Researchers reveal Australian bushfires devastate aquatic life with ash

By Stephen Beech via SWNS

Ash from deadly Australian bushfires is also killing aquatic life, warns new research.

Wildfire ash can have lethal consequences on Australian water ecosystems, say scientists.

While the impact of bushfires on terrestrial life has been well studied, research has only recently begun into the effects of ash from the infernos on aquatic organisms.

Scientists say wildfires are becoming increasingly prevalent due to the warming and drying effects of climate change - with Australia becoming especially vulnerable to dangerous bushfires.

Lead researcher Jenelle McCuaig, of the University of Alberta in Canada, said: “Many Australian species may be threatened by fires.

“This is putting them at greater risk of endangerment and possible extinction.”

She explained that wildfires release ash into the air, which can enter aquatic environments directly or be washed into bodies of water by rainfall.

McCuaig said: “Once in the water, ash may leach metals and organic combustion products, where they can affect organisms, acquired by ingestion through intestines or respiration through gills."

She said there are also serious consequences for humans, as people rely on healthy freshwater ecosystems for water and food.

The research team focused on two common Australian crustacean species, a crayfish (Cherax destructor) and a shrimp (Macrobrachium australiense).

To examine the effects of wildfire ash on the crustaceans, each species was exposed to a range of ash concentrations to determine their sensitivity and likelihood of survival.

The researchers then measured their oxygen consumption using a respirometry system and took tissue samples to look at their metabolic activity.

After exposure to just 5g of ash per litre of water, the team found that no shrimps could survive – but it took eight times as much ash to reach complete crayfish mortality.

Miss McCuaig said: “The huge difference in sensitivity between the two species was much greater than I expected."

She says the findings show that even between similar species, there can be a big difference in survival response to environmental stressors such as wildfire ash.

Miss McCuaig said: “Differences in body shape and gill structure, as well as habitat preferences, has allowed them to fulfil different niches.

“Crayfish demonstrated greater resilience to the ash exposure compared to the shrimp.”

Among the surviving crayfish and shrimp, those exposed to the highest concentrations of ash had the highest metabolic rates, suggesting a high level of physiological stress.

McCuaig said: “This is particularly concerning during ash exposure, because increased ventilation means that the animals will be taking up more of the ash particles and leached contaminants from the water, further affecting their body systems.

“This research will allow us to identify the species that are most threatened by fires and help to inform the development of breeding programs or relocation efforts.

“When it comes to wildfires, resources are limited, so we must prioritize response actions.”

Miss McCuaig says that even though many wildfires occur naturally, humans still have a responsibility to protect the living world.

She added: “Species conservation begins with wildfire prevention in the first place.

"It is incredibly important to be educated about, and to implement, fire safety into our lives to mitigate human-caused wildfires”.

The findings were presented at the Society for Experimental Biology Annual Conference in Prague, Czech Republic.

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