| A | B |
|---|
| photic zone | photosynthetic light |
| aphotic zone | little light |
| thermocline | narrow stratum of rapid temperature change |
| benthic zone | bottom substrate |
| Benthos | community of organisms |
| Detritus | dead organic matter; food for benthic organisms |
| Littoral zone | well lit, open water close to shore |
| Limnetic zone | well lit, open water further from the shore |
| Profundal zone | deep, aphotic waters |
| oligotrophic | deep, nutrient poor |
| eutrophic | shallow, high nutrient content |
| mesotrophic | moderate productivity |
| Wetland | area covered with water |
| Estuary | area where freshwater merges with ocean |
| Intertidal zone | area where land meets water |
| Neritic zone | shallow regions over continental shelves |
| Oceanic zone | very deep water past the continental shelves |
| Pelagic zone | open water of any depth |
| Benthic zone | seafloor bottom |
| Abyssal zone | benthic region in deep oceans |
| Tropical forests | equator; most complex; constant temperature and rainfall; canopy |
| Savanna | tropical grassland with scattered trees; occasional fire and drought; large herbivores |
| Desert | sparse rainfall (<30cm/yr) |
| Chaparral | spiny evergreens at midlatitudes along coasts |
| Temperate grassland | all grasses; seasonal drought, occasional fires; large mammals |
| l Temperate deciduous forest | midlatitude regions; broadleaf deciduous trees |
| Coniferous forest | cone-bearing trees (sometimes called the Taiga) |
| Tundra | permafrost; very little precipitation |
