WHAT IS A BIOME BIOME A large relatively

WHAT IS A BIOME? BIOME: A large, relatively distinct terrestrial region characterized by similar climate, soil, plants and animals, regardless of where it occurs in the world. Key ABIOTIC Factors: Temperature & Precipitation Other important abiotic factors include: Rapid temp changes Fires Floods Droughts Strong winds

Hiking up a mountain is similar to traveling towards the North Pole with respect to the major ecosystems encountered. WHY? ? As you climb up a mountain, the temperature drops & the types of organisms that live there changes.

Important Aquatic. Limiting Factors • In TERRESTRIAL environments: – Temperature & Precipitation are limiting factors – Light is plentiful • In AQUATIC environments: – – – Temperature less important Salinity Dissolved Oxygen (DO) Low light Low levels of essential nutrient minerals Temperature, p. H, presence/absence of waves/currents

Aquatic Ecosystem Organisms PLANKTON • “Free-floating” – Carried by currents • Usually small or microscopic • Can migrate vertically daily or seasonally • Two categories: – Phytoplankton (plant-like) • Photosynthetic cyanobacteria & algae • Producers: base of most aquatic ecosystems – Zooplankton (animal-like) • Non-photosynthetic organisms (protozoa, tiny crustaceans, larval stages of animals) • Feed on algae & eaten by small aquatic organisms

Aquatic Ecosystem Organisms NEKTON • Larger, stronger-swimming organisms • Fish, turtles, whales BENTHOS • Bottom-dwelling organisms • Fix themselves to one spot – sponges, barnacles, or oysters • Burrow into sand – Worms, clams, echinoderms • Walk around on the bottom – Crawfish, aquatic insect larvae, brittle stars

FRESHWATER ECOSYSTEMS 2% of Earth’s surface Recycle precipitation that flows as surface runoff to the ocean Large bodies help moderate daily/seasonaltemperature fluctuations on land Provide habitats Three Types: Flowing-Water, Standing-Water, & Freshwater Wetlands

1. Flowing. Water Ecosystem Rivers & Streams

Flowing-water Ecosystems ~Human Influence~ • Pollution – Alters physical environment – Changes biotic component downstream from the pollution source • Dams – Cause water backup & flooding – Create reservoirs (alters/destroys habitat) – Downstream river is reduced (alters habitat)

STANDINGWATER ECOSYSTEM S Lakes & Ponds

Zonation in a Large Lake • Littoral Zone: shallow-water area along the shore. • Limnetic Zone: open water beyond the littoral zone, away from shore, extends down as far as sunlight penetrates. • Profundal Zone: beneath the limnetic zone.

Standing-water Ecosystems ~Zonation: Littoral Zone~ • Most productive zone – Photosynthesis is greatest here – Many nutrients from surrounding land • Plant Life: – Emergent vegetation (cattails) – Deeper-dwelling aquatic plants & algae • Animal Life: – Tadpoles, turtles, worms, crayfish, insect larvae, many fishes (perch, carp, bass) – Surface dwellers (water striders) in calm areas

Standing-water Ecosystems ~Zonation: Limnetic Zone~ • Main organisms = phytoplankton & zooplankton • Larger fishes • Less vegetation than Littoral Zone due to its depth

Standing-water Ecosystems ~Zonation: Profundal Zone~ • Typically absent in smaller lakes & ponds • Light cannot penetrate this deep – No plants & algae • Food drifts down from other zones • Bacteria decompose dead organisms here, using up O 2 & liberating nutrient minerals in the organic material – Nutrients are not recycled well because there are no producers to absorb them • Mineral-rich & anaerobic

Standing-water Ecosystems ~Thermal Stratification~ • Caused by light penetrating to different depths • Temperature changes sharply with depth 4°C, Thermocline, Density, Fall & Spring Turnover

Standing-water Ecosystems ~Thermal Stratification~ • How it works: SUMMER • Sun warms surface waters, making them less dense. – Density of water is greatest at 4°C – Less dense above & below 4°C • Cooler, denser water remains at bottom • Thermocline: abrupt temp change

Standing-water Ecosystems ~Thermal Stratification~ • How it works: FALL • Falling temps cause layers to mix. – Called the Fall Turnover • Surface water cools (density increases) & displaces the less-dense, warmer, mineral-rich water below. • Warm water rises, where it again cools & sinks. • Cycling continues until the lake has a uniform temperature throughout.

