Satellite imagery captures bizarre substance on ocean surface – and the explanation is even weirder

Back in 2018, imagery from the European Space Agency’s Sentinel-2A satellite captured unusual ‘slicks’ in the Baltic Sea, near the Gulf of Gdansk in northern Poland – and it was only five years later that scientists pointed to its likely cause.

According to Nasa Earth Observatory, marine debris and cyanobacteria have cropped up in satellite images in the past, but academics from Florida and Maryland in the US, and Słupsk in Poland, determined in 2023 that pollen was the culprit.

Their paper, published in Remote Sensing of Environment, concludes: “A key finding is that, in certain years between May 10 and June 16, pine (Pinus sylvestris) pollen grains can be found in surface waters nearly everywhere in the Baltic Sea, well beyond nearshore or coastal waters.

“Such a discovery is attributed to the frequent multi-spectral satellite observations and the relatively unique reflectance spectral shapes of pine pollen grains, which are confirmed by laboratory experiments.”

Bizarre substance on the surface of the ocean observed from space ESA/Copernicus

The scientists referred to satellite images from 2000 to 2021 as part of their study, with 14 years indicating “large amounts of pollen grains”.

They also said that due to the grains having “a significant amount of carbon” and “distinctive optical properties from other particles”, their findings have “significant implications” for carbon sequestration (the permanent removal and storage of carbon dioxide from the atmosphere), marine ecosystems and more.

Chaunmin Hu, the study’s lead author, also told Nasa: “If we can track pollen aggregation in different places, this may provide useful data for fisheries studies.”

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