What’s the prognosis for Hawaii’s coral reefs in the face of global warming, invasive algae and other environmental threats?
— Bill Weston, San Francisco, CA

Despite sweeping protections put in place near the end of George W. Bush’s presidency for large swaths of marine ecosystems around the Hawaiian Islands, things are not looking good for Hawaii’s coral reefs. Poisonous run-off, rising ocean levels, increasingly acidic waters and overfishing are taking their toll on the reefs and the marine life they support. Biologists are trying to remain optimistic that there is still time to turn things around, but new threats to Hawaii’s corals are only aggravating the situation.

To wit, a previously undocumented cyanobacterial fungus that grows through photosynthesis is spreading by as much as three inches per week on corals along the otherwise pristine North Shore of Kauai. “There is nowhere we know of in the entire world where …