Free Living Nematodes

Free Living Nematodes

• Free-living nematodes live in the sea, in fresh water, and in the soil. They occur worldwide in all environments and most live in the interstitial spaces of sediments and soils according to Bird and Bird (2012). Vast numbers of nematodes occur.  One square meter of sea bottom mud has been estimated to hold 4.4 million nematodes and 90,000 were counted on a single decomposing apple.

•  The slender, tapered body of nematodes equips them to live in interstitial spaces. Most free-living nematodes are less than 2.5mm in length and often are microscopic.  The largest soil dwelling nematodes may be 7mm long and the largest marine forms a whopping 5cm.

• Most free-living nematodes are carnivorous. However, some feed on algae and fungi and some are detritivores. Others feed on plants, especially the roots.

•   Many root feeding nematodes are major agricultural pests.  These species pierce root cells and suck out their contents.

•   Nematodes are estimated to destroy 12% of the world’s cash crops annually.

Free-living nematodes reside in both aquatic and terrestrial habitats. Soil nematodes play a vital role in agriculture and the recycling of nutrients and minerals in the environment. These organisms are commonly grouped into four main types based on their feeding habits.

•  Bacteria-eaters feed exclusively on bacteria. They help to recycle nitrogen in the environment by decomposing bacteria and releasing excess nitrogen as ammonia.

• Fungi-eaters feed on fungi. They have specialized mouthparts that enable them to pierce the fungal cell wall and feed on the internal fungal parts. These nematodes also aid in decomposition and the recycling of nutrients in the environment.

• Predatory nematodes feed off of other nematodes and protists, such as algae, in their environment.

•  Nematodes that are omnivores feed on different types of food sources. They may consume bacteria, fungi, algae, or other nematodes.