Aquatic Zones and Characteristics Flashcards
iBiotic communities of lentic (lake) ecosystems
- Pelagic zone
- Euphotic zone
- Littoral zone
- Benthic zone
Pelgaic zone
open water, plankton, nekton (swimming organisms like fish)
Euphotic zone
enough light for photosynthesis
Littoral zone
nearshore, where photic zone hits lake bottom
Macrophytes, phytoplankton, fish, zooplankton
Benthic zone
not enough light for photosynthesis, detritus, animals fungi and bacteria, low oxygen
Freshwater Aquatic zones:
- Flowing (lotic): rivers and streams
- Nonflowing (lentic): lakes and other still wates
Freshwater Biological zones
Connect terrestrial and marine ecosystems
Flowing and nonflowing
Characterized by abiotic environment (water velocity, temp, light penetration (clarity), chemistry (O2, nutrients, pH) and biota (plants AND animals)
Aquatic Systems can be
fresh water or salt water
Lotic: flowing water systems are characterized by
order (small to high order)
1st order: beginning to flow in mountains
2nd order: any number of collections of 1st order streams
3rd order: any numbers of collections of 2nd order streams
and so on
River continuum concept
Moving downstream from 1st order to higher (small streams to bigger)
Get less input from riparian vegetation and smaller particle sizes
Biological community changes (organic detritus to algae and aquatic vascular plants, shredders to collectors)
River channel subhabitats
Lentic ecosystems: lakes and other still waters formed by
Natural depressions filling with water
Left from glaciers receding
Changing river direction (oxbow lake)
Dammed rivers
Marine Biological zones (salt water) are categorized by
physical location in relation to shore line or ocean bottom
Important environmental features for marine biological zones
Temperature
Light availability
Water depth
Stability of bottom substrate
Nearshore zones
Varied environments
Transition zones between terrestrial and marine environments
Tides: rise and fall of ocean usually twice daily
Freshwater, sediment inputs from rivers
Ex. beach at Houston
Estuaries
Part of nearshore zone
Junction of a river with ocean
Variation in salinity
Many juveniles of fish species (away from salinity variation intolerant predators
Shellfish, crabs, seagrasses, susceptible to pollution as upstream aggregators
Mangrove forests
Shallow estuaries in tropical subtropical regions
Salt tolerant evergreen trees and shrubs
Many amazing adaptations
Rocky intertidal zones
Intertidal: shoreline affected by rise and fall of tides
Organisms deal with:
Temperature variability, desiccation, wave action
Tidepools
Prime location for classic ecological studies
Sandy Shores
Unstable substrate
Challenging habitat but many invertebrates live on or within sand
Some emerge when tide comes in to feed on detritus
Buried organisms: filter detritus, plankton from water
Shallow Ocean Zones
- Coral reefs
- Seagrass deep
- Kelp Beds
Seagrass deep
Under 5 m deep
Underwater flowering plants not grasses
Algae and mussels
Coral Reefs
Warm, shallow waters
Coral live in close association with algal partners → symbiosis
Sponges
Rich habitat diversity with many fish species
Many threats: sedimentation, ocean acidification, warning
Kelp Beds (forests)
Under 15 m deep
Large brown algae
Solid substrate
Sea urchins, lobsters, mussels, abalones, sea otters
Open Ocean: Pelagic Zone
Beyond the continental shelf
Light determines photosynthetic range
Pelgaic zone: photic zone
Life abundant
Phytoplankton, zooplankton, nekton (swimming organisms), pelagic seabirds
Open ocean: Benthic zone
Ocean floor
Detritus based food chain
Cold high pressure
Bacteria protists, sea worms
Sea stars, sea cucumbers
Bioluminescence predators
Difficult to study
