EOSC 314 Final Exam Study Guide 2024 PDF

EOSC 314.99A THE OCEAN ENVIRONMENT December 2024 FINAL EXAM STUDY GUIDE 1. What is the structure of a water molecule? What is hydrogen bonding? How do these explain water’s 4 unique properties? Answer: Structure of a water molecule ○ Water molecule (H2O) is comp...

EOSC 314.99A THE OCEAN ENVIRONMENT December 2024 FINAL EXAM STUDY GUIDE 1. What is the structure of a water molecule? What is hydrogen bonding? How do these explain water’s 4 unique properties? Answer: Structure of a water molecule ○ Water molecule (H2O) is composed of 2 Hydrogen atoms covalently bonded to 1 oxygen atom. ○ The Oxygen atom has a partial negative charge, while the hydrogen atoms each have a partial positive charge, due to the electronegativity of oxygen, which attracts shared electrons more strongly ○ The molecule is bent or v-shaped, giving the molecule its polar nature. This asymmetrical shape and charge distribution make water a polar molecule Hydrogen Bonding ○ The polarity of water molecules allows them to form hydrogen bonds with each other. The slightly positive hydrogen atom of one molecule is attracted to the slightly negative oxygen atom of a neighboring molecule. ○ Each water molecule can form up to four hydrogen bonds, leading to a highly structured, interconnected network. Water’s 4 unique properties: ○ High surface tension Explanation: Water's polarity leads to hydrogen bonding, creating strong cohesion between molecules. This gives water a high surface tension, acting like a thin "skin." Importance: High surface tension allows insects to walk on water and supports energy transfer between the atmosphere and ocean. ○ A universal solvent Explanation: Water's dipole nature makes it an excellent solvent for ionic and polar compounds by forming hydration shells around them. Importance: Water dissolves a wide range of substances, making it a universal solvent and allowing for diverse ocean chemistry and biological reactions. ○ Solid water is less dense than liquid water Explanation: In ice, water molecules form a structured lattice, making it less dense than liquid water where molecules are more closely packed. Importance: Ice floats, insulating bodies of water and protecting aquatic life during cold conditions. ○ Highest heat capacity  Explanation: Water’s strong hydrogen bonds require significant energy to break, giving it a high heat capacity. Importance: This allows oceans to absorb and store heat, regulating global temperatures and stabilizing the climate. 2. What is the significance of water’s thermal properties in its role as a regulator of Earth’s climate processes? Answer: High Heat Capacity: Water can absorb or release large amounts of heat with minimal temperature change, stabilizing temperatures in oceans and on land. This moderates day-night and seasonal temperature variations, making Earth's climate more livable. Heat Transport: Oceans absorb solar heat near the equator and transport it to polar regions through ocean currents. This distribution of heat helps regulate global climate and reduce temperature extremes between different regions. Latent Heat: During evaporation, water absorbs large amounts of heat (latent heat of vaporization), which is released during condensation. This process plays a key role in weather systems, transporting heat across the globe and driving processes like rainfall and storms. 3. Explain the Principle of Constant Proportions. Which of the ocean’s dissolved components does this principle apply to? How are these components different from the others? What are the implications of this Principle on the composition of the ocean? Answer: Principle of Constant Proportions: while the total salt content (salinity) of seawater can vary significantly from place to place, the ratio of the major dissolved ions remains constant. In other words, regardless of salinity, the relative proportions of the six major ions in seawater are always consistent. Major Ions affected by the principle: ○ The principle specifically applies to the six major ions found in seawater: Sodium (Na⁺) Chloride (Cl⁻) Magnesium (Mg²⁺) Sulfate (SO₄²⁻) Calcium (Ca²⁺) Potassium (K⁺) These ions make up 99.28% of all dissolved ions in the ocean and have remained in these proportions for hundreds of millions of years. This is why they are also the least reactive and the longest-lived ions in the oceans. Why are these components different? ○ The major ions have long residence times in the ocean, meaning they are not quickly removed by biological or geological processes, allowing their proportions to remain stable.  ○ In contrast, other ions, such as nutrients (e.g., nitrate and phosphate), vary more significantly because they are involved in biological activity and geochemical cycling. Implications of the Principle ○ Since the ratio between any two major ions is always constant, salinity can be determined by measuring the concentration of just one major ion—most commonly chloride (Cl⁻) because it is the most abundant ion in seawater. ○ This means that the composition of seawater is predictable and consistent, regardless of where or at what depth the sample is taken (e.g., surface, mid-depth, deep ocean, coastal, or polar regions). ○ This consistency allows scientists to easily track changes in salinity, understand ocean circulation, and study the mixing of water masses across different regions. 4. How is river water different from seawater despite the fact that rivers are the major source of salts to the ocean? Answer: River water has low salinity and different dominant ions compared to seawater, which accumulates chloride and sodium due to oceanic processes over time. Ion Composition ○ River water is dominated by bicarbonate (HCO₃⁻), calcium (Ca²⁺), and silicate (SiO₄⁴⁻). ○ Seawater primarily contains chloride (Cl⁻) and sodium (Na⁺), along with other major ions like magnesiumand sulfate. Salinity: ○ River water has low salinity (0.1-0.5 ppt). ○ Seawater has high salinity (average 35 ppt). Transformation: ○ In the ocean, evaporation, precipitation, and biological uptake change the composition of river water. Chloride and sodium accumulate due to their long residence times and low reactivity. 5. Describe how the nutrients N and P and the gases CO2 and O2 are intimately linked via biological processes in the ocean. Answer: N, P, CO₂, and O₂ are interconnected through biological processes like photosynthesis, respiration, decomposition, and nutrient recycling. Phytoplankton uptake N, P, and CO₂ to produce organic matter and release O₂, while respiration and decomposition consume O₂ and release CO₂, cycling these elements through the ocean and influencing global carbon and nutrient dynamics. Photosynthesis: ○ Phytoplankton use CO₂, N, and P during photosynthesis to create organic matter. In this process, they release O₂as a byproduct.  ○ This process takes place near the ocean surface, where sunlight is available, leading to the production of oxygen and the uptake of nutrients and CO₂. Respiration: ○ Marine organisms (including phytoplankton, zooplankton, and fish) perform respiration, which consumes O₂ and releases CO₂ back into the water. ○ Respiration occurs throughout the water column and returns carbon to the dissolved pool, making it available for further cycles. Decomposition: ○ When organisms die, their organic matter sinks, and decomposers (bacteria) break it down, releasing CO₂, N, and P back into the water column. ○ Decomposition consumes O₂, contributing to lower oxygen levels in deeper waters. Nutrient Recycling: ○ The N and P released during decomposition become available as inorganic nutrients, which are brought back to the surface via upwelling. ○ This nutrient recycling supports new phytoplankton growth, fueling productivity in surface waters. Biological Pump: ○ The biological pump moves carbon from the atmosphere to the deep ocean. Phytoplankton take up CO₂ during photosynthesis, and when they die, the carbon sinks to the ocean floor, storing carbon for long periods. 6. How do the processes in (5) above explain the distribution (vertical and horizontal profiles, i.e. depth and latitudinal profiles) of the major nutrients and dissolved gases in the oceans. Answer: Vertical Profiles (Depth Distribution) ○ Nutrients (N and P): In the surface ocean, nutrient levels are generally low because phytoplankton rapidly take up N and P for growth during photosynthesis. As depth increases, nutrient concentrations rise due to the decomposition of sinking organic matter, which releases N and P into deeper waters. Upwelling brings these nutrients back to the surface, which explains why nutrient levels are often higher in regions where deep water is upwelled. ○ Dissolved Gases (CO₂ and O₂): O₂ levels are highest in the surface layer due to photosynthesis and exchange with the atmosphere.  