The Beauty of Bioluminescence
- Alexa
- Jun 9, 2020
- 3 min read
Updated: Aug 7, 2020
Welcome back to Ask Alexa! This week we are covering one of the coolest natural phenomena - bioluminescence in the ocean! Bioluminescence, or a chemical reaction that produces light energy within an organism's body (2a), can be found in more than 90% of animals in the deep ocean, ranging from the smallest single-celled organism all the way up to sharks (2b). And what is even more amazing is that the number of species and the variations in the chemical reactions acts as evidence that bioluminescence has evolved at least 40 separate times in history, showcasing an amazing example of convergent evolution (2a). Organisms that create their own light source in the deep seas can be extremely advantageous - it can be used for attracting/finding prey or a mate, confusing predators, and communication between individuals (2b). Creating a light source is also dangerous, as it acts as a beacon to signal to predators where their prey can be found in the deep sea. However, one set of single-celled organisms took the news by storm recently when they caused the waves in Southern California to turn blue.
These small cells, known as dinoflagellates, can aggregate in ocean waters in mass quantities, known as a "red tide". Specifically, the species of dinoflagellates responsible for the beautiful blue night tides is Lingulodinium polyedra, a species associated with relaxed upwelling and stratified water conditions (1a). The red-brown color associated with red tides acts as a "sunscreen" for the dinoflagellates and causes the red coloration in the water when the organisms swim up to the surface on sunny days (1a). The blue glow at night is emitted when the single-celled organisms are agitated by the waves (1a).
The glowing blue wave phenomena have been noticed off the Californian coast since the early 1900s and can last anywhere from a couple of days to a couple of weeks (1a). The bloom recently seen near San Diego stretched all the way from Los Angeles to Baja, California - a distance of over 300 miles (1a)! Similar red tides in the Mediterranean caused by the same species of dinoflagellates produce yessotoxin, which acts as a neurotoxin and can be dangerous to other organisms (1a). Large blooms of dinoflagellates can cause harmful algal blooms (HABs), and occur when dinoflagellates become poisonous to other animals (2a). For example, toxins from the dinoflagellates can accumulate in high concentrations in larger fish and filter-feeding shellfish, which are then eaten by marine mammals and even people (2a). This form of biomagnification, as seen in other toxins and pollutants in other food chains, can cause sickness and even death in animals higher up the food chain (2a). Red tides caused by L. polyedra in California are not toxic themselves, however, some people are sensitive to inhaling the air associated with the red tide, and, in general, there are lots of dissolved and particulate matter in the water associated with the microbial activity (1a).
All in all - bioluminescence is cool! So next time you see that cool firefly in your backyard, glowing blue waves off the coast of California, or neat pictures of deep-sea creatures, take in the awesomeness and admire one of the neatest feats of evolution!
For more information on bioluminescence, feel free to check out these resources below:
Resources:
Red tides
Basic bioluminescence
Light in the Deep Sea MBA Teaching Curriculum
MBARI Resources
TED talk on bioluminescence
Great article Alexa - do you have more pictures?