Chapter 20

Terrestrial Biomes & Aquatic Ecosystems

Section 1 Objectives:

Distinguish between abiotic factors and biotic factors in biomes.

Identify seven land biomes on Earth.

LARGE ECOSYSTEMSHuman-classified divisions

Same types of climates = similar types of vegetationSimilar vegetation = similar biome≠ exact same flora, fauna, or physical abiotic makeup

Terrestrial Ecosystems or Biomes10 Types

Aquatic Ecosystems3 types

TERRESTRIAL BIOMES

Terrestrial BiomesLarge area characterized by its climate and the plants and animals that live in the area – contains related ecosystems.

Tundra ChaparralPolar Ice Temperate GrasslandTaiga/Coniferous Forests SavannaMountainous regions DesertTemperate Deciduous Forest Tropical Rainforest

Tundra

Tundra (Polar and Alpine)

Tundra = “treeless plain”Flat terrain with low shrubs, grasses, sedge, mosses, lichens; low biodiversity

One-fourth of Earth’s terrestrial surfacePresent in northernmost latitudes (≥ 60° N)Desert-like rainfall (30-50 cm or 12-20 in per year) but bogs and marshes in summer rainy season due to permafrost

Tundra (cont’d)

Permafrost – condition of permanent frozen soil beginning ~ 1 meter (m) below surface and extending down to 500 m

Water can not drain

Plants produce in short 50-day seasonYear-round: Arctic lemmings, hares, foxesSummer migratory animals seeking foodNo reptiles or amphibians

Taiga

TaigaAlso known as the Boreal or northern forests – covered with coniferous trees such as firs, pines, spruces, and cedars (dominant vegetation) – located south of tundraLargest biome on Earth; low biodiversityWinters: very cold and snowySummers: warm, rainy, and humidLarge mammals, fur-bearing animalsVery few reptiles and amphibians

Temperate Deciduous Forest

Temperate Deciduous Forest

Majority of eastern US, as well as continental western Europe and east AsiaDeciduous trees (with seasonal leaf loss) including maples, beeches, oaks, and hickories, as well as understory of woody shrubs and vines and herbaceous plantsMuch precipitation (75 to 200 cm /yr) (3-8x that of tundra)Milder winters, warm to hot summersGreat variety of animals, including reptiles and amphibians

Temp. Deciduous Forest (cont’d)

Abundance of pines (evergreens) in the SE US is only temporary“Succession” – as ecosystem “ages,” new flora species replace previous ones (e.g., grass to low shrubs and vines to evergreens to hardwoods); as flora change so will faunaHere, climax successional stage is oak/hickory forest

Temperate Grassland

Temperate Grassland

Areas of predominantly tall, mixed, or short grasses sandwiched between temperate deciduous forests and desertsAnnual precipitation of 25-100 cmExtremely fertile soil (US Midwest farms)Natural grasslands destroyed for agriculture; very little left in worldShort grass prairie – crops and cattle

Savanna

Subtype of grassland: tropical grassland in Southern Hemisphere (Africa, South America, and Australia)

Seasonal drought, warm climate, dotted with stands of trees, and home to typical large mammals (e.g. in Africa, elephants, giraffes, zebras, lions, spring boks, cape buffalo, etc.)

Desert

Desert: “Got Water?”Desert – area receiving < 25 cm annual precipitation; evaporation > precipitationDeserts may be cold, temperate, or hotFlora and fauna specialized to survive with little water – collect and conserveSoils poor because lack of water = very little biomass, or net productivity, low organics = inability to hold water Concentration of inorganic salts high

Tropical Rainforest

Tropical Rainforest

Large warm equatorial areas, abundant annual precipitation (200-450 cm and even to 1000 cm for some) with high biomass productivity and biodiversity7% of Earth’s land mass under massive destruction; can not be replacedPoor, acidic soil: plants uptake quickly-decomposed organic nutrients

Polar Ice and Mountains

Polar Regions:Cold, dry, devoid of terrestrial plant lifeAnimals capable of living in frigid conditions and basis of survival on highly productive marine ecosystem

Mountains:Increase in altitude similar to northern latitudes (cooler climate and conifers)Rain shadow on lee side (desert area)

ChaparralNot a grassland

Punctuated with low-growing evergreen shrubs, pines, and scrub oaks

Lands on Western coast lines with Mediterranean type climate (wet mild winter/ hot dry summer, ocean winds)

Biome Ecological ConcernsTundra/Taiga– ore mining, oil drilling, ecosystem fragmentation, global warming/species changesTemperate Deciduous Forests – human destruction for resources and population Temperate Grasslands – very little remaining, non-native grass species; agricultureDeserts – In US, human encroachmentTropical Rain Forests - human destruction for resources and population; expansive loss of species, biomass net productivity

Section 2 Objectives:

List three abiotic factors that shape marine ecosystems.

Describe four major ocean zones.

Describe five marine ecosystems.

