This assessment is a modified true-false quiz. If the statement is true, simply put a “T” next to the number. If the statement is false, put an “F”, followed by correcting the underlined portion of the sentence to make it true. Example: Human-induced, or anthropogenic eutrophication is sometimes referred to as natural eutrophication. ANS: “F”; cultural or artificial eutrophication 1. An increase in eutrophication events is credited to increased carbon, and iron influx into the aquatic environment.

2.Eutrophication can cause depleted dissolved oxygen levels in aquatic ecosystems, which in turn can cause corresponding “dead zones”. Another name for these areas that contain such low levels of dissolved oxygen is “hypoxic” zones. 3.Because certain nutrients determine levels of biological productivity, they are considered “restricting” factors. 4.A sudden explosion in the growth of algae is known as an “algal bud”. 5.The more eutrophic an aquatic area becomes, the more “turbid” it becomes as well.

6. Mesotrophic waters contain the least amount of nutrients, are usually clear and cool, and can support and maintain a great biodiversity of life. 7.Currently, the largest “dead zone” in the United States is adjacent to the mouth of the Missouri River, in the Gulf of Mexico. 8.The flux of a river can also be referred to as the nutrient “load”. 9.Unhealthy dissolved oxygen levels are as low as 2 mg/L, as opposed to healthy levels you might find at Harriet Creek which average between mg/L.

10. In analyzing the graph below, it is obvious that there is a correlation between load and temporal and spacial extent of the hypoxic events.

BONUS: +10 Points Describe one reason why dissolved oxygen levels in a eutrophic body of water might drop significantly during the nighttime hours. Double-Secret Bonus: +10 Using the data table above (again), why do the scientists document the “May” flux, instead of the “June” flux, in predicting the possible eutrophic “dead zone”?