1. Terrestrial Biomes

2. Global Air Circulation & Regional Climates
Uneven heating of the Earth’s Surface
Air is more heated at the equator and less at the poles.

3. Global Air Circulation & Regional Climates
Seasonal changes in temperature and precipitation

4. Insolation B A C

5. Solar Energy

6. Seasonal shift in rainy/dry seasons
Rainy Season
Seasonal shift in rainy/dry seasons

7. Global Air Circulation & Regional Climates
Properties of air and water.
Cell 3 South
Cold,
dry air
falls
Moist air rises — rain
Cell 2 South
Cool, dry
air falls
Cell 1 South
Moist
air rises,
cools, and
releases
moisture
as rain
Cell 1 North
Cell 2 North
Cell 3 North
Cold, dry
Polar cap
Arctic tundra
60°
30° 0°
Evergreen
coniferous forest
Temperate deciduous
forest and grassland
Desert
Tropical deciduous
forest
Equator
Tropical
rain forest
Tropical deciduous forest

8. Terrestrial Biomes of the World
Biome – a large geographical region having a defining climate to which plants show a similar physiological adaptation.
Tundra
Boreal Forest
Temperate Forest
Prairies and Grasslands
Chaparral
Desert
Tropical Forest
Tropical Mountains

9. Temperature and precipitation regulate plant growth, thus the regional distribution of biomes.

10. Global Distribution of Terrestrial Biomes
Global Net Primary Productivity For Terrestrial Biomes

11. Net Primary Production of Terrestrial Biomes
NPP (g C/m2/yr)
Tropical Rain Forest
900
Tropical Dry Forest
675
Temperate Evergreen Forest
585
Temperate Deciduous Forest
540
Boreal Forest
360
Tropical Grasslands
315
Cultivated land (USA)
290
Chaparral
270
Prairie
225
Tundra
Desert 32
Extreme Desert
1.5

12. Tundra
Windswept expanses where nothing stands taller than grasses and sedges.
Average temperature is -5°C.
Water is held as ice for most of the year; growing season is from May to August
Plant growth is inhibited
Decomposition and nutrient cycling is very slow; soils are rich in organic matter
Each year, only the top meter defrosts, below that the ground remains frozen year round - Permafrost

13. Tundra The organic rich soil in the tundra called peat.
Due to the short growing season, all growth and reproduction must happen in a short period.
Young shoots are thus loaded with nutrients
Makes good grazing
Food is so abundant at this time that wading birds, ducks, geese and swans commonly migrate to the tundra; herds of caribou and reindeer arrive and support biting flies, midges, and mosquitoes.
Insects spend the winter as eggs, larvae or pupae.
Birds usually feast on the abundant newly-hatched insects

14. Tundra
Although there are a lot of individual birds, mammals, and insects, there are not many types of species.
Few plant species have evolved to withstand the harsh tundra climate.
Tundra has a low species diversity (# of species)
Naturally low diversity does not mean unimportant.
Tundra is essential to the well-being of animals such as ducks, geese, seals, polar bears, and caribou
Recovery from disturbance takes a long time
Tracks from vehicles are visible for several months

15. Tundra

16. Boreal Forest Great fir forest of Canada and northern Eurasia.
Vegetation type is defined by seasonal expansion and contraction of the Arctic and continental polar air masses.
Polar air in the winter, continental air in the summer
Very cold winters, relatively warm summers so trees can survive

18. Boreal Forest Many trees look like Christmas trees, not oak trees
Shape of tree is related to the ability to shed snow
Broken trees are not good competitors
Leaf morphology is important
Needles are more durable, can photosynthesize year round
conserve heat more efficiently
Boreal forests are low in species diversity, but not as low as tundra

19. Boreal Forest

20. Temperate Forest
Can be divide into evergreen and deciduous forest types.
Generally have a moist cool climate.
Sometimes referred to as temperate rain forests
Contain giant redwoods and Douglas fir
Redwoods can reach 120 m (~360 ft) in height.
High-quality wood makes these forests a valuable timber resource
Old Growth Forest

21. Temperate Forest (Deciduous)
Hot summers, cool winters (minimum temp rarely < -12C).
Rain is plentiful (75 – 200 cm / yr), long growing season, fertile soil, moderate diversity.
Species include oak, beech and maple.
Produce a new batch of leaves each year
Not as expensive as ‘freeze-proofing’ them
Early spring, a lot of light hits the forest floor and spring ephemerals take advantage of this.
Soils make good farmland and supports good lumber

23. Prairies and Grasslands
Climatically similar to temperate forests but are dryer.
Precipitation ranges from a low 40 mm (plants seldom grow taller than 0.5m) to a high of 80 cm (plants can grow more than 2 m – tall grass prairie).
Home to numerous herbivores
Grazing is an important ecological factor in these areas
Heat and aridity become important evolutionary factors
Panting, sweating, large ears, evapotranspiration

24. Prairies and Grasslands
Native grazers prevented any single plant from out competing the others.
Introduced domestic grazers (cattle or sheep for example) have different grazing patterns and the floristic composition has been resorted.
Soils are very rich – America’s bread basket.
Fire is an important component of grasslands.
Some areas may burn every three to five years (lightning)
Keeps trees from becoming established
Stopping these fires can alter the community, allowing trees to grow.

