- abyssal zone
- the deepest part of the ocean at depths of 4000 m or greater
- acid rain
- a corrosive rain caused by rainwater mixing with sulfur dioxide gas as it fall through the atmosphere, turning it into weak sulfuric acid, causing damage to aquatic ecosystems
- algal bloom
- a rapid increase of algae in an aquatic system
- apex consumer
- an organism at the top of the food chain
- aphotic zone
- the part of the ocean where photosynthesis cannot occur
- arctic tundra
- a biome characterized by low average temperatures, brief growing seasons, the presence of permafrost, and limited precipitation largely in the form of snow in which the dominant vegetation are low shrubs, lichens, mosses, and small herbaceous plants
- autotroph
- an organism capable of synthesizing its own food molecules from smaller inorganic molecules
- benthic realm
- (also, benthic zone) the part of the ocean that extends along the ocean bottom from the shoreline to the deepest parts of the ocean floor
- biogeochemical cycle
- the cycling of minerals and nutrients through the biotic and abiotic world
- biomagnification
- an increasing concentration of persistent, toxic substances in organisms at each trophic level, from the producers to the apex consumers
- biome
- a large-scale community of organisms, primarily defined on land by the dominant plant types that exist in geographic regions of the planet with similar climatic conditions
- boreal forest
- a biome found in temperate and subarctic regions characterized by short growing seasons and dominated structurally by coniferous trees
- canopy
- the branches and foliage of trees that form a layer of overhead coverage in a forest
- channel
- the bed and banks of a river or stream
- chaparral
- a biome found in temperate coastal regions characterized by low trees and dry-adapted shrubs and forbs
- chemoautotroph
- an organism capable of synthesizing its own food using energy from inorganic molecules
- coral reef
- an ocean ridge formed by marine invertebrates living in warm shallow waters within the photic zone
- cryptofauna
- the invertebrates found within the calcium carbonate substrate of coral reefs
- dead zone
- an area in a lake and ocean near the mouths of rivers where large areas are depleted of their normal flora and fauna; these zones can be caused by eutrophication, oil spills, dumping of toxic chemicals, and other human activities
- detrital food web
- a type of food web that is supported by dead or decaying organisms rather than by living autotrophs; these are often associated with grazing food webs within the same ecosystem
- ecosystem
- a community of living organisms and their interactions with their abiotic environment
- ecosystem services
- the human benefits provided by natural ecosystems
- emergent vegetation
- the plants living in bodies of water that are rooted in the soil but have portions of leaves, stems, and flowers extending above the water’s surface
- equilibrium
- the steady state of a system in which the relationships between elements of the system do not change
- estuary
- a region where fresh water and salt water mix where a river discharges into an ocean or sea
- eutrophication
- the process whereby nutrient runoff causes the excess growth of microorganisms and plants in aquatic systems
- fallout
- the direct deposition of solid minerals on land or in the ocean from the atmosphere
- food chain
- a linear sequence of trophic (feeding) relationships of producers, primary consumers, and higher level consumers
- food web
- a web of trophic (feeding) relationships among producers, primary consumers, and higher level consumers in an ecosystem
- grazing food web
- a type of food web in which the producers are either plants on land or phytoplankton in the water; often associated with a detrital food web within the same ecosystem
- gross primary productivity
- the rate at which photosynthetic producers incorporate energy from the Sun
- hydrosphere
- the region of the planet in which water exists, including the atmosphere that contains water vapor and the region beneath the ground that contains groundwater
- intertidal zone
- the part of the ocean that is closest to land; parts extend above the water at low tide
- neritic zone
- the part of the ocean that extends from low tide to the edge of the continental shelf
- net primary productivity
- the energy that remains in the producers after accounting for the organisms’ respiration and heat loss
- non-renewable resource
- a resource, such as a fossil fuel, that is either regenerated very slowly or not at all
- oceanic zone
- the part of the ocean that begins offshore where the water measures 200 m deep or deeper
- pelagic realm
- (also, pelagic zone) the open ocean waters that are not close to the bottom or near the shore
- permafrost
- a perennially frozen portion of the Arctic tundra soil
- photic zone
- the upper layer of ocean water in which photosynthesis is able to take place
- photoautotroph
- an organism that uses sunlight as an energy source to synthesize its own food molecules
- planktivore
- an animal that eats plankton
- primary consumer
- the trophic level that obtains its energy from the producers of an ecosystem
- producer
- the trophic level that obtains its energy from sunlight, inorganic chemicals, or dead or decaying organic material
- resilience (ecological)
- the speed at which an ecosystem recovers equilibrium after being disturbed
- resistance (ecological)
- the ability of an ecosystem to remain at equilibrium in spite of disturbances
- savanna
- a biome located in the tropics with an extended dry season and characterized by a grassland with sparsely distributed trees
- secondary consumer
- a trophic level in an ecosystem, usually a carnivore that eats a primary consumer
- source water
- the point of origin of a river or stream
- subduction
- the movement of one tectonic plate beneath another
- subtropical desert
- a biome found in the subtropics with hot daily temperatures, very low and unpredictable precipitation, and characterized by a limited dry-adapted vegetation
- temperate forest
- a biome found in temperate regions with moderate rainfall and dominated structurally by deciduous trees
- temperate grassland
- a biome dominated by grasses and herbaceous plants due to low precipitation, periodic fires, and grazing
- tertiary consumer
- a trophic level in an ecosystem, usually carnivores that eat other carnivores
- trophic level
- the position of a species or group of species in a food chain or a food web
- tropical rainforest
- a biome found near the equator characterized by stable temperatures with abundant and seasonal rainfall in which trees form the structurally important vegetation
- wetland
- environment in which the soil is either permanently or periodically saturated with water