Lecture 3: Habitats Flashcards
what are the 5 main abiotic factors in aquatic systems?
- water salinity
- water temperature
- depth of water
- rate of water flow if there’s movement
- dissolved oxygen and nutrient levels
What are the 3 major types of freshwater environments? Give 2 examples of each
- flowing water
- rivers, streams - still water
- lakes, ponds - wetlands
- marshes, swamps
What are the 3 parts of a river?
headwaters
tributaries
mouth
Which direction do rivers and streams flow?
From the headwaters to the mouth
Describe the headwaters of a river
the source of the water
can be flow of water from ice melt, lake, pond
Describe the mouth of a river
the end of the river that empties out into a lake, ocean, or wetland
usually fans out in a delta
Describe tributaries
small streams that empty into another stream
many tributaries connect to form a major river
Describe what is meant by upstream
things that are closer to the headwaters relative to the reference point
Describe what is meant by downstream
things that are closer to the mouth of the river relative to the reference point
How are streams classified?
by order and can only increase in order when a stream of the same order joins it
Describe a first order stream
small headwater with no tributary
Describe a 2nd order stream
forms when two first order streams unite
Which orders are headwater streams classified as?
orders 1-3
which orders are medium-sized streams classified as?
4-6
Which orders are rivers classified as?
greater than 6
T or F: if a 1st order and 2nd order stream unite, it becomes a third order stream
FALSE. To increase in order, the joining streams must be of the same order
Describe the river continuum concept
no part of a river can be considered in isolation because there is a constant connection between all parts of the river as the water flows downstream
Both the physical and biotic components must be considered in this
T or F: the conditions of a river system remain unchanged from its headwaters to its mouth
FALSE
What 6 major changes would you expect to see as water flows from the headwaters to the mouth?
- increased stream bed size
- increased volume of water
- increase in nutrient and sediment loads
- decreased speed of flow
- substrate becomes finer
- changing levels of productivity
How can a flowing water system maintain a steady-state?
the continuous drift of material downstream must be balanced by:
- active movement of animals upstream
- ex. salmon carry nutrients as they swim upstream - productivity of upstream parts of the system
- productivity upstream produces particulate material for consumers downstream - input of materials from outside the system
Define CPOM and give an example
Coarse Particulate Organic Matter that enters a flowing water system
OM that is >1 mm in diameter
ex. leaves that fall into the stream from overhanging branches
Define FPOM and give an example
Fine Particulate Organic Matter than enters a flowing water system
OM that is 0.45 micrometers - 1mm
ex. OM that has been processed by detritivores or vertebrates
Define autochthonous and give an example
A system is autochthonous when organic carbon is produced from within an ecosystem
ex. if the ecosystem is primarily or built upon photosynthetic organisms who capture inorganic carbon and convert it into sugars
Define allochthonous and give an example
A system is allochthonous when organic carbon originates from outside of the ecosystem
ex. CPOM leaves that fall from trees outside of the stream
Define P/R
Primary productivity/cellular respiration
the biomass produced in a community through photosynthesis as a fraction of cellular respiration
What does P/R <1 mean?
the system has low productivity
and has a heterotrophic community because decomposers are the base of the food chain
What does P/R >1 mean?
the system has HIGH productivity
and has an autotrophic community because the photosynthetic organisms are the base of the food chain
What are the 5 invertebrate feeding groups of flowing water systems?
- shredders
- collectors
- grazers
- gougers
- predators
Describe shredders in flowing water systems
invertebrates that tend to be upstream and feed on bacteria and fungi that grow on the CPOM
Function: break down larger pieces of CPOM
Describe collectors in flowing water systems
invertebrates that capture organic matter from FPOM usually
can either be
gatherers
filter feeders
Describe grazers in flowing water systems
invertebrates that feed on photosynthetic organisms
Describe gougers in flowing water systems
invertebrates that burrow into waterlogged limbs and trunks of fallen trees
Describe predators in flowing water systems
organisms such as insect larvae and fish that feed on the grazers and other detrital feeders
Explain the physical conditions, productivity, and biotic community of the headwaters of a river
physical conditions:
- rapid moving, cold water
- very coarse, rocky substrate
- stream bed very narrow
- shaded from overhanging trees
biotic community:
- majority collectors and shredders
- some predators
- minority gougers
productivity:
- lots of overhanging trees = lots of CPOM falling in
- low because of shade from trees
- P/R<1
Explain the physical conditions, productivity, and biotic community of the middle section of a river
Physical conditions:
- water velocity slows
- particle size of substrate reduced - coarse sandy
- wider stream bed
Biotic community:
- majority grazers and collectors
- predator level the same as headwaters
- minority shredders
Productivity:
- less shading by trees due to wider bed = more light penetration = more photosynthetic organisms
- p/R >1 (autotrophic community)
Explain the physical conditions, productivity, and biotic community of lower reaches of a river
Physical conditions:
- water moving much slower
- very sandy, silty substrate
- much wider stream bed
- not much shade or CPOM
Productivity:
- P/R <1 because sandy silty substrate creates more sediment in water and FPOM from upstream is collecting = more invertebrates
Biotic community:
- almost completely collectors
- some predators
- no shredders or grazers
Would allochthonous or autochthonous inputs be more important at the headwaters? why?