At deeper depths, O₂ concentrations decrease as respiration and decomposition processes consume oxygen. CO₂ concentrations are relatively low at the surface (due to photosynthesis) but increase with depth as respiration and decomposition release CO₂ in deeper waters ○ Summary: Nutrients increase with depth due to decomposition, while O₂ decreases in deeper waters because of respiration and lack of direct contact with the atmosphere. CO₂ increases with depth as it is produced by respiration. Horizontal Profiles (Latitudinal Distribution) ○ Nutrients (N and P): Nutrient levels are high in regions where upwelling occurs, such as the eastern boundaries of ocean basins (e.g., off the coast of Peru). In tropical and subtropical regions, nutrients are often depleted at the surface because of high biological activity and stratification, which prevents mixing of deeper, nutrient-rich waters. In polar regions, nutrients are generally high because of strong mixing and fewer limitations on the availability of deep nutrients. ○ Dissolved Gases (CO₂ and O₂): CO₂ is more concentrated in high-latitude waters, where cold temperatures increase the solubility of CO₂, making these areas effective at absorbing atmospheric carbon. O₂ levels are generally higher in colder polar waters due to increased solubility at lower temperatures and more mixing. Oxygen minimum zones (OMZs) are found in some regions where respiration significantly exceeds oxygen replenishment, particularly in areas with limited circulation and high organic matter decomposition. ○ Summary: Nutrients and CO₂ are often higher in polar and upwelling regions due to mixing and cold temperatures. O₂ levels are generally higher in cold, well-mixed waters but lower in regions with high organic matter decomposition. 7. What are the main vertical and horizontal patterns of salinity and SST distributions? What processes control ocean salinity and SST vertically and horizontally? Answer: Salinity and SST vary with depth (halocline and thermocline) and across latitudes due to solar heating, evaporation, currents, and upwelling. Vertical Patterns Salinity SST  Surface Varies due to evaporation and Highest near the equator precipitation. due to solar heating. Halocline/Thermocline Halocline: Rapid change in Thermocline: Rapid salinity with depth. decrease in temperature with depth. Deep Ocean More uniform salinity due to Consistently cold (0-4°C). thermohaline circulation. Horizontal Patterns Salinity SST High in subtropics (due to high Warmest at the equator. evaporation). Cooler toward the poles. Low at equator (high rainfall) and Warm currents (e.g., Gulf Stream) polar regions (melting ice). raise SST, while cold currents Varies near coasts due to river (e.g., California Current) lower it. inflows. Process Controlling Salinity and SST: ○ Vertical: Evaporation, precipitation, and mixing influence salinity and SST. The thermocline limits heat exchange. ○ Horizontal: Evaporation, precipitation, currents, and upwelling control salinity and SST, with warm and cold currents redistributing heat. 8. What is seawater density and what units of measure are used in oceanography? What are the effects of ocean salinity and temperature on density? Answer: Seawater density is affected by salinity and temperature. Higher salinity and lower temperature lead to increased density, while lower salinity and higher temperature reduce density. These interactions are crucial in driving ocean circulation and water column stability. Density is typically expressed in kg/m³ or as σt in oceanography. Seawater Density ○ Density is the measure of how much mass is present in a given volume of seawater. ○ It is expressed in units of kg/m³ or sometimes as a dimensionless value (e.g., σt) Units of measure in oceanography ○ kg/m³ (kilograms per cubic meter), indicating how much a cubic meter of seawater weighs. ○ Sigma-t (σt): A dimensionless unit derived from density to simplify comparisons between water samples. It is calculated as σt = (density - 1000), with typical ocean values ranging between 20-30.  Effects of Salinity and temperature on density ○ Salinity: Higher salinity increases density because dissolved salts add mass to the water without significantly increasing its volume. As salinity increases, seawater becomes denser. ○ Temperature: Lower temperatures increase density since cooler water molecules move less and are packed more tightly. Conversely, higher temperatures decrease density because warmer water molecules move faster and occupy more space. The relationship is inverse: as temperature increases, density decreases. 9. What is a “Temperature-Salinity-Density” (T-S) diagram? What types of information can be extracted from such a diagram? Know how to use a T-S diagram. Answer: A Temperature-Salinity (T-S) diagram is a graphical tool used by oceanographers to visualize and understand the relationship between temperature (T), salinity (S), and density of seawater. It is commonly used to identify different water masses and their properties within the ocean. Structure of a T-S Diagram Axes: ○ X-axis represents salinity (typically measured in practical salinity units, PSU). ○ Y-axis represents temperature (in degrees Celsius). Lines of Constant Density (Isopycnals):  ○ Curved lines called isopycnals are plotted on the diagram, representing lines of constant density. ○ Density is usually expressed in sigma-t (σt) units, which is density minus 1000 (e.g., if the density is 1025 kg/m³, the sigma-t is 25). Information Extracted from a T-S Diagram ○ Water Mass Identification: Water masses are formed in specific oceanic regions, each having a unique combination of temperature and salinity. By plotting the T-S characteristics of a water sample, oceanographers can identify the origin and type of water mass. ○ Stability of Water Columns: Stability is assessed by understanding the density structure. If a water parcel lies below a denser one, it will rise, indicating an unstable water column. A stable column will have denser water below less dense water. ○ Mixing of Water Masses: The mixing between different water masses can be visualized on a T-S diagram. The mixed properties will lie along a line connecting the two original points, providing insights into intermediate water formation. How to Use a T-S Diagram ○ Plotting a Sample: Measure the temperature and salinity of a water sample and plot the point on the diagram. ○ Reading Density: Find the corresponding isopycnal line that passes through the plotted point to determine the density of the water. ○ Identifying Water Mass: Compare the plotted point to known T-S characteristics of established water masses (e.g., North Atlantic Deep Water or Antarctic Intermediate Water) to identify the sample. 10. Why is the ocean stratified? What is an “unstable water column”? What conditions lead to the formation of unstable water columns? Where do these types of columns exist and what are their benefits and/or drawbacks? Answer: Ocean Stratification and Unstable Water Columns ○ Stratification: The ocean is layered by density differences due to temperature and salinity variations, with less dense water above denser water, creating stable layers. ○ Unstable Water Column: Occurs when denser water lies over less dense water, leading to sinking and mixing until stability is restored. ○ Conditions: Surface Cooling (e.g., in polar regions). Increased Surface Salinity (evaporation or sea ice formation). Wind Mixing.  ○ Locations: Common in polar regions and areas with strong winds. ○ Benefits: Nutrient upwelling, supporting marine life. Heat and gas exchange. ○ Drawbacks: Less stable habitats for marine organisms. Increased energy demands for marine species due to mixing. 11. What tools, instruments, equipment are commonly used by oceanographers to obtain information on the oceans (for example, density, salinity, temperature, water masses, wave parameters, sediments, etc.)