Explainer: Scientists say that Tongas volcanic eruption can cause environmental damage for many years

Jan 18, 2017 (Reuters) – Tongas massive underwater volcano could cause long-lasting destruction to coral reefs and erode coastlines. It could also disrupt fisheries. Scientists who study satellite images and look back at the past to predict the future in remote regions are examining the past to determine the future.

ACID RAIN

Since the eruption, the volcano has been emitting sulfur dioxide and nitrogen oxide. These gases are acid rain-causing compounds that react with water and oxygen in their atmosphere.

According to Shane Cronin, University of Auckland volcanologist, acid rain is likely to continue around Tonga’s Tongas tropical climate.

Acid rain can cause extensive crop damage and could destroy Tongan staples like corn, bananas, taro and garden vegetables. Cronin said that food security may be compromised depending upon how long the eruptions last.

Satellite imagery shows that the plume is spreading westward. This means that Tonga may be spared some of the acid rain, but Fiji could then be in its path.

The U.N. humanitarian affairs bureau stated that Fiji is monitoring its air quality and advised people to cover their water tanks and stay indoors if it rains.

FISH DIE OFFS

Tongas’ exclusive economic area of almost 700,000 marine kilometres (270.271 square miles) has a 1,000-fold greater area than its land. Tongans depend on the ocean for their food and livelihood.

Although scientists are yet to investigate the ground, Marco Brenna, a New Zealand geologist, stated that there is a blanket of ash on the land.

The ash can cause harm to marine life in the ocean. Weeks before Saturdays eruption, Tonga Geological Services Had been warnedThe toxic volcanic discharge was found in the seawater, so fishermen should assume that fish in these waters is poisoned.

The situation has only gotten worse with every eruption. Fish will be starved and wiped out by the volcanic ash-filled water. Scientists predict that some fish will die and that survivors will have to migrate. Additional changes in the structure and function of the ocean floor could pose new challenges for fishing vessels.

Brenna stated that it will take a while before the old or new fishing grounds are restored.

SMOTHERED CORALS

Falling ash can also cause coral reefs to be destroyed. Tonga’s mainstay tourism industry brought in as much as $5 million annually prior to the coronavirus pandemic.

Tongas Reefs were already at risk from disease outbreaks and climate change, including coral bleaching and stronger cyclones, even before the eruption.

Tom Schils, who is a University of Guam marine biologist and has observed the destruction of large areas of reefs in the immediate Hunga Tonga impact area, stated that these reefs are likely to have been buried by large amounts of volcanic ash. studiedCorals and volcanic eruptions in the Northern Mariana Islands.

Additionally, such eruptions can release more iron into the seawater, which can encourage the growth and development of blue-green algae as well as sponges that further degrade the reefs.

Brian Zgliczynski from the Scripps Institution of Oceanography, a coral reef expert, said that some reefs may need to be rebuilt. This can take years. He said that species that are more tolerant to poor water quality will be the first to arrive, while hard corals or fish will take longer to return.

ERODED COASTLINES

Tonga’s ability, to withstand rising waters and storm surges, would be affected by the loss of coral reefs. This is a concern for Tonga because the sea level is rising by approximately 6 millimeters per year (0.2 inches) more than the global average.

In a 2015 reportTonga valued its natural storm protections, including coral reefs, as well as coastal seagrasses (and mangroves) at around $11 million each year.

Tongan’s sea level gauge recorded the tsunami wave at 1.19 metres (nearly 4″) during the latest eruption. The gauge stopped reporting after it stopped recording. Tsunamis can cause coastal erosion. Video footage showed damage to manmade seawalls, even before communication systems were down.

Cronin stated that tsunami waves could cause damage to coastal defences and reclaimed ground, leaving islands more vulnerable.

Gloria Dickie reports; Katy Daigle, Howard Goller edit

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