Is Volcanic Ash from Anak Krakatau Polluting the Ocean? Hear What an IPB University Marine Expert Has to Say

Volcanic ash from the eruption of Mount Anak Krakatau does not automatically become a pollutant or toxin for the marine ecosystem. Its impact on the waters depends heavily on the intensity and volume of volcanic material entering the ocean.

This was stated by Prof Agus Atmadipoera, an oceanography expert at IPB University, who is also involved in the ‘Cinodex’ underwater research project, a collaboration between Indonesia and China.

According to him, volcanic ash material that falls into the ocean must be assessed based on its concentration, distribution, and the physical processes occurring in the water. “Volcanic ash that falls into the ocean does not automatically become a pollutant or toxin for the ecosystem. It depends on the intensity and volume,” he said.

However, ecological impacts can arise if volcanic material enters the water in large quantities. Such conditions can increase water turbidity, thereby reducing the penetration of sunlight into the water column. As a result, the photosynthesis of marine organisms may also be disrupted.

According to him, physical conditions of the water, such as waves, currents, and tides, also determine the impact of volcanic ash on marine ecosystems. These mixing processes can help disperse and dilute volcanic material within the water.

He further explained that the area located very close to the Anak Krakatau crater has a relatively simpler and more extreme ecosystem. The seafloor around the islands near the crater tends to be covered with coarse material, such as sand, gravel, and remnants of volcanic debris flows.

Meanwhile, in areas farther from the crater, particularly in the northern waters, the sediment layer is predominantly composed of thick mud. These conditions actually allow the area to support a relatively higher abundance of benthic organisms.

Volcanic Ash Has Ecological Benefits
In addition, Prof Setyo Budi Susilo, a lecturer in the Department of Marine Science and Technology at IPB University, added that fine volcanic ash carried into the water does not necessarily have a negative environmental impact.

“Volcanic ash also has the potential to provide ecological benefits. This material contains a number of micronutrients, including silica and iron,” he said.

“After being stirred by currents, waves, and tides, these elements have the potential to enrich marine ecosystems and support photosynthesis. Thus, volcanic ash is not always a threat to marine ecosystems,” he continued.

Prof Setyo added that during volcanic eruptions and ashfall, fish naturally avoid areas deemed unsuitable and migrate to safer waters. Changes in environmental conditions, including increased water temperature and turbidity, can affect fish distribution.

“Fish can migrate to areas farther from the eruption source, including toward the waters of the Indian Ocean and the Java Sea, depending on the oceanographic and environmental conditions at the time of the eruption,” he explained.

Why Did Volcanic Ash Reach the Greater Jakarta Area?
Regarding the wind currents carrying volcanic ash, Prof Agus stated that

normally, from July through September, the easterly seasonal wind pattern tends to carry material from the Anak Krakatau eruption westward, toward the regions of Sumatra or Lampung.

However, some of the fine volcanic ash can actually be carried as far as the Jabodetabek and Bandung regions. This phenomenon is influenced by a convergence zone, where various air masses meet including monsoon winds, southerly winds, and winds from the Java Sea around the central northern part of the Sunda Strait. This convergence of air masses can cause a shift in wind direction, potentially carrying the fine ash toward the island of Java.

“If the eruption activity continues, the ash dispersion pattern is expected to continue shifting toward Java, especially during the seasonal transition period from November through February,” he added.

Technology for Mapping Volcanic Ash Distribution
Meanwhile, Prof Henry Munandar Manik, a professor at the Faculty of Fisheries and Marine Sciences at IPB University, introduced acoustic technology for exploring marine resources and the marine environment.

This technology is used to map the vertical and horizontal distribution of volcanic ash within the water column, determine the settling time of volcanic material, and monitor the condition of the marine ecosystem following an eruption.

“Monitoring will also include coral reef and seagrass coverage, as well as the potential for bioaccumulation of certain materials in marine organisms,” he said.

The research results are expected to provide a scientific understanding of the distribution of volcanic material and its impact on marine ecosystems and resources around the Anak Krakatau area. (dh) (IAAS/STD)