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What Role Do Marine Worms Play in the Ecosystem?

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A saltwater invertebrate spanning more than 10 separate phyla, the marine worm, plays a vital role in the development and sustainability of many of the planet's watery ecosystems. Adding to the thousands of known species, the scientific community continues to discover new worms and worm behavior, not previously recorded.

Worm Role

The relationship between the marine worm and its habitats is symbiotic. The coral reef thrives from the worm's eating, building, reproduction and excretion habits, while the worm sustains itself on reef particulates and abides the security provided from the reef's rocky ridges. Not all marine worms live in the oceans, but reside in shoreline tide pools, or the brackish water out-crops of the lowlands. Here the marine worms bury themselves in the sediment. The tunneling and boring of marine worms irrigate and oxygenate the shallow water pools encouraging beneficial plant and algae growth. Whether it's in tide pools, lowland waters or oceanic reefs, the marine worm's primary ecological contribution is as sustenance for aquatic animals further up the food chain.


Marine worms have distinct sexes and ephemeral sex organs. Tiers of gonads amass inside of marine worms to produce either sperm or eggs. When the fertilizer or eggs are ready to be released, gonad ducts are formed but are eliminated by absorption after reproduction. They emerge in a larval stage, shaped like a saucer, and join the rest of the free-floating sea plankton. As plankton, the marine worms provide nutritional sustenance to a great number of the ocean's inhabitants. If the larva survives the open ocean, a miniature worm develops inside a floating sac-like encasing. Once fully formed, the marine worm eats its way out of the sac and falls to the ocean floor, where it begins the eco-cycle all over again. More egg sacs are devoured than survive, keeping marine worms to a manageable number.

Nutritional Needs

The marine worm resides at the bottom of the oceanic food chain, and many animals in the ocean feed on them. The marine worm feeds primarily on oceanic particulate. However, marine worms are accomplished predators and eat fish, snails, crustaceans and clams. They can catch snails or bivalves and wrap their bodies around their victims and inject them with digestive enzymes. The marine worm then excretes a nutritional excrement that nourishes and acts as compost, for surrounding microorganisms, bacterium and plant life.

Ecological Identity

Most marine worms fall under one of four habitually descriptive classes including tube-dwelling, boring, commensalism and parasitism. Like an oceanic barometer, the study of marine worms often gives scientists advanced notice to potential problems in aquatic habitats. Biological monitoring and mapping of marine worms can determine if hazardous aquatic pollutants, or biologically dangerous bacteria, can be detected. Other biodiversity is uncloaked at nominal levels from the study of sea worms, such as disease-causing microorganisms or physical disturbances radical enough to upset the natural function of the planet's marine reserves.