G.S. Powell and S. Deperno 8th Grade Science East Cary Middle School 2013

Importance of Oceans Remove carbon dioxide from the atmosphere and stores it. Provide oxygen to the atmosphere. Are home to many species of animals and plants and many complex food webs. Provide food for the human population. Used for travel and shipping. Drilled for oil. Mined for minerals. Recreation.

Why is the Ocean Salty? Salts slowly erode from the Earth’s crust and are carried down rivers into the oceans. Solids and gases from underwater volcanoes dissolve in the sea. Hydrothermal vents on ocean floors bring super heated water with many dissolved minerals back into the sea.

Why is the Ocean Salty? The average salinity of seawater is 35 parts per thousand (ppt). Evaporation and freezing sea ice increases salinity. Rainfall, run-off from land and melting sea ice decreases salinity. Salinity is lower in coastal waters, polar seas and near the mouths of large rivers.

Dissolved Gases in the Ocean Cold water holds more gas then warm water. Lower salinity water holds more gases then higher salinity water. Deep water holds more gas then shallow water.

Dissolved Gases in the Ocean Waves at the ocean surface release gases from the water into the air. Phytoplankton use CO2 to photosynthesize and release O2 into the water. The O2 is used by ocean animals.

Carbon Dioxide and the Ocean H2O reacts with CO2 and creates compounds animals use to make shells (carbonic acid and bicarbonates). This traps CO2 in the ocean. Coral and shell fish use these chemicals to make their skeletons and shells. Ocean acidification: As atmospheric CO2 rises, CO2 rises in the ocean, causing ocean water pH to drop. Ocean acidification is a threat to many species.

Oceans and World Climate The oceans are an important part of the world’s climate because they collect, mix and store water, heat and carbon dioxide. The oceans are the largest reservoir (a place where something is stored) of heat and water on Earth’s surface. The oceans hold and circulate more water, heat and carbon dioxide than the atmosphere. The ocean and atmosphere form weather patterns such as: El Nino

El Nino An abnormal climate event occurring every 2 to 7 yrs in the Pacific Ocean. Due to unusual patterns of winds in the West Pacific ( a vast sheet of warm water moves toward South America) Can last 1 to 2 yrs Prevents upwellings, so fish and birds die Affects the climate in North and South America

Oceans and Climate Sea water has a high density and specific heat so it stores and later releases a lot of heat energy from its surface layers. This causes milder climates near the ocean, (warmer winters, cooler summers). The ocean controls the amount of radiation released into ecosystems. Evaporation cools surface water and the air above it. (Especially near the equator)

Oceans and Temperature Heat stored in the ocean can affect climate even a year later. Air temperatures all over the world are regulated by the circulation of heat in the ocean. Ocean currents distribute energy, nutrients and ocean life.

Ocean Currents Currents circulate energy, nutrients and ocean life.

Surface Currents Wind creates surface currents in the ocean. Are several hundred meters deep Move in circular patterns As Earth rotates the paths of the winds and currents curve in relation to Earth’s surface. Gulf Stream – the largest surface current in the North Atlantic

How Surface Currents Affect Climate Climate – the pattern of temperature and precipitation typical of an area over time. Surface currents warm or cool the air above them, influencing the climate of the land near the coast Carry warm water from the tropics toward the poles and cold water from the poles towards the tropics Winds pick up moisture from warm currents Winds are cooled by cold currents so the winds bring cool dry weather.

Deep Currents Are caused by differences in density in the ocean water. Density is determined by temperature and salinity. At the North and South Poles, water cools and ice forms. The salt concentration in the remaining water increases making it more dense; the saltier, denser water sinks creating deep ocean currents. Flow more slowly than surface currents

Upwellings Winds move warm surface water offshore and cold water from the bottom rises to fill the void. Nutrients and minerals from the bottom are brought to the surface. Minerals: required by organisms in their diet; stored in ocean floor sediment Phytoplankton use these nutrients to grow. Consumers eat the phytoplankton. Home to huge schools of fish Pacific Ocean – West Coast of South America – Chile- anchovies South Africa

Upwelling and Biodiversity

Estuaries Where rivers meet the ocean. Partly closed coastal waters where fresh and salt water mix creating less salty water called brackish water. Trap nutrients and sediments from land and ocean tides. Generally shallow so sunlight penetrates to the bottom = plant growth. Pamlico Sound, Albemarle Sound, Back Sound are a few of the estuaries in NC.

Importance of Estuaries Are the nursery grounds to the oceans!!!!! No salt marshes – no seafood!!! Provide protected areas for young sea animals to grow. Estuaries are one of the most productive ecosystems on Earth. Great bio-diversity (lots of different plants and animals. Filter pollutants, chemicals and pathogens. One oyster can filter 25 gallons of water/day.