? How do they work? Answer: 1. Sediment Sampling Tools Dredge: ○ A simple bag-like device dragged across the seafloor to collect coarse-grained sediments. ○ Use: Samples bulk material over a wide area, including rocks, boulders, and nodules. ○ Condition: Delivers a mixed sample of all sediment types larger than the mesh of the bag. Grab Sampler: ○ A jaw-like device that digs into sediments, capturing material from the surface. ○ Use: Samples the uppermost layer of the seafloor, typically in soft-bottomed areas like mud. ○ Condition: Delivers disturbed sediments but usually does not retain fine particles. Corers: ○ Box Corer: A stainless steel box that isolates a block of sediment. Use: Collects undisturbed sediment blocks to study vertical layers. Condition: Minimal disturbance, providing an intact sample of the sediment column. ○ Gravity Corer: A coring tube driven into sediment by weights. Use: Extracts cylindrical cores up to 2-3 meters in length. Condition: Suitable for soft sediments with limited depth penetration. ○ Piston Corer: A corer with a piston mechanism that helps reduce friction. Use: Can take cores up to 50 meters long, useful for deep-sea sediment sampling. Condition: Produces long, continuous sediment cores, ideal for studying deep stratigraphy. ○ Rotary Drill:  Special drilling ships equipped to take sediment columns up to 1 kilometer long. Use: Used for very deep ocean cores, managed by programs like the Integrated Ocean Drilling Program (IODP). 2. Instruments for Oceanographic Properties CTD (Conductivity, Temperature, Depth): ○ A device used to measure conductivity (which relates to salinity), temperature, and depth. ○ Use: Provides data on salinity, temperature, and water density at different ocean depths. Argo Floats: ○ Autonomous instruments that drift with ocean currents, periodically diving to collect data. ○ Use: Measures temperature, salinity, and current velocity at various depths, transmitting data via satellite. ADCP (Acoustic Doppler Current Profiler): ○ Uses sound waves to measure current velocities at different depths. ○ Use: Determines wave parameters and the movement of water masses. Niskin Bottles: ○ Cylindrical sampling bottles triggered to close at specific depths. ○ Use: Collects water samples for salinity, temperature, and chemical composition analysis. Wave Buoys: ○ Floating instruments equipped to measure wave height, period, and direction. ○ Use: Records wave parameters for understanding ocean surface conditions. 12. How are the four main types of deep-sea sediments formed? Be able to explain the distribution of sediments in the bottom of the Pacific Ocean. Answer: The four main types of deep-sea sediments are: Lithogenous Sediments: Formed from the physical and chemical weathering of rocks on land, these sediments are transported to the ocean primarily by rivers, glaciers, wind, and turbidity currents. They accumulate near continental margins and can be found in areas such as the deep trenches of the Pacific Ocean. Biogenous Sediments: Derived from the shells and skeletons of marine organisms, mainly composed of calcium carbonate or silica. They are found where biological productivity is high, such as near upwelling zones, and dominate in regions like the equatorial Pacific and Southern Ocean. Hydrogenous Sediments: Formed by the precipitation of dissolved minerals from seawater, often found in areas with low biological productivity and little terrigenous input, such as the central Pacific Ocean.  Cosmogenous Sediments: Originating from space, these sediments are the remains of meteorites that reach the ocean floor. They are distributed throughout the ocean but in very small amounts. In the Pacific Ocean, sediment distribution is influenced by proximity to land, biological productivity, water depth, and the presence of deep trenches, which trap terrigenous sediments and limit their transport to the deep sea. As a result, lithogenous sediments are often found near continental margins, while biogenous sediments dominate deeper and more remote areas where biological activity is high. 13. How does the mechanism of sediment transport into/within the ocean affect its distribution in the bottom of the ocean? Answer: The mechanism of sediment transport into and within the ocean plays a crucial role in determining the distribution of sediments on the ocean floor. Different transport mechanisms influence where and how sediments accumulate: Rivers and Runoff (Terrigenous Transport) ○ Mechanism: Rivers carry weathered rock material (terrigenous/lithogenous sediments) from land to the ocean. ○ Effect on Distribution: Sediments are deposited primarily near continental margins and coastal areas, forming thick sediment layers. Fine particles are carried further offshore by ocean currents, while coarser particles settle close to the coastline. Wind (Aeolian Transport) ○ Mechanism: Wind transports fine dust and sand from deserts and land to the open ocean. ○ Effect on Distribution: Aeolian sediments are widely distributed across the ocean, often forming a layer over mid-ocean ridges or in remote areas. These sediments contribute to pelagic deposits far from land sources. Glaciers and Icebergs ○ Mechanism: Glaciers erode land, and when icebergs break off and drift into the ocean, they release sediments as they melt. ○ Effect on Distribution: Glacial sediments are found mostly at high latitudes near polar regions, with coarse materials settling near where icebergs melt. Gravity Flows (Turbidity Currents) ○ Mechanism: Underwater landslides or turbidity currents transport sediments down continental slopes into the deep ocean. ○ Effect on Distribution: These currents deposit sediments in submarine canyons and deep-sea fans, leading to a buildup of sediments on the continental rise and abyssal plains. Biological Processes (Biogenous Sediments)  ○ Mechanism: Marine organisms produce skeletal remains that settle on the ocean floor. ○ Effect on Distribution: Calcareous oozes accumulate in shallower areas where calcium carbonate does not dissolve (above the calcium carbonate compensation depth (CCD)). Siliceous oozes are found in high-productivity regions, such as upwelling zones in the equatorial and polarPacific. Ocean Currents and Gyres ○ Mechanism: Ocean currents redistribute fine sediments across the ocean basin. ○ Effect on Distribution: Currents can carry fine particles (e.g., clay) over long distances, resulting in even coverage of sediments across abyssal plains. Boundary currents (like the Gulf Stream) may concentrate sediments in certain areas or move them along continental margins. 14. What is the Carbonate Compensation Depth (CCD)? What controls the dissolution of calcium carbonate in seawater? If calcareous ooze is slowly but constantly dissolving in seawater, how can calcareous sediments accumulate on the seafloor? Answer: Carbonate Compensation Depth (CCD) ○ The CCD marks the depth at which calcium carbonate dissolves faster than it accumulates ○ The CCD is the depth at which calcium carbonate (CaCO₃) dissolves as fast as it is supplied, preventing net accumulation of calcareous sediments. ○ Below the CCD, calcium carbonate dissolves faster than it accumulates. Factors controlling CCD ○ CO₂ Concentration: Increases with depth, making water more acidic and enhancing CaCO₃ dissolution. ○ Pressure: Higher pressure at depth increases solubility of CaCO₃. ○ Temperature: Cold water dissolves more CaCO₃. ○ Water Chemistry: Deep water is often undersaturated with CaCO₃, favoring dissolution. Accumulation of Calcareous Sediment ○ Above the CCD, conditions are less favorable for CaCO₃ dissolution, allowing calcareous ooze to accumulate. ○ A high supply of carbonate material from surface waters can exceed dissolution. ○ Elevated areas like mid-ocean ridges are above the CCD, enabling accumulation of calcareous sediments. 15. Classify and contrast waves according to the “generating” or “disturbing” force that creates them. What forces “restore” waves? On what type of waves do they operate? Answer: Classification of Waves by Generating/Disturbing Forces  Wind Waves Tsunamis Tides Capillary Waves Generating Wind blowing over Seismic activity Gravitational Light winds or Force the water surface (earthquakes, pull of the surface tension volcanic moon and sun disturbances eruptions, or underwater landslide) Characteris Typically range Long Long-period Very small tics from small ripples wavelengths waves that waves (ripples) to larger waves. and travel at manifest as that form due high speeds rising and to the effects of Their size across the falling of sea wind on the depends on wind ocean. levels. water surface. speed, duration, and fetch Unlike wind They have very (distance over waves, they long which the wind affect the entire wavelengths, blows). water column often half the from surface to circumference seafloor. of the Earth. Restoring Forces ○ Restoring forces are the forces that act to return the water surface to its undisturbed state: Surface Tension Operates on small waves, such as capillary waves. Mechanism: Surface tension acts like a skin, pulling the water surface flat after a minor disturbance. Gravity Operates on larger waves such as wind waves, tsunamis, and tides. Mechanism: Gravity pulls the water back down to restore the level surface after a wave is created. It acts as the primary restoring force for most ocean waves. 