Oceanography CAS NS 221 (3 Credits)
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Coastal Processes and Causes of Shoreline Erosion and Accretion Causes of Shoreline Erosion and Accretion
Coastal Processes and Causes of Shoreline Erosion and Accretion and Accretion Erosion Causes of Shoreline Heather Weitzner, Great Lakes Coastal Processes and Hazards Specialist Photo by Brittney Rogers, New York Sea Grant York Photo by Brittney Rogers, New New York Sea Grant Waves breaking on the eastern Lake Ontario shore. Wayne County Cooperative Extension A shoreline is a dynamic environment that evolves under the effects of both natural 1581 Route 88 North and human influences. Many areas along New York’s shorelines are naturally subject Newark, NY 14513-9739 315.331.8415 to erosion. Although human actions can impact the erosion process, natural coastal processes, such as wind, waves or ice movement are constantly eroding and/or building www.nyseagrant.org up the shoreline. This constant change may seem alarming, but erosion and accretion (build up of sediment) are natural phenomena experienced by the shoreline in a sort of give and take relationship. This relationship is of particular interest due to its impact on human uses and development of the shore. This fact sheet aims to introduce these processes and causes of erosion and accretion that affect New York’s shorelines. Waves New York’s Sea Grant Extension Program Wind-driven waves are a primary source of coastal erosion along the Great provides Equal Program and Lakes shorelines. Factors affecting wave height, period and length include: Equal Employment Opportunities in 1. Fetch: the distance the wind blows over open water association with Cornell Cooperative 2. Length of time the wind blows Extension, U.S. Department 3. Speed of the wind of Agriculture and 4. -
Basic Concepts in Oceanography
Chapter 1 XA0101461 BASIC CONCEPTS IN OCEANOGRAPHY L.F. SMALL College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, United States of America Abstract Basic concepts in oceanography include major wind patterns that drive ocean currents, and the effects that the earth's rotation, positions of land masses, and temperature and salinity have on oceanic circulation and hence global distribution of radioactivity. Special attention is given to coastal and near-coastal processes such as upwelling, tidal effects, and small-scale processes, as radionuclide distributions are currently most associated with coastal regions. 1.1. INTRODUCTION Introductory information on ocean currents, on ocean and coastal processes, and on major systems that drive the ocean currents are important to an understanding of the temporal and spatial distributions of radionuclides in the world ocean. 1.2. GLOBAL PROCESSES 1.2.1 Global Wind Patterns and Ocean Currents The wind systems that drive aerosols and atmospheric radioactivity around the globe eventually deposit a lot of those materials in the oceans or in rivers. The winds also are largely responsible for driving the surface circulation of the world ocean, and thus help redistribute materials over the ocean's surface. The major wind systems are the Trade Winds in equatorial latitudes, and the Westerly Wind Systems that drive circulation in the north and south temperate and sub-polar regions (Fig. 1). It is no surprise that major circulations of surface currents have basically the same patterns as the winds that drive them (Fig. 2). Note that the Trade Wind System drives an Equatorial Current-Countercurrent system, for example. -
Hydrothermal Vents. Teacher's Notes
Hydrothermal Vents Hydrothermal Vents. Teacher’s notes. A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. They are usually volcanically active. Seawater penetrates into fissures of the volcanic bed and interacts with the hot, newly formed rock in the volcanic crust. This heated seawater (350-450°) dissolves large amounts of minerals. The resulting acidic solution, containing metals (Fe, Mn, Zn, Cu) and large amounts of reduced sulfur and compounds such as sulfides and H2S, percolates up through the sea floor where it mixes with the cold surrounding ocean water (2-4°) forming mineral deposits and different types of vents. In the resulting temperature gradient, these minerals provide a source of energy and nutrients to chemoautotrophic organisms that are, thus, able to live in these extreme conditions. This is an extreme environment with high pressure, steep temperature gradients, and high concentrations of toxic elements such as sulfides and heavy metals. Black and white smokers Some hydrothermal vents form a chimney like structure that can be as 60m tall. They are formed when the minerals that are dissolved in the fluid precipitates out when the super-heated water comes into contact with the freezing seawater. The minerals become particles with high sulphur content that form the stack. Black smokers are very acidic typically with a ph. of 2 (around that of vinegar). A black smoker is a type of vent found at depths typically below 3000m that emit a cloud or black material high in sulphates. White smokers are formed in a similar way but they emit lighter-hued minerals, for example barium, calcium and silicon. -
