Aquatic Communities Flashcards
Holoplankton
Spend entire life cycle as plankton.
Meroplankton
Spend only part of life cycle as plankton (usually larvae of adults in Benthic Realm).
Phytoplankton
Free-floating organisms capable of photosynthesis.
Zooplankton
Free-floating organisms with limited locomotion.
Bacterioplankton
Free-floating bacteria and blue-green algae.
Viroplankton
Free-floating viruses.
Epibenthic
Organisms on or above the bottom of the ocean.
Infauna
Organisms below sediment surface.
What are the 3 classes of infauna?
- Macrofauna: > 0.5 mm
- Meiofauna: 0.062-0.5 mm
- Microfauna: <0.062 mm
Equal Chance (Lottery) Hypothesis
Larvae of different species have an equal chance of settling on an open spot.
- Limited space but species competitvely equal
- First to settle is able to retain spot
What are the Pelagic Zone’s separate components and what criteria define them?
From top to bottom:
- Epipelagic: lower limit is where photosynthesis equals carbon waste (respiration) [surface to 100-200 m]
- Mesopelagic: lower limit where water equals 10ºC [700-1000 m]
- Bathypelagic: lower limit where the water equals 4ºC [2k-4k m]
- Abyssopelagic: All water under the bathypelagic level, excluding trenches.
- Hadalpelagic: Trench water [>6k m]
What are the Benthic Zone’s separate components and what criteria define them?
From top to bottom:
- Shelf: emcompasses the land depth equivalent to the combined epipelagic and mesopelagic realms
- Bathyal: land that covers the same depth limits as the bathypelagic realm.
- Abyssal: land that covers the same depth limits as the abyssolpelagic realm.
- Hadal: trench land [>6k m]
Nekton
Animals capable of moving against water flow
Plankton
Organisms incapable of moving aginst water flow.
Epibenthic
Organisms on or above the bottom surface of a marine body.
Infauna
Organisms below the sediment surface.
- Macrofauna: >0.5 mm
- Meiofauna: 0.062-0.5 mm
- Microfauna: <0.032 mm
Net Primary Production (NPP)
The amount of plant matter produced per unit area of the earth’s surface per unit time.
What is the ultimate fate of oceanic kelp?
- ~5% is consumed within the kelp forest itself.
- ~95% is exported out of the forest to adjacent ecosystems.
- Greatest export occurs during large wave events.
Giant kelp accounts for __% of the particulate carbon reaching the deep sea floor and __% of the diet of sea urchins that live there.
80; 60
Amensalism
A (0, -) relationship.
- An example is the amensalic relationship between deposit feeders and suspension feeders, whereby the fine particles that deposit feeders stir up via bioturbation end up clogging the feeding apparatus of suspesion feeders.
Stipate Kelp
Possess a thick, rigid stipe and small holdfast.
- Extend up to 2m off the bottom to produce a subsurface canopy.
Giant kelp has a(n) _____ _____ effect on understory algae and a(n) _____ _____ effect on sessile invertebrates.
direct negative; indirect positive
The kelp shading limits understory algae growth, which in turn promotes sessile invertebrate expansion.
What are the two classes of the tidal cycle?
- Daily: Typically semi-diurnal (2 high and low tides)
- Lunar: alternates between spring and neap tide series
- 2 Spring and 2 Neap every ~29 days as the moon rotates around the Earth
- Spring Tide: greater tidal amplitude
- Neap Tide: smaller tidal amplitude
Recruitment Limitation
The supply of new individuals of any species is low, and thus no one species dominates.
- Abundant resources → weak competition
- No exclusion
Storage Effect (Lottery)
Since the settlement of new recruits generally fluctuates greatly, periodic high recruitment can result in persistance.
Meiofauna are found exclusively in ______ communities.
Soft bottom
Average particle size _____ with increased water flow.
increases; high water flow also typically leads to more frequent disturbances.
Give 3 examples of deposit feeder types.
- Surface browsers: have tentacles or siphons and ingest surface sediment.
- Head-down deposit feeders: ingest particles at depth and defecate at surface.
- Mobile browsers: burrow in sediment ingesting and defecating.
Shallow seas have a higher proportion of _____ feeders, while deep seas have a higher proportion of _____ feeders.
suspension; deposit
Initial colonizers of soft bottom communities tend to be _____ _____ species, while later colonizers tend to be _____ _____ species.
surface dwelling; deep burrowing
What are the two components of diversity?
- Species Richness: number of different species present.
- Species Evenness: distribution of relative abundances among the species.
What are two important niche aspects?
- Niche Breadth: how broad the range of conditions within which a species can survive, grow and reproduce
- Niche Overlap: degree to which different species require the same resources.
