Problems in the water

 

Inside Climate News has a story about threats to the drinking water supply of New York City. It's something that has been happening around the world. It doesn't really qualify as climate change, though climate change may help in some circumstances.  Put it more broadly, it's ecosystem change.

Invasive Species Spell Trouble for New York’s Beloved Tap Water 

Zebra mussels, hydrilla and now a waterflea have made their homes in New Croton Reservoir.

Yes, there are invasive species in the water; so what can they do to it?

In the case of the zebra mussels:

"The mollusks were eventually washed into the reservoir due to extreme precipitation events. These zebra mussels are filter feeders, which means they take in water and feed on plankton within the water column. This reduces the food available to small fish and native mussels, thus disrupting the natural food web. They can also latch on to native mussels, surrounding them and hindering their ability to feed or reproduce, sometimes causing death.

Their ability to accumulate on surfaces can also clog water supply systems, which has happened at the Croton Reservoir. ... Their presence can also influence water chemistry. Zebra mussels feed on specific types of algae and discard others, releasing byproducts in their feces. This can be a breeding ground for cyanobacteria, which is a type of algae that, when found in high concentrations, can create a “bloom.”

These blooms sit on the surface of the water, impeding fishing and boating, often emitting an unpleasant odor which can translate to the water supply, and reducing the amount of oxygen in the water, which affects the survival of native fish in the water body. It can even carry harmful toxins."

In the case of the hydrilla:

"The presence of hydrilla in the reservoir can have implications for not just the marine ecosystem, but also the water quality and the survival of local birds. Hydrilla is also known to harbor cyanobacteria, which can turn into a toxin–Aetokthonos hydrillicola. This type of harmful algae can kill waterfowl and bald eagles, and has the potential to harm human health.

“It’s a neurotoxin, so in places where Aetokthonos is found on hydrilla, lots of wildlife have died from brain lesions,” said White. “So fish have died, reptiles, like turtles, have died, waterfowl that eat the hydrilla, and then the predators of those waterfowl as well.”

Climate change leads to warmer weather in the fall and more extreme precipitation events which move sediments around in the water column. This creates better conditions for the spread of hydrilla, of cyanobacteria blooms, and, by proxy, of these toxins. Their presence has not been confirmed in New York state, though the Department of Environmental Protection is sampling for it."

And how about the water flea?

 

 

"The fishhook waterflea was found in the reservoir last year. The novelty of its arrival means that the Department of Environmental Protection officials have not seen adverse impacts on the marine ecosystem yet, and its wider implications for the food chain are unknown. The waterflea can impact water quality by eating large quantities of zooplankton, which creates better conditions for the growth of harmful algae blooms. Taylor believes it was likely transferred through fishing gear because the waterflea’s eggs can survive drying out for long periods of time."

So that's what they can do. And once change gets started in one direction, it's hard to stop.