Bio 105 Chapter 11

Editor's Notes

• #6: Figure 8.5: Marine systems provide a number of important ecological and economic services ( Concept 8-2 ). Questions: Which two ecological services and which two economic services do you think are the most important? Why?
• #7: Figure 8.15: Freshwater systems provide many important ecological and economic services ( Concept 8-4 ). Questions: Which two ecological services and which two economic services do you think are the most important? Why?
• #9: Figure 11.2: N atural capital degradation. These photos show an area of ocean bottom before (left) and after (right) a trawler net scraped it like a gigantic bulldozer. These ocean-floor communities could take decades or centuries to recover. According to marine scientist Elliot Norse, “Bottom trawling is probably the largest human-caused disturbance to the biosphere.” Trawler fishers disagree and claim that ocean bottom life recovers after trawling. Question: What land activities are comparable to this?
• #11: Figure 11.3: One scientist has described this common lionfish as “an almost perfectly designed invasive species.” It reaches sexual maturity rapidly, has large numbers of offspring, and is protected by venomous spines. In the eastern coastal waters of North America, it has few if any predators, except perhaps for people. It is hoped that commercial fishers can find ways to capture lionfish economically and that consumers will choose them from seafood menus.
• #13: Figure 11.A: Lake Wingra in Madison, Wisconsin (USA) has become clouded with sediment partly because of the introduction of invasive species such as the common carp. Removal of carp in the experimental area shown here resulted in a dramatic improvement in the clarity of the water and subsequent regrowth of native plant species in shallow water.
• #15: Figure 11.4: N atural capital degradation. The Nile perch (right) is a fine food fish that can weigh more than 91 kilograms (200 pounds). However, this deliberately introduced fish has played a key role in a major loss of biodiversity in East Africa’s Lake Victoria (left).
• #16: Figure 11.5: Invasive water hyacinths, supported by nutrient runoff, blocked a ferry terminal on the Kenyan shores of Lake Victoria in 1997. By blocking sunlight and consuming oxygen, this invasion has reduced biodiversity in the lake. Scientists reduced the problem at strategic locations by removing the hyacinth and by introducing two weevils (a type of beetle) that feed on the invasive plant.
• #18: Figure 11.6: This Hawaiian monk seal was slowly starving to death before a discarded piece of plastic was removed from its snout. Each year, plastic items dumped from ships and garbage barges, and left as litter on beaches threaten the lives of millions of marine mammals, turtles, and seabirds that ingest, become entangled in, or are poisoned by such debris.
• #21: Figure 11.7: N atural capital degradation. This graph illustrates the collapse of Canada’s 500-year-old Atlantic cod fishery off the coast of Newfoundland in the northwest Atlantic. Beginning in the late 1950s, fishers used bottom trawlers to capture more of the stock, reflected in the sharp rise in this graph. This resulted in extreme overexploitation of the fishery, which began a steady decline throughout the 1970s, followed by a slight recovery in the 1980s, and then total collapse by 1992, when the fishery was shut down. Despite a total ban on fishing, the cod population has not recovered. The fishery was reopened on a limited basis in 1998 but then closed indefinitely in 2003 and today shows no signs of recovery. (Data from Millennium Ecosystem Assessment)
• #25: Figure 11.9: Several major species of sea turtles have roamed the sea for 150 million years. The hawksbill, Kemp’s ridley, and leatherback turtles are critically endangered . Flatbacks live along the coasts of northern Australia and Papua, New Guinea, and are not classified as endangered because they nest in very remote places, but the Australian government classifies them as vulnerable . The loggerhead, green, and olive ridley are classified as endangered . See the photo of an endangered green sea turtle on the title page.
• #26: Figure 11.10: This endangered leatherback sea turtle was entangled in a fishing net and could have starved to death had it not been rescued.
• #35: Figure 11.11: There are a number of ways to manage fisheries more sustainably and protect marine biodiversity. Questions: Which four of these solutions do you think are the most important? Why?
• #37: Figure 11.12: This human-created wetland is located near Orlando, Florida (USA).
• #40: Figure 11.13: The world’s largest ecological restoration project is an attempt to undo and redo an engineering project that has been destroying Florida’s Everglades (USA, see photo) and threatening water supplies for south Florida’s rapidly growing population.
• #42: Figure 11.14: These zebra mussels are attached to a water current meter in Lake Michigan. This invader entered the Great Lakes through ballast water dumped from a European ship. It has become a major nuisance and a threat to commerce as well as to biodiversity in the Great Lakes.
• #43: Figure 11.15: According to U.S. Environmental Protection Agency, two species of Asian carp were close to invading Lake Michigan in 2010. If they become established in Lake Michigan, they are likely to spread rapidly and disrupt the food web that supports the lakes’ native fish populations. Eventually, they could become the dominant fish species in the interconnected Great Lakes .