Standing-water Ecosystems ~Thermal Stratification~ • How it works: WINTER • Surface water cools below 4°C – 4°C has greatest density! • As it cools below 4°C, it becomes less dense, and can even form ice, which will form on the surface. • Water on the lake bottom is warmer than the ice on the surface.

Standing-water Ecosystems ~Thermal Stratification~ • How it works: SPRING • Ice melts, warming surface to 4°C – Surface water, now denser, sinks. – Bottom water, now less dense, rises. • Layers mix again – Called Spring Turnover. • Thermal stratification occurs again in the summer, continuing the cycle.

Standing-water Ecosystems ~Effects of Fall & Spring Turnover~ • Turnovers bring: – Essential nutrients to the surface – Oxygenated water to the bottom • These nutrients encourage the growth of large algal & cyanobacteria blooms! – Causes Eutrophication, red tides, etc.

Standing-water Ecosystems ~Thermal Stratification~ • Where are the fish all this time? • There is varying seasonal distribution of temperature & O 2 – We know how temps change. – How does O 2 change? • Cooler water holds more DO • Fish follow these distributions according to their individual tolerance levels!

FRESHWAT ER WETLANDS Marshes & Swamps

Freshwater Wetlands • Covered by shallow water for at least part of the year. • Have characteristic soil and water-tolerant vegetation. • Anaerobic & therefore low decomposition. • Types: – Marshes (grasslike plants) – Swamps (woody trees or shrubs) – Hardwood bottomland forests (along streams & rivers that periodically flood) – Prairie potholes (shallow ponds) – Peat moss bogs (acidic, mossy wetland)

Freshwater Wetlands • Highly productive! • Ecosystem Services: – Food sources – Habitat for migratory birds – Control flooding • act as water holding areas, then release water slowly back – Groundwater recharge areas – Cleanse and purify water

Freshwater Wetlands • Problems protecting wetlands: – Formerly considered wastelands • Filled in or drained to create real estate, farms, or industrial sites. – Breeding grounds for mosquitoes • Seen as a nuisance to public health. • Importance is now widely recognized. – Some legal protection – Still threatened by development & pollution

ESTUARIES Where freshwater meets saltwater

ESTUARIES • Where a freshwater stream or river meets the salty ocean water. • Creates BRACKISH water. • Water level rises & falls with tides. • Salinity level changes with tidal cycles, time of year, and precipitation. – Organisms must tolerate these changes!!

ESTUARIES • Among the most fertile & most productive ecosystems in the world. • High productivity created by: 1. Nutrients are transported from the land into rivers/creeks that flow into the estuary. 2. Tides promote rapid nutrient circulation & helps remove waste products. 3. High light penetration. 4. Many plants provide an extensive photosynthetic base for the food chain.

ESTUARIES • Usually contain salt marshes or mangroves. • Salt Marsh = shallow wetlands dominated by salt-tolerant grasses. – Often seen as worthless, and experience similar problems as other wetlands. – Also acts as a storm buffer. • Mangrove Forest = tropical equivalent of salt marsh. – Cover 70% of tropical coastlines. – Ecosystem services: • Breeding & nesting grounds • Roots stabilize submerged soil (prevent erosion) • Storm buffer: actually stronger than concrete seawalls in dissipating wave energy during tropical storms.

Marine Ecosystems. OCEANS

Marine Ecosystems Oceans differ from streams/lakes in several ways: 1. Depth (up to 6 km or 3. 6 miles)

2. Tides (gravitational pull of the moon)

3. Currents (surface & density)

Marine Ecosystems are divided into 3 main zones: 1. Intertidal 2. Benthic 3. Pelagic Divided into 2 zones based on distance from shore 1. Neritic 2. Oceanic

Pelagic (Consists of the neritic and oceanic provences) Continental Margin (shelf, slope, rise) Inter-Tidal Zone Area of shoreline between high and low tides Neriticsurface to 200 m Oceanic: open ocean overlying ocean floor at depths greater than 200 m High Tide Low Tide Cont inen tal s helf ~200 m Euphotic Zone: upper part of pelagic- light penetrates for photosynthesis. Up to 150 m (488 ft) nti Co tal n ne pe Slo MAJOR OCEANIC ZONES Benthic Environment: Ocean bottom or floor (composed of benthic, abyssal, and hadal) Co nti n en tal R 4000 m ise Abyssal Zone: 4000 -6000 m Abyssal Plain >6000 m Hadal Zone