26. Chaparral The summer drought is what drives this biomes ecology
Wet and mild winter climate, dry and mild summer
Found in coastal California, Israel, parts of South America and Australia
Mediterranean climate
The summer drought is what drives this biomes ecology
Plants either limit the water they lose, or gain as much water as possible

27. Chaparral Plants can gain as much water as possible
Plants can limit water loss by producing small hard green leaves
Hardness due to a waxy outer covering used to prevent water loss
Most of these plants are evergreen, so they can photosynthesize during the wet part of the year
By retaining leaves year round – they are able to take advantage of all rainfall
Plants can gain as much water as possible
Deep tap roots
Extensive root system (bare ground between plants)

28. Chaparral
Eradication of top predators when these areas are settled leads to a proliferation of herbivores.
Sometimes, native herbivores have been replaced with goats
Goats are indiscriminate browsers and kill many of the plants they eat
Overgrazing has reduced many Mediterranean hillsides to bare rock with very few patches of vegetation
Urbanization in California

29. Chaparral

30. Desert
Dry air descends usually at Latitudes 20 – 30 North and 20 – 30 South.
Too dry to support most life forms
Cloudless skies permit wide temperature fluctuations
50 C during the day, near 0 C at night.
Desert plants and animals must be obsessive about water retention

31. Desert
Rainshadow

32. Desert
Desert animals usually hide from the full strength sun and come out when the temp is lower.
Top predators are usually snakes and lizards – need less water than mammals
Camels have a highly developed nasal structure that prevents water loss and its hair is efficient at reflecting the sun’s heat.
Desert plants can not escape the sun.
Evolution has shaped them to minimize exposure to the sun

33. Desert

34. Desert
Desert plants are also designed to retain as much water as possible.
Stem and leaves appear to be thick and fleshy, skin very leathery.
Needles create microclimate in still air.
Extensive root network; leaves are recycled

35. Desert

36. Tropical Forest Key feature is constant temperature
Average temperature from one month to the other is usually within ± 2C
However, daytime temp may be 34 C during the day and 20 C at night.
Much rain: annual rainfall ranges from 2,000 mm to 15,000 mm (79 – 591 inches; 1.6 inches per day).
Wet and dry seasons
Length of dry season determines the areas ecology

37. Tropical Forest Long Dry Season Short Dry Season
Dry season = 6-8 months
Many trees drop their leaves during the dry season not to escape cold, but to prevent overheating
Short Dry Season
Dry season < 3 months
Tropical rain forest: 2,300 – 5,000 mm of rain per year (extreme years some places may get 15,000 mm = 50 feet).

38. Tropical Forest (Rain)
Huge diversity
Perhaps % of all organisms on Earth inhabit theses forests.
Temperate forest may have tree species per hectare (2.47 acres); rain forests can support more than 350 – 450 tree species per hectare
To fit that many tress each species may only be represented once or twice
Most productive terrestrial biome
High temp, moisture, uninterrupted growing season
Decomposers / nutrient cycling

39. Tropical Rain Forest

40. Tropical Mountains
Go from tropical forest to shrubs to ice as you move up in altitude.
Similar phenomena seen as you move from the equator north

41. Tropical Mountain

42. Temperate Deciduous Forest Northern Coniferous Forest Arctic Tundra
Alpine
Tundra
Tropical
Forest
Tropical Forest
Temperate Deciduous Forest
Northern Coniferous Forest
Arctic Tundra
Low
High
Moisture Availability
Elevation

43. Tropical Mountains

44. Aquatic Biomes

45. Aquatic Biomes Marine Fresh Water Ocean Estuary
Rivers and Streams (Lotic)
Lakes and Ponds (Lentic)

46. Oceans
Continental Shelf – the portion of the continental plate that lies submerged under the ocean.
Usually has a gentle slope
Width can vary from a few to ten kilometers
Continental Slope – that area that drops from the continental shelf to the full depth of the ocean floor.

47. Oceans
Oceanic zone – any portion of the ocean beyond the continental shelf.
Neritic zone – section of ocean that lies over the continental shelf.
Littoral zone – shoreline between the high and low tide marks.

48. Oceans Photic Zone – area of water that sunlight penetrates
Aphotic zone – area of water that sunlight does not penetrate

49. Oceans
Thermocline – vertical area where temperature abruptly changes; restricts the mixing of upper and lower water masses.

50. Oceans Salinity averages 35 ppt (full strength sea water).
Due to high concentrations of sodium and chloride
Ocean is more than salt and water, but most ocean waters are very poor in nutrients
Phosphate, nitrate, ammonium, iron
Oceans cover ~71% of Earth, but only account for 50% of the Earth’s primary production.
Biological deserts not limited by water, but by nutrients
Unlike terrestrial biomes, production is not higher at equator and lower at the tropics –respond to nutrient concentrations like upwellings.

