Chapter 4 - Climate and the world's biomes (CHAPTER + SLIDES) Flashcards
slides notes are included!!
The world’s climate
the earth’s surface would still be different even if the climate is the same all over
- the geography of the earths life is due to the climate
What controlls the climate?
Differential heating by sunlight AND the interaction of the atmosphere with the oceans & mountain ranges
=> the ridistribution of heat is done through aatmospheric movement.
Spinning of the earth impact on air motion
Coriolis effect: winds tend to go east and west
Rising and falling of air masses cause precipitation
Seasonality by the earths’s tilt is a complication within the model
Large scale climatic patterns are influenced by
1) Indecent sunlight at different latitudes
2) Atmospheric circulation
3) Ocean currents
4) Land topography.
Rain shadows
Mountain ranges
- side hit by winds, cool down and then precipitate
- whereas the downwind side has dry air and so deserts form
Ocean currents redistribute heat
- The cold water becomes hot and then recircles
- it is driven by the wind and affected by the coriolis effect
- the ocean density plays a role in the pattern and the current strength of the heat redistirbution
Biomes
Characteristic regions with particular types of vegetation
Biomes are areas dominated by plants with characteristic shapes, forms and phyisology
There is a mosaic of bioms
Tropical rain forest
Most diverse in resources
- covers 12% of the earth
- covers 50% of all terrestrial biomass
- has a high rate of primary production (800g of carbon dioxide fixed per square metre per year)
- high solar radiation (therefore the seeds only sproud after the canopy forms above them)
- Dramatically high species richness with not many single dominating species in communities
Tropical canopy
All action happens in the canopy
- plant forms that reach up to the canopy vicarously by tree climbing
Epiphytes
plants that grow on other plants
Species richness
the number of species
Tropical rain forests during the ice age
- the drought caused them to become ‘islands’ in a ‘sea’ of just savanna.
- this lead to lots of genetic isolation and so speciateion occured.
- the ice would retreat and then come back
- this generated a lot of YUMMY diversity for herbivores and plants
Flower diversity in tropical rain forests
Is equivalent to the polliantor diveristy
- has intense biological activity in the soil
- soil has lots of nutrients
- the regeneration of the soil can take centuries
Savanna
- warm
- rains reliably only during part of the year
- covers 9% of all land area
- is a grassland with small, scattered trees
- has limited moistures
- has fires and the grazing that lead to not much growth bc no rain
- favors the protective regenerative surfaces of organisms
- theres a seasonal glut and shrotage of food
Temperate grasslands
- natural vegetation over large areas (not antartica)
- has both tall and short grass
- has moderate rainfall, the soilsa re rich
used to be 9% but now its only 5% of land due to agriculture. - large populations of invertebrates
- the majority of this land has been transformed by humans.
Desert
- the rain timing is unpredictable
- covers 10% of the earths surface
- has 2 life styles
- freezing temperatures at night so greates frost tolerance. (therefore drought tolerance = frost tolerance)
- very few perennials grow there
- some small ants and rodents eat seeds
- the birds are nomadic and are driven by the need to find water
Desert oppotuinsitc life style
stiumlated gemination by the unpredictable rian timing.
- therefore those that do germinate grow fast and complete their life cycles after just a few weeks.
Desert long lived sluggish phisiological lifestyle
CAM photosynthesis, thick waxy cuticle, short leaves
- cacti and succulents
Temperate forest
- Varying altitudes
- 8% of terrestrial biosphere, mainly deciduoud
- patchiness is due to the tree deaths
- red oaks or sugar maple dominate them
- the vegetation provides foods for animals that are seasonal in occurance
- usually rich soils
- sometimes the soils become peat due to acidic waterlogging
- need for ecological succession process to recolonize agricultured lands
Low latitutes (temperate forests)
- full of evergreens
- winters are mild
- frosts and droughts are rare
- there are broad-leaved evergreen trees
Northern limits (temperate forest)
- Deciduous trees
- strong seasons
- short winter days
- six months of freezing temperatures
- deciduous trees, dormant after fall
Boreal Forests (Taiga)
- Coniferous. cold, short growing season
- 8% of land surface
- limitaed tree flora
- evergreen pines, birch, spruce (Further north)
- used to be an ice-sheet during the ice age.
- little vegitation which shows a slow recovery from the ice age
Permafrost
water in the soil frozen and now theres a permanent drought in taigas
Diversity in boreal forests (taiga)
Low diversity
- hence a greater change of pest outbreak
- likely to have a low resistance
- takes a 40 year recovery
- major fires can occur periodically (every 75-100years) which reset the field for ecological succession
Tundra
North of the boreal forest
- freezing
- full of shrubs & grasses
- little flowering plants very few
- lichens and mossess
- 5% of all land surface
Aquatic ecosystems on the continents (like water on land)
- covers only 1% of land mass
- covers only 0.007% of the water on the planet
BUT are immensly important
Streams and Rivers
- manipulated by humans
- linear form (that makes a continuum)
- uniderctional flow
- fluctuating discharge
- unstable beds
- have a watershed
- oxygen concentration is higher in upstream areas
-> thats why active upstream fish need more oxygen - rivers tend to drain the landscape
Continuum
The idea that multiple rivers branch into one continous river
Watershed
“The land area where all the water draining from it comes to the particular stream or river—through groundwater flows, surface runoff, or both. “
if you have no clue what this means, because i didnt either i think its just like the area around the river that water can get caught in and flow towards the river when it rains and stuff
Vegetation of the watershed
- impacts the stream of water
- if there are trees on the shed then there will be less algea in the water because it is too shaded
- there usually is lots of organic mater from the forest that some specialized organisms eat
- there are riperian trees that have specifically adapted to grow along the stream with all that water and nutrients
Floodplan
the water that flows onto the nearby land
Lakes and ponds
- Stationary water
- ponds are shallow therefore they tend to have rooted plants nearby as primary producers.