Introduction to Co2 Chemistry in Sea Water
INTRODUCTION TO CO2 CHEMISTRY IN SEA WATER Andrew G. Dickson Scripps Institution of Oceanography, UC San Diego Mauna Loa Observatory, Hawaii Monthly Average Carbon Dioxide Concentration Data from Scripps CO Program Last updated August 2016 2 ? 410 400 390 380 370 2008; ~385 ppm 360 350 Concentration (ppm) 2 340 CO 330 1974; ~330 ppm 320 310 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 Year EFFECT OF ADDING CO2 TO SEA WATER 2− − CO2 + CO3 +H2O ! 2HCO3 O C O CO2 1. Dissolves in the ocean increase in decreases increases dissolved CO2 carbonate bicarbonate − HCO3 H O O also hydrogen ion concentration increases C H H 2. Reacts with water O O + H2O to form bicarbonate ion i.e., pH = –lg [H ] decreases H+ and hydrogen ion − HCO3 and saturation state of calcium carbonate decreases H+ 2− O O CO + 2− 3 3. Nearly all of that hydrogen [Ca ][CO ] C C H saturation Ω = 3 O O ion reacts with carbonate O O state K ion to form more bicarbonate sp (a measure of how “easy” it is to form a shell) M u l t i p l e o b s e r v e d indicators of a changing global carbon cycle: (a) atmospheric concentrations of carbon dioxide (CO2) from Mauna Loa (19°32´N, 155°34´W – red) and South Pole (89°59´S, 24°48´W – black) since 1958; (b) partial pressure of dissolved CO2 at the ocean surface (blue curves) and in situ pH (green curves), a measure of the acidity of ocean water. -
Hydrogeology of Near-Shore Submarine Groundwater Discharge
Hydrogeology and Geochemistry of Near-shore Submarine Groundwater Discharge at Flamengo Bay, Ubatuba, Brazil June A. Oberdorfer (San Jose State University) Matthew Charette, Matthew Allen (Woods Hole Oceanographic Institution) Jonathan B. Martin (University of Florida) and Jaye E. Cable (Louisiana State University) Abstract: Near-shore discharge of fresh groundwater from the fractured granitic rock is strongly controlled by the local geology. Freshwater flows primarily through a zone of weathered granite to a distance of 24 m offshore. In the nearshore environment this weathered granite is covered by about 0.5 m of well-sorted, coarse sands with sea water salinity, with an abrupt transition to much lower salinity once the weathered granite is penetrated. Further offshore, low-permeability marine sediments contained saline porewater, marking the limit of offshore migration of freshwater. Freshwater flux rates based on tidal signal and hydraulic gradient analysis indicate a fresh submarine groundwater discharge of 0.17 to 1.6 m3/d per m of shoreline. Dissolved inorganic nitrogen and silicate were elevated in the porewater relative to seawater, and appeared to be a net source of nutrients to the overlying water column. The major ion concentrations suggest that the freshwater within the aquifer has a short residence time. Major element concentrations do not reflect alteration of the granitic rocks, possibly because the alteration occurred prior to development of the current discharge zones, or from elevated water/rock ratios. Introduction While there has been a growing interest over the last two decades in quantifying the discharge of groundwater to the coastal zone, the majority of studies have been carried out in aquifers consisting of unlithified sediments or in karst environments. -
Worksheet 5.1--The History of Oceanography
Worksheet 5.1--The History of Oceanography Reading: Introduction to the World’s Oceans pages 4-22 1. The field of oceanography today is so broad that oceanography is usually broken down into a number of sub disciplines: a. ________________________________________ includes the study of the earth at the sea’s edge and below its surface b. ________________________________________ investigates how and why the oceans move c. ________________________________________ is the study of heat transfer, water cycles, and air-sea interactions. d. ________________________________________ studies the composition and history of the water e. ________________________________________ concerns the marine organisms and the relationship between these organisms and the environment. f. ________________________________________ is the discipline that designs and plans equipment and installations for use at sea. 2. When did oceanography begin to develop as a modern science? ____________________ The Early Times 3. Around 200 BC the Egyptian scientist Eratosthenes mapped the known world and calculated the circumference of the earth as 40,250 km. Today’s measurement is ______________ . How far from the correct value was Erathosthenes? 4. Approximately 350 years later the Roman Scientist Ptolemy produced the world’s first atlas. His atlas listed more than 8,000 places by latitude and longitude but his work contained a major flaw. What was it? 5. What difference would it have made for Columbus and other explorers if they had used Erathosthenes’ more accurate estimate of the earth’s circumference rather than Ptolemy’s flawed estimate? The Middle Ages 6. When did the Vikings reach North America? _______________ 7. Who first established regular trade routes across the Indian Ocean? _______________ 8. -
