November 15, 2023 - A Tasmanian Blaze and an Offshore Bloom


A long swirl of bright turquoise marked a large bloom of phytoplankton off of eastern Tasmania in mid-November 2023 and, at the same time, a long plume of gray smoke marked a fierce bushfire. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired a true-color image of the unusual duo on November 13.

On November 12, an emergency bushfire warning was issued for the town of Dolphin Sands, but by the time some residents received the warning, it was too late to leave as fire had cut off the only road out of the area. Strong winds were driving the fire eastward rapidly towards Dolphin Sands. Several residents that could not evacuate to Swansea (west of the fire) gathered on a jetty or beaches that were out of the fire’s path. By November 13, the fire had been declared “contained”, but was still burning. It was reported that about 120 hectares of coastal heath had been burnt, with at least two homes, a shed, and a car consumed in the blaze. No fatalities or injuries have been reported.

Meanwhile, the warming waters south of Dolphin Sands hosted a gorgeous bloom. The colors stretched from Coles Bay southward through the Tasman Sea to end east of the Tasman Peninsula. The white tint to the large floating colony of microscopic plant-like organisms suggests that the bloom contains coccolithophores. This is a type of phytoplankton that contains chalky-appearing outer plating made of limestone (calcite). These scales, known as coccoliths, look a bit like hubcaps in shape but are only three one-thousandths of a millimeter in diameter. Despite their tiny size, when present in large numbers these scales reflect enough light to add a milky tone to blooms.

Image Facts
Satellite: Aqua
Date Acquired: 11/13/2023
Resolutions: 1km (155.3 KB), 500m (384.1 KB), 250m (1.4 MB)
Bands Used: 1,4,3
Image Credit: MODIS Land Rapid Response Team, NASA GSFC