16. How are very large wind waves produced? What conditions are necessary to develop very large wind waves? Where do the largest wind waves occur and why do they occur there? Answer: Very large wind waves are produced when wind energy is transferred effectively to the water surface, leading to the development of high waves. The generation of these waves depends on specific conditions Conditions: ○ Wind Speed: Higher wind speeds produce larger waves as more energy is transferred to the water surface.  ○ Wind Duration: The longer the wind blows without interruption, the larger the waves will become. ○ Fetch: Fetch is the distance over which the wind blows without changing direction. A long fetch allows waves to build up, leading to greater wave height. ○ Constructive Interference: When individual waves combine through constructive interference, they can form very large waves by temporarily merging their energy. Where do the largest wind waves occur and why ○ Largest wind waves location: The Southern Ocean around Antarctica and the North Pacific and North Atlantic Oceans are known for having the largest wind waves. ○ Reasons: Strong, Persistent Winds: These regions experience strong winds (e.g., the "Roaring Forties" and "Furious Fifties" in the Southern Ocean). Large Fetch: The Southern Ocean has a virtually unlimited fetch with no major landmasses to interrupt the wind flow, allowing waves to grow continuously. Wind Duration: Strong winds often blow for long periods, which contributes to the growth of large waves. 17. Contrast deep water, transitional, and shallow water waves. What controls their speed? How do the water particles behave as these waves pass by? How do waves behave as they approach the shoreline? Answer: Deep Water Waves Transitional Waves Shallow Water Waves Definition Waves that travel in Waves traveling in Waves traveling in water depths greater water depths between water depths less than half their half and one-twentieth than one-twentieth wavelength (Depth > of their wavelength of their wavelength λ/2). (λ/20 < Depth < λ/2). (Depth < λ/20). Speed Wave speed depends Speed is influenced by Speed is controlled Control on wavelength. The both wavelength and by water depth longer the wavelength, water depth. alone. Shallow water the faster the wave waves move slower travels. in shallower depths. Water Water particles move in Particle motion is Particles move in Particle circular orbits that elliptical, becoming flattened, Motion decrease in diameter more flattened as the back-and-forth with depth. These orbits depth decreases. ellipses that reach do not reach the the seafloor, seafloor. influencing sediment movement. Wave Behavior as They Approach the Shoreline  ○ Wave Shoaling: As waves move from deep to shallow water, they slow down, wavelength shortens, and wave height increases. This process is called shoaling. ○ Breaking Waves: Near the shoreline, the wave becomes too steep (height to wavelength ratio exceeds 1:7), causing the wave to break. ○ Refraction: Waves bend towards areas of shallower depth, aligning more parallel to the shoreline. ○ Particle Motion Near Shore: The elliptical motion of water particles in shallow water enhances sediment transport, contributing to coastal erosion and deposition. 18. How do waves interact with each other? Explain constructive and destructive interference. Know examples of these processes in real life. Answer: When waves interact with each other, they combine through a process called interference, which can be either constructive or destructive. Constructive Interference Destructive Interference Definition Occurs when two or more waves meet Occurs when the crest of one in such a way that their crests and wave aligns with the trough of troughs align another, causing them to cancel each other out. Result The resulting wave has a greater The resulting wave has a amplitude (height) than the individual reduced amplitude, and in some waves, leading to larger waves. cases, they can completely cancel each other, resulting in a flat water surface. Example Rogue Waves: These are abnormally Calm Water Spots: In the ocean, large waves that occur in the open certain areas may appear ocean. They are often formed due to relatively calm due to destructive constructive interference when multiple interference where opposing wave systems align. waves cancel each other out. Concerts or Public Gatherings: The Noise-Cancelling Headphones: sound waves from speakers can These headphones use constructively interfere to amplify the destructive interference by sound, making it louder in certain areas. generating sound waves that are out of phase with ambient noise, reducing the noise heard by the user. 19. How do waves behave as they approach the shoreline? How and why do waves break? What physical conditions promote this process? Answer: Wave behavior as they approach shoreline  ○ As waves move into shallower water near the shoreline, their behavior changes due to interactions with the ocean bottom: 1. Wave Shoaling: ○ As waves enter shallow water, their speed decreases due to increased friction with the seafloor. ○ The wavelength shortens, and the wave height increases because the energy is compressed into a smaller depth. ○ This process of change is called shoaling. 2. Wave Refraction: ○ Wave crests bend to align more parallel to the shore as different parts of the wave enter shallow water at different times. ○ This process is called refraction and helps concentrate wave energy on headlands while spreading it out in bays. How and why do waves break ○ Breaking Process: As waves shoal, their height increases and their wavelength decreases. The steepness of the wave eventually exceeds a ratio of 1:7 (height to wavelength), making it unstable. When the crest of the wave can no longer support itself, it collapses forward, resulting in a breaking wave. Types of Breaking Waves: ○ Spilling Waves: Occur on gently sloping seafloors; the wave crest slowly spills down the front. ○ Plunging Waves: Found on moderately sloped beaches; the crest curls over and plunges down, forming a tunnel. ○ Surging Waves: Found on steep beaches; the wave surges forward without spilling or plunging. Physical conditions promoting wave breaking: ○ Shallow Water Depth: As the water depth becomes shallower than about 1.3 times the wave height, the wave becomes unstable and breaks. ○ Slope of the Seafloor: Gentle Slopes lead to spilling breakers. Moderate Slopes produce plunging breakers. Steep Slopes result in surging breakers. ○ Wave Energy and Speed: Higher energy waves (from stronger winds) tend to plunge when approaching the shore, whereas low-energy waves spill. 20. How are tsunami generated? Why are tsunami considered shallow water waves? How do they differ from regular wind waves? Where are they most likely to occur? How do tsunami behave as they approach the shoreline? What are the main underlying causes for their destructiveness? Answer: Tsunami are generated by underwater earthquakes, volcanic eruptions, or landslides that displace large water volumes.  They are considered shallow water waves due to their extremely long wavelengths relative to ocean depth. Unlike wind waves, tsunami travel much faster, have longer wavelengths, and carry energy throughout the entire water column. They are most likely to occur in tectonically active regions, particularly around the Pacific Ring of Fire. As they approach the shore, tsunami slow down, grow in height, and release tremendous energy, leading to significant destruction due to wave impact, flooding, and lack of early warning. 21. How would you ensure your safety and those of others around you during a tsunami? Answer: Prepare by understanding warnings, having an evacuation plan, and creating an emergency kit. Respond immediately to any warnings by moving to higher ground without delay. Stay away from coastal areas and follow all official instructions. After the event, stay alert for additional waves and avoid floodwaters, assisting others safely. Prioritizing early evacuation and following official guidance are the most effective ways to ensure safety during a tsunami. 22. According to the Equilibrium Theory of Tides, what is the expected pattern of high and low tides? How does the rotation of the moon around Earth influence the daily tidal cycle? How do the solar and lunar tides interact to produce spring tides and neap tides through wave interference? Answer: High and Low Tides: The Equilibrium Theory of Tides predicts two high tides and two low tides each day due to tidal bulges caused by the moon's gravity and centrifugal force. Moon’s Influence: The moon’s orbit causes daily shifts in the timing of high tides, with each tide occurring 50 minutes later each day. Spring and Neap Tides: Spring tides occur when the sun and moon align, producing constructive interference and larger tidal ranges, while neap tides occur when the sun and moon are at right angles, resulting in destructive interference and smaller tidal ranges. 