World Ocean Thermocline Weakening and Isothermal Layer Warming
applied sciences Article World Ocean Thermocline Weakening and Isothermal Layer Warming Peter C. Chu * and Chenwu Fan Naval Ocean Analysis and Prediction Laboratory, Department of Oceanography, Naval Postgraduate School, Monterey, CA 93943, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-831-656-3688 Received: 30 September 2020; Accepted: 13 November 2020; Published: 19 November 2020 Abstract: This paper identifies world thermocline weakening and provides an improved estimate of upper ocean warming through replacement of the upper layer with the fixed depth range by the isothermal layer, because the upper ocean isothermal layer (as a whole) exchanges heat with the atmosphere and the deep layer. Thermocline gradient, heat flux across the air–ocean interface, and horizontal heat advection determine the heat stored in the isothermal layer. Among the three processes, the effect of the thermocline gradient clearly shows up when we use the isothermal layer heat content, but it is otherwise when we use the heat content with the fixed depth ranges such as 0–300 m, 0–400 m, 0–700 m, 0–750 m, and 0–2000 m. A strong thermocline gradient exhibits the downward heat transfer from the isothermal layer (non-polar regions), makes the isothermal layer thin, and causes less heat to be stored in it. On the other hand, a weak thermocline gradient makes the isothermal layer thick, and causes more heat to be stored in it. In addition, the uncertainty in estimating upper ocean heat content and warming trends using uncertain fixed depth ranges (0–300 m, 0–400 m, 0–700 m, 0–750 m, or 0–2000 m) will be eliminated by using the isothermal layer. -
Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future
Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future As more and more states are incorporating projections of sea-level rise into coastal planning efforts, the states of California, Oregon, and Washington asked the National Research Council to project sea-level rise along their coasts for the years 2030, 2050, and 2100, taking into account the many factors that affect sea-level rise on a local scale. The projections show a sharp distinction at Cape Mendocino in northern California. South of that point, sea-level rise is expected to be very close to global projections; north of that point, sea-level rise is projected to be less than global projections because seismic strain is pushing the land upward. ny significant sea-level In compliance with a rise will pose enor- 2008 executive order, mous risks to the California state agencies have A been incorporating projec- valuable infrastructure, devel- opment, and wetlands that line tions of sea-level rise into much of the 1,600 mile shore- their coastal planning. This line of California, Oregon, and study provides the first Washington. For example, in comprehensive regional San Francisco Bay, two inter- projections of the changes in national airports, the ports of sea level expected in San Francisco and Oakland, a California, Oregon, and naval air station, freeways, Washington. housing developments, and sports stadiums have been Global Sea-Level Rise built on fill that raised the land Following a few thousand level only a few feet above the years of relative stability, highest tides. The San Francisco International Airport (center) global sea level has been Sea-level change is linked and surrounding areas will begin to flood with as rising since the late 19th or to changes in the Earth’s little as 40 cm (16 inches) of sea-level rise, a early 20th century, when climate. -
Deep-Sea Mining: the Basics
A fact sheet from June 2018 NOAA Office of Ocean Exploration and Research Deep-sea Mining: The Basics Overview The deepest parts of the world’s ocean feature ecosystems found nowhere else on Earth. They provide habitat for multitudes of species, many yet to be named. These vast, lightless regions also possess deposits of valuable minerals in rich concentrations. Deep-sea extraction technologies may soon develop to the point where exploration of seabed minerals can give way to active exploitation. The International Seabed Authority (ISA) is charged with formulating and enforcing rules for all seabed mining that takes place in waters beyond national jurisdictions. These rules are now under development. Environmental regulations, liability and financial rules, and oversight and enforcement protocols all must be written and approved within three to five years. Figure 1 Types of Deep-sea Mining Production support vessel Return pipe Riser pipe Cobalt Seafloor massive Polymetallic crusts sulfides nodules Subsurface plumes 800-2,500 from return water meters deep Deposition 1,000-4,000 meters deep 4,000-6,500 meters deep Cobalt-rich Localized plumes Seabed pump Ferromanganeseferromanganese from cutting crusts Seafloor production tool Nodule deposit Massive sulfide deposit Sediment Source: New Zealand Environment Guide © 2018 The Pew Charitable Trusts 2 The legal foundations • The United Nations Convention on the Law of the Sea (UNCLOS). Also known as the Law of the Sea Treaty, UNCLOS is the constitutional document governing mineral exploitation on the roughly 60 percent of the world seabed that lies beyond national jurisdictions. UNCLOS took effect in 1994 upon passage of key enabling amendments designed to spur commercial mining. -