Zones: 1. Intertidal: between high & low tide • • Biologically productive habitat Stressful for organisms • The Sandy Beach is constantly changing. Organisms must continuously burrow and follow the tides up and down on the beach (must avoid drying out- no adaptations) • The Rocky Shore is exposed to wave action (at high tide) and drying out/temp changes (exposed to air at low tides) • Organism adaptions to seal in moisture • closing shell, thick skin , special glands, gummy coating, burrowing, etc

2. Benthic Zone – Ocean Floor – Consists of mostly sediment (sand/mud) – Bacteria are common Two kinds of benthic zones A. Shallow Water 1. Sea grass 2. Kelp 3. Coral B. Deep Water 1. Abyssal 2. Hadal

A. SHALLOW WATER BENTHIC ZONE – Productive with sea grass beds, kelp forests and coral reefs 1. SEAGRASS BEDS Provide habitat/food for organisms Roots stabilize sediments (warm, tropical waters) 2. Kelp Beds vital primary food producer for the Kelp forest ecosystem (cold waters) Remember Sea Otters? Importance? ? ?

3. Coral Reefs – Built from accumulated layers of Ca. CO 3 – Found in warm (>21 C) shallow water – Most diverse marine environment – Protect shorelines from erosion – Grow very slowly - build on the remains of organisms before them

Note: 2 types of coral! – Without Zooxanthellae (do not build reefs) – With Zooxanthellae (do build reefs) Zooxanthellae = Symbiotic relationship between coral polyp and algae (commensalism) – Daytime: Zooxanthellae photosynthesize for the coral – Nighttime: Coral polyps feed with tentacles & stingers – BLEACHING: Zooxanthellae leave the polyp (they give coral its color) because: – Water is too cloudy for photosynthesis – Water temperature is too high

Types of Coral Reefs & Their Formation FRINGING BARRIER ATOLL Reef begins attached to land, then as the land subsides below the surface, the coral continues to grow vertically. Largest Barrier Reef? ? ? (1200 mi long, 62 mi wide) Great Barrier Reef!

Human Impact to Reefs Threats – 27% of the world’s coral reefs are in danger (UN) – Of 109 countries with coral reefs, 90 are damaging them. Asian reefs contain the most diversity and are also the most endangered reefs in the world.

Coral Damage is caused by…. . Silt washing downstream High salinity due to fresh water diversion Overfishing Sewage Discharge/Agricultural Runoff Boat Grounding Oil Spills Fishing w/ Dynamite/Cyanide Hurricane Damage Land Reclamation Tourism Mining for Building Materials

B. DEEP SEA BENTHIC ZONES 1. Abyssal Benthic Zone: Bottom ~4, 000 -6, 000 m 2. Hadal Benthic Zone: Trenches > 6, 000 m to bottom 3. Pelagic Zone – two parts: Neritic & Oceanic A. Neritic Province: shallow waters Open ocean: shoreline depth of 200 m Organisms are floaters or swimmers Large numbers of phytoplankton – produce food – are the base of the food web diatoms & dinoflagellates Zooplankton (and jellyfish, barnacles, urchins & crabs) feed on phytoplankton and then are consumed by planktoneating nekton (sardines, squid, baleen whales, manta rays)

B. Oceanic Province: open ocean zone Part of the pelagic zone Overlies ocean floor at depths >200 m Largest marine environment (75% of ocean) Cold temps, high hydrostatic pressure, absence of sunlight Organisms depend on marine snow (organic debris that drifts down from the lighted regions) – Filter feeders, Scavengers & Predators – Unique adaptations (bioluminescence, reduced bone/muscle mass)

Impact of Human Activities on the Ocean Coastal development – Damages mangrove forests, salt marshes, sea grass beds, coral reefs Pollution from land – (enters via runoff) Pollution from atmosphere – (enters via precipitation Human sewage contaminates seafood Trash (plastics, fishing nets, packing materials) Offshore Mining & oil drilling (oily ballast) Mechanized fishing/Dredging (scallops/shrimp)