Plankton are tiny organisms that play a crucial role in the marine ecosystem. Among these organisms, phytoplankton are a type of plankton that undergoes a massive migration from deep in the sea toward the surface. However, not all phytoplankton have the ability to propel themselves upward due to the lack of limbs. This has led researchers to question how these organisms manage to undertake such a long journey.
A recent study conducted by a team of researchers at Stanford University has shed light on the ingenious solution adopted by one species of phytoplankton. The researchers discovered that a species of phytoplankton called Pyrocystis noctiluca has the ability to swell to six times its original size, reducing its density and allowing it to float upward like a helium balloon. This unique adaptation was detailed in a study published in Current Biology.
Andre Visser, an oceanographer at the Technical University of Denmark, expressed his admiration for the research findings, stating that the team has presented a novel way in which these cells can stay buoyant near the surface of the water. The researchers collected water samples off the coast of Hawaii to study the behavior of Pyrocystis noctiluca, which typically undertakes a once-in-a-lifetime journey from 125 meters deep to about 50 meters to access more sunlight for photosynthesis.
In the laboratory, the researchers utilized special microscopes to observe the movement of Pyrocystis noctiluca as it traveled up the water column. The phytoplankton swells at the beginning of its life cycle, reducing its density and enabling it to ascend. As the cell reaches the end of its seven-day life cycle, it divides into two daughter cells that inflate by filling up with seawater, expanding to six times their original size in just 10 minutes.
The team hypothesizes that aquaporin proteins in the cell filter out dense salt from the incoming seawater, making the cell less dense and more buoyant. Additionally, experiments suggest that calcium in the seawater may play a role in triggering and facilitating this transformation. The inflation process not only helps the phytoplankton rise but also offers benefits such as lower predation risk, improved nutrient uptake, and enhanced photosynthesis due to the increased surface area of the cell.
Overall, the research highlights the fascinating adaptations of phytoplankton and their ability to thrive in challenging marine environments. The findings provide valuable insights into the biology of these tiny but vital organisms and their impact on marine ecosystems.