23. Distinguish between semi-diurnal, diurnal, and mixed tides by looking at tide charts. Answer: Semi-Diurnal Tides Diurnal Tides Mixed Tides Characterist Twice daily. Two high Daily. One high tide Two high tides and ics tides and two low tides and one low water two low tides per day, per day, (level) per day. but unequal in height. Similar heights for both The tidal cycle is 24 There may be high and low tides, hours and 50 minutes significant differences Each high tide is long. in the height of  roughly 12 hours apart. successive high and low tides. Tide Chart Shows a regular, Shows a single high Shows an unequal Appearance repeating pattern of and single low tide tidal cycle, where one four tidal events each each day, forming a high tide is much day: two high and two simple up-and-down higher than the other, low tides, all with nearly pattern. and one low tide is equal heights. significantly lower. The chart appears more irregular compared to semi-diurnal or diurnal tides. Example Atlantic Coast of the Gulf Coast of the West Coast of the United States (e.g., United States (e.g., United States (e.g., East Coast). parts of Texas and California and Alaska). Louisiana). Not common but can be observed in Victoria BC 24. What are the Ekman spiral and Ekman transport? How do these explain the motion of surface water currents relative to prevailing wind directions? Answer: Ekman Spiral and Ekman Transport are key concepts in understanding how surface currents in the ocean move in response to wind and Earth's rotation. Ekman Spiral ○ The Ekman Spiral is a theoretical model that describes how surface ocean currents change direction and speed with increasing depth. ○ Mechanism: When wind blows over the ocean surface, it exerts a force that moves the surface water. Due to the Coriolis effect (resulting from Earth's rotation), the direction of water movement is deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. As you go deeper below the surface, each successive layer of water is moved by the layer above, but is further deflected by the Coriolis effect. This results in a spiraling pattern of water movement, with the direction of flow rotating gradually as depth increases, while the speed decreases. Depth and Effect: ○ The spiral continues until the water motion effectively stops, which is typically at a depth of around 100-150 meters.  ○ The net effect is that each layer of water moves at an angle relative to the layer above it, creating a spiral of movement known as the Ekman spiral. Ekman Transport ○ Ekman Transport refers to the net movement of water in the upper layer of the ocean as a result of the Ekman Spiral. ○ Direction of Transport: The net movement of the water column is 90 degrees to the right of the wind direction in the Northern Hemisphere and 90 degrees to the left in the Southern Hemisphere. This means that if the wind blows in a certain direction, the overall transport of water (Ekman transport) is at a right angle to that direction due to the combined influence of the wind and the Coriolis effect. Explaining the motion of surface water currents relative to wind direction ○ Surface Water Movement: When wind blows across the ocean surface, the surface water moves at an angle (typically around 45 degrees) to the direction of the wind because of the Coriolis effect. As depth increases, this deflection continues and results in the spiral pattern of water movement (the Ekman spiral). Net Transport (Ekman Transport): ○ The combined effect of the spiraling layers leads to Ekman transport, which causes the net movement of water to be at 90 degrees to the wind direction. ○ For example, a northward wind in the Northern Hemisphere will result in the net movement of surface water to the east. Implications of Ekman transport ○ Coastal Upwelling and Downwelling Upwelling: When Ekman transport moves surface water away from the coast, deeper, nutrient-rich water rises to replace it. This process is common along west coasts in the Northern Hemisphere where winds blow southward. Downwelling: When Ekman transport pushes water toward the coast, surface water sinks, resulting in downwelling. ○ Gyre Formation In the open ocean, Ekman transport contributes to the formation of ocean gyres by driving surface currents that are deflected due to the Coriolis effect, ultimately forming large circular currents. 25. Explain geostrophic flow and the processes leading to the formation of ocean circulation gyres. What drives the surface circulation in the ocean? How would these processes be affected if the Earth were not rotating? If the Earth rotated in the opposite direction? If the Earth did not have continents? Answer: Geostrophic flow  ○ Occurs when the pressure gradient force (caused by differences in sea surface height) is balanced by the Coriolis force (due to Earth's rotation), resulting in a circular movement of ocean currents. ○ Formation: Wind action pushes surface water, causing it to pile up in certain areas of the ocean. This creates a pressure gradient, where water wants to flow from areas of higher to lower elevation. However, the Coriolis effect (due to Earth's rotation) deflects this flow to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. The balance between these forces leads to a stable, rotational movement called geostrophic flow, which forms around ocean gyres. Formation of Ocean Circulation Gyres ○ Ocean gyres are large, circular systems of surface currents found in all major ocean basins. Their formation is driven by several key processes: Wind Patterns: ○ Trade winds (easterlies) push water from east to west near the equator. ○ Westerlies push water from west to east in mid-latitudes. Coriolis Effect: ○ The Coriolis effect deflects the moving water to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, causing the currents to bend and form a circular flow. Continental Boundaries: ○ As surface currents are deflected, they encounter continental boundaries, which help trap the water and create circular patterns. Pressure Gradients and Geostrophic Balance: ○ The combination of winds, continental boundaries, and the Coriolis effect causes water to pile up, creating a pressure gradient. ○ The resulting geostrophic flow leads to the circular movement that maintains the gyres. If Earth didn't rotate, currents would flow in straight lines; if it rotated in the opposite direction, gyre rotation would reverse. Without continents, currents would be simpler and more linear, without the circular gyres observed today. 26. What are western boundary currents? How do they compare with other surface currents? Answer:  Western boundary currents are a type of surface current found along the western side of ocean basins. These currents are significant because of their speed, temperature, and volume of transport. Characteristics Western Boundary Eastern Boundary Currents Currents Temperature Warm Cold Speed Fast Slow Width Narrow Broad Depth Deep Shallow Direction of Transport Poleward Equatorward Examples Gulf Stream, Kuroshio California Current, Canary 27. Where is the Gulf Stream located? Describe its importance in mediating global climate. How is it involved in the thermohaline circulation? How does global warming affect the GS? How does the GS affect global warming? Answer: Location ○ The Gulf Stream is a powerful western boundary current located in the North Atlantic Ocean. ○ It originates in the Gulf of Mexico and flows along the eastern coast of the United States before crossing the North Atlantic towards Western Europe. ○ The Gulf Stream merges with the North Atlantic Current, continuing towards the north and influencing regions like Western Europe and the British Isles. Importance in Mediating Global Climate  ○ Heat Transport: The Gulf Stream carries warm water from the tropics toward the North Atlantic, which helps moderate temperatures in nearby regions. For example, it provides milder winters to regions in Western Europe, such as the British Isles and Scandinavia, even though these regions are at similar latitudes to much colder places like Labrador in Canada. Climate Stabilization: The warm waters influence atmospheric circulation, which results in warmer and more stable climates over large parts of Europe. Storm Intensification: The Gulf Stream also provides heat energy to developing storms and hurricanes, potentially influencing their