3What is meant by the term “world ocean”? The world ocean is a great body of water that surrounds the continents of the Earth. All of the “oceans” are interconnected.The world ocean is often divided into subdivisions that we call “oceans “.There are five oceans: Atlantic, Pacific, Indian, Arctic & Southern
5Facts About the World Ocean Oceans cover over 71% (or almost ¾) of the Earth’s surface (which amounts to 361 million square km)The Pacific is the largest ocean and covers about 1/3 of the EarthThere is more ocean in the Southern HemisphereThe word ocean comes from Oceanus, one of the Greek TitansThe average depth is about 4000 metres (sort of like a damp basketballThe deepest point in the ocean is Challenger Deep in the Mariana Trench at 11,035 metres
19Surrounds the ice covered continent of Antarctica Named in 2000
20Ocean Fact Finder Challenge Complete the handout and submit as Assignment #1 on the due date
21Our Ocean Neighbourhood Can you locate some of the following features:Bras d’Or LakeSydney BightSydney Harbour (an estaury)Cabot StraitGulf of St. LawrenceSable IslandGrand BanksGeorges BankBay of FundyGulf of MaineLabrador CurrentGulf Stream
22Plate TectonicsComplete the anticipation guide and watch the following videoThen, review your answers and make any necessary changes.Video
23How did the different oceans form? The oceans formed when the huge supercontinent of Pangea broke apartThe result were a number of ocean sub-basins and continents, all of which are sitting on plates.Pangea AnimationVideo
24What is plate tectonics? Plate Tectonics is the study of the origin and arrangement of the broad physical features of the Earth.Plate tectonics is the basic idea that the Earth is divided into a few large plates that move slowly and change in size.Intense geological activity (earthquakes, volcanoes, mountain building) occur where the plates meet. Where the plates meet are called plate boundaries. Plates can move toward each other, away from each other or slip past one another.
31Divergent Plate Boundary This happens when two plates separate and magma (liquid rock) flows from the crust to form new mountainsExample: Mid- Atlantic Ridge
32Divergent Plate Boundary Mid-ocean ridges are formed when plates move apart. They are giant undersea mountain ranges that extend around the world.Earthquakes & eruptions of rock are frequent along the ridges. Iceland formed atop a ridge.Exotic creatures often live along ridges.
34Convergent Plate Boundaries With convergent plate boundaries, plates move toward each otherThere are three possible collisions:1. Oceanic crust colliding with oceanic crust causes one to dive under the other (often forming deep trenches or island chains)2. Heavier, denser and thinner oceanic crust colliding with the continental crust causes the oceanic crust to dive (often forming deep trenches)3. Two colliding continental crusts cause crumpling & mountain building (ex. Himalayas & Mt. Everest; Appalachians of Eastern North America, including the mountains of Eskasoni)
35Transform BoundariesWith transform boundaries, one plate slides horizontally past another plateThe result is often a fault or massive “crack” in the Earth’s crust (ex. San Andreas fault in California; Aspy Fault in C.B. Highlands)Earthquakes are very common (and often violent) along transform boundaries
44Continental shelf: These are the shallow parts of the sea floor next to the land. The slope is about 2m per km; avg. depth is 130 m; avg width is 70 km (up to 1000km)Continental slope: This occurs at the end of the continental shelf. The slope is greater (70m/km) and in some places drops 3600 metres down.
45Continental rise: The continental slope ends here Continental rise: The continental slope ends here. The continental rise slopes very slowly here. The rise can be wide (up to 1000km), and has huge amounts of sediments.Sea floor (abyssal plain): The sea floor is the flattest area on Earth. It covers about 42% of the Earth’s surface. The floor may have trenches or canyons.
