The identification of natural carbon sinks and understanding how they work is critical if humans are to mitigate global climate change. Tropical coastal wetlands are considered important but, so far, there is little data to show the benefits. This study, led by the University of Göttingen with the Leibniz Centre for Tropical Marine Research in Bremen, and the University of Bremen showed that mangrove ecosystems need to be conserved and restored as part of the battle against rising carbon levels in the atmosphere. The research was published in Global Change Biology.
Researchers conducted the study in the mangrove-fringed Segara Anakan Lagoon in Java, Indonesia. This coastal lagoon is known to be one of the most effective carbon sinks amongst mangrove ecosystems around the world. The researchers analysed a five-meter-deep core of sediment for its age and biogeochemical composition, as well as elements, pollen and spores. They investigated four different time periods across 400 years and varying climates, integrating data from ecological and societal changes with land and coastal changes.
The results show that the environmental dynamics in the lagoon and carbon accumulation were controlled mainly by fluctuations in the climate and human activity. The researchers found that the interaction of these two factors affected the lagoon’s sediment and saltiness, which then went on to alter the composition of the organic matter (which contains carbon), and how it was deposited in the lagoon thus adding to the “sink of carbon”. They also found that the weather was the chief driver in washing carbon compounds, in the form of organic matter, to the lagoon from remote areas far from the coast. In earlier times, these remote areas consisted of natural mixed forest but more often now they are agricultural land.
Read more at University of Göttingen
Image: Mangroves growing around the edge of the Segara Anakan Lagoon in Java, Indonesia (Credit: Tim Jennerjahn)