Pamlico Sound The largest estuary in NC Water from Northeastern NC and Southeastern VA drains into the Pamlico Our Neuse River Basin drains into the Pamlico Late summer fish kills are common in the mouth of the Neuse River/Pamlico Sound Estuary due to excess nutrients that stimulate algal and bacterial growth (Eutrophication – low dissolved oxygen)

Importance of Estuaries Bacteria eat organic matter in marsh sediments and release carbon dioxide, hydrogen sulfate, and methane giving the marsh its characteristic rotten egg odor Benthic = bottom dwellers; ocean floor

Estuary Ecosystems Salt Marshes Common in temperate regions throughout the world; Salt marsh grasses such as Spartina are common Mangrove Forests Common in warmer waters such as South Florida and equatorial regions Mangrove trees are common

Threats to Estuaries Chemicals washed from land end up in rivers that feed into estuaries. Toxins can accumulate in sediments and animals. Leaking septic tanks can make shell fish hazard- ous to eat.

Marine Ecosystems Ecosystem: living organisms and the non living components of their environment interacting as a system. Shore Ecosystem: Intertidal zone (between high and low tide lines); along the edge of the ocean Ocean Ecosystem: Neritic Zone (over continental slope) and Oceanic Zones. Deep Ocean Ecosystem: >500 M deep; under Oceanic Zones

Ocean Zones: Vertical Zonation Patterns Photic Zone – surface layers where light penetrates; Photosynthesis occurs here; most ocean organisms exist here Phytoplankton need sunlight and nutrients to survive. Aphotic Zone – dark, cold, tremendous pressure; Includes Deep Ocean Ecosystems. Animals are specially adapted to survive: ex: bioluminescense –animals produce light through a chemical reaction extremophiles: organisms that thrive in extreme conditions

Ocean Organisms Plankton – carried by currents and waves; Nekton – free swimmers Benthos – bottom dwellers

Examples of Plankton and Benthos Bottom Plankton: free floating; usually very small Benthos: bottom dwellers

Food Chains and Food Webs Marine ecosystems have tremendous biodiversity Examples of diverse marine ecosystems: estuaries, lagoons, coral reefs, kelp forests, open ocean Many individual food chains overlap to form food webs in all these ecosystems. Ocean food chains can intersect with land food chains when land animals feed on ocean animals or plants. Examples: humans, shore birds, seals, polar bears, sea otters, penguins

Simple Ocean Food Chain Producers: Phytoplankton Consumers: All other organisms Many food chains form a food web Land and ocean food webs are linked

Ocean Life Phytoplankton are an important food source in the ocean. Food webs show how ocean organisms are connected.

Deep Ocean Ecosystem: Hydrothermal Vents Chemosynthesis: Bacteria convert sulfur and methane gases to food Bacteria live in tube worms who they supply with food Clams filter the water Shrimp eat bacteria Fish eat shrimp Heat from Volcanic Activity Water Temp. >400 oC Extremophiles!!

Ocean Resources Biotic – food, biomedical organisms Fish: 16% of total world protein for human population Seafood species are rapidly declining in numbers. We are overfishing the worlds oceans! Mineral – diamonds, gold, manganese nodules Dredging the ocean floor for minerals destroys plant and animal life Tourism – 200 million jobs worldwide Leads to pollution of coastal ecosystems Ecotourism – favors low impact tourism

Energy Resources from the Ocean Oil and Natural Gas – drill exploratory wells; requires government permits; permanent rigs are put in place for production; Has many impacts on the environment: rigs impact sea life; drilling affects the ocean and sea life; accidental spills occur and can be disastrous Wind – NC has best potential sites on the East coast; two sites off Wilmington; one off Outer Banks Conservation - of energy resources should be a critical part of our energy plan to minimize damage to the environment

Ocean Exploration Ships: Submersibles – Satellite Technology – Sonar – determines ocean depth via sound waves Drop floats and drifters into the currents Collect water samples Collect marine life Submersibles – view and collect samples of ocean floor and ocean life designed to withstand tremendous pressures Remote controlled or human occupied Robots Satellite Technology – Photographs, ocean temperatures; ocean color; phytoplankton,

Many of the images used were taken from: http://www.ck12.org/book/CK-12-Earth- Science-For-Middle- School/r5/section/14.0/MS- Earth%25E2%2580%2599s-Atmosphere- %253A%253Arev%253A%253A-1- %253A%253Aof%253A%253A-Earth-Science- For-Middle-School/