46Seamount: A seamount is an isolated or stand-alone mountain Seamount: A seamount is an isolated or stand-alone mountain. Some become islands such as Hawaii and the Midway Islands.Island of Surtsey, born 1963Nishino-shima volcanic island;Born Nov 20, 2013
55Measuring BathymetryThere are several ways to measure bathymetry (or the depth of the ocean):Plumb lines - lines suspended from shipsSonar – sound waves are bounced off the bottomSatellites – satellites (ex. SEASAT) measures small differences in the height of the sea surfaceLasers – planes use laser beams that bounce off the ocean bottomMulitbeam sonar – several sonar beams are used to create a highly detailed map of the ocean bottom
67Elements in SeawaterThe two most important parts of seawater are: 1. Water (H2O) –> 96.5% 2. Salt (NaCl) –> 3.5%Other parts of seawater include dissolved oxygen (O2), carbon dioxide (CO2), nitrogen (N) and other dissolved chemicalsInteresting fact: In seawater, there is grams of gold per ton of seawater. So, the total amount of gold in the ocean is about 9 million tons!!!
69Universal SolventWater has been described as the universal solvent. Just like a sugar cube dissolving in water, many substances dissolve easily in water. The elements in seawater come from land runoff, cosmic dust and the atmosphere.
70Measuring SalinitySalinity is the measure of the amount of salt in water.Salinity is measured in a unit called parts per thousand or pptAverage seawater has a salinty of 35 ppt. This would mean that 1000 grams (or 1 litre) of seawater has about 35 grams of salt. This is about 1.5 tablespoons per litre of water.
71The salinity of ocean water in the open ocean away from land is 35 ppt or 35‰ Salinity of East Bay is low – 21 pptSalinity of Seal Island – 29 ppt
72A Little About DensityThe term density refers to the mass of a substance per unit volume (or the amount of stuff). Helium would have a low density, wood would have a medium density and iron would have a high density.Pure water (at 3.98°C) has a density of exactly 1 gram per cubic centimetre (1 g/cm3)If a substance has a density of less that 1 g/cm3, it will floatIf a substance has a density greater than 1 g/cm3, it sinks
74Pop Quiz______ & _______ water floats, while ______ & _______ water sinks!!Word Bank:fresh coldsalty warm
75Freshwater vs Saltwater Freshwater has a density of close to 1 g/cm3. Saltwater is heavier with a density of g/cm3Therefore, when saltwater and freshwater mix, the saltier water sinks and the fresher water floatsDensity is also affected by temperature. Warm air rises, cold air sinks. Warmer, less dense water rises while colder, more dense water sinks
77What is thermohaline circulation? “Thermo” refers to temperature while “haline” refers to salt. So, thermohaline circulation is about ocean circulation that involves water temperature and salt content.
80What does thermohaline circulation mean? Cold, salty water sinks to the bottom of the ocean. Warm, less salty water stays at the top of the ocean.Cold, salty water at the poles sinks to the ocean bottom. Eventually, this water makes its way to the surface near the equator. This warm water is pushed back to the Poles with the help of winds.
83What is the “Global Conveyor Belt” and why is it important? The Global Conveyor Belt moves cold water away from the Poles and warm water back to the Poles. Currents act like a conveyor belt to transfer heat to the Poles. Therefore, the Poles (and Nova Scotia) never get super cold, and the Equator (near Brazil) never gets super hot.Read article & answer questions
86Facts about surface currents: There can be cold currents (ex. Labrador Current) or warm (ex. Gulf Stream)They can be fast movingThey spin clockwise in the Northern Hemisphere (in NS) and counter-clockwise in the Southern Hemisphere (in Australia)What causes this spin? Answer: Coriolis Force
87What are currents? Currents are like rivers in the ocean. There are three main factors that cause currents: 1. Heat energy from the sun causes winds which push on the surface of the ocean2. Heat energy from the Sun causes density changes. So, warm water rises, cold water sinks, salty 3. rotation of the EarthDeep water currents carry cold water away from the poles, while surface currents carry warm water to the poles.
88Global Warming & Global Currents Some people think that 250 million years ago, global warming caused a malfunction of the global conveyor belt.This may have lead to the extinction of 90% of all life on Earth.Is this gradually happening now? Maybe.