strength. Involvement in Thermohaline Circulation ○ Thermohaline Circulation (also known as the global conveyor belt) is a deep-ocean circulation driven by differences in temperature and salinity. ○ Gulf Stream Role: As the Gulf Stream flows northward, the warm water cools and becomes denser. In the North Atlantic, as the water cools further and loses heat to the atmosphere, it becomes saltier due to evaporation and eventually sinks. This process is called North Atlantic Deep Water (NADW) formation. This sinking of cold, dense water helps to drive the deep-water component of the thermohaline circulation, contributing to the movement of water masses around the world. Effect of Global Warming on the Gulf Stream ○ Slowdown of Circulation: Global warming leads to increased melting of Greenland's ice sheets and increased freshwater input into the North Atlantic, which makes the surface water less salty and thus less dense. This reduced density impedes the Gulf Stream’s ability to sink, potentially slowing down the thermohaline circulation. Disruption of Climate Patterns: ○ A weaker Gulf Stream may reduce the amount of warm water transported to Western Europe, leading to colder winters in those regions and potentially altering regional climate patterns. ○ A weakened Gulf Stream could also result in higher sea levels along the U.S. East Coast due to reduced transport of water northward. How GS Affects Global Warming ○ Heat Redistribution: The Gulf Stream plays a crucial role in redistributing heat from the equator to higher latitudes, which helps regulate global temperatures. By transferring heat energy northward, it indirectly influences carbon uptake by the ocean, as warmer surface waters enhance the capacity for carbon exchange between the atmosphere and the ocean ○ Carbon Sequestration:  The Gulf Stream also contributes to carbon sequestration through its role in the thermohaline circulation, where the sinking of dense water helps to carry carbon from the surface to the deep ocean for long-term storage. 28. Describe how cold-water/warm-water eddys are generated. Be able to compare and contrast between the two in the Northern Hemisphere setting. How are these important to ocean biota and the distribution of energy? Answer: Eddies are rotating masses of water that break off from ocean currents, forming circular currents that transport heat, nutrients, and marine organisms. They are generated primarily through the meandering and instability of strong ocean currents like the Gulf Stream. How Eddies Are Generated ○ Meandering Currents: Major currents like the Gulf Stream often have meanders or large bends. As these meanders grow, they can pinch off, forming isolated swirling masses of water known as eddies. ○ Separation from the Main Current: Depending on the nature of the meander, an eddy will carry water with distinct temperature characteristics: Cold-Water Eddy (Cold-Core Ring): Formed when a loop of warm current surrounds cold water from higher latitudes or the deep ocean, typically on the shoreward side of the main current. Warm-Water Eddy (Warm-Core Ring): Created when a loop of cold current surrounds warm water from subtropical regions, generally on the seaward side of the main current. Comparison Between cold-water and warm-water eddies in the Northern Hemisphere Feature Cold-Water Eddy Warm-Water Eddy Temperature Colder than the Warmer than the surrounding water surrounding water Rotation Direction Counterclockwise in the Clockwise in the Northern Northern Hemisphere Hemisphere Location Typically formed Formed seaward of a cold shoreward of a warm current current Nutrient Content Rich in nutrients due to Low in nutrients, due to upwelling from deeper downwelling of surface water water Vertical Movement Causes upwelling, Causes downwelling, bringing cold, nutrient-rich pushing warm, water to the surface nutrient-poor water downward  Biological productivity High, supporting marine Low, less conducive to life due to nutrient supply biological productivity Both types of eddies play a crucial role in distributing energy in the ocean, transporting heat from equatorial to polar regions, and influencing marine ecosystems by altering nutrient availability and habitat conditions. 29. Describe/Contrast coastal and equatorial upwelling. How are these generated? How do these processes affect ocean surface seawater chemistry and biology? Where (specific coasts) would you expect coastal upwelling to occur? Answer: Upwelling is the process where deep, cold, nutrient-rich water rises to the ocean surface. It is crucial for marine ecosystems as it brings nutrients that stimulate primary productivity. Feature Coastal Upwelling Equatorial Upwelling Driving Force Wind parallel to coast + Trade winds + Coriolis Coriolis effect effect along equator Location Along specific coasts Along the equator Direction of Movement Surface waters move away Surface waters move away from coast from equator Nutrient Supply Brings nutrient-rich deep Brings nutrient-rich deep water to coast water to equatorial surface Biological Productivity Creates biological hotspots High primary productivity near coasts along equator Examples California, Peru, Canary, Pacific and Atlantic Benguela Equators Both processes are crucial for marine productivity, fisheries, and carbon cycling, making them fundamental components of the ocean's biological and chemical balance. 30. Describe the general circulation pathway of the ocean known as the thermohaline or “conveyor belt” circulation. Where do deep/bottom/intermediate masses form? Where do these waters go? Why are all areas of deep water formation at high latitude? Why is deep water formed in the North Atlantic but not in the North Pacific? Answer: Thermohaline circulation is a global oceanic conveyor belt driven by density differences (due to temperature and salinity). Deep water masses form in the North Atlantic (NADW) and around Antarctica (AABW and AAIW), while intermediate masses like MIW form in regions of high evaporation. High-latitude regions are the primary sites for deep water formation because of cold temperatures, brine rejection, and lack of strong stratification.  Deep water forms in the North Atlantic but not in the North Pacific because the Atlantic has higher salinity and better exposure to cold Arctic air, while the Pacific is influenced by freshwater input and warmer currents. 31. How are water masses identified? Describe how the concentrations of nutrients and dissolved O2 change as the water mass they are in transits from the deep North Atlantic and Antarctic Ocean to the deep Indian and Pacific Oceans. Answer: Identification of water masses ○ Water masses are identified by their characteristic temperature and salinity, often visualized using Temperature-Salinity (T-S) diagrams. ○ They retain stable T-S properties during their transit, which helps in tracking them across ocean basins. Nutrient and oxygen levels are also key identifiers. Nutrient and dissolved O2 changes in Thermohaline Circulation ○ As deep water masses (e.g., North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW)) move from the North Atlantic and Antarctic Ocean to the Indian and Pacific Oceans, their nutrient and oxygen concentrations change significantly. ○ Nutrient Changes: NADW and AABW start with low nutrients. As they move through the Indian and Pacific Oceans, they accumulate nutrients from decomposing organic matter, making the deep Pacific highest in nutrient concentrations. Oxygen Changes: ○ NADW and AABW are oxygen-rich initially. ○ Respiration of organic matter depletes oxygen over time, leading to lower dissolved oxygen in the deep Pacific. 32. Discuss the impacts of thermohaline circulation on global heat transport and climate, and the potential effects of climate change on the “conveyer belt” circulation. Answer: Impacts of Thermohaline Circulation on Global Heat Transport and Climate ○ Global Heat Distribution: The thermohaline circulation, also known as the global conveyor belt, plays a key role in distributing heat across the world's oceans. It moves warm surface waters from the equator to polar regions, and cold deep waters from the poles back towards the equator. ○ Climate Moderation: This circulation helps regulate the global climate by transporting heat: North Atlantic: Warm waters carried by currents like the Gulf Stream moderate climates in Western Europe, giving the region relatively mild winters. Heat Absorption and Release: In the tropics, warm surface waters absorb solar heat, which is then redistributed, helping to balance temperature extremes globally.  