In early November 2023, it was observed that Keālia Pond on Maui exhibited a distinct pink hue. https://www.mauihawaii.org/sights/kea...

This phenomenon is attributed to the proliferation of halobacteria, a type of single-celled organism. Halobacteria flourish in environments with high salt concentrations. At Keālia Pond, the salinity levels have been recorded at over 70 parts per thousand. This is about double the salinity found in normal seawater, making it a perfect habitat for these organisms. Here are some fun facts:

• Extremophiles - Halobacteria are classified as extremophiles, meaning they thrive in extreme environmental conditions. In their case, they prefer highly saline, or salty, environments.

• Salt Lovers - They are particularly fond of environments with salt concentrations much higher than that of seawater, often thriving in salt mines, saline lakes, and salt evaporation ponds. We've had very little water on Maui for months now, so Kealia is very salty.

• Pigmentation - Many halobacteria species have a distinctive pink or red pigmentation. This coloration is due to the presence of bacteriorhodopsin, a protein that absorbs light and uses its energy to produce ATP, the energy currency of the cell.

• Unique Photosynthesis - Unlike plants and algae, halobacteria do not perform photosynthesis using chlorophyll. Instead, they use bacteriorhodopsin or other similar proteins for a process known as phototrophy, where light energy is directly converted into chemical energy.

• Archaea Domain - Halobacteria belong to the domain Archaea, a group of single-celled microorganisms that are distinct from bacteria and eukaryotes (organisms with complex cells).

• Adaptation to High Salinity - Their cell membranes and proteins are adapted to function in high-salinity environments, which would be inhibitory or lethal to most other life forms.

• Ancient Lineage - Archaea, including halobacteria, are some of the oldest forms of life on Earth, with a history dating back billions of years.

• Biotechnological Applications - Some species of halobacteria are being researched for their potential applications in biotechnology, such as in bioplastics production and in biofuel generation.

• Genetic Diversity - Despite their extreme living conditions, halobacteria exhibit a high level of genetic and metabolic diversity, allowing them to adapt to various harsh environments.

• Contribution to Salt Flats’ Color - Halobacteria are often responsible for the pink or red hues observed in salt flats and saline bodies of water, as their pigments color the environment.