89What is the Coriolis force? Simply put, it affects everything that moves through the air (and currents in the ocean), and it makes everything turn a little bit. When you look at a satellite picture of the Earth you see all these storms and clouds swirling around. Objects normally move in a straight line when you're on a non-spinning world. However, in a spinning world, if you move in a straight line, you really wind up curving and never get to the place you want to go.
94What is the real world effect of the Coriolis Force? In the Northern Hemisphere, weather patterns (such as hurricanes) and oceanic currents tend to rotate in a clockwise pattern. This is called the North Atlantic Gyre off of NS.In the Southern Hemisphere, the rotation is counter-clockwise.
98Facts About the Gulf Stream The Gulf Stream was discovered by Benjamin Franklin in 1769 or 1770Max. speed is 16.6 km/h which occurs off the coast of MiamiMax. volume is 90 million cubic metres (or “bathtubs”)Once described as a “river in the ocean”The Gulf Stream carries warm water from the Gulf of Mexico to northern waters. This is why people swim in Sweden in the summer!Video
102Warm core rings are “bubbles” that pinch off from the Gulf Stream Warm core rings are “bubbles” that pinch off from the Gulf Stream. The water in these rings is warmer than the surrounding water.They slowly spin clockwise at about 3 km/hThey are raised from the sea surface by about 50cmThey last from a few months to a yearSometimes, tropical fish become trapped and wash up along NSCold core rings are “bubbles” of colder water surrounded by the warmer waters of the Gulf Stream
103What is upwelling?Winds blowing across the ocean away from land tend to push warmer, surface water away from the land. Colder water from the ocean bottom rises up to replace this water.The colder upwelling water carries many nutrients for plant growth, which supports a huge ecosystem.DemoVideo
108The tides are caused by the difference in the force of gravity between the end of the Earth closest to the Moon, and the opposite end, which is furthest away. While the Moon is pulling at the waters of the seas closest to it, causing a high tide, at the opposite end of the Earth, the pull is the least. This causes the waters to bulge away from the Moon, and therefore another high tide is formed on the side furthest away from the Moon. Somewhere in between these two points of high tides are two areas of low tides. This is what causes two high tides and two low tides daily.
112Spring & Neap TidesWhen the Sun & Moon are aligned, higher than normal high tides occur. This is called spring tide. When the Sun & Moon are at right angles, lower than normal high tides occur. This is called neap tide.
113Label high & low tides on this diagram and explain
114More on Tides:A tide is like a huge wave that is bulging out from the Earth. This wave (or high tide) enters bays, harbours, etc. Certain bays are shaped in such a way that extra high tides are produced. This is the case with the Bay of Fundy.At the head of the Bay of Fundy, the difference between high & low tides is about 14 metres (42 feet). Here, the tidal current has a speed of about 15 km/h
116Tide Table for Sydney, NS In Nova Scotia, we have two high tides and two low tides every day. This is called semi-diurnal. Other areas of the world have one high and one low tide every day. This is called diurnal.Tide Table for Sydney, NS
117What is a tidal boar?A tidal boar is when the incoming high tide is slowed by the water coming out of a river. As a result, a large wave (or “boar”) is produced.This occurs in the Salmon River near TruroThe tidal boar near the mouth of the Amazon River is 5m high and moves at 22 km/h (fast enough for surfing)
118What is a storm surge?A storm surge can occur during severe storms and hurricanes. Three factors have to be present: 1. High on-shore winds 2. Extreme low pressure 3. High tidesThese conditions cause massive coastal flooding and destruction.
120Ocean Waves There are two general types of ocean waves: Progressive waves -These waves continue moving forward -Ex. A rock tossed into the oceanStanding waves -This happens when water sloshes back and forth as in a bathtub -Ex. Happens in ponds; Great Lakes; Northwest Arm of Halifax HarbourDemo of a standing wave
121Types of Progressive Waves: Capillary wavesGravity wavesTidesTsunami
122Capillary Waves:These are the smallest waves with a very small wavelength of less than 1.73cm. Wind blowing over calm waters causes these tiny waves (like ripples). As soon as the wind stops, the surface tension (or “stickiness”) of the water causes the water to become calm again.Video
124Gravity WavesThese are the most common types of waves. The wavelength of gravity waves is greater than 1.73 cm. Gravity is the only force that will stop these waves and restore the sea surface to a calm state.