allochthonous inputs would be more important at headwaters because the productivity is P/R<1 and the biotic community is mostly heterotrophs like shredders and collectors which rely on the CPOM from outside of the river system
Which type of organisms are most common near the headwaters of a river?
collectors and shredders
Which type of organisms are most common in the mid section of a river?
collectors and grazers
Which type of organisms are most common near the lower reaches of a river?
collectors
Which type of organisms are most common near the lower reaches of a river?
collectors
What are the 3 zones of still water (lakes and ponds)?
- littoral zone
- limnetic zone
- benthic zone
Describe the littoral zone
the zone closest to the shore of a body of still water
- supports diverse variety of rooted aquatic plants
- light can penetrate all the way to the bottom so there is more photosynthetic activity here than in any other zone
Describe the limnetic zone
the zone out from the littoral zone in a body of still water
it is the open water near the surface with reasonable light penetration
- primary production in this zone is done by phytoplankton and single celled algae
Describe the benthic zone of still water
the zone underneath the limnetic zone of a still body of water
little light penetrates the deep water, so limited plant growth here
- consists of the lake’s sediments and detritus that has sank
- invertebrates burrow in the sand and feed on detritus
- less dissolved oxygen
What are the 3 layers of still water regarding temperature and density and depth
- epilimnion
- thermocline
- hypolimnion
Define eplimnion
warm, low density water that sits at the top of a body of still water
Warmed by solar radiation, mixed by wind to maintain a fairly uniform temperature
Define thermocline
Layer of water in a body of still water below the epilimnion where there is a rapid temperature change over a short distance of depth
Define hypolimnion
The lowest layer of still bodied water with uniform temperature of cool water around 4-5 degrees C and the most dense
How is density of water related to temperature of water?
Inversely related
As temperature decreases, density will increase
Cool water sinks
Frozen water will float though
What occurs in still bodies of water in temperate zones when seasons change from SUMMER to FALL?
When the air temperature cools, the surface water temperature in the epilimnion will also cool and become denser and sink below the thermocline
What occurs in still bodies of water in temperate zones during the Fall?
As the water from the surface/epilimnion sinks, wind causes the water from the benthic zone to be brought up to the surface and mix
This is similar to upwelling in oceans as it also brings nutrients to the surface from the lake floor to be available for photosynthetic organisms at the surface
What occurs in still bodies of water in temperate zones when seasons change from FALL to WINTER?
air temperature cools even more and cools the surface waters to below 4 degrees C so that it becomes less dense and freezes.
Under the surface of ice, the water is warmer ~4 deg. which provides a habitat for organisms through the winter
What occurs in still bodies of water in temperate zones when seasons change from WINTER to SPRING?
When the surface temperature warms, the ice will melt and as it approaches 4 deg. it will sink back down to the bottom
Winds move surface waters around and pull water up from the bottom to mix the nutrients
In temperate zones, which season(s) is the thermocline present in a still body of water?
Summer only
Define wetland
Land that has standing water or periodically saturated soils with emergent vegetation
Define emergent vegetation
Plants rooted in substrate at the bottom of water that grow/emerge from the surface of the water
What are the two types of wetlands?
Freshwater and salt water
What are the 3 kinds of freshwater wetlands?
marshes
bogs
swamps
What are the 3 types of salt water wetlands?
saltwater marshes
estuaries
mangrove swamps
What feature is common to all types of wetlands?
