Even as sea foam along the Alappuzha coast has heightened apprehensions and residents linked it to the container ship accident, the presence of fish body oil in the list of materials inside the containers is said to be a possible cause. According to Shaju SS of the Department of Chemical Oceanography at CUSAT, Kerala, the fish body oil is an organic matter and can be conducive to foam formation. "However, this has to be tested and verified," Shaju says.

According to him, foaming is a natural phenomenon and nothing to worry about. It's primarily caused by two factors. First, organic matter from coastal areas, ranging from food waste to animal carcasses, washes into the sea via rainwater. This organic matter, less dense than saltwater, floats on the surface. Monsoon winds then create turbulence, leading to foam formation.

Secondly, upwelling—the rising of cold, nutrient-rich water from the ocean depths—fuels phytoplankton growth. It plays a crucial role in nutrient cycling and marine ecosystems. When phytoplankton release various substances into the water, including dissolved organic matter, as part of their metabolic processes, the commotion on the sea surface triggered by high-speed winds can generate foam. 

However, some phytoplankton species produce and excrete toxic compounds, particularly during blooms. These toxins can harm marine life, including fish and shellfish, contaminate seafood, and pose a threat to human health. "However, what kind of foam has been witnessed on the Kerala coast recently can be confirmed only after conducting tests," Shaju says. 

"Sea foaming is not an unprecedented phenomenon. A similar form formation was reported on Kollam beach around five years ago," he adds.

After the Liberian container ship MSC ELSA 3, carrying 640 containers, capsized in May last week southwest of Alappuzha, there have been serious environmental concerns, including the potential for an oil spill and debris, including cargo, washing ashore along the coastline.