Lecture 4: Aquatic Ecosystems Flashcards
Abiotic factors in aquatic ecosystems
- salinity
- hardness
- temperature
- availability of sunlight
- dissolved oxygen
- pH
- nutrient
- turbidity
Biotic factors in aquatic ecosystems
- plankton
- nekton
- benthos
- decomposers
Abiotic factor
- the amount of dissolved salt in the water
- formed by the weathering of rocks
- higher __ water is more dense
Salinity
Abiotic factor
- amount of minerals (calcium and magnesium) in freshwater
Hardness
Abiotic factor
- measure of the average kinetic energy of the water molecules
- warmest at the surface and near the equator
Temperature
Abiotic factor
- decreases with water depth
Availability of sunlight
Abiotic factor
- the amount of oxygen gas per mL of water
- highest in cold, turbulent water
- lowest in stagnant water
Dissolved oxygen
Abiotic factor
- measurement of the acidity or alkalinity of water
pH
Rainwater and acid rain pH
- 5.6 due to mixing with CO2
- < 4.5 due to mixing with sulfur (pollutant)
pH of pure water and ocean water
- 7
- 8.1 due to carbonate ions
Abiotic factor
- nitrates and phosphates that runoff from land
Nutrients
Abiotic factor
- measures water cloudiness
- the measure of relative clarity of a liquid
Turbidity
Biotic factor
- small, free-floating, or weakly swimming
__ - plant-like
__ - animal-like
plankton
- phytoplankton
- zooplankton
Biotic factor
- large, independent, swimmers
Nekton
Biotic factor
- bottom-dwellers (live in substrate)
Benthos
Biotic factor
- break down dead organisms and waste, cycling nutrients back into the water
Decomposers
Freshwater Ecosystem
Parts of the pond and lake
- Littoral Zone
- Limnetic Zone (photic zone)
- Profundal Zone (Aphotic zone)
Freshwater Ecosystem
Parts of the pond and lake
- small animals and animals
- emergent vegetation can be seen
- roots are submerged but their top emerges
- nearest to the shore
- warm, shallow, sunlight
Littoral Zone
Freshwater Ecosystem
Parts of the pond and lake
- next to littoral zone
- open water area too deep for emergent plants
- warm and sunlit, supports phytoplanktons
Limnetic Zone (photic)
Freshwater Ecosystem
Parts of the pond and lake
- cold and habitat for benthos
Profundal Zone (Aphotic)
Types of Lakes
- Oligotrophic
- Eutrophic
Type of Lake
- have low nutrients limiting algae and phytoplankton growth
- low turbidity
Oligotrophic
Type of lake
- have high nutrient levels and excessive algae growth
- very high turbidity
Eutrophic
Difference between stream and river
Stream
- narrow channels that carry runoff toward rivers
River
- wide and carry more water
Different Parts of the River
- Headwater/River source
- Transition Zone
- Floodplains - Mouth
Part of the River
- high dissolved oxygen (O2)
- low nutrients (NO3 (Nitrate),NO2 (Nitrite),PO4 (Phosphate))
- cold, no salinity
- low turbidity (oligotrophic)
Headwater/rive source
Part of the River
- widens and deepens
- becomes warmer
- decreased dissolved oxygen
- increased nutrient level
Transition zones
Part of the River
- within the transition zone
- regularly flood
- Floods deposit soil sediments dissolved from upstream,
increasing soil nutrient levels.
- very fertile as a result.
Floodplains
Part of the River
- lowermost part of the river where it meets a larger body of water, such as an ocean, sea, or lake.
- soil runoff
- Low dissolved oxygen (O2)
- High nutrients (NO3, NO2,PO4)
- Warm water temperatures
- High turbidity (eutrophic)
- Moderate salinity
Mouth
Freshwater Inland Wetlands
- marshes
- swamps
- bogs
soil that is completely saturated in water
waterlogged
- are areas containing soils that are usually waterlogged – completely saturated in water.
- Soil tends to be oxygen-poor due to the lack of air
exposure.
Wetlands
found in low-lying, treeless areas.
marshes
low-lying wetlands dominated by trees.
swamps
- have floating mats of plant matter that living plants grow on.
- Slow rates of decomposition result in nutrient-poor water.
bogs
Adaptations of Wetland Organisms
1) Floating - Fewer vascular tissues are needed since water is abundant, making them lighter.
2) Carnivorous - Capture and digest insects to increase
nitrogen and phosphorous absorption.
3) Emergent - Many empty spaces in tissues allow oxygen to flow through the plant and into the submerged roots.
