 10 to 18 percent of all marine carbon – making them incredibly efficient blue carbon stocks. Source 1 As they store such high amounts of carbon, seagrass habitat loss is a serious concern as tons of carbon could be released into the atmosphere, accelerating climate change. (source)
Seagrass habitats (yellow) in the Bazaruto Archipelago. (source of information)
Mangrove habitat
Mangrove forests are important coastal ecosystems protecting shore communities from storms, floods, and erosion, while simultaneously purifying water and providing an excellent environment for juvenile marine species to seek shelter and reach maturity. Acting as a carbon sink, mangrove trees absorb carbon from the atmosphere and trap the carbon in the soil beneath the roots, which often extend multiple meters deep (source). Studies have found that mangrove forests sink four times more organic carbon than rainforests. Despite the significant role of the trees against climate change, estimations reveal that between the years 2000 and 2015, around 20 million tons of carbon were released globally due to mangrove forests loss (source). These soil carbon emissions came mostly from mangrove deforestation in Indonesia, Myanmar, and Malaysia, accounting for over 75 percent of the loss of carbon. The mangrove forests are being cut to make room for shrimp farming, among other forms of aquaculture, and wood supply.
Coral reef habitat
Zooxanthellae, a type of algae living on the corals’ tissue in a symbiotic relationship with the coral polyps, feed on carbon and, through photosynthesis, provide the corals with oxygen and nutrients. This algae species is also responsible for the remarkable colourful appearance of corals. Additionally, the zooxanthellae provide the corals with another service, biomineralisation (organisms hardening already present tissues), as the algae produces limestone for their skeletons using carbon and bicarbonate ions. Though, simultaneously carbon is also produced during the transformation of hydrogen ions – causing ongoing debate in the science community regarding the storing and releasing of CO2 by coral reefs. (source)
Generally, the storage of carbon is thought to be far larger (an estimated 70 to 90 megatons) than the release of carbon via coral reefs (just under two megatons) per year. However, these numbers remain rough estimations, and more research is needed to determine the true value of coral reefs as a blue carbon sink.
Through continuous data collection, research and collaborations, we can better understand these crucial habitats and therefore provide the data to justify potential changes aimed at safeguarding blue carbon ecosystems from both national and international legislative perspectives. BCSS provides all professional logistics needed to mobilise fieldwork, combined with scientific support and thorough knowledge of the area. Our station on Benguerra Island warmly welcomes researchers and scientists providing them access to high-end laboratory equipment and multiple boats. This setup facilitates the collection of data during expeditions in the open ocean and store them on the same day. For more information, please see our logistical support overview.
For questions about this article, please contact:
Iris Uijttewaal, Bazaruto Center for Scientific Studies
Iris.Uijttewaal@bcssmz.org
Bazaruto Center for Scientific Studies
Host of the first permanent Ocean Observatory focused on multi-ecosystem time series research in Africa, the Bazaruto Center for Scientific Studies (BCSS) was established in 2017 as in independent, non-profit organisation with a mission to protect and support the fragile ecosystems of the Bazaruto Archipelago, Mozambique. The research station is located on Benguerra Island, off the coast of Mozambique.
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