- Lakes tend to be deeper and therefore they will have some phytoplankton as primary producers
Stratification
the formation of separate vertical water layers that differ in themperature or/and salinity
- in the tropics stratification tends to be permanent
- elsewhere where there is seasonal change it fluctuates a lot
Stratification via temperature
Ice tends to be insulating
- Warm water is less dense than cold so it goes up
- this water becomes heavily oxygenated.
- 4°C is when water is at its greatest density
Summer lakes
The warm water on top
- there is a “thermocline zone” which is where it suddenly turns cold
- here theres little light, no photosynthesis and is depleted of oxygen
Spring & Fall lakes
there is heavily mixed stratification
Winter lakes
The temperate water (also known as surface water) is the coldest area.
Grasslands and Savanna lakes
in grasslands and savanna the water is usually only depleted through evaporation means, this means that the lakes can get very salty and fertile
Wetlands
The intermediate between land and water
- is full of waterlogged soil
- has the highest plant production
(because it is high in water and nutrients. there is a limit in bogs though because they’re acidic.)
- there is limited oxygen in water so slower diffusion rates
- which means that the oxygen supply is rapidly depleted by the microbial decomposition happening in the mud
- denitrification in anaerobic conditions!!! occurs
Wetland classification
- is classified by dominant vegetation
–> Swamps are dominated by trees
–> Marshes/fens are dominated by grasses/sedges
–> Bogs are dominated by Sphagum genus mosses (which are quite acidic)
Photic Zone
surface layer where light penetrates
Ocean Biomes
- 70% of all earth area
- 97% of all water
- 4 km deep to 11km at deepest
- 1/2 rate of primary production than on land
The deep ocean
-96% of all water in oceans is below the photic zone
- there is lots of dead organic matter which becomes food for what can live there
- therefore theres lots of co2 produced
- it is strongly stratified
- full of tiny invertebrates
- near hot vents you can find hydrogen sulfide areas which provide the energy for chemoautotrophic bacteria which break it down
–> there bacteria are usually symbionts.
Subtropical Gyres
5 Gyers only.
- Cover 35% of planet surface
- they are large massess of semi isolated surface water surrounded by a circular current of water
- 2 Gyres in the northern hemisphere Move clockwise
- 3 Gyres in the southern hemisphere move counterclockwise
- they have low rates of primary production therefore there is no obstructing algea so theres lots of light penetration.
- low in nutrients
- full of small phytoplankton not many fish
- HIGH ASF biodiversity because of how much it is plankton-dominated
- still have no clue why its so plankton dominated
Coastal Upwelling Systems
- Basically the area of water that moves up from the photic zone near the sandy land and then outwards into the sea (like when you go to a beach but not really because not a beach)
- so all the rich nutrients from deep water move up into these streams
- creates good area for primary production so high rates of that
- caused by strong prevailing winds and the coriolis effect.
- replensih nutrients due to moving water.
- low biodiversity, but highly rich in nutrients
- also largely dominated by phytoplankton (short food webs)
Broad continental shelves
- 80km away from shore
- 150m in depth so very surface
- HIGH primary productivity and nutrients that come from the rivers.
- there is a stratified water column in the summer.
- it has a shallow photic zone
- phytoplankton die in the bottom of the water, which creates an anaerobic dead zone in the summer that no fish can live in.
- the deep sea also provides nutrients to these continental shelves
- are largely phytoplankton dominated (short food webs)
- have low biodiveristy but are highly nutient rich.
Nearshore costal marine ecosystems
- they lie on a costal fringe
3 types:
- intertidal zone
- near-shore submerged littorial zone
- estuaries
- is a nursery fround for fish and invertibrates
- tend to be beautiful and provide lots of habitats
Intertidal zone
- submerged at a high tide but are air fills them up at low tide
2 types:
Rocky Shores
- full of anemones, barnacles, mussels on the rocks
- limpets and snails and microalgae
- rocks act as holdfasts for kelps
Shallow slopping shores
- Mollusks and polychaete worms
- have waterfilters
Submerged littorial zone
- Permanently submerged
- light goes all the way to the bottom so there are rooted photosynthetic producers such as the giant kelp
- there is high diversity of sea grasses
- global warming causes the bleaching of corals here
Estuaries
- Salty, semi-enclosed water bodies
- they exchange water with open costal waters (its where the river meets the sea)
Many types but heres one example:
Salt-wedge estuary
- dense salty water from the ocean travels bottom up
- freshwater from the river travels downstream over the salt water
- creates lots of specialized fauna
- there is low oxygen levels in the bottom of the water because of the high salinity, this creates a salinity type of stratification.