Coastal ecosystems (7)
- tidal flats
- coastal lagoons
- estuaries
- deltas
- salt marshes
- seagrass beds
- mangrove forests
Coastal ecosystem
- saltwater wetland areas that are continually covered and uncovered by the tides
Tidal flats
Coastal ecosystem
- saltwater pools that are separated from the ocean by sandbank or coral reefs
Coastal Lagoons
Coastal ecosystem
- partially enclosed bodies of water where river water mixes with seawater
Estuaries
Coastal ecosystem
- landforms at river mouths formed by deposited sediment
deltas
- As rivers reach the ocean, their current __.
- __ cannot carry as much sediment.
- The sediment is deposited at the __.
- Eventually the sediment expands the coastline and forms __.
- slows
- Slow-moving waters
- shallow ocean shore
- large landmasses
Coastal ecosystem
- tidal flats dominated by herbs and grasses
Salt marshes
Coastal ecosystem
- submerged plants that resembled grass
Seagrass bed
Coastal ecosystem
- have trees with roots that can filter salt
- provide coastal protection
Mangrove forests
Mangrove forests provide coastal protection by dissipating up to __ of wave energy
90%
Ocean ecosystem parts (biomes) with definition (5)
- coastal zone
- intertidal zone - shallow parts
- photic zone - highest zone of open ocean (100m)
- aphotic zone - 100m and deeper
- abyssal plain - bottom-dwellers
ocean ecosystems
- alternates from submerged during high tide to dry during low tide
intertidal zone
the result of the gravitational pull of the sun and the moon
tides
- sun and moon’s gravity aligned
- Occurs during the new moon and full moon phases
high tide or spring tide
- sun and moon’s gravity is perpendicular
- Occurs during the first and third quarter moon phases.
low tide or neap tide
The Bay of Fundy in Canada has a tidal range of __ – more than a 3-story building
16.3 meters
intertidal zone ecosystems with definitions
- rocky shores
- substrate is hard and stable
- erosion is slow - sandy shores
- substrate is shifting and unstable
- erosion is rapid
- color depends on source
Common types of sand
- Black - volcanic rock
- Brown - quartz
- White - coral
Ocean ecosystems
- shallow sea ecosystem immediately above the continental shelf.
- Abundant sunlight and nutrients.
- Contains 90% of the ocean’s biodiversity.
coastal zone
- ecosystems built on the exoskeletons of the coral polyps
- found mostly in warm, shallow, sunlit waters
coral reefs
coral is a symbiotic relationship between two organisms
coral polyps - built the calcium carbide skeleton
algae- photosynthetic most of the coral’s food
important in the carbon cycle and helps to maintain the ocean’s pH
calcium carbonate
- includes all areas beyond the continental shelf
- low nutrient available limit phytoplankton
- “marine desert”
Open ocean
Ocean Ecosystems
- contain sunlight enough to perform photosynthesis in the topmost layer
photic zone
Ocean Ecosystems
- no sunlight
- can’t photosynthesize
- bioluminescent
Aphotic Zone
- Many aphotic zone species are __ and can produce and emit light.
- Light is the result of chemical reactions by __.
- what is its purpose?
- bioluminescent
- symbiotic bacteria
- find prey or attract mates.
gives vibrant colors to corals
zooxanthellae
Ocean Ecosystems
- receives no sunlight
- all food webs are based around scavenging and decomposition
Abyssal plain
constant flow of detritus from above
marine snow
fissures in the abyssal plain where heated water and minerals are released. organisms that can generate food from these chemicals perform ___
Hydrothermal vents
- chemosynthesis
why is dissolved oxygen higher in cold, turbulent waters? why is it lowest in warm, stagnant waters?
Temperature:
Cold Water: Cold water can hold more dissolved oxygen than warm water. The solubility of oxygen decreases as water temperature increases. In colder water, molecules are closer together, making it easier for oxygen molecules to dissolve and remain in the water.
Warm Water: In warmer water, the molecules are more spread out, reducing the ability of water to hold dissolved gases, including oxygen. This is why, generally, colder waters tend to have higher dissolved oxygen concentrations.
Turbulence:
Turbulent Waters: Turbulent or flowing water promotes the exchange of gases at the water’s surface. Waves, currents, and turbulence can introduce more oxygen into the water through the process of aeration. This allows atmospheric oxygen to mix with the water, increasing dissolved oxygen levels.
Stagnant Waters: In stagnant or slow-moving waters, the exchange of gases is limited. Stagnant conditions can lead to stratification, where different layers of water form with different temperature and oxygen profiles. The bottom layers, being cut off from atmospheric oxygen, may experience lower dissolved oxygen concentrations.
