Plankton Communities

Flashcards about Plankton Communities

What are Plankton?

Organisms and viruses that do not swim or are weak swimmers, and do not live on or attached to the seafloor (suspended in water, and drift with currents or swim weakly)

What is Nekton?

Actively swimming organisms that swim against the flow.

What are the four major functional groups of plankton?

Viruses; Bacterioplankton; Phytoplankton; Zooplankton

Describe Viruses

• Extremely small – femtoplankto

• Highly abundant

• Two main types based on host ï Bacteriophages – infect bacteria ï Phycoviruses – infect phytoplankton (algae)

• Rely on their host for metabolic requirements

What is Picoplankton?

Bacteria and cyanobacteria, ranging in size from 0.2 – 2.0 μm.

What is the ecological role of viruses?

• Play a major role in marine ecosystems (recognised since 1980s)

• Most abundant biological entity in the water column of the world's oceans

• Equivalent to the carbon in ∼75 million blue whales

• Play roles in host infections

• Harbour enormous genetic and biological diversity (mostly undiscovered!)

What is Microplankton?

Diatoms and dinoflagellates, ranging in size from 20 – 200 μm.

What is Mesoplankton?

Zooplankton and larval fish, ranging in size from 0.2 mm – 2 cm.

What is Macroplankton?

Gelatinous zooplankton and krill, ranging in size from 2 cm – 20 cm.

What is Megaplankton?

Large jellyfishes that are greater than 20 cm.

What are the two main types of viruses based on the host that they infect?

Bacteriophages infect bacteria, while phycoviruses infect phytoplankton (algae).

What are the major phytoplankton groups?

Cyanobacteria, Diatoms, Dinoflagellates, and Coccolithophores.

What is Cyanobacteria (blue-green algae)?

Autotrophic bacteria that account for up to 80% of all primary productivity in the oceans and are picoplankton.

What are Diatoms?

Single-celled phytoplankton with a rigid silica cell wall (frustule) enclosing the cells.

What is Primary production?

The process of converting inorganic compounds to organic matter.

What are common methods of measuring rates of primary production?

Light/dark bottle technique, oxygen sensors, chlorophyll concentration (spectrophotometry; satellite images), and 14C.

What factors affect primary productivity?

Nitrogen (N), Phosphorus (P), and Iron (Fe).

What are Phytoplankton Blooms?

Occur when phytoplankton grows rapidly, often associated with nutrient additions.

What do Zooplankton eat?

Consume phytoplankton, are herbivorous, and are heterotrophic.

What is Holoplankton?

Their entire life cycle is planktonic.

What is Meroplankton?

Planktonic for only part of their life cycle.

What are copepods?

Phylum Arthropoda – Class Crustaceans, that are the most numerous animals on earth, and are often herbivorous.

What is Krill (Euphausiids)?

Phylum Arthropoda – Class Crustaceans that occur in large aggregations and are abundant in polar regions.

What are Chaetognaths?

Phylum Chaetognatha, also known as arrow worms, that are translucent and voracious predators.

What are Foraminifera?

Single-celled amoeba-like microplankton with shells composed of calcium carbonate that feed on diatoms and their sensitivity to temperature makes them indicators of past climates.

What are some types of Gelatinous zooplankton?

Jellyfish (phylum Cnidaria), Comb jellies (Ctenophores), and Salps & doliolids (Phylum Chordata).

How many food webs exist in pelagic water?

Two food webs ‐ Classical food web and Microbial loop

How do plankton adapt to prevent sinking?

Stores of lipids/fats, long spines/antennae (increase drag), and being neutrally buoyant.

How do plankton adapt to avoid predation?

Spines, transparency, stinging, hiding (among jellyfish), and vertical migration.

What is Marine snow?

‘Rain’ of detritus that sinks from the photic zone to the deep sea comprised of fecal pellets from zooplankton, mucus, gelatinous feeding houses, and carcasses.