What are blue carbon ecosystems and why are they important?

Mangroves, saltmarsh and seagrasses are referred to as blue carbon ecosystems. They are ‘mega’ carbon storers, at 6 to 8 Mg per hectare. This increased carbon storage is where blue carbon ecosystems get their name! When these ecosystems are degraded, much of this carbon is lost and cycled back into the atmosphere and water. Carbon sequestration and conservation of carbon stores can significantly control global warming, and so lots of current research on these ecosystems is focused on how to protect them from degradation. We do this through monitoring possible impacts upon blue carbon systems and we work hard to produce strategies to protect them. This has the added benefit of informing market evaluations of carbon storage. So, the more precise our monitoring, the higher the value of the ecosystem!

The difficulty of monitoring blue carbon ecosystems.

Monitoring of blue carbon ecosystems is hard: much harder than terrestrial systems! Marine systems are fluid (pun unintended), and this means that monitoring them becomes increasingly complex.

There are several reasons why monitoring blue carbon ecosystems is difficult. Well firstly we’re working within water. This means stuff such as creatures and nutrients don’t stay in the same place as much as in terrestrial ecosystems. Marine species move between ecosystems more easily especially in the case of blue carbon ecosystems. We’re also learning that blue carbon ecosystems cycle and move nutrients between them in a way which makes them intrinsically linked. As an example, mangroves and saltmarsh break down nutrients which help seagrasses to grow!

Also, ecosystems look different at different times of the year and with variations in tide! This is true for both terrestrial and marine ecosystems, but in the case of blue carbon ecosystems this variation is so much greater.

Plus, there’s bugs, mud, sticks and even crocodiles. Imagine trying to complete some physical height assessments and coming across a crocodile! Pretty scary stuff.

So how do we get precise monitoring without putting our scientists at risk?

We can use remote sensing to make accurate assessments of blue carbon environments without having to get our feet wet (Wahoo!). Remote sensing refers to sensors and platforms which can obtain high resolution imagery. This could be through the use of drones, satellites or even airplanes, to take images of an environment at different times and evaluate their changes.

Sounds easy? While the capture of the data is certainly easier than physically monitoring, the problems that come with this new way of looking at ecosystems are vast. One of these problems is that we don’t know what normal function looks like within blue carbon ecosystems.  

Scientists control for this natural variation to identify what normal looks like! This sounds a lot easier than it is. If you look at a healthy ecosystem or, one that you know is un-affected by stress, it might be easy to assume that data taken from this ecosystem will be the measure of what ‘normal’ looks like. However normal has a ‘bounds’ at which it moves within. Normal function at, for example, high tide in mangroves, may look completely different from when it is low tide. If we can identify what the bounds of this normality looks like and create an ‘envelope’ of condition we can start to understand this complexity.

Remembering this fluidity is important in our monitoring and model making and the development of comprehensive models that we can rely on. Ecosystems and nature are complex, and it would be wrong to assume that we can ever fully capture this complexity. However, if we can expand the bounds of our thinking concerning ecosystem complexity, maybe we can hope to capture enough of it to help assess, protect and value this hugely important resource in the sequestration of carbon!