Introduction to Oceanography
Introduction to Oceanography Introduction to Oceanography Lecture 14: Tides, Biological Productivity Memorial Day holiday Monday no lab meetings Go to any other lab section this week (and let the TA know!) Bay of Fundy -- low tide, Photo by Dylan Kereluk, . Creative Commons A 2.0 Generic, Mudskipper (Periophthalmus modestus) at low tide, photo by OpenCage, Wikimedia Commons, Creative http://commons.wikimedia.org/wiki/File:Bay_of_Fundy_-_Tide_Out.jpg Commons A S-A 2.5, http://commons.wikimedia.org/wiki/File:Periophthalmus_modestus.jpg Tides Earth-Moon-Sun System Planet-length waves Cyclic, repeating rise & fall of sea level • Earth-Sun Distance – Most regular phenomenon in the oceans 150,000,000 km Daily tidal variation has great effects on life in & around the ocean (Lab 8) • Earth-Moon Distance 385,000 km Caused by gravity and Much closer to Earth, but between Earth, Moon & much less massive Sun, their orbits around • Earth Obliquity = 23.5 each other, and the degrees Earth’s daily spin – Seasons Photos by Samuel Wantman, Creative Commons A S-A 3.0, http://en.wikipedia.org/ wiki/File:Bay_of_Fundy_Low_Tide.jpg and Figure by Homonculus 2/Geologician, Wikimedia Commons, http://en.wikipedia.org/wiki/ Creative Commons A 3.0, http://en.wikipedia.org/wiki/ File:Bay_of_Fundy_High_Tide.jpg File:Lunar_perturbation.jpg Tides are caused by the gravity of the Moon and Sun acting on Scaled image of Earth-Moon distance, Nickshanks, Wikimedia Commons, Creative Commons A 2.5 Earth and its ocean. Pluto-Charon mutual orbit, Zhatt, Wikimedia Commons, Public -
Causes of Sea Level Rise
FACT SHEET Causes of Sea OUR COASTAL COMMUNITIES AT RISK Level Rise What the Science Tells Us HIGHLIGHTS From the rocky shoreline of Maine to the busy trading port of New Orleans, from Roughly a third of the nation’s population historic Golden Gate Park in San Francisco to the golden sands of Miami Beach, lives in coastal counties. Several million our coasts are an integral part of American life. Where the sea meets land sit some of our most densely populated cities, most popular tourist destinations, bountiful of those live at elevations that could be fisheries, unique natural landscapes, strategic military bases, financial centers, and flooded by rising seas this century, scientific beaches and boardwalks where memories are created. Yet many of these iconic projections show. These cities and towns— places face a growing risk from sea level rise. home to tourist destinations, fisheries, Global sea level is rising—and at an accelerating rate—largely in response to natural landscapes, military bases, financial global warming. The global average rise has been about eight inches since the centers, and beaches and boardwalks— Industrial Revolution. However, many U.S. cities have seen much higher increases in sea level (NOAA 2012a; NOAA 2012b). Portions of the East and Gulf coasts face a growing risk from sea level rise. have faced some of the world’s fastest rates of sea level rise (NOAA 2012b). These trends have contributed to loss of life, billions of dollars in damage to coastal The choices we make today are critical property and infrastructure, massive taxpayer funding for recovery and rebuild- to protecting coastal communities. -
Baja California Sur, Mexico)
Journal of Marine Science and Engineering Article Geomorphology of a Holocene Hurricane Deposit Eroded from Rhyolite Sea Cliffs on Ensenada Almeja (Baja California Sur, Mexico) Markes E. Johnson 1,* , Rigoberto Guardado-France 2, Erlend M. Johnson 3 and Jorge Ledesma-Vázquez 2 1 Geosciences Department, Williams College, Williamstown, MA 01267, USA 2 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada 22800, Baja California, Mexico; [email protected] (R.G.-F.); [email protected] (J.L.-V.) 3 Anthropology Department, Tulane University, New Orleans, LA 70018, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-413-597-2329 Received: 22 May 2019; Accepted: 20 June 2019; Published: 22 June 2019 Abstract: This work advances research on the role of hurricanes in degrading the rocky coastline within Mexico’s Gulf of California, most commonly formed by widespread igneous rocks. Under evaluation is a distinct coastal boulder bed (CBB) derived from banded rhyolite with boulders arrayed in a partial-ring configuration against one side of the headland on Ensenada Almeja (Clam Bay) north of Loreto. Preconditions related to the thickness of rhyolite flows and vertical fissures that intersect the flows at right angles along with the specific gravity of banded rhyolite delimit the size, shape and weight of boulders in the Almeja CBB. Mathematical formulae are applied to calculate the wave height generated by storm surge impacting the headland. The average weight of the 25 largest boulders from a transect nearest the bedrock source amounts to 1200 kg but only 30% of the sample is estimated to exceed a full metric ton in weight.