| A | B |
|---|
| Producers require nitrogen to be turned into ______, ____ and ____, which are used to make _____. | ammonia, nitrates and nitrites, used to make proteins |
| _______ is required by plants in order to make molecules like DNA and RNA plus an energy carrying molecule called ATP. | Phosphorus |
| Which two types of elements are the key ingredients in fertilizer, because plants need them to grow. | Nitrogen and phosphorus |
| The process by which bacteria convert nitrogen gas (N2) into ammonia (NH3) is called ____. | nitrogen fixation |
| The conversion of nitrogen from one form to another in the nitrogen cycle is carried out primarily by ___. | bacteria |
| Which type of plants help make soil more fertile because they can fix nitrogen out of the air and convert it into useable forms? | Legumes (they include peas, beans, lentils, peanuts, alfalfa. Legumes actually don't do the converting themselves, but have bacteria that grow in their root nodules that can fix nitrogen from the atmosphere and turn it into fertilizer) |
| A lake that receives a large input of a limiting nutrient, like nitrogen or phosphorus, can develop a(n) ____. | algal bloom (basically means an explosion in the growth of algae),  |
| The rate at which producers create organic matter (by growing) in an ecosystem is called ____. | primary productivity |
| What is most likely to be a limiting nutrient in a freshwater pond? | phosphorus |
| If a nutrient is in such a short supply in an ecosystem that it affects the growth of organisms, it is called a(n) ___. | limiting nutrient |
| Aquatic ecosystems are most likely to receive heavy doses of limiting nutrients that can cause algal blooms from the runoff from ___. | fertilized fields (like farmland or golf courses) |
| What is the process called where nitrogen containing compounds in dead organisms are converted back into nitrogen gas (N2) so that nitrogen can re-enter the atmosphere? | denitrification |
| Ammonia is converted by bacteria into ________ so that it can be used by plants to grow. | nitrates and nitrites (which are also key ingredients in fertilizer) |
| Nitrogen is mainly required by plants to make _____. | proteins |
| Which cycle DOES NOT have a phase where it is part of a molecule that is a gas? | phosphorus |
| Phosphorus in the phosphorus cycle is often in the form of _______ because it is usually bonded to several oxygen atoms. | phosphate |
| Nutrient-rich waters that have a lot of algae can experience a ______ in the fall when the algae die and bacteria that come in to decompose them use up the dissolved oxygen in the water. | fishkill |
| Which household item used to have a lot of phosphorus in it and was causing some nearby lakes and ponds to become nutrient-rich and choked with algae? | laundry detergent (look for low or no phosphorus laundry detergent when shopping) |
