Question 20 Match each term to its corresponding example. eutrophication a. lack of oxygen on the ocean floor at the mouth of the Mississippi River due to seasonal algal blooms dead zone b. condition of low oxygen in the seawater at the mouth of the Mississippi River re- sulting from seasonal agricultural runoff anoxia seasonal overgrowth of algae at the mouth of the Mississippi River due to agricultural runoff upstream C. hypoxia d. seasonal loss of fish at the mouth of the Mississippi River due to migration away from hypoxic conditions created by eutrophication

Biome distribution depends on ______. a. climate b. elevation c. soils d. all of the above

Emergent vegetation grows in the __________ zone of freshwater lakes, (a) littoral (b) limnetic (c) profundal (d) neritic (e) intertidal

The _______________ is open ocean from the shoreline to a depth of 200 m. (a) benthic environment (b) intertidal zone (c) neritic province (d) oceanic province (e) aphotic region

The process whereby oxygen is depleted by the growth of microorganisms due to excess nutrients in aquatic systems is called _________. a. dead zoning b. eutrophication c. retrophication d. depletion

Two arctic marine mammals that live in the same waters differ in the level of pollutants in their bodies. Bowhead whales have a lower pollutant load than ringed seals. What are some factors that might explain this difference?

Figure 20.28 In which of the following regions would you expect to find photosynthetic organisms? a. The aphotic zone, the neritic zone, the oceanic zone, and the benthic realm. b. The photic zone, the intertidal zone, the neritic zone, and the oceanic zone. c. The photic zone, the abyssal zone, the neritic zone, and the oceanic zone. d. The pelagic realm, the aphotic zone, the neritic zone, and the oceanic zone.

A key feature of estuaries is: low light conditions and high productivity salt water and fresh water frequent algal blooms little or no vegetation

Changes in the Air To assess the impact of human activity on the carbon dioxide level in Earth's atmosphere, it helps to take a long view. One useful data set comes from deep core samples of Antarctic ice. The oldest ice core that has been fully analyzed dates back a bit more than 400,000 years. Air bubbles trapped in the ice provide information about the gas content in Earth's atmosphere at the time the ice formed. Combining ice core data with more recent direct measurements of atmospheric carbon dioxideas in FIGURE 46.20can help scientists put current changes in the atmospheric carbon dioxide into historical perspective. FIGURE 46.20 Changes in atmospheric carbon dioxide levels (in parts per million). Direct measurements began in 1980. Earlier data are based on ice cores. 4. Was the rise in the carbon dioxide level between 1800 and 1975 larger or smaller than the rise between 1980 and 2013?

Changes in the Air To assess the impact of human activity on the carbon dioxide level in Earth's atmosphere, it helps to take a long view. One useful data set comes from deep core samples of Antarctic ice. The oldest ice core that has been fully analyzed dates back a bit more than 400,000 years. Air bubbles trapped in the ice provide information about the gas content in Earth's atmosphere at the time the ice formed. Combining ice core data with more recent direct measurements of atmospheric carbon dioxideas in FIGURE 46.20can help scientists put current changes in the atmospheric carbon dioxide into historical perspective. FIGURE 46.20 Changes in atmospheric carbon dioxide levels (in parts per million). Direct measurements began in 1980. Earlier data are based on ice cores. The industrial revolution occurred around 1800. What was the trend in carbon dioxide level in the 800 years prior to this event? What about in the 175 years after it?