On the Front Lines: Neustons
The ocean surface is teaming with life. Plants, animals and microscopic organisms make their home at the top of the water and sometimes even form entire ecosystems. These organisms are called neustons and play an essential role in marine foodwebs and marine lifecycles.
The surface is intrinsically linked to a healthy ocean, but also entirely unprotected from pollution and climate change. Is the stress at the surface more than skin deep?
The sparkling ocean surface is a thing of wonder. But its beauty, and perhaps it’s woes, is more than skin deep, says Rebecca Helm, assistant professor at the University of North Carolina, Asheville, who has written on the topic.
Photo source PLOS Biology.
The ocean’s surface is actually a habitat that supports life above and below the waterline. It is home to a unique community of floating life forms, from microscopic organisms to plants and animals, termed neustons (Sometimes also referred to as pleustons, these living communities are found in both saline and fresh water.)
One of the more well known examples of neustonic life is the golden seaweed Sargassum, which, in part, gives name to the region of the Atlantic Ocean known as the Sargasso Sea. This seaweed, along with the floating barnacles, snails, nudibranchs, and cnidarians, is one of the ocean’s most visible, and appreciated neustonic regions. It serves as a nursery and feeding ground for turtles, shrimp, crab, fish, and other marine species.
While not all neustonic organisms are as recognizable or well-studied as sargassum, their role in healthy oceans and a healthy earth is vital. Neustonic organisms and communities play essential roles in food webs, below the surface and above it for seabirds. What’s more, some ocean creatures spend part of their lifecycle at the ocean’s surface making this vast area a nursery for important species, not unlike the valuable work of seagrass meadows and coral reefs.
While neustonic life has many common attributes, the reality is that individual neustonic organisms and nustonic communities will vary greatly across the ocean. Because of the vastness of the ocean and the diversity of these living creatures, studying them is a “global challenge” that will require the work of many organizations to help build a knowledge base.
Understanding these organisms and communities is only half the challenge. The ocean surface is all but unprotected from the challenges of climate change, ocean exploitation and especially pollution. Helm calls it “a concentrating front for floating pollutants from plastic to petroleum” in her paper, The mysterious ecosystem at the ocean’s surface (PLOS Biology April 2021).
Helm calls out the need to study and protect neustonic communities and identify regions of high importance, including surface areas that provide critical food sources and habitat for the various life stages of economically valuable fisheries.
“Despite the diversity and importance of the ocean’s surface in connecting disparate habitats, and the risks it faces, we know very little about neustonic life,” she says.