the changing marine environment charting the deep charting the deep understanding of the sea...
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The Changing Marine The Changing Marine EnvironmentEnvironmentThe Changing Marine The Changing Marine EnvironmentEnvironment• Charting the DeepCharting the Deep• Understanding of the sea requires a Understanding of the sea requires a
shift in perspective toward a shift in perspective toward a “geological perspective” that allows for “geological perspective” that allows for our five-billion-year history and vast our five-billion-year history and vast distances greater than several distances greater than several thousand kilometers.thousand kilometers.
The Changing Marine The Changing Marine EnvironmentEnvironmentThe Changing Marine The Changing Marine EnvironmentEnvironment
The Changing Marine The Changing Marine EnvironmentEnvironmentThe Changing Marine The Changing Marine EnvironmentEnvironment
• Charting the DeepCharting the Deep• The interrelated concepts of The interrelated concepts of
continental drift and plate tectonics continental drift and plate tectonics have radically changed our view of the have radically changed our view of the ocean’s structure.ocean’s structure.
The Changing Marine The Changing Marine EnvironmentEnvironmentThe Changing Marine The Changing Marine EnvironmentEnvironment
•Fig. 1.5 The major plates of the earth's crusts. Fig. 1.5 The major plates of the earth's crusts.
The World OceanThe World OceanThe World OceanThe World Ocean
– Earth’s Earth’s oceans oceans exist as a exist as a large large inter-inter-connecteconnected system d system of mixing of mixing seawater.seawater.
Fig. 1.10 An equatorial view of the world ocean.
Visualizing the World Ocean
The World OceanThe World OceanThe World OceanThe World Ocean
•Seeing in the DarkSeeing in the Dark– Water is nearly opaque to light, yet Water is nearly opaque to light, yet
very transparent to sound. very transparent to sound.
The World OceanThe World OceanThe World OceanThe World Ocean
•Fig. 1.11 Some large-scale features of the North Atlantic seafloor. Fig. 1.11 Some large-scale features of the North Atlantic seafloor.
Properties of SeawaterProperties of SeawaterProperties of SeawaterProperties of Seawater• Pure WaterPure Water
Properties of SeawaterProperties of SeawaterProperties of SeawaterProperties of Seawater
•Pure WaterPure Water– The unique characteristics of pure water are The unique characteristics of pure water are
established by an electrical charge separation established by an electrical charge separation within water molecules that forms hydrogen within water molecules that forms hydrogen bonds between adjacent water molecules. bonds between adjacent water molecules.
Fig. 1.14 Hydrogen bonding between adjacent molecules of liquid water. Blue dashed lines represent hydrogen bonds.
Fig. 1.13 The arrangement of H and O atoms in a molecule of water.
Properties of SeawaterProperties of SeawaterProperties of SeawaterProperties of Seawater•SeawaterSeawater•Salt water contains a great variety of Salt water contains a great variety of dissolved salts, gases, and other inorganic dissolved salts, gases, and other inorganic and organic substances. and organic substances. •These dissolved molecules and These dissolved molecules and compounds affect many characteristics of compounds affect many characteristics of seawater, including its density, osmotic seawater, including its density, osmotic properties, buffering capacity, and other properties, buffering capacity, and other biologically significant features.biologically significant features.
Properties Properties of of SeawaterSeawater
Properties Properties of of SeawaterSeawater•Fig. 1.20 A Fig. 1.20 A comparison of the comparison of the osmotic osmotic conditions of a conditions of a sea cucumber sea cucumber and a salmon in and a salmon in seawater and seawater and fresh water.fresh water.
PropertieProperties of s of SeawaterSeawater
PropertieProperties of s of SeawaterSeawater
•Fig. 1.21 Fate of Fig. 1.21 Fate of sunlight as it enters sea sunlight as it enters sea water. The violet and red water. The violet and red ends of the visible ends of the visible spectrum are absorbed spectrum are absorbed first.first.
Properties of SeawaterProperties of SeawaterProperties of SeawaterProperties of Seawater
•Fig. 1.27 Earth's sea surface temperatures obtained from two weeks of Fig. 1.27 Earth's sea surface temperatures obtained from two weeks of satellite infrared observations July 1984. satellite infrared observations July 1984.
Properties of SeawaterProperties of SeawaterProperties of SeawaterProperties of Seawater
•Fig. 1.30 Variations in water temperature (orange curve) and salinity Fig. 1.30 Variations in water temperature (orange curve) and salinity (blue curve) at a GEOSECS station in the western South Atlantic Ocean.(blue curve) at a GEOSECS station in the western South Atlantic Ocean.