Potential Effects of Climate Change on Thermohaline Circulation ○ Freshwater Input: Climate change leads to increased melting of polar ice and increased rainfall, especially in the Arctic and Greenland, which adds freshwater to the North Atlantic. This reduces water salinity and makes it less dense, impacting the sinking process required for North Atlantic Deep Water (NADW) formation. ○ Slowdown of Circulation: Reduced sinking of water could slow down the thermohaline circulation, weakening the global conveyor belt. A weakened circulation could lead to: Regional Cooling: Western Europe may experience cooler temperatures if less warm water is transported northward. Climate Shifts: Changes in heat distribution could lead to more extreme weather patterns, such as stronger storms, altered monsoons, and changes in precipitation. ○ Feedback Loop: Slower circulation also impacts carbon sequestration in the deep ocean, potentially reducing the ocean's capacity to absorb CO2. This could lead to more CO2 in the atmosphere, exacerbating global warming. 33. What oceanic physical properties (sea surface and subsurface) are affected by an El Niño or by a La Niña? What kinds of changes occur in the ocean? Describe how ENSO affects the coastal upwelling process along the eastern edges of the Pacific Ocean. Answer: El Nino weakens coastal upwelling, increases sea surface temperature, and reduces nutrient availability along the eastern Pacific, leading to a decrease in marine life productivity. La Nina strengthens upwelling, enhances nutrient availability, and lead to cooler sea surface temperatures, fostering high productivity and healthy marine ecosystems in the eastern Pacific Oceanic physical properties affected by: Oceanic physical El Nino La Nina properties Sea Surface warm water from the western The SST in the eastern Temperature (SST) Pacific flows eastward, Pacific becomes cooler leading to increased SST than average, due to enhanced upwelling of along the equatorial and cold, nutrient-rich water. eastern pacific The temperature difference between the western and eastern Pacific becomes even greater Thermocline Depth the thermocline (the Thermocline becomes boundary between warmer more pronounced and  surface water and colder shallow in the eastern deep water) flattens and Pacific, allowing cold deep deepens, especially in the water to reach the surface more easily eastern Pacific, due to the movement of warm surface water Ocean Currents The equatorial trade winds Stronger trade winds push weaken or even reverse surface waters westward, direction, reducing westward intensifying the warm water “pile-up” in the water movement and western pacific, and allowing warm water to flow enhancing the strength of toward the eastern Pacific the Walker Circulation Sea Surface warm water accumulating Sea level tends to be Elevation along the South American lower along the eastern coast causes sea level to Pacific due to enhanced upwelling and cooling, rise due to thermal while the western Pacific expansion experiences a rise in sea surface elevation Nutrient with a deeper thermocline, Distribution nutrient-rich deep water cannot reach the surface, leading to nutrient-poor surface waters and low productivity, which adversely affects marine life, particularly off the coasts of Peru and Ecuador Kinds of changes occur in the ocean: El Nino La Nina Circulation Changes Weakened trade winds Stronger trade winds reduce the flow of surface lead to intensifying the waters from east to west, normal flow of water allowing the warm water toward the western normally confined to the Pacific western Pacific to flow eastward Temperature Widespread warming of the Enhanced cooling in the Anomalies equatorial pacific eastern Pacific  Marine Life Impact Disrupts the availability of Leads to higher nutrients do to a deeper productivity due to thermocline, leading to stronger upwelling decline in phytoplankton productivity, which impacts the entire marine food web How ENSO affects the coastal upwelling process along the eastern edges of the Pacific Ocean? ○ Coastal upwelling during El Nino: El Nino significantly reduces or halts upwelling along the eastern edges of the Pacific, particularly off the coast of Peru and Ecuador. Normally, trade winds drive surface water away from the coast, allowing cold, nutrient-rich deep water to rise to the surface. During El Nino, these trade winds weaken, and the deeper thermocline prevents nutrient-rich water from reaching the surface, leading to lower biological productivity ○ Coastal upwelling during La Nina: During La Nina, the strengthened trade winds enhance upwelling along the eastern Pacific, bringin more cold, nutrient-rich water to the surface. This results in increased phytoplankton blooms and a boost in marine productivity, supporting fisheries along the coast of South America 34. How does carbon circulate among its oceanic sub-reservoirs? What are the timescales of these exchanges? What factor(s) determines how fast or slow these processes occur? Answer: ​Carbon circulates through the ocean's sub-reservoirs of surface water, marine organisms, deep ocean, and sediments. Exchange rates range from days (surface-atmosphere) to millennia (deep ocean and sediments). Key factors influencing these rates include temperature, ocean circulation, biological productivity, and carbonate chemistry. The ocean's ability to store and release carbon is crucial for regulating atmospheric CO₂ and global climate. 35. Define/describe/contrast the ocean’s biological and solubility pumps. What are the roles of these pumps in creating CO2 sinks in certain regions of the oceans and CO2 sources in other regions. What are the roles of these processes in driving global climate? What factors affect the ability of the ocean to absorb excess atmospheric CO2? Answer: Feature Biological Pump Solubility Pump Mechanism Photosynthesis, organic Dissolution of CO₂ in cold matter sinking waters Driven By Biological activity Temperature and ocean (phytoplankton) circulation CO2 Sink Location Surface waters with high Cold, high-latitude regions  phytoplankton productivity CO2 Source Location Upwelling regions releasing Upwelling regions bringing deep CO₂ CO₂-rich water to the surface Role in Climate Sequesters organic carbon Sequesters inorganic in deep ocean carbon in deep ocean Roles in Driving Global Climate ○ Both pumps work together to remove CO₂ from the atmosphere and store it in the deep ocean for long periods, thereby helping to regulate global temperatures. ○ The biological pump is influenced by nutrient availability and productivity of marine organisms, while the solubility pump is dependent on temperature and ocean currents. Factors Affecting Ocean’s Ability to Absorb Atmospheric CO2 ○ Temperature: Cold water absorbs more CO₂ than warm water. As the ocean warms due to climate change, its ability to absorb CO₂ decreases. ○ Stratification: Increased stratification (due to warming) can reduce vertical mixing, limiting nutrient availability and reducing the efficiency of the biological pump. ○ Nutrient Availability: The presence of nutrients (like iron and nitrate) in surface waters controls phytoplankton productivity, directly impacting the biological pump. ○ Ocean Circulation: Changes in ocean currents or thermohaline circulation can affect the transport of CO₂ to deeper waters, altering the efficiency of the solubility pump. 36. Explain why the ocean is important in understanding changes in the atmospheric carbon reservoir, hence greenhouse warming. Answer: The ocean is vital in regulating atmospheric CO₂ levels and mitigating greenhouse warming. It absorbs a significant portion of human-emitted CO₂ through the solubility and biological pumps, acting as a major carbon sink. By buffering excess CO₂ and redistributing heat, the ocean helps moderate global temperatures. However, ocean warming and acidification could weaken these processes, reducing the ocean’s ability to mitigate climate change and contributing to an increase in atmospheric greenhouse gases. Understanding the ocean’s role in the carbon cycle is therefore crucial for addressing climate change. 37. Describe jetties, groins, breakwaters, and seawalls. Why are they built? i.e. for what purpose(s)? What effects, intended and unintended, do these have on the shoreline? Answer: Jetties Groins Breakwaters Seawalls Definition Long structures Short, Offshore Vertical extending from perpendicular structures that structures built shore, usually in structures built reduce wave parallel to the  pairs at harbor along a beach. energy. shore. entrances. Purpose Keep navigation Trap sand to Create calm Protect channels open by reduce beach waters for infrastructure preventing erosion. harbors or from waves and sediment protect storm surge. deposition. shorelines. Effects Maintain Build up sand on Create calm Protect the coast channels up-drift side waters and trap (intended), (intended), cause (intended), sand behind cause increased erosion increase erosion them (intended), erosion at the down-drift down-drift cause erosion in base and beach (unintended). (unintended). adjacent areas loss (unintended). (unintended). 