Aquatic Biomes

Question 1

what are the two major categories of aquatic biomes?

Answer 1

-marine ecosystems
-freshwater ecosystems.

Question 2

what is a marine ecosystem?

Answer 2

• saltwater
• open-water
• coastal

Question 3

what is a freshwater ecosystem?

Answer 3

lotic – flowing water (rivers and streams)
lentic – nonflowing water (ponds, lakes, wetlands)

Question 4

lentic

Answer 4

nonflowing water (ponds, lakes, wetlands)

Question 5

logic

Answer 5

flowing water (rivers and streams)

Question 6

describe the hydrological cycle

Answer 6

• Water that evaporates from oceans and terrestrial environments falls as precipitation.
• Precipitation on land follows a path determined by geomorphology, flowing from streams to rivers.
• may collect in basins or floodplains to form ponds, lakes, inland waterways
• Rivers eventually flow to estuaries, the transition between freshwater and marine ecosystems, and then to the oceans

Question 7

what are wetlands?

Answer 7

areas where aquatic and terrestrial ecosystems meet.

Question 8

describe the environment of a wetland

Answer 8

• They can be saturated or flooded and include marshes, swamps, bogs, and fens.
• They are home to many different types of organisms, from aquatic insect larvae to large birds.

Question 9

what are the three topographic situations of a wetland?

Answer 9

Basin wetlands, Riverine wetlands, and Fringe wetlands.

Question 10

what is a basin wetland?

Answer 10

develop in shallow basins, from upland depressions to filled-in lakes and ponds – water flow is vertical

Question 11

what is a riverine wetland?

Answer 11

develop along shallow and periodically flooded banks of rivers and streams – water flow is unidirectional

Question 12

what is a fringe wetland?

Answer 12

occur along the coasts of large lakes – water flow is in two directions

Question 13

what do topographic situations transport?

Answer 13

nutrients and sediments in and out

Question 14

where do wetlands receive their water?

Answer 14

receive most of their water from surface water, but some are fed by groundwater.

Question 15

what are the nutrients like in wetlands?

Answer 15

Nutrients are plentiful and the pH is usually neutral leading to an abundance of plant and animal life.

Question 16

what are the two primary categories of wetlands?

Answer 16

• Tidal wetlands
• Non-tidal wetlands

Question 17

what are marshes?

Answer 17

• Wetlands frequently or continually inundated with water, characterized by emergent soft-stemmed vegetation adapted to saturated soil conditions

Question 18

what are swamps?

Answer 18

any wetland dominated by woody plants

Question 19

how is a swamp characterized?

Answer 19

saturated soils during the growing season, and standing water during certain times of the year

Question 20

describe the soil of a swamp

Answer 20

The highly organic soils of swamps form a thick, black, nutrient-rich environment for the growth of water-tolerant trees

Question 21

mangrove wetland

Answer 21

• Found in tropical and subtropical regions – covers 60% of the coastlines in the tropical regions
• Develop where wave action is absent
• Have mud and anaerobic sediments accumulate
• Are colonized by salt-tolerant woody plants called mangroves

Question 22

describe the mangrove plant

Answer 22

• Seeds germinate while attached to parent plant
• Drop to water and float upright until deposited in shallow water
• Have prop roots weakly penetrating mud
• Easily damaged by storms

Question 23

what are fens

Answer 23

• Are freshwater peat-forming wetlands covered mostly by
  grasses, sedges, reeds, and wildflowers.
• Typically receive water from groundwater.
• Characterized by accumulation of organic materials.

Question 24

what are bogs?

Answer 24

• Are freshwater wetlands, often formed in old glacial lakes, characterized by spongy peat deposits, evergreen trees and shrubs, and a floor covered by a thick carpet of sphagnum moss.
• Also characterized by accumulation of organic materials.

Question 25

what are estuaries?

Answer 25

partially enclosed bodies of water where saltwater from the sea mixes with freshwater from rivers, streams and creeks as well as runoff and groundwater.

Question 26

how are estuaries protected from the full force of ocean waves, winds, and storms?

Answer 26

landforms as barrier islands or peninsulas.

Question 27

what is the salinity like for estuaries?

Answer 27

The salinity of these areas can vary greatly.

Question 28

describe life in an estuary

Answer 28

• They are crucial feeding and resting areas for many
  types of migratory water fowl and waders.
• High diversity with nursery grounds for fish and crustaceans
• Primary production is mostly via detrital food webs

Question 29

Aquatic biomes occupy the largest part of the biosphere

Answer 29

• Marine biomes – salt concentration of approximately 3%.
• Freshwater biomes - salt concentration of less than 1% and are closely linked to the soils and biotic components of the terrestrial biomes that they are in contact with.

Question 30

what are the three layers?

Answer 30

Epilimnion, thermocline, and hypolimnion

Question 31

Epilimnion:

Answer 31

upper layer, which is warmed by the sun and mixed well by wind

Question 32

Hypolimnion

Answer 32

A cool layer too far below the surface to be warmed or mixed

Question 33

Thermocline

Answer 33

A transition zone between the two other layers

Question 34

photic zone

Answer 34

zone through which light penetrates and photosynthesis can occur.

Question 35

aphotic zone

Answer 35

where very little light reaches and usually no photosynthesis occurs.

Question 36

the littoral zone

Answer 36

shallow and close to shore shore to depth where rooted plants stop growing.
* Defined by where light reaches the bottom
* Most diversity of living organisms here

Question 37

limnetic zone

Answer 37

open sunlit surface water past littoral zone; depth goes to where photosynthesis is insignificant .
* Phytoplankton & zooplankton dominate

Question 38

The profundal zone

Answer 38

all open water from limnetic zone to depth of no photosynthesis.
* Detritus fuels communities of bacterial decomposers.

Question 39

The benthic zone

Answer 39

the region near the bottom and comprised of organic debris settling down from the littoral and limnetic zones.
Little oxygen present and it is dominated by anaerobic bacteria.
* “Muck” is rich in organic matter.

Question 40

Oligotrophic lakes

Answer 40

• nutrient-poor
• tend to be deep (low surface to volume ratio)
• Lots of different species but not each one not very abundant
• The largest freshwater species richness in the world is found in oligotrophic lakes!
• nutrient-poor conditions result in low production of organic material for decomposers

Question 41

Mesotrophic lakes

Answer 41

have a moderate amount of nutrients and phytoplankton productivity.

Question 42

Eutrophic lakes

Answer 42

shallower (high surface to volume ratio) and have increased nutrients.
* Generally surrounded by nutrient-rich deciduous forests * Life is more abundant but often less diverse
* Often high in nitrogen and phosphorus

Question 43

Oligotrophic lakes may become mesotrophic and eventually eutrophic as nutrients accumulate

Answer 43

brought in by runoff from the surrounding land surface.

Question 44

Streams and rivers

Answer 44

bodies of water moving continuously in one direction.

Question 45

Headwaters

Answer 45

Cold and clear and carry little sediment and relatively few mineral nutrients.
* may be small, straight and swift

Question 46

As the stream travels down

Answer 46

the water picks up oxygen and nutrients on the way.

Question 47

When the gradient is less steep downstream

Answer 47

velocity decreases and the stream begins to meander and deposit sediment.

Question 48

Nutrients fail to accumulate

Answer 48

phytoplankton fail to bloom due to flowing water

Question 49

Current thoroughly mixes water, providing a well-aerated regime.

Answer 49

Therefore, animals are not well adapted to low oxygen environments, and are particularly susceptible to oxygen-reducing pollution (e.g., sewage)

Question 50

what is the difference between the littoral zone and photic zone?