Oceanography Notes

Abrasion: The mechanical wearing down of rock and surface materials through repetitive friction and impact, primarily driven by the erosive forces of wind, water, or glacial ice, resulting in the alteration of landscapes and the creation of finer sediments.

Breakwave: A dynamic ocean phenomenon characterized by the instability and subsequent collapse of incoming waves as they approach the shoreline, crucial for shaping coastal environments by redistributing sediments and influencing coastal erosion processes.

Coriolis Effect: The apparent deflection of moving objects, such as wind and ocean currents, due to the Earth's rotation; in the Northern Hemisphere, this effect causes them to veer to the right (clockwise), while in the Southern Hemisphere, it causes them to veer to the left (counterclockwise), impacting weather patterns, ocean circulation, and navigation.

Gyre: Large circular systems of ocean currents created by the interplay of the Coriolis effect, trade winds, and westerlies; the five major gyres (North Atlantic, South Atlantic, North Pacific, South Pacific, and Indian Ocean) play a crucial role in global climate regulation, nutrient distribution, and the transport of marine debris, including impacts like the Great Pacific Garbage Patch.

Longshore Current: A current that flows parallel to the shoreline, generated by waves breaking at an angle to the coast; this current plays a vital role in the transportation and redistribution of sediments along the beach, influencing coastal erosion, deposition, and the formation of various coastal features.

Seawall: A man-made structure constructed along coastlines to protect against wave action and erosion; seawalls aim to prevent shoreline retreat and coastal flooding but can also lead to increased erosion in adjacent areas.

Submergent Coast: A coastal configuration formed when sea levels rise or land subsides, leading to the inundation of coastal areas; characteristics may include river valleys drowned by rising seas, leading to the creation of bays and estuaries.

Surf: The zone of turbulent water formed by breaking waves near the shore; surf is important in shaping coastlines, affecting marine ecosystems, and providing recreational opportunities.

Thermohaline Circulation: The large-scale circulation of ocean water driven by differences in temperature and salinity, which influences global oceanic currents; this circulation is crucial for regulating climate and distributing heat across the planet.

Upwelling: The process by which deeper, colder, and nutrient-rich waters rise to the ocean surface, often stimulated by wind patterns; upwelling regions are typically associated with high biological productivity and support diverse marine ecosystems.

Wave Height: The vertical distance between the crest (top) of a wave and its trough (bottom); wave height is influenced by wind speed, duration, and the fetch (distance over which the wind blows), impacting coastal processes and marine navigation.

Wavelength: The horizontal distance between consecutive wave crests or troughs; wavelength is a key factor in determining wave energy and propagation speed, influencing ocean dynamics.

Wave of Oscillation: A type of wave in deep water where water particles move in circular orbits, transmitting energy without significant water displacement; this oscillatory motion is typical of waves traveling across open ocean.

Wave of Translation: A wave type that occurs in shallow water, characterized by the forward movement of both energy and water; these waves break as they approach the shore, contributing to coastal erosion and sediment transport.

Wave Period: The time interval between consecutive wave crests passing a fixed point; wave period is crucial for understanding wave dynamics and predicting coastal interactions.

Wave Refraction: The bending of wave fronts as they approach shallow water and alter direction; wave refraction focuses wave energy on headlands and disperses it in bays, influencing coastal erosion patterns and sediment deposition.

Active Continental Margin: A geologically active region where oceanic and continental crust converge, characterized by tectonic plate interactions that create features such as trenches, volcanic arcs, and frequent seismic activity.

Aphotic Zone: The layer of the ocean that is devoid of sunlight, typically found at depths greater than 200 meters; this zone lacks photosynthetic life, relying instead on organic matter falling from upper layers for sustenance.

Biogenous Sediment: Sediments primarily composed of the remains of marine organisms, such as shells and skeletons, which contributes to ocean floor composition and play a vital role in the carbon cycle.

Continental Margin: The zone of interaction between continental and oceanic crust, consisting of the continental shelf, slope, and rise, representing a transition from terrestrial to marine environments.

Continental Rise: The gently sloping region at the base of the continental slope, formed by the accumulation of sediments that have cascaded down from the shelf and slope, contributing to ocean floor morphology.

Continental Shelf: The submerged extension of a continent, characterized by shallow waters and a gradual slope, supporting rich marine ecosystems and significant marine resources.

Continental Slope: The steeply inclined seaward edge of the continental shelf that marks the transition to the deep ocean floor; it is significant in sediment transport and underwater geological processes.

Deep-Ocean Trench: Narrow, elongated depressions in the ocean floor formed at convergent plate boundaries, representing the deepest parts of the ocean where subduction occurs, often associated with volcanic activity.

Graded Bedding: A sedimentary structure characterized by a gradual change in particle size, where coarser materials settle first, followed by progressively finer materials; this feature typically indicates variations in energy levels during deposition.

Halocline: A stratified layer in ocean water characterized by a rapid change in salinity with depth; the halocline affects water density and can influence marine life and ocean circulation.

Hydrogenous Sediment: Sediments that originate from the precipitation of dissolved minerals from seawater, often forming features such as manganese nodules and phosphorites, contributing to oceanic mineral deposits.

Intertidal Zone: The coastal area that is alternately submerged and exposed by tidal movements, hosting a unique array of organisms adapted to fluctuating environmental conditions.

Mid-Ocean Ridge: A divergent plate boundary located along underwater mountain ranges where new ocean floor is generated; this geological feature is integral to plate tectonics and ocean floor spreading.

Oceanography: The comprehensive study of the ocean encompassing its physical, chemical, geological, and biological processes, aimed at understanding marine systems and their interactions with the Earth.

Outgassing: The release of gases from the Earth's interior, particularly from volcanic activity, contributing to the formation of the atmosphere and oceans and influencing climate over geological time scales.

Passive Continental Margin: A stable region where the continental crust transitions gently into the oceanic crust without significant tectonic activity, typically characterized by wide continental shelves and slopes.

Photic Zone: The upper layer of the ocean where sunlight penetrates, supporting photosynthetic life; this zone is critical for marine ecosystems and energy transfer in oceanic food webs.

Rift Valley: A landform created by the divergence of tectonic plates, characterized by a long, narrow depression; rift valleys can form on land or under the ocean, often leading to the creation of new ocean basins.

Salinity: The concentration of dissolved salts in water, typically expressed in parts per thousand (ppt); salinity plays a crucial role in determining water density and influencing ocean circulation patterns.

Submarine Canyon: A deep, steep-sided valley carved into the seafloor, often formed by the erosion of sediments and currents; these features can enhance sediment transport and influence marine ecosystems.

Terrigenous Sediment: Sediments primarily derived from terrestrial sources, transported to the ocean by rivers, wind, and glaciers, contributing to the composition of ocean floor deposits.

Thermocline: A distinct layer in the ocean characterized by a rapid decline in temperature with depth, acting as a barrier that separates warmer surface waters from colder deep waters, influencing marine life and circulation.

Turbidite: A sedimentary deposit characterized by graded bedding, formed by turbidity currents that transport suspended sediments down Continental slopes and into deeper ocean basins.

Turbidity Current: A fast-moving underwater flow of sediment-laden water that occurs along the ocean floor, usually triggered by disturbances such as earthquakes or sediment accumulation, playing a key role in sediment transport and the formation of deep-sea deposits.