What is pelagic larval stage?

Pelagic larvae can disperse large distances, colonize new territory, and move away from habitats that has become overcrowded or otherwise unsuitable. A long pelagic larval phase can help a species to break its parasite cycles. Pelagic larvae avoid benthic predators.

Why do many benthic invertebrates produce planktonic larvae?

The ecological significance of planktonic larvae is two-fold: they are a dispersal stage for benthic organisms (Shanks, 2009), determining the potential of benthic species to colonize adjacent habitats, but they can also constitute a major portion of zooplankton communities in high latitude waters (Gluchowska et al..

In which of the following locations would you expect meroplankton to live in great abundance?

Generally, shallow coastal waters contain far greater numbers of meroplankton than deep, open ocean waters. Most abundant regions occur at depths between 0 and 200 meters of the water column, where light penetration is highest.

Why do invertebrates have larval stages?

A larva sometimes functions as a food gatherer—in many species the larval stage occurs at a time when food is abundant—and has a well-developed alimentary system. It stores food so that the transformation to the adult stage can occur. Many invertebrates (e.g., cnidarians) have a simple ciliated larva called a planula.

Do marine larvae have spines?

They have spines and feathery projections that keeps them afloat. Larvae are usually transparent so predators have difficulty time seeing them. All these organisms – phytoplankton, zooplankton and larval forms are key to the ecology of the oceans. They support the oceanic food web and cycle elements in the sea.

What organisms in the ocean do not have a planktonic larval stage?

Corals, sea stars, and bivalves can all have a planktonic larval stage (although the length of time in the plankton may vary greatly, and some species do not have a planktonic stage at all). Animals such as these that live on or associated with the sea floor are called benthic.

What are benthic invertebrates?

Benthic (meaning “bottom-dwelling”) macroinvertebrates are small aquatic animals and the aquatic larval stages of insects. They include dragonfly and stonefly larvae, snails, worms, and beetles.

What’s the difference between meroplankton and Holoplankton?

Depending on their life cycle, plankton are identified as either holoplankton or meroplankton. Holoplankton are organisms that are planktonic their whole life cycle, such as jellyfish, krill, and copepods. Meroplankton, on the other hand, are only planktonic for part of their life cycle.

Are clams meroplankton?

Temporary plankton, or meroplankton, such as young starfish, clams, worms, and other bottom-dwelling animals, live and feed as plankton until they leave to become adults in their proper habitats.

What is an advantage of having planktonic larval stages?

The presumed advantages of such larvae include the avoidance of competition for resources with adults, temporary reduction of benthic mortality while in the plankton, decreased likelihood of inbreeding in the next generation, and increased ability to withstand local extinction.

What is a benthic invertebrate?

Benthic invertebrates are organisms that live on the bottom of a water body (or in the sediment) and have no backbone. The size of benthic invertebrates spans 6-7 orders of magnitude 1. They range from microscopic (e.g. microinvertebrates, <10 microns) to a few tens of centimetres or more in length (e.g. macroinvertebrates, >50 cm).

What are the advantages of benthic macroinvertebrates in stream ecology?

In addition to being sensitive to changes in the stream’s overall ecological integrity, benthic macroinvertebrates offer other advantages to scientists looking for indications of stream pollution. Such advantages are: • Benthic macroinvertebrates are relatively easy to sample.

What are the macroinvertebrates in the ocean?

Macroinvertebrates include aquatic insects (such as mayflies, stoneflies, caddisflies, midges, beetles), snails, worms, freshwater clams, mussels, and crayfish. Some benthic macroinvertebrates, such as midges, are small and grow no larger than 1/2 inch in length.

What causes the biomass of benthic invertebrates in estuaries to decline?

The biomass of benthic invertebrates in estuaries and coastal embayments is often high. It declines if communities are affected by prolonged periods of poor water quality especially when anoxia and hypoxia are common 14.