TOPIC 2 - BIOMES

Biome

large geographical region characterized by specific climate conditions, plant life, and animal communities.

Ecosystem

smaller unit within a biome, consisting of living organisms interacting with each other and their physical environment.

biome

contains many ecosystems.

Terrestrial

Aquatic

two major types of biome

Terrestrial biomes

Biomes found on land

Temperature

Amount of rainfall

Altitude or elevation

Latitude

factors influencing the physical environment of terrestrial biome

Aquatic Biomes

biomes found in water, either freshwater or saltwater.

Salinity (or salt concentration)

Water depth

Sunlight penetration

Current or water flow

factors influencing the physical environment of aquatic biome

Tropical Rainforest

Tropical Savanna

Desert

Temperate Grassland

Temperate Forest

Northwestern Coniferous Forest

Boreal Forest (Taiga)

Tundra

Mountains

Earth's Major Land Biomes

sunlight

the main source of energy in land biomes and aquatic biomes (especially in shallow or surface waters)

Photosynthesis

Plants capture the energy of sunlight through _______.

True

[True or False] The amount of sunlight, along with seasonal changes, affects how much energy is available to living organisms.

chemosynthesis

In deep parts of the ocean where sunlight doesn't reach some organisms rely on ______________.

This means they get energy from chemicals, usually near hydrothermal vents on the ocean floor.

Tropical Rainforest

Warm and wet year-round; nutrient-poor, thin soil

Dense trees, epiphytes, monkeys, birds.

Flora/Fauna in Tropical Rainforest

Deforestation

biodiversity loss.

Human Impacts on Tropical rainforest

Tropical Savanna

Seasonal rainfall; clay-like, compact soil.

Grasses, acacia trees, lions, elephants

Flora/Fauna in Tropical Savanna

Overgrazing

farmland expansion

Human Impacts on Tropical Savanna

Desert

Low precipitation; sandy or rocky soil.

Cacti, succulents, reptiles, foxes

Flora/Fauna in desert

Water extraction

desertification

Human Impacts on Desert

Temperate Grassland

Moderate rainfall; fertile, deep soil.

Grasses, bison, prairie dogs.

Flora/Fauna in Temperate Grassland

Farming

soil erosion

Human Impacts on Temperate Grassland

Temperate Forest

Four seasons; rich, leaf-littered soil.

Oak, maple, deer, raccoons

Flora/Fauna in Temperate Forest

Urbanization

deforestation

Human Impacts on Temperate Forest

Northwestern Coniferous Forest

Mild and wet; acidic, nutrient-poor soil.

Douglas fir, mosses, bears, owls.

Flora/Fauna in Northwestern Coniferous Forest

Logging

habitat loss

Human Impacts on Northwestern Coniferous Forest

Boreal Forest (Taiga)

Cold winters; acidic, slow-decomposing soil.

Pines, moose, lynx, wolves.

Flora/Fauna in Boreal Forest (Taiga)

Logging

oil drilling

Human Impacts on Boreal Forest (Taiga)

Tundra

Cold, dry; permafrost layer.

Lichens, mosses, arctic foxes.

Flora/Fauna in Tundra

Melting permafrost

drilling

Human Impacts on Tundra

Mountains

Varies with altitude; rocky, shallow soil.

Alpine plants, mountain goats, eagles

Flora/Fauna in Mountains

Mining

tourism

Human Impacts on Mountains

Deforestation

Desertification

Pollution

Urban development

Human Impacts on Land Biomes

Freshwater biomes

Marine biomes

two basic regions of aquatic biomes

Freshwater biomes

have less than 1% salt and are typical of ponds and lakes, streams and rivers, and wetlands.

Marine biomes

have more salt and are characteristic of the oceans, coral reefs, and estuaries.

Photic Zone

where enough sunlight penetrates for photosynthesis to occur

Aphotic Zone

This is where too little sunlight penetrates for photosynthesis to occur.

True

[True or False] Water near the surface of lakes and the ocean usually has more dissolved oxygen than does deeper water.

True

[True or False] Water near shore generally has more dissolved nutrients than water farther from shore. This is because most nutrients enter the water from land.

True

[True or False] Water near the bottom of lakes and the ocean may contain more nutrients than water closer to the surface.

Plankton

tiny aquatic organisms that cannot move on their own. They live in the photic zone. They include phytoplankton and zooplankton.

Nekton

aquatic animals that can move on their own by ''swimming" through the water. They may live in the photic or aphotic zone. Examples of nekton include fish and shrimp.

