Aquatic Zones and Characteristics

Question 1

iBiotic communities of lentic (lake) ecosystems

Answer 1

1. Pelagic zone
2. Euphotic zone
3. Littoral zone
4. Benthic zone

Question 2

Pelgaic zone

Answer 2

open water, plankton, nekton (swimming organisms like fish)

Question 3

Euphotic zone

Answer 3

enough light for photosynthesis

Question 4

Littoral zone

Answer 4

nearshore, where photic zone hits lake bottom
Macrophytes, phytoplankton, fish, zooplankton

Question 5

Benthic zone

Answer 5

not enough light for photosynthesis, detritus, animals fungi and bacteria, low oxygen

Question 6

Freshwater Aquatic zones:

Answer 6

1. Flowing (lotic): rivers and streams
2. Nonflowing (lentic): lakes and other still wates

Question 7

Freshwater Biological zones

Answer 7

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)

Question 7

Aquatic Systems can be

Answer 7

fresh water or salt water

Question 7

Lotic: flowing water systems are characterized by

Answer 7

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

Question 8

River continuum concept

Answer 8

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

Question 9

Lentic ecosystems: lakes and other still waters formed by

Answer 9

Natural depressions filling with water
Left from glaciers receding
Changing river direction (oxbow lake)
Dammed rivers

Question 10

Marine Biological zones (salt water) are categorized by

Answer 10

physical location in relation to shore line or ocean bottom

Question 11

Important environmental features for marine biological zones

Answer 11

Temperature
Light availability
Water depth
Stability of bottom substrate

Question 12

Nearshore zones

Answer 12

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

Question 13

Estuaries

Answer 13

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

Question 14

Mangrove forests

Answer 14

Shallow estuaries in tropical subtropical regions
Salt tolerant evergreen trees and shrubs
Many amazing adaptations

Question 15

Rocky intertidal zones

Answer 15

Intertidal: shoreline affected by rise and fall of tides
Organisms deal with:
Temperature variability, desiccation, wave action
Tidepools
Prime location for classic ecological studies

Question 16

Sandy Shores

Answer 16

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

Question 17

Shallow Ocean Zones

Answer 17

1. Coral reefs
2. Seagrass deep
3. Kelp Beds

Question 18

Seagrass deep

Answer 18

Under 5 m deep
Underwater flowering plants not grasses
Algae and mussels

Question 19

Coral Reefs

Answer 19

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

Question 20

Kelp Beds (forests)

Answer 20

Under 15 m deep
Large brown algae
Solid substrate
Sea urchins, lobsters, mussels, abalones, sea otters

Question 21

Open Ocean: Pelagic Zone

Answer 21

Beyond the continental shelf
Light determines photosynthetic range

Question 22

Pelgaic zone: photic zone

Answer 22

Life abundant
Phytoplankton, zooplankton, nekton (swimming organisms), pelagic seabirds

Question 23

Open ocean: Benthic zone

Answer 23

Ocean floor
Detritus based food chain
Cold high pressure
Bacteria protists, sea worms
Sea stars, sea cucumbers
Bioluminescence predators
Difficult to study