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Scientists to offer eco technology to have salmon back in Arctic lakes

It is stated that the first condition to restore the lakes is to cut the emissions

TASS, December 20. The Russian Academy of Sciences' Siberian Branch finalizes work on a technology to restore most quickly the salmon population in Taymyr's lakes, an expert in hydrobiology at the Krasnoyarsk Scientific Center's Institute of Biophysics, Mikhail Gladyshev, told TASS.

"I hope we'll be able to offer an eco technology to restore most quickly those Arctic lakes," he said. "By the way, their productivity may be restored right with the purpose to have more reservoirs, where the North's low-numbered indigenous peoples may fish. The basis is the biodiversity, the understanding of the impact zones, which the Great Scientific Expedition has studied. This is a fundamental base for any practical works."

The first condition to restore the lakes is to cut the emissions, he continued. Nornickel (the Norilsk Nickel Company) has been cutting air and water emissions for 20 years, and thus, the water quality, which in the mid-1990s was of the fourth or rarely third class in the Taymyr Peninsula's lakes, now has improved to the second class. Gradually, over 20 years, the water quality in lakes in the plant's impact zone has improved due to lower emissions. However, this slow improvement could be accelerated by using natural fertilizers like migratory birds' droppings. The northern water reservoirs are not rich in nutrients, and therefore such an addition boosts in them bacteria reproduction and consequently the entire food chain up to valuable fish species.

How lakes need extra nitrogen and phosphorus

The middle zone is struggling against green water in reservoirs, which smells badly. The reason is an excessive intake of nitrogen and phosphorus from wastewater or from fertilizers washed off fields. At the same time, the situation in the northern lakes is quite opposite - they lack nutrition and require additional nitrogen and phosphorus.

"I can barely stand the temptation to pour nitrogen and phosphorus fertilizers into there. The Swedes and Canadians have done exactly so, but here it's very easy to be facing what everyone is fighting - the greening. Birds effect differently. The Papanin Institute of Inland Water Biology (the Russian Academy of Sciences) studies how bird colonies may change water conditions. They have found that birds' droppings also seem to contain nitrogen and phosphorus. However, they do not support cyanobacteria, which kill everything but crucian carp. The droppings cause the growth of useful algae, which begin the food chain leading up to useful fish. Cyanobacteria start the food chain where at the end are crucian carp or non-valuable fish, while useful algae begin the chain leading to salmon species," the scientist said.

Experts have found the reason is not just nitrogen and phosphorus, but their molecular ratio. They describe the so-called cascade effect: a bird that feeds on fish, it growing that fish for itself. The scientists have even come up with a comic term: a heron as an aquaculture manager.

"These fertilizers may be taken at bird rookeries or poultry farms and added directly into lakes. Chicken droppings are similar to goose droppings. Or, an option is to understand what's going on there, and make fertilizers artificially. This is a way to restore lakes without loss of quality, so that to preserve the salmon food chain. First of all, we must preserve the quality of Arctic ecosystems, where live most valuable fish species that are the golden gene pool for aquaculture," the scientist concluded.

About expedition

The basic biodiversity survey continues the work, which the Norilsk Nickel Company (Nornickel) and the Russian Academy of Sciences’ Siberian Branch began in 2020. Since the Great Norilsk Expedition, this work has extended into another three regions. The survey’s purpose is to identify Nornickel’s impact zones and to assess biodiversity in areas of Nornickel’s operations. The research results will be used in building out a corporate biodiversity management system and biodiversity monitoring and conservation programs.