Benthos

aquatic organisms that crawl in sediments at the bottom of a body of water. Many are decomposers. Benthos include sponges, clams, and anglerfish.

Marine regions

cover about three-fourths of the Earth's surface

Coral Reefs

Found in shallow, warm tropical waters (usually within 30° of the equator)

Built by reef-building corals with symbiotic algae (zooxanthellae)

Extremely biodiverse: often called "rainforests of the sea"

staghorn & brain corals

clownfish

parrotfish

sea urchins

giant clams

Key Species in Coral Reefs

Coral reefs

Nursery grounds for fish

Protect shorelines from erosion

Support fisheries and tourism

Coral bleaching

Ocean acidification

Pollution, overfishing, and destructive fishing

Major Threats to Coral Reefs

Open Ocean (Pelagic)

Covers ~70% of Earth's surface, includes multiple depth zones: Epipelagic, and Mesopelagic to Abyssal

phytoplankton

krill

jellyfish

tuna

dolphins

Key Species in Open Ocean

Open Ocean (Pelagic)

Produces ~50% of Earth's oxygen (via plankton)

Regulates global climate and carbon cycles

Overfishing and bycatch

Plastic pollution (macro and microplastics)

Climate change and acidification

Major Threats to Open Ocean

Estuaries

Where freshwater rivers meet the ocean; include salt marshes, lagoons, mangroves

Highly productive due to nutrient-rich waters

oysters

crabs

shrimp

salmon

seagrass

mangroves

Key Species in Estuaries

Estuaries

"Nurseries of the sea" for juvenile fish/shellfish

Filter pollutants and improve water quality

Protect coasts from floods and storm surges

Habitat destruction

Agricultural runoff (eutrophication)

Pollution and sea-level rise

Major Threats to Estuaries

Deep Sea

Begins ~200-1000 m below surface, includes abyssal plains, seamounts, hydrothermal vents

Cold, dark, high pressure, low food availability

anglerfish

giant squid

deep-sea corals

tube worms

bioluminescent fish

Key Species in Deep Sea

Deep Sea

Carbon sequestration ("biological pump")

Unique biodiversity and genetic resources

Bottom trawling

Deep-sea mining

Climate change and acidification

Major Threats to Deep Sea

Polar Seas (Arcrtic & Antartic)

Defined by cold, seasonal ice cover and extreme light/dark cycles

polar bear

narwhal

penguin

seal

Key Species in Polar Seas

Polar Seas

Critical for thermohaline circulation

Support migratory species and Indigenous communities

Sea ice loss due to rapid warming

Ocean acidification

Increased shipping, fishing, and oil exploration

Major Threats to Polar Seas

Freshwater

makes up only about 2.5% of the Earth's total water supply. Of this small percentage of freshwater, a large portion is inaccessible, being locked up in glaciers, ice caps, and ground water.

Lakes and Ponds

Rivers and Streams

Wetlands

Types of freshwater biomes

Lakes and Ponds

Vary in size from meters to thousands of square kilometers

Often isolated; some are glacial remnants from the Pleistocene

Littoral Zone

Limnetic Zone

Profundal Zone

Lakes and Ponds Zones (based on depth and distance from shore)

Littoral Zone

Shallow, warm, supports algae, plants, snails, fish, amphibians

Limnetic Zone

Sunlit open water, home to plankton and freshwater fish

Profundal Zone

Cold, dark, low light; organisms consume dead matter

Rivers and Streams

Streams and rivers are flowing freshwater systems that begin at sources like springs, snowmelt, or lakes and end at larger bodies of water or the ocean.

Wetlands

Areas of standing water that support aquatic plants

Home to hydrophytes - moisture-adapted plants like pond lilies, cattails, sedges, tamarack, and black spruce

Contain the highest species diversity of all ecosystems

Marshes

Swamps

Bogs

Types of Wetlands

True

[True or False] Not all are freshwater — salt marshes host species like shrimp, shellfish, and salt-tolerant grasses

Pollution

Habitat Destruction

Climate Change

Invasive Species

Overextraction

Eutrophication

Pollution

From agricultural runoff, industrial waste, and household chemicals

Habitat Destruction

Wetland draining, dam construction, land development

Climate Change

Alters water temperature, ice patterns, and rainfall

Invasive Species

Outcompete or prey on native species (e.g., zebra mussels, Asian carp)

Overextraction

Excessive water withdrawal for farming, cities, and industry

Eutrophication

Nutrient overload causes harmful algal blooms, reducing oxygen for other life