51. Oceans
Coastal regions are much more productive than non-coastal areas.
Rich nutrient input from coastal rivers
Most of the worlds great fisheries come from the continental shelf
Too many nutrients can lead to algal blooms, which may deoxygenate the water (eutrophication)

52. Some Fish Life History
Anadromous – fish that spend their adult life in salt water but spawn in freshwater
Salmon, striped bass, American shad
Catadromous – fish that spend their adult life in freshwater but spawn in saltwater
American eel

53. Sargasso Sea

54. Ocean Benthic Zone Benthic zone is the ocean bottom
a thick blanket of mud that consists of fine particles that have settled from the overlying water and accumulated over millions of years.
Scientists originally thought that life could not exist in the benthic zone.
Too much pressure, too dark, too cold, lack of food
We now know that there is a lot of life down there.

55. Chemoautotrophic Organisms
Photosynthetic organisms are labeled as autotrophs, specifically phototrophs.
Organisms that are able to harvest energy from inorganic compounds without photosynthesis are called chemoautotrophs.
Usually sulfur-oxidizing (harvesting energy rich electrons from sulfur compounds) organisms

56. Chemosynthetic Communities
Organisms use organic material seeping from the ocean floor as an energy source
Colorful crab perched on top of a large tubeworm cluster at GC 354, depth 532 m. This community was first discovered on this MMS/LSU subdive, August 24, 2000

57. Symbiotic Relationships
Consumer organisms found in chemosynthetic communities rely on a symbiotic relationship with chemoautotrophic bacteria.
Consumer organisms must take up inorganic carbon (CO2) and sulfides and get rid of the bacterial waste.
The bacteria are able to capture energy (oxidize) from the sulfides to reduce carbon dioxide (primary production).
Consumers then absorb nutrients from the bacteria!
Consumer organisms do not have a mouth or gut!

58. Estuaries Where the river meets the sea Most productive biome on Earth
Sometimes classified freshwater, sometimes classified marine
Most productive biome on Earth
Support a diverse fauna including a variety of worms, oysters, crabs, and waterfowl.
Serve as nursery habitat for many organisms.

59. Marsh Types Fresh water marsh salinity < 1.0 ppt.
Plants are not salt tolerant and include maidencane, bulltongue, alligatorweed, cattails, and spikerush
Intermediate marsh salinity averages 3.3 ppt.
Plants are slightly salt tolerant and include spikerush, three-corner grass, arrowhead, cordgrass, wiregrass, roseau cane, and deer pea
Brackish marsh salinity averages about 8 ppt.
typically dominated by cordgrass or wiregrass
Salt marsh salinity averages about 16 ppt.
oyster grass is common, but few other plant species can survive

60. Freshwater Marsh Brackish Marsh Intermediate Marsh Salt Marsh

61. Rivers and Streams
Generally represent the excess of precipitation on land areas over evaporation from them.
Precipitation that falls is either evaporated, transpirated, enters the ground water supply, or flows down rivers
Flow is down-hill and varies seasonally
Related to rainfall and ice/snow melt
Beginning of a river = the source and the end of a river = the mouth
Discharge - volume of water passing a given point during a period of time
Channel Width X Depth X Velocity

62. Rivers and Streams
Flow velocity is important in determining abiotic and biotic components.
Flow related to slope and precipitation
Sediment type, current strength
Only certain organisms can withstand strong flow
The faster the flow, the more material can be transported in the water
Materials are transported by running water in three principal states
Dissolved matter
Suspended solids
Bed load

63. Stream Order
Used to classify a stream in relation to tributaries, drainage area, total length, and age of water. 1 2 3
Stream Order – Strahler Method
1  1 = 2
1  2 = 2
2  2 = 3
1  3 = 3
2  3 = 3
3  3 = 4
Mississippi River is classified as a 10th or 12th order stream.
Headwater stream classification matters

65. Major Rivers of The World
Name
Discharge 103 m3/sec
Length 103 km
Drainage Area 106 km2
Amazon, South America
212.40
6.44
5.78
Congo, Africa
39.65
4.70
4.01
Ganges-Brahmaputra, India
38.50
2.90
1.62
Yangtze, China
21.81
5.98
1.94
Yenisei, Russia
17.39
5.54
2.59
Mississippi North, America
17.30
6.02
3.22
Mekong, Asia
11.04
4.00
0.80
Nile, Africa
3.10
6.65
3.35

67. Mississippi River (Main Stem) Atchafalaya River (Distributary)
Distributary – A smaller channel that takes water away from the main stem river.
Mississippi River (Main Stem)
Atchafalaya River (Distributary)
Flow

68. River Channel
Deep Holes
Sand Bars

69. Oxbow Formation

70. Lakes and Ponds Ponds – light can reach the entire bottom
Lakes – light can not reach some parts of the bottom

71. Dissolved O2 concentration
Lake Overturn
Epilimnion
Hypolimnion
Thermocline
Summer
Fall overturn
22˚
20˚
18˚ 8˚ 6˚ 5˚
4˚C 0˚ 2˚ 4˚
Winter
Spring overturn
Dissolved O2 concentration
High
Medium
Low