EAE3311 Lecture 8 Flashcards
<p><strong><span>What is Ocean productivity?</span></strong></p>
<div>Ocean productivity refers to the production of organic matter by "<strong>phytoplankton</strong>", plants suspended in the ocean, most of which are single-celled. </div>
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<p><strong><span>What is GPP?</span></strong></p>
<p><span>Gross Primary Production<br></br>The total rate oforganic carbonproduction byplants</span></p>
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<p><strong><span>What is NEP?</span></strong></p>
<p><span>Net ecosystem production</span></p>
<div><strong>GPP</strong>minus the<strong>respiration</strong>by all organisms in the ecosystem</div>
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<p><strong><span>What is a nutrient?</span></strong></p>
<p><span>Anutrientis a chemical elementused by an organism to survive, grow, and reproduce </span></p>
<div>The availability of nutrients in the upper ocean frequently limits the activity and abundance of these organisms</div>
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<p><strong><span>What is the main limiting nutrient in the ocean?</span></strong></p>
<p>2 points.</p>
<p><span>Nitrogen</span></p>
<ul> <li>Phosphorus is typically in excess of nitrogen relative to cellular requirements, but not everywhere</li> <li>Surface depletion of micronutrients, such as Fe, Co, Zn, Cu, Ni and Cd, is also observed in many region</li></ul>
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<p><strong><span>How does the atmosphere impact nutrients?</span></strong></p>
<p>2 points.</p>
<ul><li>Atmospheric deposition is a very important transport process for gases and particles from the atmosphere to the terrestrial and aquatic surfaces.</li><li>While emitted to the atmosphere from various natural and anthropogenic sources, gases and particles are transported with air masses and undergo dry and wet deposition from the air to water and land.</li></ul>
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<p><strong><span>How do terestial nutrients reach the ocean?</span></strong></p>
<p><span>Terrestrial nutrients primarily reach the ocean through atmospheric and fluvial fluxes </span></p>
In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. <p style="text-align: right;"><span>EAE3311 6ag</span></p>
<p><strong><span>What are the main sources of nitrogen for the oceans?</span></strong></p>
<p>3 points.</p>
<ul><li>Fluvial</li><li>Atmospheric</li><li>Biological nitrogen fixation</li></ul>
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<p><strong><span>What is DIN?</span></strong></p>
<p><span>Dissolved Inorganic Nitrogen</span></p>
<div>Readily bioavailable or "fixed" forms of N are primarily nitrate (NO₃⁻), nitrite (NO₂⁻), and ammonium (NH₄⁺). They are collectively called dissolved inorganic nitrogen (DIN) and can be taken up (via membrane transporters) and assimilated by many microorganisms.</div>
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<div>The oceans represent a very large planetary reservoir of fixed or reactive nitrogen, i.e., nitrogen that is in forms other than the unreactive gaseous N₂. </div>
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<p><strong><span>What is DON</span></strong></p>
<p><span>Dissolved Organic Nitrogen</span></p>
<div>DON compounds include a wide range of chemical compounds varying in size, complexity, and resilience to degradation. For example, amino acids, urea, proteins </div>
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<div>DON can be in large amounts in the oceans (especially in coastal waters)</div>
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<p><strong><span>Why is Phosphorous important?</span></strong></p>
<p><span>Phosphorus is required by all living organisms to make DNA, RNA, ATP (energy molecules), and other essential organic compounds. </span></p>
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<p><strong><span>How is Phosphorous found in the ocean?</span></strong></p>
<p>3 points.</p>
<ul> <li>Mostly exists in the form of orthophosphate (PO₄³⁻)</li> <li>River runoff represents the main phosphorus source in the ocean. It delivers annually about 1.5 Mt of dissolved phosphorus and more than 20 Mt of suspended phosphorus into the ocean.</li> <li>In recent years it has been recognized that phosphorus limitation in the ocean may be more prevalent than previously thought.</li></ul>
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<p><strong><span>What are the types of atmospheric deposition?</span></strong></p>
<div><strong>Dry deposition </strong>mostly refers to the gravitational settling of atmospheric particles. </div>
<div><strong>Wet deposition </strong>refers to deposition with precipitation or snow. </div>
<div><strong>Diffusive deposition </strong>refers to the transfer of chemicals from the atmospheric gas phase to the water dissolved phase</div>
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<p><strong><span>What are the freshwater nitrogen inputs to the world oceans?</span></strong></p>
<div>Freshwater nitrogen inputs to the world oceans include riverine (dominant) and submarine groundwater inputs plus some direct discharges (e.g. the recent floods!). </div>
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<div>A global flux estimate of 23 Tg N yr⁻¹ for dissolved inorganic nitrogen (DIN) and 11 Tg N yr⁻¹ for dissolved organic nitrogen (DON). </div>
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<div>As noted earlier global fluvial nitrogen fluxes to the oceans have probably doubled since preindustrial times</div>
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<p><strong><span>What is Flocculation?</span></strong></p>
<p><span>A process by which colloidal particles come out of suspension to sediment under the form of floc or flake</span></p>
<div>The action differs from precipitation in that, prior to flocculation, colloids are merely suspended, under the form of a stable dispersion, in a liquid and are not truly dissolved in solution.</div>
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<div>(From Wikipedia)</div>
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