The term neopelagic describes a new biological community that has emerged in the open ocean. This community consists of coastal organisms that have colonized floating plastic pollution, creating permanent habitats where none previously existed. These ecosystems are a consequence of human activity and are changing scientific understanding of species distribution. The term combines “neo,” meaning new, with “pelagic,” which refers to the open ocean.
Defining the Neopelagic Environment
The neopelagic environment is defined not by a body of water but by the substrate provided by floating plastic debris. This pollution, from discarded fishing nets to consumer waste, has accumulated in large systems of circulating ocean currents known as gyres. These gyres, often called “garbage patches,” concentrate the debris in stable regions of the ocean far from any coastline.
The North Pacific Subtropical Gyre, between California and Hawai’i, is the most studied of these accumulation zones. It holds an immense mass of plastic, providing a persistent surface for colonization. Unlike natural rafts like wood or seaweed that biodegrade, plastic debris can persist for decades. This longevity allows coastal species to establish long-term populations in the open ocean.
This artificial habitat is vast, with the Great Pacific Garbage Patch estimated to cover 1.6 million square kilometers. The plastic creates a new type of surface ecosystem that alters the surface ecology of the high seas. The characteristics of the raft, such as its size and surface texture, can influence the diversity of the community that develops on it.
Life within the Neopelagic Zone
The neopelagic community is a mix of coastal creatures and open-ocean species. Researchers have discovered coastal life thriving on this plastic debris, including anemones, hydroids, and shrimp-like amphipods. These organisms are adapted for coastal waters and were not thought capable of surviving for long periods in the open ocean.
These coastal colonizers now live alongside and compete with native open-ocean rafting species. Traditional rafters include organisms like the gooseneck barnacle (Lepas) and certain crabs that use natural floating objects as a substrate. The introduction of permanent plastic habitats has led to direct interactions between these two historically separate groups.
The discovery of reproducing coastal populations on plastic debris suggests these communities are becoming established in ocean gyres. The number of coastal species on plastic rafts has, in some studies, surpassed native rafting organisms, indicating an ecological shift is underway. This creates a new food web and competitive dynamic at the ocean’s surface.
Unique Adaptations for Survival
The survival of coastal organisms in the neopelagic community is less about specific biological adaptations and more about the properties of the plastic they inhabit. The primary factor is the durability and buoyancy of plastic pollution. This material resists degradation, providing a stable habitat that allows multiple generations to live and reproduce in the open ocean.
This permanence is a stark contrast to the ephemeral nature of natural rafts. Kelp, logs, and pumice stone eventually break down or sink, limiting the time any attached community can survive at sea. Plastic offers a reliable platform that enables a continuous presence, turning a temporary journey into a permanent residence.
Furthermore, the scale of plastic pollution has created an interconnected network of potential habitats. This increases the chances for species to move between different pieces of debris, like stepping stones. This connectivity can facilitate gene flow between populations, supporting the long-term viability of these communities.
The Paleopelagic Distinction
To understand what makes the neopelagic community “new,” it helps to contrast it with the original inhabitants of the ocean surface, known as the neuston. The neuston are organisms that have evolved to live at the air-sea interface, a group considered the “paleopelagic” or old community. This group includes species with specialized mechanisms for staying at the surface, such as the bubble-rafting snail Janthina and the hydrozoan Velella velella.
The neopelagic community, composed of coastal arrivals, is different because its existence is not the result of evolutionary adaptation to the open ocean. It is an artificial assemblage created by the introduction of plastic substrates. These coastal species lack the specialized traits of the native neuston and are dependent on the plastic rafts for their survival.
This distinction highlights how the boundary between coastal and open-ocean ecosystems is being blurred by plastic pollution. The neopelagic communities now compete with native oceanic species for resources and space on the surface. The emergence of the neopelagic represents a shift in the ecological rules of the high seas, driven by human impact.