125Ocean/Gravity Waves Gravity vs. Capillary Waves:Video Surfing Waves in Hawaii:VideoRough Seas
126Tsunamis This means big wave in harbour in Japanese A tsunami is a huge wave with a very large wavelength (hundreds of kilometres)Tsunamis are caused by earthquakes, rockslides, volcanoes, meteor impacts and even an atomic bomb blastNational Geographic VideoScuba Diving in Tsunami
127Tides Tides are the biggest waves in the oceans Tides have a wavelength (from one crest to the next) of ½ of the circumference of the Earth.
128Rogue WavesThese are higher than normal waves, that come out of nowhere.Rogue waves are very dangerous for boaters, and beach goers.Rogue Waves: News Video 1Rogue Waves: News Video 2
129How do ocean waves form? What affects the height of waves? Most surface waves are caused by the wind.As the wind blows, it pushes the water. This energy continues to pass along, forming a wave of water.What affects the height of waves?The area of open water the wind can blow over (this is called fetch)The strength of the wind
130The stronger the wind and the longer the fetch (or distance), the bigger the waves
131Beaches & ErosionWhy do waves crash along the shore? The actual cresting wave begins to form when the depth of the water is 1/7 of the wavelength. So, if the wavelength is 7m, the wave will crash when the water is 1m deep
132What is beach erosion? Waves usually hit beaches at an angle, causing the waves to bounce back out into the water. In this way, a current is formed. This is called a longshore current. It is this current that causes beach erosion.Animation
133Beaches are dynamic and always changing due to erosion (taking away) and deposition (building up). More erosion occurs in the winter because there are storms with more wave energy.So, beach erosion is a natural phenomenon that occurs along coastlines.However, people feel that with Global Warming and rising sea levels, beach erosion may be more severe in the years to come.
134How does human activity affect beach erosion? More erosion occurs due to the following:Rising water levels (due to melting icecaps because of global warming)Removing sand & rocks from beachesBusy ports change the currents that naturally transport sandBeachside construction may destroy sand dunes that protect beachesBeach goers may trample vegetation that helps to stabilize the shoreline.
136What have people done to slow erosion? Structures called groins are built into the water to slow erosion. The problem is that erosion still occurs on one side and not the other.
137Build a seawallHowever, seawalls become undercut over time
138Beach nourishment This involves adding sand, rocks, etc Beach nourishment This involves adding sand, rocks, etc. to a beach that is eroding. This is the best solution (or most natural). But, this only slows erosion. Simply put, beach erosion cannot be stopped.
139Oceans 11 Module 2: The Marine Biome What is a biome? A biome is a distinct natural community consisting of certain types of plants, animals and other organisms. A biome has a certain type of climate and geography. There are many types of biomes (ex. Desert biome, arctic biome, rainforest biome). The marine biome is the largest on Earth.
140What is the marine biome What is the marine biome? This is the living (or “bio”) part of the ocean.What is needed to support life in the ocean?SunlightOxygenFood or nutrientsWaterThese are called limiting factors because they limit or control life. In other words, organisms are controlled by the amount of oxygen, sunlight, food and water.
141Comparing Marine Biome with the Terrestrial Biome 1. Air Pressure: Stays the same1. Water Pressure: Increases with depth2. Temperature: Drastic temperature extremes2. Temperature: Slow temperature changes; many areas have a constant temperature3. Oxygen: Usually plenty of oxygen3. Oxygen: Some areas have low oxygen levels4. Weather: Changing weather conditions all of the time4. Weather: Most of the ocean is not affected by weather (just the first few metres)5. Sunlight: Lots of sunlight5. Sunlight: Amount of sunlight decreases with depth
142LightThe amount of light in the ocean is an important factor in determining the level of photosynthesis (more light means more photosynthesis).In general, the maximum depth of photosynthesis is 125m (actually, it is 125m in clear tropical waters in places like the Caribbean, but only 10m in the waters off NS).The amount of light getting through depends on sediments, sewage and other organisms in the water.The uppermost layer of the ocean where light is present is productive (produces or makes food) while the rest of the ocean is consumptive (consumes or eats).
