1) Here is a map of surface chlorophyll during the spring of the northern (top p

Question

1) Here is a map of surface chlorophyll during the spring of the northern (top panel) and southern (bottom panel) hemisphere.

a) Explain the main mechanisms that contribute to the patterns of chlorophyll observed within the 5 circled regions. Be explicit in your answers, make sure to explain the sources (or lack of sources) of nutrients for each region, and the mechanisms involved in supplying nutrients to the euphotic zone (e.g., upwelling, seasonal mixing, etc).

b) On the map shown above, locate with a marker the High Nutrient Low Chlorophyll areas of the ocean, and list them in writing below. Why do these regions have high nutrients but low chlorophyll?

Explanation / Answer

1. Very low chlorophyll 2. High 3. High   4. High 5. High

Bright green color, yellow and red color indicates the northern and southern hemisphere’s chlorophyll pattern where chlorophyll is high or where is low. The chlorophyll concentrations are measured by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite and the Moderate Resolution Imaging Spectroradiometer (MODIS). The Observations of global chlorophyll patterns tell scientists where ocean surface plants are growing, which is an indicator of where marine ecosystems are growing. These surface plants, called phytoplankton, are the base of the food chain, and regions that support large phytoplankton blooms also tend to support a diverse marine population too. Such global maps also gives an idea of how much carbon the plants are soaking up, which is important in understanding the global carbon budget. Phytoplankton’s live in the surface waters of the ocean, where they soak up sunlight and CO2 and convert them into their food. In addition to light, the plants also need nutrients like iron and nitrogen, which come from run-off, wind-blown dust, the ocean floor, carried to the surface on upwelling currents (Euphotic zone). Not surprisingly, high chlorophyll concentrations line the coasts where such nutrients wash into the ocean from the land. Upwelling is also more common in coastal regions, where the temperature difference between land and ocean fuels the winds that stir the ocean surface and drive upwelling. Phytoplankton’s grow more during spring in the northern oceans. During the winter, ocean waters are cold at the surface. This means that the temperature difference between surface waters and deep waters is small, and the water can mix vertically. Rising deep water brings nutrients to the surface across the North. When sunlight returns to the far north in the spring, the surface waters have both light and nutrients, and plants thrives more. As result in plants use available nutrients, the annual bloom goes away. The second pattern in chlorophyll can be seen near the Equator, particularly in the Pacific Ocean. Because of the spinning of the Earth, ocean waters move to the right of winds in the Northern Hemisphere and to the left in the Southern Hemisphere. East-blowing winds along the Equator push water North in the Northern Hemisphere, and South in the Southern Hemisphere. This leaves a sort of awake in the ocean along the Equator where cool water rises to replace the wind-blown surface water. So region along the Equator shows that phytoplankton’s were growing along this area of equatorial upwelling. The transferring of organic matter to depth depletes the surface ocean of nutrients, causing the nutrients to accumulate in deep waters where there is no light available for photosynthesis Because of the density difference between surface water and the deep sea across most of the ocean, ocean circulation can only very slowly reintroduce dissolved nutrients to the euphotic zone. By driving nutrients out of the sunlight, buoyant surface waters, ocean productivity effectively limits itself.i e High nutrients but low chlorophyll. b) On the map shown above, locate with a marker the High Nutrient Low Chlorophyll areas of the ocean, and list them in writing below. Why do these regions have high nutrients but low chlorophyll? Ans b. 1. I will mark no 1 which is already marked having high nutrient low chlorophyll area   

2. The region which is blue in color is considered to be having HNLC. The transfering of organic matter to depth depletes the surface ocean of nutrients, causing the nutrients to accumulate in deep waters where there is no light available for photosynthesis Because of the density difference between surface water and the deep sea across most of the ocean, ocean circulation can only very slowly reintroduce dissolved nutrients to the euphotic zone. By driving nutrients out of the sunlight, buoyant surface waters, ocean productivity effectively limits itself.i e High nutrients but low chlorophyll  

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.