Bomb craters also threaten coastal life. Invasive species take advantage of freshly exposed sand, while chemicals can alter the makeup of the soil in fragile dune ecosystems, seeping into lagoons and the sea.

Doug Weir, research and policy director at the UK-based Conflict and Environment Observatory, said: “Generally, in commercial weapons, you find heavy metals and TNT, RDX, HMX [chemicals in explosives].

“Heavy metals are very persistent in the environment. Most of the explosives are toxic to some degree. And some – like TNT – break down on exposure to light into other toxic chemicals.”

While the harm caused by these pollutants may not be immediately apparent, one of the most visible examples of damage to Ukraine’s coastline is the Kinburn Spit, a 25-mile (40km) stretch of sand in the Ramsar-designated Black Sea biosphere reserve. In early May, rockets caused fires – which burned for more than a week and were visible from space – over more than 4,000 hectares (10,000 acres).

The fires also highlighted a wider consequence of war: the absence of environmental governance. Protected environments are not only threatened by fighting but also by conservationists’ inability to access war-torn areas.

“Obviously the fire would have been brought under control and put out quicker under normal conditions,” Weir says. “Most protected environments are heavily managed sites, and they tend to be imbalanced ecosystems for whatever reason – be it pollution or overfishing. And that loss of oversight and support can have severe impacts.”

Similarly, Rusev says he and his team have been unable to survey the extent of the harm to the Black Sea’s dolphins, because they cannot reach large stretches of Ukrainian coastline, and cannot say how many dolphins have been stranded.

He estimates up to 2,000 may have been affected. “It’s a tragedy because we have a very small population of three species of dolphin, so any individual is a rare individual,” Rusev says.

The Azovstal steel plant in Mariupol, where large stores of sulfite are at risk of leaking. Photograph: Pictorial Press /Alamy
© Provided by The GuardianThe Azovstal steel plant in Mariupol, where large stores of sulfite are at risk of leaking. Photograph: Pictorial Press /Alamy

Remote monitoring also posed similar challenges around the Azovstal steel plant, Ukraine’s last stronghold in Mariupol, where large stores of sulfite could leak. “Because the Azov and Black Sea are enclosed, they’re particularly susceptible to pollution pressures,” Weir says. “On satellite images, it looks like the potentially sulfite-rich area has been increasing, but we can’t say for certain.”

Ukraine is determined to seek accountability for all of this damage. Vira Porieva, who is coordinating a taskforce collecting evidence of war crimes against bodies of water, is part of a wider group preparing an environmental case against Russia. In theory, the international criminal court can prosecute intentional attacks that knowingly cause “widespread, long-term and severe damage to the natural environment”.

Thanks to an international grant, Porieva’s team have collected and analysed water samples from the Melitopol and Berdyansk regions to evaluate the war’s impact on quality. “Thanks to brave national park inspectors, who stay in Russian-occupied regions, we can do this work,” she says. Preliminary results are expected in two months, but even with evidence, prosecuting environmental war crimes under the ICC’s definition is considered virtually impossible.

In the Tuzly Lagoons, the shelling continues. But Rusev works tirelessly at as many of his usual duties as he can, recording the damage where he finds it.

“Yesterday there were several bombs nearby – people are safe, but animals were disturbed again,” he says.

“Very few people really worry about this, but I am the voice of voiceless nature. I will fight to the end.”