143PressureEvery 10m of the depth = the pressure of air on land (or, 1 atmosphere).In the Marianna Trench, the pressure is 1100 atmospheres.Scientists once thought that pressure limited biological activity, but deep water organisms have adapted over millions of yearsDeep water organisms cannot survive in shallower water/lower pressure conditions, while shallow water organisms are unable to withstand high pressures.
144TemperatureDifferences in temperature causes species variation (changes) from north to south (tropical species at the Equator; polar species at the North and South Poles)Polar species (at the poles; within the Arctic Ocean)Boreal species (near the poles; NS to Labrador)Temperate species (from North Carolina to NS/Nfld.)Tropical species (at the Equator)Temperature also causes a different distribution with respect to depth (e.g. shrimp migrate vertically according to the temperature and time of year)Obviously, species become adapted to a certain temperature range, and are unable to survive if the water temperature is outside of this range (too hot or too cold)Ocean water can cool below 0°C and still remain a liquid. As a result fish often have special “antifreeze compounds” in their bloodIn general, northern organisms are usually more robust, and often a lot more feeding takes place in northern waters (e.g. whales migrate north in the summer months because there is more food here in the summer than there would be in the tropical ocean)
145Light Zones in the Ocean Sunlight Zone (or euphotic zone) -This is the top layer of the ocean -Because photosynthesis occurs here, 90% of marine life is here -Goes down as far as 600 feetTwilight Zone (disphotic zone) -Very little light present; high pressure -No photosynthesis; all animals -Very strange creatures that glow (called bioluminescence)Midnight Zone (aphotic zone) -90% of the ocean is in this zone -Extreme pressure and freezing temperatures -Very little life except for creatures that live around cracks in the ocean floor
146Videos Zones of the Ocean Twilight Zone (not the movie!!) Midnight Zone (verrrryyy darrrrk!)
150What is a hydrothermal vent? The vents are cracks in the ocean floor that heat the surrounding water and release sulphur chemicalsBacteria feed on these chemicals (called chemosynthesis)Strange animals live around the ventsAll life here is based NOT on sunlight, but on the chemosynthesis of the chemical eating bacteria.
151More on Light Zones Depth Characteristics 0 – 200 metres -Layer of plant production -Roughly the depth of the continental shelfmetres-Very little light -Big decrease in temperature -The amount of available food decreases4000 metres-No light present -Very little food of any type -Very stable environment (constant temperature, salinity & oxygen) -Most stable environment on Earth4000 – 11,000 metres-Food is non-existent -Pressure is extremely high -At this depth, the only life that occurs is around vents in the crust called hydrothermal vents
152Open vs. Coastal Ocean Characteristics of Open Ocean Characteristics of Coastal OceanDeep water eliminates bottom dwelling seaweed communitiesShallow water allows bottom-dwelling seaweed communities to thriveNo cross currents or upwelling to help stir up nutrients from the bottomMany currents, tides and upwelling areas stir up nutrients for plant growthFar from land run-off which provides nutrientsClose to land run-off which helps to promote plant growthCooler temperatures that limit the number of organismsWarmer coastal temperatures promote spawning & migration
154Parts of a Food WebDecomposers - These are organisms that break down dead organisms -In the ocean, most decomposers are bacteria, but worms and fungus are also marine decomposersNon-living chemicals – Usually, these are the chemicals needed for plant growth (nitrogen, phosphorous, silicon)Plants, algae & seaweed – Mostly single-celled algae called phytoplankton. Some are seaweed such as kelp and rockweed. A few are actual plants such as eelgrass. These are the producers.
155Consumers – Most marine animals are consumers, such as fish, shellfish, seals, whales, sharks etc.
156Loss of Energy at Each Level in a Food Chain There is a 90% loss of energy at each feeding level. This energy is lost in the form of heat. This means that only 10% of the energy is actually transferred from one feeding level to the next.
