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 Hot Tropical Temperate Subpolar Polar 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

General Biome Types 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 ‘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

Tropical deciduous forest Global air circulation affects local precipitation 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 A combination of insolation and precipitation determines global biome distribution

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

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 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

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

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 http://www.lmrcc.org/ARMP%20folio.pdf

Net Primary Production (measure of available energy) 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)

Where Are We? Ponchartrain Atchafalaya N Barataria Terrebonne

Terrestrial Vegetation Growth During Low Water Nutrients Released During High Water

More Nutrients = More Plants = More Animals Simply put: More Nutrients = More Plants = More Animals = Happy Cajuns!! Inundation of the floodplain is the mechanism of energy and nutrient transfer from terrestrial vegetation to the aquatic community.

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

Barataria-Terrebonne National Estuary 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

Mean Surface Dissolved Oxygen in Open Water and Plants at Each Site Normoxic Hypoxic Green Brown Black

Atmospheric oxygen diffuses into water Air-Water Interface Atmospheric oxygen diffuses into water Fish ‘pipe’ at the microsurface layer Low DO Water

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

Terrestrial leaf litter/detritus input during Flood Pulse Detritus Based Food Web. From Cole 1988, Waveland Press

Major Ocean Currents Effect on Climate Insolation (and associated effects), the Earth’s rotation, plus difference in water density, create warm and cool currents.

Ocean currents can affect local climate

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 4 – 6 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 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)