Aquatic EcosystemsMarine

Intertidal AreasCoral ReefsEstuaries – fresh water from streams and rivers spills into oceansSargasso Sea (middle of Atlantic Ocean – floating rafts of algae called sargassum)Polar Ice – Arctic Ocean and ocean around Antarctica

FreshwaterStream and River; Pond and Lake

WetlandMarshes and Swamps

Marine EcosystemsPhotic zone = surface to 100 m down; photosynthesis occurs

Saltwater oceans cover ¾ of Earth’s surface.

Marine Ecosystems, cont.• Intertidal Zone: the place where the ocean meets the land; area is exposed to the air for part of the day; sea grasses, periwinkle snails, and herons are common in intertidal mudflat; sea stars and anemones live on rocky shores; clams, crabs, snails, and conchs are common on sandy beaches

•Neritic Zone: Ocean floor starts to slope downward as you move away from shore; water is warm and receives a lot of sunlight; plankton and seaweeds common; sea turtles, dolphins, corals, sponges, and colorful fishes dominate – CORAL REEFS!

Marine Ecosystems, cont.

•Oceanic Zone: Sea floor drops sharply; contains deep water of open ocean; many unusual animals are adapted to this zone, such as whales, squids, fishes that glow, sharks, etc.

•Benthic Zone: Ocean floor; deepest parts do not get any sunlight and are very cold; animals, such as fishes, worms, sea urchins, and crabs, have special adaptations to the deep, dark water

Marine EcosystemESTUARY -

Coastal point of contact between freshwater and saltwater; mix = “brackish” waterConstant mixing stirs up nutrients for photosynthesizers; animal life abundantAs productive as tropical rainforests and coral reefsConcerns:

Although protected, human pollution and encroachment threaten health of estuaries

Marine cont’dAbundance of life is generally greater:

Nearer coast (intertidal zone) due to stirring action of waves and nearer surface from light

In polar regions rather than tropical regions

(abundant food – plankton - for large organisms)

In tropical coral reefs along shallow coastlines

Marine cont’d

Ecological Concerns:Overfishing and industrial fishing techniques that destroy deep water habitats

Human pollution of the coastal waters (sewage, construction erosion, chemical use, etc.)

Human physical destruction of sensitive ecosystems such as coral reefs, tidal pools

Section 3 Objectives:

Describe one abiotic factor that affects freshwater ecosystems.

Describe the three zones of a lake.

Describe two wetland ecosystems.

Explain how a lake becomes a forest.

Freshwater Ecosystems

Inland freshwater streams, ponds, and lakes cover 2.1% of Earth’s surface.

Freshwater EcosystemsLittoral Zone - area of water closest to edge of lake or pond; cattails, rushes, algae, water lilies; small animals, snails, insects, clams, worms, frogs, salamanders, turtles, fish, and snakes

Open-Water Zone – the zone of a pond or lake that extends from the littoral zone and that is only as deep as light can reach – bass, lake trout, and other fishes

Deep-Water Zone – the zone of a lake or pond below the open-water zone, where no light reaches – carp, catfish, worms, crustaceans, fungi, and bacteria

Freshwater cont’d

Natural lake nutrient concentrations (phosphorus often is limiting factor)

Shallow, nutrient rich = eutrophic• Abundant aquatic photosynthesis and animals

(cloudy, murky water)• Occurs naturally over long periods of time

Deeper, nutrient poor = oligotrophic• Few nutrients to aid photosynthesis, little animal life

(clear water)

Freshwater ConcernsArtificial eutrophication of lakes: nutrient rich sewage, fertilizers, construction erosion, etc. feed algae

Algal bloom leads to accumulation of dead algae; decomposition by oxygen-using bacteria; fish kills

Clean Water Act has helped, but battle not over (Pollutants regulated under the CWA include "priority" pollutants, including various toxic pollutants; "conventional" pollutants, such as biochemical oxygen demand (BOD), total suspended solids (TSS), fecal coliform, oil and grease, and pH; and "non-conventional" pollutants, including any pollutant not identified as either conventional or priority. The CWA regulates both direct and indirect discharges. )

WetlandLand remaining wet for at least part of the year (bog, marsh, swamp, tidal marshes) and very productiveMost are inland, freshwaterSoils and plants can capture pollutants, act as wastewater system and clean upPlay important role in flood controlConcerns:

Federal protection requires restoration, but many destroyedLoss of migratory bird habitat

Marshes and SwampsMarshes

Treeless wetland ecosystem where plants grow; found in shallow areas along shores of lakes, ponds, rivers, and streams; grasses, reeds, bulrushes, wild rice, muskrats, turtles, frogs, and birds dominate

SwampsWetland ecosystem in which trees and vines grow; found in low-lying areas and beside slow-moving rivers; flooded part of the year; willows, bald cypresses, oaks, poison ivy, water lilies, orchids, fish, snakes, and birds dominate