Science 8Text: Discovering Science 8

Unit One:Water Systems on Earth

The Water Cycle

Atmosphere

Hydrosphere

Lithosphere

Earth’s Water Facts

• Water is found all over the earth.• Earth is called the “blue planet”• 97% of Earth’s water is saltwater.• 3% of Earth’s water is fresh. • 2/3 of Earth’s freshwater if frozen (cryosphere)• 1% of Earth’s fresh water is in liquid form. In the

atmosphere and the lithosphere) Much of this water is located underground.

• All areas were water is found on Earth is called the hydrosphere.

Global Warming – The Ice Age

• Global warming would melt the icecaps destroying animal habitats and flood huge tracks of land..

Ice Age

• Glaciers influence the water cycle by slowing down its evaporation rate.

• 120 000 – 11 000 (most recent ice age).• It covered about 28% of land on Earth.• The mean average temperature was 100C.

Macro-Ecosystems vs. Micro-Ecosystems

Marine Environments: Pelagic zone (areas not close to the bottom) and benthic zone (ocean bottom).

Ocean Water vs. Freshwater

Ocean Water Fresh WaterGround water, glaciers, rain, drainage basins

Salinity More salt35 g/L

Less salt0 g/L

Density More dense1.022 kg/L

Less dense1.000 kg/L

Freezing point Lower-1.9 0C

Higher0 0C

Freshwater Environments

• Lakes and pondsPlankton - Phytoplankton and zooplankton

• Streams and RiversRiffles, turdity, …

• Wetlands – A low lying area saturated with water for most of the year.Filters, habitat, prevents erosion, water storage, …

• Estuaries – a wetland that builds up where a river meets the oceanDistribution of nutrients , brackish, …

Saltwater Environments

• Ocean is the world’s largest saltwater aquatic habitat.

• Most life found within the first 200 m of water (continental shelf – penetration of sunlight)

• Bioluminescence• Largest animals on Earth live in the ocean

The Effects of Abiotic Factors on Plant and Animal Distribution in Marine and Fresh Water

Ecosystems

• Temperature• Dissolved oxygen• Phosphates• Increased acidity• Turbidity• Pollution• Upwelling• Amount of Sunlight• Salinity

Upwelling

• Upwelling occurs most commonly along the western coastlines of continents, but may occur anywhere in the ocean.

• Upwelling results when winds blowing nearly• parallel to a continental coastline transport the light

surface water away from the coast.• The upwelling water contains an abundance of

nutrients which support plant life near the surface. These plants, in turn, attract animal life.

Upwelling

The Development of Ocean Basins and Continental Drainage Systems

• Plate Tectonics

• Volcanic activity

• Erosion

• Glaciation

The Oceanic Basin

Public and Private Canadian Institutions for Scientific and technological Research of the

Oceans

• Environment Canada

• Federal Fisheries

• Ocean Sciences Center

• Center for Cold ocean Research (C-CORE) Memorial University of Newfoundland

Investigative Technologies for Underwater Ocean Research

• Sonar

• Satellites

• Underwater photography/videography

• Deep sea submarines

• Diving

Ocean Current

• The Labrador Current• Gulf Stream (.. and North Atlantic Drift)

Surface Currents

Causes:1.) Wind (Speed and Direction)2.) Earth’s Spin (Coriolis Effect)3.) Shape of the continent (circulation is clockwise in northern

hemisphere)

Deep Water Currents

Causes:1.) Salinity 2.) Temperature

Tides and Waves

Wave Model

Tsunami

Waves - Swells and Breakers

• Swells – caused by winds and storms far out in the ocean

• Breakers – The tumbling of water as a wave breaks on shore.

Waves Interact With Shorelines

• Slope of the Shore:

Rock Type:

Erosion and Deposition

• Beaches• Shoals• Sand Bars• Sea Caves• Sea Stacks• Sea Arches

Neap Tides and Spring Tides• The gravitational pull of the moon affects tides on Earth

The Influence of Ocean Currents and Winds on Regional Climates

• Ocean warm the air above it creating thermals. As the warm air rises, cooler denser air replaces it. This movement creates wind which bring the warm and cool air to various parts of the continent.

Convection Currents• The transfer of heat in the air is called convection.

Currents Effect Climate• Warm surface currents transfer tropical heat to the

atmosphere and colder currents remove heat from the atmosphere. When the warm, moist air above the Gulf Stream blows over the colder water of the Labrador current, it cools and condenses, producing fog.

• Temperature fluctuations occur rapidly in Newfoundland and Labrador due to our location between warm, tropical winds moving north and cold, arctic winds moving south. Local atmospheric temperatures depend on which of these prevail.

Oceans and Temperature

Oceans staying warmer than land masses through he fall and winter months due to the high heat capacity of water.

Oceans remain cooler through the spring months and into the summer. This regulates the temperature of coastal areas. It prevents the area from being extremely hot in the summer and extremely cold during the winter.

El Nino and La Nina

El Nino La Nina

Trade Winds Decrease Increase

Ocean Temperatures

Warming Cooling

Weather More Extreme(Drought/Floods)

Less Extreme

Marine Productivity

Decrease Increase

El Nino

La Nina

“Positive” and “Negative” effects of Marine Technologies on Ocean

(i) Oil rigs(ii) Confederation bridge(iii) Sable gas development(iv) Fundy tidal power(v) Factory freezer trawlers(vi) Oil tankers (113-2)

Negative Effects* Scouring of the ocean floor destroying marine habitats.

* The introduction of foreign species that can occur when oil tankers release their bilge water endangering native habitats and organisms. - invasive species include the green crab in Placentia Bay and the violet tunicate in Belleoram.

* Accidental release of organisms into native populations, and spread of diseases.- concerning some of the negative impacts that may arise as a result of increased organic matter from mussel farms, referred to as detritus rain, which can accumulate on the sea floor.

Neg. Continue

• Oil and gas exploration can result in negative environmental impacts (e.g., oil spills killing sea birds or destroying ecosystems),

• Economic impacts (e.g., price of housing increasing so people can not afford to buy homes), negative social/cultural impacts (e.g., changes in the way of life for many communities, increases in the gap between rich and poor, etc),

Positive

• Economic impacts (e.g., good paying jobs, money for governments to build roads, etc),

• Social/cultural impacts (e.g., better quality education for everyone, more leisure time for people, etc).

Answers and Responsibility

Many people have the concept that any problem can be solved by science if enough time and money are put into it.

But, …

Understanding

• We need to recognize that science cannot answer all questions, or solve all problems. We all need to look at our own behaviors and take responsibility. Such behaviors as recycling, reducing and other related activities all contribute to a healthy planet.