KEY TERMS

abyssalzone

the deepest part of the ocean at depths of 4000 m or greater

acidrain

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

algalbloom

a rapid increase of algae in an aquatic system

apex consumer

an organism at the top of the food chain

aphoticzone

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

benthicrealm

(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

biogeochemicalcycle

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

borealforest

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

coralreef

an ocean ridge formed by marine invertebrates living in warm shallow waters within the photic zone

coralreef

the invertebrates found within the calcium carbonate substrate of coral reefs

cryptofauna

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

deadzone

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

detritalfoodweb

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

ecosystemservices

the human benefits provided by natural ecosystems

ecosystem

a community of living organisms and their interactions with their abiotic environment

emergentvegetation

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

foodchain

a linear sequence of trophic (feeding) relationships of producers, primary consumers, and higher level consumers

foodweb

a web of trophic (feeding) relationships among producers, primary consumers, and higher level consumers in an ecosystem

grazingfoodweb

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

grossprimaryproductivity

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

intertidalzone

the part of the ocean that is closest to land; parts extend above the water at low tide

neriticzone

the part of the ocean that extends from low tide to the edge of the continental shelf

net primaryproductivity

the energy that remains in the producers after accounting for the organisms’ respiration and heat loss

non-renewableresource

a resource, such as a fossil fuel, that is either regenerated very slowly or not at all

oceaniczone

the part of the ocean that begins offshore where the water measures 200 m deep or deeper

pelagicrealm

(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

photiczone

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

primaryconsumer

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

secondaryconsumer

a trophic level in an ecosystem, usually a carnivore that eats a primary consumer

sourcewater

the point of origin of a river or stream

subduction

the movement of one tectonic plate beneath another

subtropicaldesert

a biome found in the subtropics with hot daily temperatures, very low and unpredictable precipitation, and characterized by a limited dry-adapted vegetation

temperateforest

a biome found in temperate regions with moderate rainfall and dominated structurally by deciduous trees

temperategrassland

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

trophiclevel

the position of a species or group of species in a food chain or a food web

tropicalrainforest

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