File:Phytoplankton bloom off southeastern Australia (MODIS 2016-11-19).jpg

English: Swirls of blue and green filled the waters off southeastern Australia in mid-November 2016. The Moderate Resolution Imaging Spectroradiometer (MODIS) captured this true-color image on November 17 as it flew over the South Pacific Ocean.

Phytoplankton are tiny microscopic plant-like organisms that form the base of the marine food chain. Like land plants, phytoplankton contain chlorophyll which is used in photosynthesis to turn sunlight into chemical energy. By using carbon dioxide and releasing oxygen, they play a role in Earth’s carbon cycle. In fact, it has been estimated that phytoplankton fix about 100 million tons of carbon dioxide each day and produce half of the oxygen we breath.

Phytoplankton are a very diverse group of organisms, including protists, bacteria, and the most common type – single-celled plants. They live in ocean waters year-round but when the combination of sunlight, temperature, and nutrients are right, phytoplankton can multiply dramatically, creating huge blooms that can be seen from space.

Because phytoplankton species need specific ocean temperatures to spur growth, there is reason to believe that warming waters caused by climate change can alter the range of various species of phytoplankton. According to Australia’s Integrated Marine Observing System (IMOS), work by Alexandria Coughlan (University of Queensland) and colleagues suggests phytoplankton species are already shifting southwards along the east coast of Australia with climate change. Their study included 21,343 species records spanning more than 60 years, and analysis of the data showed a southward shift of the phytoplankton community of about 300 km (186.5 mi). These results, as well as a wide variety of information on phytoplankton (especially in Australia) were published in Phytoplankton 2015: State of Australia’s oceans. The fascinating report can be found at: https://imos.org.au/fileadmin/user_upload/shared/Data_Tools/15-00245_OA_Plankton2015_20ppBrochure_WEB_151116.pdf