They’re smaller than chia seeds, but they inspired one of the most popular cartoon villains of this century. They are arguably the most abundant animal in the world, and by keeping their embryos in suspension for decades, they have even challenged our idea of what it means to be alive.
Meet the calanoid copepods.
Calanoid copepods are a superfamily of plankton. For oceanographers, they are the most reliable animals that can be found almost anywhere you can throw a net into the sea, much like beetles on land. To everyone else, considering copepods or their ilk, it’s certainly from the cartoon SpongeBob SquarePants, in which the character Evil Plankton can be clearly identified as a calanoid copepod by means of his distinctive antennae and his cyclopartic eye. These tiny crustaceans, which feed on even smaller plant plankton, feed huge food webs in the oceans and provide scientists with clues about invisible marine changes to the ecosystem.
The supportive role these creatures often play, be it on Nickelodeon or in food web analysis, could easily lead to overlooking just how fascinating the calanoid copepods are in themselves. Many of them can produce fertilized eggs that stay in suspension for decades or even centuries before growing and hatching. Although scientists discovered this mystery more than a century ago, even fundamental aspects of the mindless, boneless species remain unsolved.
A team of researchers, led by Brad J. Gemmell, documented some species of calanoid that leap from the surface of the ocean to escape predators. Jumping out of the water may be unremarkable for large animals like dolphins, but it’s a big deal for microscopic swimmers who are struggling with much more resistance to break the surface of the water. At least one species can soar sixty times its own length before reentering the sea – the equivalent of a humpback whale that can travel twice the length of the Empire State Building in a single leap.
Although scientists have studied thousands of species of calanoid copepods, gaps remain in our understanding of them. We know that as the basis of so many marine food webs, calanoid copepods are vulnerable to the full range of marine threats, from chemical runoff and spills, to ocean acidification, to warming and plastic pollution. In that sense, calanoids represent the diversity, mystery, and vulnerability of the ocean, perhaps much better than the larger and more famous marine animals ever could.
Support JSTOR every day! Join our new membership program on Patreon today.
JSTOR is a digital library for scientists, researchers and students. JSTOR Daily readers can access the original research on our articles for free on JSTOR.
By: JA Lindley
Journal of Crustacean Biology, Vol. 2, No. 17, No. 4 (Nov. 1997), pp. 569-576
Oxford University Press on behalf of the Crustacean Society
By: Brad J. Gemmell, Houshuo Jiang, J. Rudi Strickler and Edward J · Buskey
Proceedings: Biological Sciences, Vol. 2, No. 279, No. 1739 (July 22, 2012), pp. 2786-2792
Contributors: Alan J. Mearns, Donald J. Reish, Philip S. Oshida, Thomas Ginn, Mary Ann Rempel-Hester, Courtney Arthur, Nicolle Rutherford, and Rachel Pryor
Water-Environment Research, Vol. 2, No. 87, No. 10, Literature Review 2015 (October 2015), pp. 1718-1816