What do oceans and wildfires have to do with each other, and what is the interaction of carbon between them?

Dr Glynis Humphrey says she started pondering this question when she read a paper that “highlighted for the first time in history that the African continent has shifted to being a carbon source and is no longer a sink. This signified an ecological tipping point.”

Humphrey’s project proposal for the JWO Research Grant is entitled “Fire to Sea: Tracking wildfires and oceanic Carbon (C) dynamics for biodiversity conservation in Southern Africa.”

She says that “recent research has shown that Africa is emitting more Carbon (C) than it stores, and the C sink capacity is decreasing due to land use conversion to agriculture. Fires in Africa play a significant role in maintaining functional ecosystems, yet are responsible for 70% of global burned area with 46%-65% of C related to fire emissions, that have widespread impact on climate, biogeochemical cycles, and human wellbeing.

“Oceans help regulate the climate, provide oxygen, and store carbon dioxide, and interactions between fire and ocean ecosystems play a crucial role in C cycling.

“Yet, the impacts of fire on coastal and marine ecosystems, and the reciprocal influences of oceanic processes on fire regimes, are poorly understood in the African context. Wildfire byproducts such as aerosols, ash, and sediments enter the oceans and other water bodies via terrestrial and atmospheric routes. These byproducts pose a challenge to the sustainability of marine ecosystems, especially under the current increase in fire activity. Novel research approaches are needed to unravel the dynamics between wildfires and marine ecosystems, and the oceans’ potential to mitigate wildfire emissions. An understanding of the mechanisms that uphold biodiversity in ‘fire-prone’ marine and land ecosystems is essential for conservation in Africa.”

Humphreys notes that “climate change is increasing the frequency and the intensity of wildfires globally, with significant impacts on society and the environment. Yet, there are unanswered research questions about the recent increase in phytoplankton and Harmful Algal Blooms (HAB) and the link to wildfires. There is a large-scale ecological connection from terrestrial to marine ecosystems and to the current scientific uncertainty around carbon dynamics in relation to climate change.

“Wildfires have been occurring for millennia, and so have upwelling systems and nutrient cycling in the ocean,” she says, “but there are questions given climate change about how these systems will change in the future. Gathering an understanding of the differences in red-tides and algal blooms helps in addressing the specific causes, impacts, and management strategies for each phenomenon. For example, how will these ecological changes socially impact communities living alongside coastal areas that are dependent on natural resources? In 2023, the development of red tides saw thousands of rock lobsters walk out the sea on the West Coast in the Western Cape. These HABs appear to be occurring more frequently, and these events have consequences for fisheries management and the socio-economic sector and can have consequences for vulnerable communities dependent on natural resources for their livelihoods.”

While wildfires stoke her research, Humphrey says surfing stokes her passion for the outdoors. “I’m an avid surf ski downwind paddler,” she says, “and passionate about surfing at an average speed of 20km/h down waves across False Bay. My dream is to have a GoPro with a high-resolution interface to capture images of the offshore birds, because I can’t take my binoculars out to sea while paddling and balancing on waves; the identification is tricky out there in the ocean turbulence.”

Humphreys is a postdoctoral research fellow at the African Climate Development Institute (ACDI) in the TES NbS project. Her current research project is centred on understanding the socio-economic benefits and constraints of nature-based solutions in achieving social equity in southern Africa. Her core interests are in people (indigenous knowledge), biodiversity, climate, fire, ecosystem services, and the use of trans and inter-disciplinary research to address adaptive management and conservation policies.