Weakening of Nature’s Blue Carbon Sinks

Human activities in coastal areas frequently cause loss of benthic macrophytes (e.g. seagrasses) and concomitant increases in microalgal production.  Whether such changes translate into shifts in the composition of sediment detritus is largely unknown, yet such changes could impact the role these ecosystems play in sequestrating CO2.  

Dr. Peter Macreadie of the University of Technology Sydney, and his research team reconstructed the sedimentary records of cores taken from two sites within Botany Bay, Sydney – the site of European settlement of Australia – to look for human-induced changes in dominant sources of detritus in this estuary.  Cores covered a period from the present day back in time (>6000 yrs) using ‘paleoreconstruction’ to see what effect humans have had on the ability of coastal ecosystems to mitigate climate change through capture and storage of carbon.

The research found that there has been a 100-fold weakening in the ability of coastal ecosystems to sequester carbon since the time of European settlement.  In other words, we have severely hampered the ability of nature to help reset the planet’s thermostat.

Read more in the Sydney Morning Herald November 2011 feature.

Photo Credit: Dr Peter Macreadie