Nekton

Definition

Nekton refers to the group of aquatic animals that are capable of swimming freely and independently in the water column, including fish, squid, and marine mammals. Unlike plankton, which drift with currents, nekton can actively navigate and inhabit various aquatic biomes, influencing both ecological dynamics and food webs in these environments.

5 Must Know Facts For Your Next Test

1. Nekton includes a wide variety of organisms, from small fish to large marine mammals like whales, showcasing diverse adaptations for swimming and hunting.
2. These animals are essential for maintaining the balance in aquatic ecosystems by acting as predators or prey, impacting populations of other species.
3. Nekton can be found in various aquatic biomes, including freshwater lakes, rivers, and oceans, thriving in environments with varying temperatures and salinity levels.
4. Many nektonic species have migratory behaviors, traveling long distances between feeding and breeding grounds, which affects their populations and interactions with other marine life.
5. Human activities such as overfishing and pollution significantly impact nekton populations, leading to shifts in ecosystem dynamics and biodiversity loss.

Review Questions

• How does the presence of nekton influence the food web within aquatic ecosystems?
  • Nekton plays a crucial role in aquatic food webs by serving as both predators and prey. Their ability to swim freely allows them to actively hunt smaller organisms like plankton and smaller fish, while also being a food source for larger predators such as sharks and marine mammals. This dynamic creates a balance within the ecosystem, as changes in nekton populations can lead to cascading effects on both prey and predator species.
• Discuss the adaptations that enable nekton to thrive in diverse aquatic biomes.
  • Nekton has evolved various adaptations that enhance their swimming abilities and survival across different aquatic environments. For instance, streamlined bodies reduce drag while swimming, while specialized fins aid in maneuverability. Additionally, some nektonic species possess gills for efficient oxygen extraction in water or blubber for insulation in colder marine regions. These adaptations allow them to occupy niches in both freshwater and marine ecosystems effectively.
• Evaluate the impact of human activities on nekton populations and the potential consequences for aquatic biomes.
  • Human activities such as overfishing, habitat destruction, and pollution pose significant threats to nekton populations. Overfishing can lead to declines in key species, disrupting predator-prey relationships within ecosystems. Pollution can cause physiological stress or mortality among nektonic organisms, further destabilizing food webs. As these populations decline, the overall health of aquatic biomes can deteriorate, leading to reduced biodiversity and altered ecological functions.

Related terms

plankton: Small organisms that drift in water currents, forming the base of the aquatic food web and including both phytoplankton (plants) and zooplankton (animals).

benthic zone:

The ecological region at the lowest level of a body of water, including the sediment surface and sub-surface layers where organisms such as clams and worms live.

pelagic zone:

The open water column in oceans and seas, which is home to a diverse range of nektonic species and other marine life.