38. Be able to describe how sediments are moved along the shoreline. Answer: Sediments are moved along the shoreline primarily by the combined actions of waves, currents, and longshore drift. Longshore Drift ○ The movement of sediments (like sand and gravel) along the coast by wave action. ○ Process: Waves approach the shore at an angle, carrying sediments up the beach with the swash. Backwash (return flow of water) moves sediments back down the beach at a perpendicular angle, resulting in a zigzag movement. This continuous zigzag pattern, known as longshore drift, moves sediments parallel to the coastline. Longshore Current ○ A current that flows parallel to the shoreline, caused by waves hitting the coast at an angle. ○ Role: The longshore current transports sediments suspended in the water along the coastline, contributing to erosion and deposition along the beach. Beach Drift ○ The movement of sediment along the beach face due to wave action. ○ Process: Sediments move up and down the beach in a zigzag pattern as waves wash up and flow back, leading to gradual transport along the coast. Wave Action ○ Swash and Backwash: The swash (water moving up the beach) and backwash (water moving back into the ocean) are critical in transporting sediments onshore and offshore, contributing to beach erosion and formation.  Sediments along the shoreline are primarily moved by longshore drift, driven by waves hitting the coast at an angle, and transported by longshore currents parallel to the shore. The combination of swash and backwash also moves sediments in a zigzag pattern along the beach. This movement plays a significant role in shaping coastal landscapes and redistributing sediments along the shore. 39. Be able to describe/compare/contrast BC’s Outer and Inner Waters, including salinity, general depth, currents, circulation, mixing, and seasonal events. Answer: British Columbia (BC) has two distinct marine environments: Outer Waters (the Pacific Ocean) and Inner Waters(Strait of Georgia, Juan de Fuca Strait, and other inshore areas). These areas differ significantly in terms of salinity, depth, currents, circulation, mixing, and seasonal changes. Salinity: Outer Waters are more saline compared to Inner Waters, which are influenced by freshwater. Depth: Outer Waters are deeper, while Inner Waters are relatively shallow. Currents and Circulation: Outer Waters are driven by large-scale ocean currents and upwelling, while Inner Waters have tidal and river-driven circulation. Mixing: Inner Waters have more intense mixing due to tidal forces, while Outer Waters have less mixing. Seasonal Events: Outer Waters have upwelling in summer, while Inner Waters show stratification during summer and mixing during winter. 40. Be able to describe / differentiate the terms within each line; what is the importance of these terms to oceans or oceanography? BC Coastal Waters: narrows / fjord / plume front / tidal mixing / deep water renewal Biogenous (calcareous and siliceous) / lithogenous / hydrogenous / cosmogenous continental shelf / continental slope / continental rise / abyssal plain / oceanic trench density / sigma-tee / pycnocline flood current / ebb current / tidal wave.5 major constituent / nutrient / trace element surface ocean / deep ocean circulation upwelling / downwelling wave crest / trough / base wave length / height / amplitude spilling / plunging / surging waves Answer: · BC Coastal Waters ○ Narrows: Narrow channels between landmasses; important for constraining tidal currents and affecting local hydrodynamics ○ Fjord: A deep, glacially carved inlet, often with steep sides; fjords are significant for studying glacial processes and deep water mixing ○ Plume front: The boundary between river outflow (plume) and ocean water; crucial for nutrient transport and primary productivity  ○ Tidal mixing: The process where tidal forces mix water columns; influencing nutrient distribution and marine ecosystem ○ Deep water renewal: the replenishment of deep waters by denser water; essential for maintaining oxygen levels and the overall health of fjor ecosystems · Biogenous (calcareous and siliceous) / lithogenous / hydrogenous / cosmogenous ○ o Biogenous Sediment: Derived from living organisms Calcareous: Made of calcium carbonate, from shells of organisms like foraminifera and coccolithophores Siliceous: Composed of silica, derived from diatoms and radiolarians Importance: these sediments form biogenic ooze, essential for studying ocean productivity and past climates ○ o Lithogenous Sediment: Originates from the weathering of rocks on land Importance: provides information on terrestrial processes and helps map ocean currents ○ o Hydrogenous sediment: Precipitated directly from seawater Importance: provides insights into chemical processes in the ocean ○ o Cosmogenous Sediment: Derived from extraterrestrial sources like meteorites Importance: provides clues about cosmic activity and impacts on earth · continental shelf / continental slope / continental rise / abyssal plain / oceanic trench ○ Continental Shelf: The submerged edge of a continent; rich in marine life and important for fishing and resource extraction ○ Continental Slope: steeper descent from the shelf to the deep ocean floor; a transition area for sediment transport ○ Continental Rise: An accumulation of sediments at the base of the slope; linking the slope to the abyssal plain ○ Abyssal plain: flat, deep ocean floor covered with fine sediments; crucial for understanding sediment deposition ○ Oceanic trench: deep depressions formed by subduction; critical for studying plate tectonics and earthquake activity · density / sigma-tee / pycnocline ○ Density: Mass per unit volume of seawater, affected by temperature and salinity; it controls water movement and stratification ○ Sigma-tee: A measure of seawater density; used in oceanography to determine stability and mixing of water layers ○ Pycnocline: A layer in the ocean where density changes rapidly with depth; acting as a barrier to vertical mixing  · flood current / ebb current / tidal wave ○ Flood current: The flow of water toward the land as the tide rises ○ Ebb current: The flow of water seaward as the tide falls ○ Tidal Wave: A wave formed by tidal forces, sometimes confused with tsunami; important for understanding tides and coastal flooding · major constituent / nutrient / trace element ○ Major constituent: Elements found in constant proportions in seawater, such as sodium and chloride; Essential for ocean salinity ○ Nutrient: Substances like nitrates, phosphates, and silicates that are vital for marine plant growth ○ Trace element: elements present in minute quantities, like iron and zinc, critical for biological processes in marine ecosystems · surface ocean / deep ocean circulation ○ surface ocean circulation: movement of water primarily driven by wind, forming currents such as the Gulf Stream; important for climate regulation and heat transport ○ deep ocean circulation: movement driven by density differences (thermohaline circulation); crucial for nutrient transport and long-term climate regulation · upwelling/downwelling ○ upwelling: the upward movement of nutrient-rich deep water to the surface; promoting high productivity and supporting fisheries ○ downwelling: the sinking of surface water; transporting oxygen to deeper layers and affecting glbal nutrient cycles · wave crest / trough / base ○ crest: highest point of a wave ○ trough: lowest point of a wave ○ base: the depth to which the wave’s energy reaches, about half the wavelength. Important for understanding wave interactions with the seabed · wave length / height / amplitude ○ wavelength: the distance between two successive crests or troughs; important for determining wave energy and speed ○ height: the vertical distance from trough to crest; and indicator of wave energy ○ amplitude: half of the wave height; used in calculating wave energy and interactions · spilling / plunging / surging waves ○ spilling waves: waves that breaks gently, spilling water down the front; common on flat shorelines and important for beach formation ○ plunging waves: waves that break with force, forming a hollow tube; occur on steep shorelines, affecting coastal erosion ○ surging waves: waves that surge up the beach without breaking; common on very steep beaches and can cause strong backwash