158Food Web Activity (25 pts) Use Google to create a food webFind 8-10 marine organisms found around NS and create a simple food web.You will need to include an algae (seaweed or phytoplankton), small animals (such as copepods or krill; clams, snails, mussels), smaller fish, bigger fish, and then maybe larger predators (seals, whales, sharks)
159Photosynthesis & Primary Productivity Primary productivity is the production of sugar (or “food”) by plants, algae & seaweed. It is called “primary” because the entire marine food web depends on this process.Primary productivity occurs because of a reaction called photosynthesisPhotosynthesis occurs in all plants, seaweed and algae.
161Photosynthesis Reaction Carbon dioxide and water react with sunlight (a type of energy) to form sugar and oxygen.CO2 + H2O CH2O + O2An important chemical called chlorophyll that is present in all plants & algae makes this reaction possibleSo, in many ways, chlorophyll is the most important chemical in the ocean.sunlightchlorophyll
162Oceans 11 Quiz Name three (3) light zones. Which part of the ocean is most productive: open or coastal ocean?What is primary productivity?Name two (2) producers in the ocean.What percentage of energy is lost from one level of a food web to the next level?
163Oceanic OrganismsAll organisms in the ocean can be classified according to where they live:Plankton: comes from the Greek word “planktos” meaning “to drift”. Plankton drift about in the ocean. Plankton are unable to swim against the currents. Ex. jellyfishNekton: these are organisms (mainly animals) that are able to move freely instead of just drifting. Ex. FishBenthic organisms: these are organisms that live on the ocean bottom or in the ocean sediments. Ex. worms
167Types of Plankton There are three main types of plankton: Phytoplankton: single-celled algae (seaweed) that undergo photosynthesisZooplankton: usually tiny animals that float in the ocean. Zooplankton feed mainly on phytoplanktonMeroplankton: floating larvae (juveniles) from certain types of organisms.
168Diatoms and Dinoflagellates (Phytoplankton) Along with certain types of bacteria, diatoms and dinoflagellates are the most important producers in the marine ecosystem. Diatoms and dinoflagellates are one-celled algae or “plants” which we call phytoplankton. All phytoplankton are the basis for nearly every marine food chain. In fact, phytoplankton produce nearly 90% of all food in the ocean, and about 2/3 of all food on Earth. Phytoplankton filter carbon dioxide (a waste gas released by animals) while producing important oxygen.
169Diatoms: Most abundant type of phytoplankton Thousands of different species with a huge variety of shapes and coloursLive in “glass houses” (make delicate shells in two halves that fit together)Dead diatoms sink to the bottom forming layers of sediments that are hundreds of metres thick
171DinoflagellatesSome are plant-like, while others are actually parasites and carnivoresSome actually live within the issues of sea anemones and coralsSome are responsible for harmful algal blooms (or “red tides”)
173Zooplankton (animal plankton) These are like insects in the seaZooplankton are probably as plentiful as land insects and just as importantZooplankton feed directly on phytoplankton, and form the second level in most marine food webs.Most zooplankton are food for larger animals such as fish and whales.Two common types of zooplankton are copepods and krill
176What is an algal bloom or phytoplankton bloom? An algal bloom happens when phytoplankton grow very quickly and form dense patches near the surface of the water.These blooms normally happen in the early spring and late summer, but sometimes blooms can be harmful because some types of dinoflagellates produce powerful poisons that get into the food web. This kind of a bloom is called a “red tide”Red tides produce poisons called paralytic shellfish poisons (or PSP’s)
178Questions What are harmful algal blooms (HAB’s)? What are some of the causes of HAB’s?What are paralytic shellfish poisons (or PSP’s)?What are some of the effects of PSP’s?What are some of the effects of PSP’s on humans?
179Atlantic Canada Fisheries What are the most productive (or biggest) fisheries in Atlantic Canada?What is the richest fishery in terms of money?What species are caught by fishers from Eskasoni?What happened to the cod fishery in the early 1990’s? What is the current health of the cod fishery?