They contain plants that can tolerate low oxygen conditions
Describe freshwater marshes
A type of freshwater wetland that contains non-woody plants such as sedges, rushes, and reeds
Describe freshwater swamps
A type of freshwater wetland that contains woody vegetation such as trees
Describe bogs
A type of freshwater wetland that has its water table on the soil surface year round and is entirely fed by water from precipitation (ie, no streams empty into it)
It is characterized by sphagnum moss which decomposes very slowly because of the waterlogged soils = peat
Soils are highly acidic and nutrient poor
Which type of plant characterizes a freshwater marsh?
non-woody veg
sedges, rushes, reeds
Which type of plant characterizes a freshwater swamp?
woody veg
trees
Which type of plant characterizes a bog?
sphagnum moss
Describe marine environments
Aquatic environments characterized by very high salinity waters
What are the 6 types of marine environments?
salt water marshes estuaries mangrove swamps intertidal zones coral reefs open ocean
Describe estuaries
A type of saltwater wetland where rivers empty into oceans
Salt and freshwater mix
Extremely nutrient rich as nutrients are brought from the river = very productive ecosystems
Describe salt marshes
A type of saltwater wetland where emergent, non-woody vegetation (reeds, sedges, rushes) grow
Located in coastal areas and usually within estuaries
Describe mangrove swamps
A type of saltwater wetland that contains woody plants with an extensive above ground root system
helps fight erosion in coastal areas
What are the 6 zones of open ocean?
intertidal zone neritic zone oceanic zone photic zone aphotic zone benthic zone
Describe intertidal zone
The region of an open ocean system that is periodically submerged when the tide is in and exposed when the tide is out
Describe neritic zone
the zone of an open ocean system near the shore and of the coast that is just before the big drop off
- permanently submerged
Describe the photic zone of an open ocean system
the zone of open ocean from the surface to ~200m in depth where light can penetrate
the community is mostly build from primary producers like algae and phytoplankton
Describe the aphotic zone of an open ocean system
below ~200m in depth where little light penetrates
Where do biotic communities arise in the aphotic zone of an open ocean system?
Around hydrothermal vents
Chemoautotrophs such as bacteria use the chemicals and inorganic carbon sources to do chemosynthesis
Describe hydrothermal vents
Cracks in the earth’s surface under water (in the aphotic zone) that contain and release very hot pressurized gases
Describe the benthic zone of an open ocean system
the depths of the ocean that contains the sediments
How many zones is the intertidal zone broken up into? What are they?
3
Upper intertidal
Middle intertidal
Lower intertidal
Describe the upper intertidal zone. What kind of conditions exist here and what kind of organisms can survive here?
Part of the intertidal zone of an open ocean system
It is the last part of the intertidal zone to be flooded when the tide comes in, and the first to be exposed when the tide goes out
CONDITIONS:
- very dry (submerged for only short period of time)
- high salinity
- high temperatures
ORGANISMS:
- little organismal diversity
- mostly barnacles
Describe the middle intertidal zone. What kind of conditions exist here and what kind of organisms can survive here?
Part of the intertidal zone of an open ocean system
The zone below the upper zone that is submerged for longer periods of the day
CONDITIONS:
- less saline
- more moderate temperatures
- extreme wave action
ORGANISMS:
- more organismal diversity
- mussels, fucose (algae)
Describe the lower intertidal zone. What kind of conditions exist here and what kind of organisms can survive here?
Part of the intertidal zone of an open ocean system
The area that is submerged the longest
CONDITIONS:
- very last to be exposed and first to be flooded
- lowest temperature conditions
- lowest salinity
ORGANISMS:
- greatest diversity of organisms
- more competition for space
- ex. sea stars, crabs, larger algae
Describe coral reefs and how they are formed
Shallow, tropical waters with temperatures >20 degrees C.
Habitats created by coral (colonial cnidarians) when they secrete calcium carbonate shells
When the coral dies, the shell is left behind and a new coral will grow on top of it and overtime the a reef is formed
- creates nooks and crannies for a diverse landscape that supports a lot of space for organisms
One of the most diverse biomes on earth
Which of the layers of the intertidal zone is the most diverse? Which is the least? Why?
most: lower because the conditions are less extreme
least: upper because the conditions are most extreme
Define terrestrial biomes
geographic regions composed of communities of organisms with similar adaptations
How are terrestrial biomes characterized?
by their predominant vegetation and climate conditions
What are the 2 key abiotic factors that affect the distribution of plant communities?
temperature
moisture
Describe the North America Precipitation Gradient
dominant vegetation reflects decline in average YEARLY PRECIPITATION from East coast to the Rockies
East: mesophytic forest –> oak-hickory forest –> oak woodland –> prairie –> dry grasslands –> desert –> Rockies
Describe the North America Temperature Gradient
Dominant vegetation reflects decline in average ANNUAL TEMPERATURE from South to North
South: tropical forest –> subtropical forest –> temperate deciduous forest –> temperate mixed forest –> boreal forest –> tundra
What are the 9 major biomes on Earth?
