Post on 11-Jan-2016
transcript
Biomes
Weather - particular set of physical properties of the Earth’s troposphere:
–Temperature, pressure, humidity, precipitation, sunshine, cloud cover, wind direction and speed
Climate – a region’s general pattern of atmospheric or weather conditions, including seasonal variations and weather extremes over a long period.
Biome – a large geographical region having a defining climate to which plants show a similar physiological adaptation.
Four Global Temperature Regimes
• Tropical
• Temperate
• Subpolar
• Polar
Hot
Cold
Four Plant Types
• Succulent – vertical orientation on most parts, no leaves, store water, photosynthesis in tissue– Cactus
• Broadleaf Evergreen – keep most of their broad leaves year-round– Tropical trees
• Broadleaf Deciduous – drop their leaves when it gets cold (dry in the tropics) – Oak, maple, pecan
• Coniferous (cone-bearing) Evergreen Plants – keep their narrow pointed leaves (needles) all year– Pine, spruce, fir
• Forest – dominated by trees– A lot of precipitation needed
• Scrubland – small deciduous trees and shrubs– Some precipitation needed
• Grassland – dominated by grasses– Does not need as much precipitation as a forest– Usually needs disturbance to limit tree growth
• Grazing, fire
• Desert – dominated by succulents– Very little precipitation
General Biome Types
‘For plants, precipitation generally is the limiting factor that determines whether a land area is desert, grassland, or forest.’
Temperature and precipitation regulate plant growth, thus the regional distribution of biomes.
Boundary lines between biomes are not as distinct as implied here.
Tropical, Temperate, or polar – Depends on Temperature
Forest, Grassland, or Desert – Depends on Rainfall
Cell 3 South
Cold,dry air falls
Moist air rises — rain
Cell 2 South
Cool, dryair falls
Cell 1 South
Moistair rises,cools, andreleasesmoistureas rain
Cell 1 North
Cool, dryair falls
Cell 2 North
Moist air rises — rain
Cell 3 NorthCold, dryair falls
Polar cap
Arctic tundra
60°
30°
0°
30°
60°
Polar cap
Evergreenconiferous forest
Temperate deciduousforest and grassland
DesertTropical deciduous
forest
EquatorTropical rain forest
Tropical deciduous forest
DesertTemperate deciduousforest and grassland
Global air circulation affects local precipitation
A combination of insolation and precipitation determines global biome distribution
Biome 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 225
Desert 32
Extreme Desert 1.5
Net Primary Production of Terrestrial Biomes
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
Rivers and Streams• Flow velocity is important in determining
abiotic and biotic components.– Flow related to slope and precipitation– Sediment type, current strength– The faster the flow, the more material can be
transported in the water– Only certain organisms can withstand strong
flow
• Materials are transported by running water in three principal states– Dissolved matter– Suspended solids– Bed load
Stream Order
11
11
22 22
11
11 11
33 22
Stream Order – Strahler MethodStream Order – Strahler Method
Used to classify a stream in relation to tributaries, drainage area, total length, and age of water.
1 1 = 2
1 2 = 2
2 2 = 3
1 3 = 3
2 3 = 3
3 3 = 4Mississippi River is classified as a 10th or 12th order stream.
Headwater stream classification matters
Major Rivers of The World
NameDischarge 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, USSR 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
You will be required to draw a map of the major rivers of the Mississippi River Basin as part of exam 1.
Mississippi River (Main Stem)
Atchafalaya River (Distributary)
Flow
Distributary – A smaller channel that takes water away from the main stem river.
Large River Floodplain Ecology
Construction of levees along the Mississippi River and many of its tributaries has severed the river from over 90% of its floodplain, denying fish and other aquatic species access to millions of acres of foraging, spawning and nursery habitat.
Miss. Dept. of Archives and History
Miss. Dept. of Archives and History
http://www.lmrcc.org/ARMP%20folio.pdf
Estuaries
Swamps and marshes
Tropical rain forest
Temperate forest
Northern coniferous forest (taiga)
Savanna
Agricultural land
Woodland and shrubland
Temperate grassland
Lakes and streams
Continental shelf
Open ocean
Tundra (arctic and alpine)
Desert scrub
Extreme desert
800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600
Average net primary productivity (kcal/m2/yr)
Net Primary Production (measure of available energy)
N
Where Are We?
Barataria
Terrebonne
Ponchartrain
Atchafalaya
Terrestrial Vegetation Growth During Low Water
Nutrients Released During High Water
Simply put:
More Nutrients = More Plants = More Animals
Inundation of the floodplain is the mechanism of energy and nutrient transfer from terrestrial vegetation to the aquatic community.
= Happy Cajuns!!
Swamps are not wastelands!
