Why Learn Oceanography

	Welcome to Poorna's Oceanography Pages	Updated on 05.05.15
	Why Learn Oceanography

This 3-unit physical science lecture course examines the physical, chemical and geological aspects of oceans and the oceanic environment. The companion laboratory course is: Ocean-116 (Laboratory Exercises in Physical Oceanography). Also try Biol-125 (Marine Biology) and Biol-126 (Marine Biology Lab.) in order to round up your Marine Sciences learning at the Glendale College.

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Ocean-115, Ocean-116

Earth is called the “Blue Planet” because water is abundant on this “3^rd Rock from Sun”. Indeed, oceans dominate the Earth’s surface and have been crucial to the evolution of our living environment, including that of the life on Earth. The study of oceans thus offers the most comprehensive approach to understand our natural habitat. Specifically, our discussions during this course will explore the following questions.

u	What processes create and sustain the ocean basins, making Earth the water planet?	*Textbook Chapters**
		Chapter 1:	An Ocean World
	Hydrogen and oxygen, the two constituents of water, are abundant in the universe. Why not water? Looking at our immediate neighborhood, too, Earth, Venus and Mars are compositionally alike and their surfaces receive comparable amount of Solar heat. Why does only Earth have abundance of water, then?	Chapter 3:	Plate Tectonics
		Chapter 4:	Continental Margins and Ocean Basins
		Ga: Billion years; Ma: Million years

Oceans cover ~71% of the earth's surface and have an average depth of ~4 km. Run-off, a crucial component of the hydrological cycle, deposits land materials in the ocean basins at the rate of ~2 cm per 1000 years, however. Nonetheless, oceans have existed on the earth for the past 3.5 Ga or longer. How?

How to reconcile the facts that ocean floor rocks are <200 Ma old, compared to <4.2 Ga old rocks on land, even though oceans cover >70% of the Earth’s surface and appeared 3.7-3.8 Ga ago, particularly as the geological evidence supports no appreciable growth of the Earth’s surface?

NASA's Mars Exploration Spirit is sending back images from the surface of Mars. This engineering feat is particularly remarkable because of recent problems in receiving signals from European Space Agency's British craft Beagle 2 that too has probably landed on Mars. The overall scientific goal here is to look for possibility of life, and the immediate goal is to look for water, on Mars. Click on the picture for updates from JPL or here for the updates from BBC.


v	What can we learn from the geology, chemistry and physics of the materials that fill ocean basins?			*Textbook Chapters**
				Chapter 5:	Sediments
	How do we know that the site where we now have the Himalayas was once a deep ocean or that Utah was once in the tropics?		Why are scientists looking for water on Mars if the goal there is to look for life? What would be the significance of finding limestone there? What does finding jarosite on Mars mean?	Chapter 6:	Water and Ocean Structure
				Chapter 7:	Seawater Chemistry


	Why is the seawater salty? What does it tell of the origin of seawater? Where has water on Earth come from? Earth’s Interior? Outer Space?	This Himalayan peak, Mt. Annapoorna, is made up of limestone, essentially a marine rock that, based on the presence of ~200 Ma old Ammonite fossils, formed in the Triassic times.
	Will global warming first make the Earth drier or the oceans cooler? Why is the beach sand so hot, but water cold, on a hot, sunny, summer afternoon whereas the opposite occurs in the night? Or, for that matter, why are the desert days so hot but the desert nights cold?



