Aquatic Biomes Flashcards
what are the two major categories of aquatic biomes?
-marine ecosystems
-freshwater ecosystems.
what is a marine ecosystem?
- saltwater
- open-water
- coastal
what is a freshwater ecosystem?
lotic – flowing water (rivers and streams)
lentic – nonflowing water (ponds, lakes, wetlands)
lentic
nonflowing water (ponds, lakes, wetlands)
logic
flowing water (rivers and streams)
describe the hydrological cycle
- 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
what are wetlands?
areas where aquatic and terrestrial ecosystems meet.
describe the environment of a wetland
- 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.
what are the three topographic situations of a wetland?
Basin wetlands, Riverine wetlands, and Fringe wetlands.
what is a basin wetland?
develop in shallow basins, from upland depressions to filled-in lakes and ponds – water flow is vertical
what is a riverine wetland?
develop along shallow and periodically flooded banks of rivers and streams – water flow is unidirectional
what is a fringe wetland?
occur along the coasts of large lakes – water flow is in two directions
what do topographic situations transport?
nutrients and sediments in and out
where do wetlands receive their water?
receive most of their water from surface water, but some are fed by groundwater.
what are the nutrients like in wetlands?
Nutrients are plentiful and the pH is usually neutral leading to an abundance of plant and animal life.
what are the two primary categories of wetlands?
- Tidal wetlands
- Non-tidal wetlands
what are marshes?
- Wetlands frequently or continually inundated with water, characterized by emergent soft-stemmed vegetation adapted to saturated soil conditions
what are swamps?
any wetland dominated by woody plants
how is a swamp characterized?
saturated soils during the growing season, and standing water during certain times of the year
describe the soil of a swamp
The highly organic soils of swamps form a thick, black, nutrient-rich environment for the growth of water-tolerant trees
mangrove wetland
- 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
describe the mangrove plant
- 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
what are fens
- Are freshwater peat-forming wetlands covered mostly by
grasses, sedges, reeds, and wildflowers. - Typically receive water from groundwater.
- Characterized by accumulation of organic materials.
what are bogs?
- 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.
what are estuaries?
partially enclosed bodies of water where saltwater from the sea mixes with freshwater from rivers, streams and creeks as well as runoff and groundwater.
how are estuaries protected from the full force of ocean waves, winds, and storms?
landforms as barrier islands or peninsulas.
what is the salinity like for estuaries?
The salinity of these areas can vary greatly.
describe life in an estuary
- 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
Aquatic biomes occupy the largest part of the biosphere
- 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.
what are the three layers?
Epilimnion, thermocline, and hypolimnion
Epilimnion:
upper layer, which is warmed by the sun and mixed well by wind
Hypolimnion
A cool layer too far below the surface to be warmed or mixed
Thermocline
A transition zone between the two other layers
photic zone
zone through which light penetrates and photosynthesis can occur.
aphotic zone
where very little light reaches and usually no photosynthesis occurs.
the littoral zone
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
limnetic zone
open sunlit surface water past littoral zone; depth goes to where photosynthesis is insignificant .
* Phytoplankton & zooplankton dominate
The profundal zone
all open water from limnetic zone to depth of no photosynthesis.
* Detritus fuels communities of bacterial decomposers.
The benthic zone
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.
Oligotrophic lakes
- 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
Mesotrophic lakes
have a moderate amount of nutrients and phytoplankton productivity.
Eutrophic lakes
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
Oligotrophic lakes may become mesotrophic and eventually eutrophic as nutrients accumulate
brought in by runoff from the surrounding land surface.
Streams and rivers
bodies of water moving continuously in one direction.
Headwaters
Cold and clear and carry little sediment and relatively few mineral nutrients.
* may be small, straight and swift
As the stream travels down
the water picks up oxygen and nutrients on the way.
When the gradient is less steep downstream
velocity decreases and the stream begins to meander and deposit sediment.
Nutrients fail to accumulate
phytoplankton fail to bloom due to flowing water
Current thoroughly mixes water, providing a well-aerated regime.
Therefore, animals are not well adapted to low oxygen environments, and are particularly susceptible to oxygen-reducing pollution (e.g., sewage)
what is the difference between the littoral zone and photic zone?
