Chapter 8 Aquatic BiodiversityName _____________________________Key Termsbenthos(p. 164)coastal wetland(p. 166)coastal zone(p. 165)cultural eutrophication(p. 175)decomposers(p. 164)drainage basin(p. 176)inland wetlands(p. 178)intertidal zone(p. 168)lakes(p. 174)mesotrophic lake(p. 176)nekton(p. 164)open sea(p. 170)plankton (p. 164)runoff(p. 176)surface water(p. 176)watershed(p. 176)Key Questions and Concepts8-1 What is the general nature of aquatic systems?CORE CASE STUDY: Coral reefs are highly biodiverse, and they provide us with many ecological and economic services. They serve to sequester ____________, buffer _____________________, and provide valuable habitat. Globally, 15% of reefs have been destroyed and another 20% have been damaged. An additional 20–33% could be lost in the coming decades. Degradation and loss of reefs is an __________________ that should serve as a warning about threats to the health of oceans.A.Saltwater and freshwater aquatic zones cover about ____% of the earth’s surface. B.________________ of the water determines the major types of organisms found in an aquatic environment.C.There are four major types of organisms in aquatic systems:1.________________ are free-floating, weakly swimming, generally one-celled organisms. There are three major types of plankton: ____________________ (plant plankton), _____________________ (animal plankton), and ultraplankton, which are no more than two micrometers wide and are photosynthetic _________________.2.________________________ may be responsible for as much as 70% of the _______________ productivity near the ocean surface.3.__________ is a second group of organisms. These are fish, turtles, and whales4.______________ are bottom dwellers.5.______________________ are a fourth group. These organisms break down organic matter.D.Three layers of aquatic life zones can be used: surface, middle, bottom. 1.Temperature, _________________ availability, dissolved _____________, and nutrient availability determine the type and number of _____________________ found in these zones.2._______________ zone describes the upper layer where sunlight can penetrate.3.Dissolved oxygen levels are higher near surface due to _____________________________ in this area.4.O2levels are lower in deeper, dark layers due to aerobic _____________________ and because less O2gas ___________________ in deeper and colder water.5.Productivity in open oceans tends to be limited by amounts of _______________, phosphates, ________, and other nutrients. 6.Shallow waters are generally well supplied with ________________ for growth.