	Why do the beaches in temperate latitudes disappear in winter?

w	How do oceans modulate the climate?		*Textbook Chapters**
	Why does land at ~30ºN and	Why is Europe warmer than other locations at the same latitudes? Is Europe heading for an Ice Age?	Chapter 8:	Atmospheric Circulation
	~30ºS latitudes tend to have deserts and oceans at these latitudes a halocline all year round?		Chapter 9:	Ocean Circulation


	What is El Niño? What is La Niña? 2004-5 has been about the wettest season in Southern California for the past 30 years ― is it because we just had an El Niño event? How about our hurricane season? Why does it run from April through November? Should we expect this year’s Atlantic hurricane season to be stronger, or milder, than normal? Than last year? Should we expect this summer in California to be warmer and drier, or cooler and wetter, than normal? Would it be similar to that in Florida?

x	What processes affect the coast? How?		*Textbook Chapters**
	Why do waves break on reaching the shore? Would you expect Hawaii to have milder surf than Bahamas, or wilder? Why does a beach get inundated on full and new moon nights but a boat in the open ocean has no such experience? How about tsunamis — when the tsunami strikes the shore, the effect is often devastating, but a boat in the open ocean would ride a tsunami without even feeling it?		Chapter 10:	Wave Dynamics
				and Wind Waves
			Chapter 11:	Tides, Tsunamis
				and Seiches
			Chapter 12:	Coasts


	How does coastal construction — a groin or a break-water wall or the seawall — affect the coast?

	Click on this image of tsunami travel times or the URLs below to learn about the tsunami produced by the magnitude 9 earthquake of Dec 26, 2004 off Sumatra that devastated the Indian Ocean coastal regions:






	http://iri.columbia.edu/~lareef/tsunami/ http://wwwneic.cr.usgs.gov/neis/bulletin/bulletin.html

y	What factors define the marine ecosystem and how?		*Textbook Chapters**
	Does life really owe its existence to the Sun? What is SLiME? Archea? Why do we believe that plant evolution was not intrinsic to the oceanic environment?	Snakes occur in the Pacific and Indian oceans, but not in Atlantic, except for the reefs. Why?	Chapter 13: Chapter 14: Chapter 15: Chapter 16:	Life in the oceans Primary Producers Marine animals Marine communities


	How about the marine mammals?
	How about the marine mammals?
	Shark attacks are most frequent during summer in temperate latitudes, not in the tropics. Why?



	Click on this image to visit NASA's SeaWiFS Project.
	Click on this image to visit NASA's SeaWiFS Project.
	Launched on August 1, 1997, SeaWiFS began collecting global data operationally in mid-September and has continued to perform flawlessly for the past six years. The image above is the average ocean chlorophyll-a concentration as derived from SeaWiFS since launch. What is clear from this image is the tight coupling between the physical and chemical processes in the ocean and their resulting biological signature. What SeaWiFS has allowed us to do as never before, is to not only monitor the short-term spatial and temporal variability in the ocean's biology, but to have the first well calibrated, long-term data set that allows us to quantify the ocean's biological response to global change. Images and digital data sets based upon the SeaWiFS climatology for seven different geophysical parameters at a number of different temporal scales are available HERE. One of the interesting insights that came out of the generation of this chlorophyll-a climatology is the identification of the region of the world's oceans that has the lowest chlorophyll concentration. That area, slightly west of Easter Island in the South Pacific centered at 26 degrees South and 115 degrees West had an average concentration of 0.0186 milligrams chlorophyll-a per cubic meter. You can download a PNG-formatted or JPG-formatted full resolution version of the image above as well as a version centered at 180 degrees longitude (PNG or JPG) and an equirectangular projection of the image and the digital data in HDF-format.
z	What resource and environmental factors make the oceans so critical to our collective survival?		*Textbook Chapters**
			Chapter 17:	Marine resources
	Can oceans augment the world food resources? Water resources? Energy resources?		Chapter 18:	Environmental concerns

	How relevant are oceans to the current concerns about climate change? Waste disposal? Does marine life tell us something about the sharing of resources? Diversity?

*Textbook: "Oceanography - An Invitation to Marine Science" by Tom Garrison (Brooks/Cole, 2005)

Updated on Tuesday May 05, 2015

Hydrogen and oxygen, the two constituents of water, are abundant in the universe. Why not water? Looking at our immediate neighborhood, too, Earth, Venus and Mars are compositionally alike and their surfaces receive comparable amount of Solar heat. Why does only Earth have abundance of water, then?