INTRO TO ENVIRONMENTAL SCIENCE: CHAPTER 6

Biome

A large, relatively, distinct terrestrial region with similar climate, soil, plants, and animals

May include more than one ecosystem

Tundra

Treeless, dominated by lichens and small plants; characterized by permafrost

Temperature-cold

Precipitation-dry

Growing season-short

Species richness-low

Primary productivity-low

Boreal forest

Dominated by coniferous trees

(e.g. pine, spruce, fir)

Temperature-cold

Precipitation- dry

Growing season- short

Species richness-low

Primary productivity-low

Temperate rainforests

Dominated by coniferous trees

Temperature- cool

Precipitation- high

Growing season-moderate

Species richness-moderate

Primary productivity-moderate

Temperate deciduous forest

dominated by deciduous trees

(i.e those that lose their leaves annually)

Temperature-moderate

Precipitation-moderate(more than temperate grassland)

Growing season-moderate

Species richness-moderate

Primary productivity-moderate

Chaparral

Dominated by small trees and evergreen shrubs

Temperature- moderate

Precipitation-dry

Growing season-moderate

Species richness-moderate

Primary productivity-moderate

Deserts

Dominated by drought-tolerant plants

Temperature-hot or cold

Precipitation-low

Growing season-Short

Species richness-low

Primary productivity-low

Tropical grassland

Dominated by grasses with widely scattered trees

Temperature-warm

Precipitation-moderate to low

Growing season-long

Species richness-moderate

Primary productivity-moderate

Tropical rainforest

Dominated by broad-leaved evergreen trees

Temperature-warm

Precipitation-high

Growing season-long

Species richness-high

Primary productivity-high

Similarity between change in latitude and change in elevation

Biomes change with increasing elevation in similar manner as with increasing latitude

because of decreasing temperature with increasing elevation

Lotic ecosystem

Rivers and streams

River continuum concept

Variation in abiotic and biotic structure from headwaters to mouth

Lentic ecosystem

Lakes and ponds

Characterize by zonation

Littoral zone

Shallow water near shore

Light penetrates

High oxygen content

High productivity

Limnetic zone

Open water away from shore

Light penetrates

High oxygen content

Moderate productivity

Profundal zone

Beneath limnetic zone

no light penetration

low or no oxygen content

low productivity

Thermal stratification in temperate lakes

Sunlight warms upper water during summer

bottom water remains cool throughout year

abrupt transition from warm to cool water is the thermocline

Seasonal turnover in temperate lakes

Fall turnover as cooling surface water sinks

Spring turnover as ice melt sinks

Mixing brings minerals to surface and oxygen to bottom

Marshes

Dominated by grasses

Swamps

Dominated by trees or shrubs

Estuary

coastal body of water, partly surrounded by land, where freshwater meets salt water

brackish water (salinity in-between freshwater and saltwater)

pronounced tidal cycle high productivity

Pelagic zone

open water of the ocean

divided into

neritic province

oceanic province

Neritic zone

overlies ocean floor from shoreline to depth of 200 m(continental shelf)

Benthic zone

ocean floor and associated substrate

shallow benthic environment includes

seagrass beds

kelp forests

coral reefs

Plankton

float in water column (phytoplankton and zooplankton)

Nekton

Actively swim in water column

Benthos

bottom-dwellers

Seagrass beds

Dominated by flowering plants

High light and oxygen content high productivity

Kelp forest

dominated by brown algae

high light and oxygen content and high productivity

Coral reefs

dominated by corals

coral (animals) live in mutualistic relationship with photosynthetic zooxanthellae (algae)

high productivity and species richness