The Ocean in MotionThe Ocean in MotionThe Ocean in MotionThe Ocean in Motion
• The sea is constantly moving, both The sea is constantly moving, both horizontally and vertically. Winds, horizontally and vertically. Winds, waves, tides, currents, sinking waves, tides, currents, sinking water masses, and upwelling all water masses, and upwelling all contribute to the remarkable contribute to the remarkable homogeneity of the world ocean.homogeneity of the world ocean.
The Ocean in MotionThe Ocean in MotionThe Ocean in MotionThe Ocean in Motion• Wind WavesWind Waves• The character of wind-driven ocean waves The character of wind-driven ocean waves
depends on the wind’s speed, duration, and fetch. depends on the wind’s speed, duration, and fetch.
Fig. 1.35 Wave form and pattern of water motion in a deepwater wave as it moves to the right in to shore.
The Ocean in MotionThe Ocean in MotionThe Ocean in MotionThe Ocean in Motion
• Surface CurrentsSurface Currents– Ocean surface currents are driven by Ocean surface currents are driven by
stable patterns of surface winds .stable patterns of surface winds .
The Ocean in MotionThe Ocean in MotionThe Ocean in MotionThe Ocean in Motion
•Fig. 1.38 The major surface currents of the world ocean. Fig. 1.38 The major surface currents of the world ocean. •Adapted from Pickard and Emory, 1982.Adapted from Pickard and Emory, 1982.
The Ocean in MotionThe Ocean in MotionThe Ocean in MotionThe Ocean in Motion
•Ocean TidesOcean Tides– Ocean tides are driven by the Ocean tides are driven by the
gravitational interactions of the Sun, gravitational interactions of the Sun, Earth, and Earth’s moon.Earth, and Earth’s moon.
The Ocean in MotionThe Ocean in MotionThe Ocean in MotionThe Ocean in Motion
•Fig. 1.40 A point on the earth's Fig. 1.40 A point on the earth's surface (indicated by the marker) surface (indicated by the marker) experiences high tides when under experiences high tides when under tidal bulges and low tides when at tidal bulges and low tides when at right angles to tidal bulges.right angles to tidal bulges.
Fig. 1.41 Weekly tidal variations caused by changes in the relative positions of the earth, moon, and sun.
The Ocean in MotionThe Ocean in MotionThe Ocean in MotionThe Ocean in Motion
•Vertical Water MovementsVertical Water Movements– Vertical circulation of ocean water results Vertical circulation of ocean water results
from density-driven sinking processes.from density-driven sinking processes.
The Ocean in MotionThe Ocean in MotionThe Ocean in MotionThe Ocean in Motion
•Fig. 1.44 The general pattern of deep-ocean circulation in the Fig. 1.44 The general pattern of deep-ocean circulation in the major ocean basins. major ocean basins. Adapted from Broecker et al, 1985.Adapted from Broecker et al, 1985.
Classification of the Marine Classification of the Marine EnvironmentEnvironmentClassification of the Marine Classification of the Marine EnvironmentEnvironment
• Energy from the sun warms the Energy from the sun warms the sea’s surface and creates winds sea’s surface and creates winds that result in a two-layered world that result in a two-layered world ocean, with a shallow, well-mixed, ocean, with a shallow, well-mixed, warm, sunlit layer overlaying a warm, sunlit layer overlaying a much deeper, cold, dark, high-much deeper, cold, dark, high-pressure layer of slowly moving pressure layer of slowly moving water below.water below.
Classification of the Marine Classification of the Marine EnvironmentEnvironmentClassification of the Marine Classification of the Marine EnvironmentEnvironment
•The three-dimensional marine The three-dimensional marine environment can be separated into two environment can be separated into two broad divisions, broad divisions,
– the benthic realm of the sea floor the benthic realm of the sea floor
– and the pelagic water column. and the pelagic water column.
•These in turn may be subdivided into These in turn may be subdivided into smaller categories based on water depth, smaller categories based on water depth, light availability, and ambient light availability, and ambient temperature.temperature.
Classification of the Marine Classification of the Marine EnvironmentEnvironmentClassification of the Marine Classification of the Marine EnvironmentEnvironment
• The marine environment is a large The marine environment is a large and complex system, so we create and complex system, so we create classification systems to better classification systems to better understand the relationships understand the relationships between the physical characteristics between the physical characteristics of the ocean.of the ocean.
Classification of the Marine Classification of the Marine EnvironmentEnvironmentClassification of the Marine Classification of the Marine EnvironmentEnvironment
•Fig. 1.46 A system for classifying the marine environment. Fig. 1.46 A system for classifying the marine environment. •Adapted from Hedgpeth 1957Adapted from Hedgpeth 1957..