GEOG 1290 Section G F2024 Oceanography PDF

Section G. Oceanography Introduction to Physical Geography GEOG 1290 Department of Environment and Geography University of Manitoba Janna Wilson and Lisa Ford  Copyright Lecture slides, course notes, and educational resourc...

Section G. Oceanography Introduction to Physical Geography GEOG 1290 Department of Environment and Geography University of Manitoba Janna Wilson and Lisa Ford  Copyright Lecture slides, course notes, and educational resources are copyright-protected and made available to you for your personal educational use and private study only. Unless stated otherwise, further copying and distribution of these materials is strictly prohibited. © Janna Wilson & Lisa Ford, 2024. Further electronic or hard copy reproduction and or distribution of this content in part or in whole is strictly prohibited. Section G. Oceanography G.1 Oceanic physical & chemical properties G.2 Oceanic Circulation G.1 Oceanic Physical & Chemical Properties Learning Objective: To list the major physical & chemical properties of the oceans.  Ocean Facts Covers 71% of Earth’s surface One World Ocean - 5 Ocean Basins Regulate atmosphere’s chemical composition 70% of O2 in atmosphere comes from photosynthesis in oceans Modify Earth’s climate and weather systems ~ ½ of world’s population depends directly on oceans as main food source Figure G.1.a World Ocean Basins (https://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/World_map_ocean_locator- en.svg/1920px-World_map_ocean_locator-en.svg.png) CC license: https://en.wikipedia.org/wiki/Ocean#/media/File:World_map_ocean_locator-en.svg  Light Penetration Zones 1. Euphotic (sunlight) zone 2. Dysphotoic (twilight) zone 3. Aphotic (midnight) zone Figure G.1.b The ocean is divided into three zones based on depth and light level. Figure 10.45 Depth of penetration of solar Although some sea creatures depend on light to live, others can do without it radiation (Gervais, 2019, p. 307). (NOAA, 2020d)  Ocean Salinity The concentration of dissolved minerals in water Ocean salinity ~35 (3.5% of seawater by weight are salts) (NOAA, 2020c) Practical Salinity units: 1 PSU = 1 ppt Sources of oceans 1. runoff from the land and 2. openings in the seafloor Table 5.3.1 The six major ions in seawater (Webb, n.d., p. 104)  Ocean Salinity Variations Salinity varies with changes in temperature, evaporation precipitation and freshwater input from rivers ITCZ /Polar front: ⇡ rain ⇢ ⇣ salinity SHPB: ⇡ evaporation ⇢ ⇡ salinity Arctic Ocean salinity is less (~30-35) Due to: 1. fresh water from melting ice 2. ⇡ precipitations ⇣ evaporation 3. emptying of major rivers into smaller Arctic Ocean Figure 9-7 Average ocean salinity (Hess and Finch, 2022, p. 262)  Ocean Acidity Historically, the ocean has had an average pH of 8.16 (alkaline) atmospheric CO2 absorbed by seawater ⇢ carbonic acid (H2CO3) ⇢ decreases seawater pH 30% increase in seawater acidity since industrial revolution (~200 years ago) (NOAA, 2020) Figure G.1.g pH scale (NOAA, PMEL Carbon Program, n.d.) Figure G.1.h Ocean Acidification (NOAA, 2020a)  G.2 Oceanic Circulation Learning Objective Discuss the nature of oceanic circulation & how it compares with atmospheric circulatory patterns.  Ocean Currents Currents essential in sustaining global energy balance Exchange heat between low and high latitudes Accounts for 13% of total heat movement from low to high latitudes Figure G.2.a The Gulf Stream Current https://oceanservice.noaa.gov/education/tutorial_currents/media/supp_cur04d.html  Ocean Currents Describes the movement of water from one location to another Oceanic currents are driven by: 1. Wind 2. Density Differences 3. Coriolis 4. Tides 5. Shape of Ocean Basins Figure G.2.b Water movement in ocean (https://www.usgs.gov/media/images/schematic-showing-how-sediment-seafloor- moves) Ocean currents help move warmer water towards the poles cooler water (which has upwelled from below) towards the equator  Surface Ocean Currents Warm Currents – East coast Cold Currents – West coast Figure G.2.c Warm and cold currents https://www.weather.gov/jetstream/circulation Figure G.2.d Global surface currents http://oceanmotion.org/global-surface-currents.htm  Gyres Large circular currents (STH - 30° N & S) Major: N. Pacific, S. Pacific, N. Atlantic, S. Atlantic, Indian Rotation: dependent on the wind & the Coriolis Effect impacting the surface currents and the blocking effects of continents strong western boundary current weak & broad “eastern boundary current” Figure 10.11 Surface Ocean Currents (Gervais, 2019, p. 311)  Upwelling Zones Deep cold water rises to the surface West side of continents Figure G.2.e Upwelling https://oceanservice.noaa.gov/facts/upwelling.html Productive fishing areas/arid coastlines Figure 2.14. Locations of significant coastal upwelling regions in the world ocean (Kämpf & Chapman, 2016).  Great Ocean Conveyer Thermohaline circulation Circulation driven by density differences (temperature & salinity) Figure 9-12 Idealized global conveyor-belt circulation (Hess and Finch, 2022, p. 267)  Antarctic and Arctic Circulation Figure G.2.i Complex circulation system in the Arctic (https://www.whoi.edu/know-your-ocean/ocean-topics/polar-research/arctic- ocean-circulation/) Figure G.2.h Antarctic Circumpolar Current http://polardiscovery.whoi.edu/antarctica/circulation-en.html  References Arctic Climate Impact Assessment (ACIA). (2004). Impacts of a Warming Arctic: Arctic Climate Impact Assessment. Cambridge University Press. (http://www.acia.uaf.edu) Arbogast, A., Ford, L., & Dagesse, D. (2018). Discovering Physical Geography, (Canadian ed.). Wiley. Gervais, B. (2019). Living Physical Geography, (2st ed.). W. H. Freeman & Company, 633 pp. Kämpf, J., & Chapman, P. (2016). Upwelling Systems of the World: A Scientific Journey to the Most Productive Marine Ecosystems. In Upwelling Systems of the World. Springer International Publishing AG. https://doi.org/10.1007/978-3-319-42524-5 Miyazaki, Y., Ikeda, Y., & Senou, H. (2015). The northernmost records of Chromis notata and Sagamia geneionema from Hokkaido, Japan. Marine Biodiversity Records, 8. https://doi.org/10.1017/S1755267214001390 National Oceanic and Atmospheric Administration (NOAA). (2020a). Ocean Acidification, Retrieved July 18, 2020, from https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification National Oceanic and Atmospheric Administration (NOAA). (2020b). Upwelling, Retrieved July 18, 2020, from https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification National Oceanic and Atmospheric Administration (NOAA). (2020c). Why is the Ocean Salty? Retrieved July 20, 2020, from https://oceanservice.noaa.gov/facts/whysalty.html National Oceanic and Atmospheric Administration (NOAA). (2020d). How far does light travel in the ocean? Retrieved August 15, 2020, from https://oceanservice.noaa.gov/facts/light_travel.html#:~:text=Light%20may%20be%20detected%20as,others%20can%20do%20without%20i t. National Oceanic and Atmospheric Administration (NOAA), PMEL Carbon Program. (n.d.). A primer on PH. Retrieved January 3 2023 from https://www.pmel.noaa.gov/co2/story/A+primer+on+pH Webb, P. (n.d.). Introduction to Oceanography, CC-BY 4.0 international license. Retrieved August 15, 2020, from http://rwu.pressbooks.pub/webboceanography