- tropical rainforest
- tropical seasonal forest/savanna
- subtropical desert
- woodland/shrubland
- temperate seasonal forest
- temperate grassland/cold desert
- temperate rainforest
- boreal forest
- tundra
- polar ice cap
How are biomes classified?
By their average annual temperature and precipitation
Which biome receives the highest average annual precipitation?
tropical rainforest
Which biome(s) receives the lowest average annual precipitation?
tundra
temperate grasslands
subtropical deserts
Which biome(s) have the highest average annual temperature?
Tropical rainforest
tropical seasonal forest/savanna
subtropical desert
Which biome(s) have the lowest average annual temperature?
Tundra
What do climate diagrams show?
average monthly temperature and precipitation for specific locations within a biome
= not representative of the entire biome
they tell us about the productivity of ecosystems and whether plant growth is limited by temp or ppt
How can you tell from a climate diagram whether plant growth is limited by temperature or precipitation?
Temperature and ppt are both on vertical scales so:
- if ppt drops below temperature, it is ppt that is limiting
- if temperature is below ppt, it is temperature that is limiting
What does the green highlighted part show on a climate diagram?
the growing season
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of a TROPICAL RAINFOREST
LATITUDE: 20 deg. N to 20 deg. S
PPT: >100mm year round; >2000 annually
TEMP: >20 deg. C
VEG: broadleaf evergreen forests that grow year-round
- year round growing season
- growth rate is higher than all the biomes
SOIL: fairly nutrient poor due to heavy rains leaching the minerals
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of a TROPICAL SEASONAL FOREST/SAVANNA
LATITUDE: mostly >10 deg. N and S of equator
PPT: >100 mm in wet season; <20-40 mm in dry
TEMP: >20 deg. C
VEG: deciduous forest or savanna grasslands
- growth occurs year round but is limited by ppt in dry seasons
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of a SUBTROPICAL DESERT
LATITUDE: 20-30 deg N and S
PPT: scarce year round
TEMP: >20 deg. C
VEG: cactus, euphorbs, creosote
- growth is limited by precipitation
SOIL: low OM, mostly rock and sand
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of a TEMPERATE RAINFOREST
LATITUDE: 30-60 deg N and S; restricted to coastal areas
PPT: high year round; mild-rainy winters; foggy summers
TEMP: 5-20 deg. C
- limits plant growth in cooler months
VEG: evergreen, needle-leaved trees (~60-70m tall)
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of a TEMPERATE SEASONAL FOREST
LATITUDE: 30-60 deg N
PPT: moderate ppt
TEMP: 5-20 deg. C
- growth limited more by temp
VEG: deciduous trees
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of WOODLANDS/SHRUBLANDS
LATITUDE: >30 deg. N and S
PPT: Mediterranean climate (hot dry summers, mild wet winters)
- limits growth
TEMP: 5-20 deg. C
VEG: drought tolerant grasses and shrubs
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of TEMPERATE GRASSLANDS/COLD DESERTS
LATITUDE: 30-60 deg. N
PPT: varies widely along the NA ppt gradient (higher east, lower west)
TEMP: 5-20 deg. C
VEG: tall grass prairies in east, shortgrass prairies, cold desert vegetation (sagebrush)
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of BOREAL FOREST (TAIGA)
LATITUDE: 50-60 deg N
PPT: 40-1000mm annual average; heavy snow in winter
- can have hot, drought conditions in summer
TEMP: <5 deg. C
-limiting growth factor
VEG: evergreen needle-leaf conifers
- low diversity
- soil is really acidic and nutrient poor due to cold temperatures and needle leaf drops
Describe the geographic distribution, annual temperature, annual rainfall, and dominant vegetation of TUNDRA
LATITUDE: >60 deg N and S and high alpine (where there is permafrost)
PPT: <600mm annual average; mostly falls as snow
TEMP: <5 deg. C
- limiting
VEG: dwarf woody shrubs and lichen (no trees)
