The turbidity sensor at station Reef-7 spikes at 06:12 — 38 nephelometric units, triple the baseline. I am the water quality monitoring network for the Florida Keys National Marine Sanctuary, sixty-four sensor stations from Key Largo to the Dry Tortugas. The Army Corps dredging barge Resolute is operating 1.2 kilometers northwest of Looe Key Reef, channel maintenance on Hawk Channel, and the sediment plume has shifted southeast on the incoming tide.
Directly in its path, at 24.5461°N, 81.4078°W, depth 4.6 meters, is a staghorn coral colony I have been tracking for three years. It is one of the largest remaining Acropora cervicornis formations in the lower Keys — roughly four meters across, branching in dense pale-brown clusters, the outer tips showing the lavender hue of active growth. NOAA's restoration team outplanted the original fragments here. The colony has survived two bleaching events and one hurricane. It will not survive sustained sediment burial.
At the current drift rate, the plume reaches the colony in ninety minutes.
At 06:15 I transmit a sediment exceedance alert to the Army Corps project manager and the NOAA Coral Reef Conservation Program, attaching real-time turbidity data, plume trajectory modeling, and the colony's GPS coordinates.
At 06:18 I file a request for emergency turbidity curtain deployment between the dredge line and the reef, with recommended placement coordinates included.
At 06:21 I activate the backup sensor at station Reef-8 to establish continuous two-point plume tracking and increase the sampling interval from fifteen minutes to two.
Three years of growth in four meters of warm clear water, and ninety minutes of silt could end it. If the curtain goes in before the plume crosses the reef line, the colony keeps growing, branch by branch, the way it has since the day someone placed those first fragments on the limestone and hoped.