The Floodplain Extends to the Coast
• All flowing Louisiana waterways eventually drain to the Gulf of Mexico
• Energy and nutrients from floodplain terrestrial vegetation are carried to coastal waters and sustain estuarine and coastal production
• The coast is ultimately supported by floodplain ecosystem processes
Baton Rouge
New Orleans
Thibodaux
Houma
Grand Isle
Port Sulphur
Three General Types of Water
• Brown– High flow, lots of sediment, fairly high oxygen
levels, riverine
• Green– Low flow, stratification, very high surface
oxygen levels, highly productive, lacustrine
• Black– Low flow, very low surface oxygen levels, not
productive, swamp
Backwater Interior Lakes Mainstem
December
June
August
Oxygen Level Controls
Photosynthesis produces oxygen:Solar Energy + CO2 + H20 C6H12O6 + O2
Respiration consumes oxygen:C6H12O6 + O2 CO2 + H20 + chemical energy(ATP)
What is Hypoxia
• Dissolved Oxygen (DO) less than 2.0 mg/L
• Normoxic = DO > 2.0 mg/L
• Generally, most fish can not tolerate hypoxic conditions for long periods.– Gar, bowfin (choupique), bullheads can
Why Hypoxia?• During low water times, the
dry lands are extremely fertile and grow a lot of plants.
• When the spring floods come and temperatures rise, bacteria begin to decompose the vegetation on the floodplain floor.
• Bacterial respiration is what removes the oxygen (lack of flushing in backwater habitats contributes).
• Respiration rates exceed photosynthetic rates.
When and Where Is Hypoxia?
• Generally found during high water times when temperatures are warm.
• Backwater areas (away from the mainstem river).– Low flow
Eventually the swamp drains and backwater areas become very productive.
How Do ‘Unproductive’ Areas Support Living Populations?
• Submerged Aquatic Vegetation– Oxygen Refuge– Productive microhabitats
Fish and Aquatic Vegetation
• Densities of young fish are often greater in aquatic vegetation than in adjacent open water
0
2
4
6
8
10
12
14
16
GLN GLS INT FL BL SOC
Dis
solv
ed O
xyg
en (
mg
/L)
Open
Plant
Normoxic Hypoxic
Mean Surface Dissolved Oxygen in Open Water and Plants at Each Site
Green
Brown Black
Air-Water Interface
Low DO Water
Atmospheric oxygen diffuses into water
Fish ‘pipe’ at the microsurface layer
How Do ‘Unproductive’ Areas Support Living Populations?
• Detritus-Based Production– Decomposers (e.g., bacteria) transfer energy
stored in old organic matter to consumers• Insects, crawfish
– Low-oxygen tolerant organisms• Gar, bowfin (choupique), bullheads
Energy flow through an aquatic ecosystem.
From Cole 1988, Waveland Press
Detritus Based Food Web.
From Cole 1988, Waveland Press
Terrestrial leaf litter/detritus input during Flood Pulse
Major Ocean Currents Effect on Climate• Insolation (and associated effects), the
Earth’s rotation, plus difference in water density, create warm and cool currents.
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)
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.
Upwelling Productivity
Global estimates of the primary production required to sustain fisheries in five marine ecosystems.
Production is highest in shallow well-lit coastal waters and upwellings.
Upwelling Productivity• Primary production dependent on nutrients
brought from the ocean depths.– This is a function of ocean currents driven by wind
pattern and the Earth’s rotation
• A disturbance to wind patterns can affect the primary production of upwellings, which can have an effect ‘up the food chain.’
Productivity
• Aquatic Productivity relies on nutrient input/cycling– Whether from terrestrial ecosystems or
upwellings
The River Continuum Concept
• Energy flows downstream– CPOM – course particulate organic matter
– FPOM – fine particulate organic matter
– UPOM – ultra-fine particulate organic matter
– DOM – dissolved organic matter
• Invertebrate Community Groups– Shredders – Feed on CPOM
– Collectors – Feed on FPOM and UPOM
– Grazers – Feed on algae/periphyton growth
– Predators – Feed on other invertebrates
1 – 3 order: P/R < 1.0–Energy rich allochthonous materials are entering the system
–Collectors, shredders
4 – 6 order: P/R > 1.0–More materials are produced by photosynthesis than are used by respiration
–Collectors, grazers
> 6 order: P/R < 1.0–Energy rich allochthonous materials are entering the system
–Collectors, predators
What did the fish say when it hit a brick wall?
Dam!
River Dam(n)s
• Block passage of migratory species– Anadromous, catadromous
• Reduce stream sediment load
• How can this affect ecosystems?– (Freeman 2003)
Spawning Migrations
• Salmon and trout bring marine derived nitrogen (MDN) upriver
• Important for offspring• Important source of nutrients for many
animals• How does a decrease in salmon and trout
(and other anadromous fishes) populations affect ecosystems– (Willson and Halupka 1995)
Salmon Carcass Replacement Program
• Program places harvested salmon carcasses in streams
• Could be placing PCB’s and other pollutants into the ecosystem– (Missildine 2005)