Colorful swirls off the Kimberley coast -

Today’s Image of the Day from NASA Earth Observatory features the coast of Kimberley, located in the northern region of Western Australia. The coastline is renowned for its rugged and remote beauty. 

A state of constant change

The blue-green waters along the Kimberley coast are in a state of constant change. The region’s significant tidal currents stir up sediment in the shallow waters of the continental shelf and incoming water from Western Australian rivers, creating vibrant and colorful patterns.

On April 22, 2024, the Operational Land Imager (OLI) on Landsat 8 captured this stunning image of the dynamic waters. Sediment can be seen swirling between the rocky islands of the Bonaparte Archipelago, giving the water a striking turquoise hue. 

“Beautiful scenes like this are common off the 20,000-kilometer-long Kimberley coast, which has one of the largest tidal ranges (up to 11 meters) in Australia and the world,” said NASA.

The role of phytoplankton 

Phytoplankton, the tiny plant-like organisms that form the foundation of the marine food web, may also contribute to the water’s vibrant colors. In the upper ocean, sediment particles often bind with larger phytoplankton, such as diatoms, dinoflagellates, and ciliates. 

However, the specific density and types of phytoplankton cannot be determined from this satellite image alone.

Phytoplankton productivity 

Some modeling studies suggest that climate change could reduce phytoplankton productivity by up to 20 percent by 2100. Despite this, certain types of phytoplankton are thriving in Kimberley’s waters. 

A 2020 study of sediment cores revealed that populations of diatoms and dinoflagellates along a large section of the coast have increased by 150 to 300 percent since the 1950s. 

The study authors suggest that rising rainfall and cyclone activity in northwestern Australia have enhanced water mixing, creating favorable conditions for phytoplankton growth.

Kimberley coast 

The Kimberley coastline is characterized by dramatic cliffs, secluded beaches, and ancient rock formations. 

The area is rich in Aboriginal history, with many sacred sites and ancient rock art galleries that provide a glimpse into one of the world’s oldest continuous cultures. 

Kimberley is renowned for its relatively untouched coastal zones, supporting a diverse array of marine habitats, including mangroves, seagrass beds, and coral reefs. 

Vibrant marine life thrives in the crystal-clear waters, which are ideal for snorkeling and diving. 

Wildlife of Kimberley coast

The unique combination of terrestrial and marine environments along the Kimberley coast creates a rich tapestry of biodiversity.

Saltwater crocodiles are a prominent feature, often seen basking along the riverbanks and estuaries. 

Marine wildlife

The coastal waters are a haven for marine life, including dolphins, dugongs, and various species of sea turtles. 

Humpback whales migrate through these waters, providing spectacular sightings, especially during their breeding season.

Terrestrial wildlife

On land, the Kimberley coast supports diverse bird species such as the iconic black-necked stork, the white-bellied sea eagle, and numerous parrots and finches. 

The rugged terrain and lush mangroves provide habitats for wallabies, dingoes, and a variety of reptiles. 

The tidal flats and mangrove forests are teeming with life, including mud crabs, shellfish, and other invertebrates, which play a crucial role in the ecosystem. 

Image Credit: NASA Earth Observatory 


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