Newly discovered species of plankton could be an overlooked food source in the sea


Experts announce the discovery of two new and unusual species of diatoms found in the waters off the east coast of Hawaii. In the nutrient-poor open ocean they live in, the creatures have also been found to fix nitrogen, which is a vital function that boosts production.

Scientists from the C-MORE Center for Microbial Oceanography – Research and Education (C-MORE) in the Department of Oceanography, along with collaborators from the University of California, Santa Cruz and California State University in San Marcos, shared their article in Nature Communications.


(Photo: Photo by NOAA on Unsplash)

The best known and most fascinating phytoplankton are the diatoms, with highly structured cell walls formed of vitreous silica. In nutrient-rich environments, they do best.

Diatoms struggle to thrive in the nutrient-poor ocean waters surrounding Hawai’i because they don’t have enough nitrogen to thrive. Some diatoms have formed symbiotic associations with nitrogen-fixing cyanobacteria to alleviate this problem.

These endosymbiotic cyanobacteria can convert dissolved nitrogen gas, which is abundant in salt water but unavailable to diatoms, into ammonia, a type of nitrogen that diatoms can readily consume but is scarce in the deep sea.

Diatoms have their nitrogen generators because they keep cyanobacteria in their glass dwellings. In this way, they become self-fertilizing systems.

C-MORE researcher and lead author of the study, Christopher Schvarcz, noted in a report published in Nature: “Oceanographers have known about these diatom-cyanobacteria symbioses in seas near Hawaii for many years, but species that we have discovered are something completely separate.”

Because host diatoms are large “centric” cells with radial symmetry, the cyanobacterial endosymbionts living inside form chains of cells that emit a bright yellow-orange fluorescent glow when illuminated with blue light; the best-known examples of these types of symbioses are very easy to spot under a microscope.

Related Article: Experts Warn of Severe Consequences of Continuing Rising Ocean Temperatures

New discovery

According to Science Daily, he discovered two new species of smaller diatoms and a distinct lineage, with an elongated or “pinnate” shape with bilateral symmetry. Because they lack chlorophyll, their symbionts are also smaller, single-celled, and don’t glow under fluorescent light, making them virtually undetectable inside the diatom.

That’s probably why they went unnoticed for so long. Using nitrogen-poor growth medium in the lab, Schvarcz found the new species by carefully analyzing cultures under a microscope for weeks and months to see what types of phytoplankton would grow.

“The results were unexpected,” said Grieg Steward, a UHM professor who collaborated on the experiment with Schvarcz. The new diatoms, he claimed, are related to freshwater diatoms.

They had no idea that we could discover their cousins ​​living in the middle of the ocean. Chris’ work, he said, is a good reminder of all that can be learned with a little patience and diligent attention.

More to discover

Plankton propulsion mechanisms of oceanic copepods studied on a high-speed camera

(Photo: Wikimedia Commons)

When the researchers measured the crops’ daily nitrogen fixation patterns, it was another surprise. Nitrogen-fixing activity in previously studied species tends to be concentrated either during the day or at night, but not both.

Cultivating and discovering these species offers many fascinating research opportunities. We can still learn a lot from the water seen by these animals.

Also read: More than 500 new species were discovered by the Natural History Museum in 2021

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