Funny thing about dragon fly.. there might be a possibility..
[Erythrodiplax berenice] "Reproduction Comments: This species is nearly marine, capable of breeding in waters with high salt concentrations. Populations of males are often found defending relatively small territories around isolated pools. The female lays eggs accompanied by the male in these pools by dipping her abdomen numerous times while hovering in place (Abbott, 2007). Males defend small territories around pools and tidal creeks. Females oviposit in tandem on algal mats in saline wetlands and salt marshes (Nikula et al., 2003)."
"exposed larvae to increasing concentrations of salt in water, finding that it was only at three times the typical ocean-water concentration of salt that nymphs finally showed distress."
Searching google for nymph images. No luck yet. I see your profile says Iowa, while these are Atlantic/Gulf coast.
Did you buy any Macroalgaes from the East Coast?