National park officials have temporarily closed Crater Lake to scuba diving over the threat of invasive species.

Park officials announced Wednesday that the closure will remain in effect while they develop rules to be sure that microscopic species, such as quagga mussels, spiny water fleas and viruses, don't hitchhike into the pristine lake waters on diving gear.

Park Superintendent Craig Ackerman says the lake is becoming more popular with divers, raising the threat that some new creature could invade the lake ecosystem and change it forever.

 Lying in the caldera created by the collapse of a huge volcano more than 7,000 years ago, Crater Lake is the nation's deepest and clearest lake.