Using 903 robotic buoys, a research team at Dalhousie University in Canada estimates the global phytoplankton biomass to be around 346 million tons, equivalent to 250 million elephants.
According to the research team, half of this biomass is located at depths that satellites cannot detect, Interesting Engineering reported on October 28. Ecosystems and biogeochemical processes on Earth rely heavily on marine phytoplankton. Ocean color data from satellites allows for the estimation of chlorophyll-a (Chla), which is commonly used to study carbon biomass. However, satellites do not directly monitor phytoplankton biomass in the ocean’s depths because they can only measure a small area on the surface. Additionally, cellular physiology exhibits significant variability, making Chla a poor representative of carbon biomass.
Scientists deploying BGC-Argo robotic buoys in the Labrador Sea. (Photo: Adam Stoer).
In a new study published in the Proceedings of the National Academy of Sciences, the Biogeochemical (BGC)-Argo network of robotic buoys helps fill the gaps left by satellites. These buoys can observe deeper to measure what is happening below the surface. According to the research team, this combined approach provides a more complete picture of ocean conditions and phytoplankton.
They utilized a network of 903 robotic buoys to collect nearly 99,350 bio-optical records over the past decade. By analyzing data from these buoys, the research team obtained new insights into the global distribution and changes of phytoplankton over time and across regions. The new findings emphasize the importance of using robotic buoys to complement satellite observations, offering a clearer view of what is occurring beneath the ocean’s surface.
The research team stated that the new results are significant for long-term monitoring of ocean health, especially under the impacts of climate change caused by human activities. They also suggested that geoengineering projects should consider the variability in phytoplankton biomass when assessing potential environmental impacts.
