Chapter 5: Environmental Systems and Ecosystem Ecology

aquifers

underground reservoirs of sponge-like regions of rock and soil that hold groundwater

atmosphere

the air surrounding our planet

biogeochemical cycles

"nutrient cycles." the movement of nutrients through ecosystems (atmosphere, hydrosphere, lithosphere, biosphere)

biosphere

the planet's living organisms and the abiotic (non living) portions of the environment

carbon cycle

describes the route of Carbon atoms through the environment

conservation biologists

scientists who study the loss, protection, and restoration of biodiversity. particularly the fragmentation of habitat into small and isolated patches resulting from human development pressures

denitrification

the conversion of nitrate to nitrogen gas

denitrifying bacteria

convert nitrates in soil and water to gaseous Nitrogen, releasing it back into the atmosphere

dynamic equilibrium

system processes move in opposite directions, balancing their effects

ecological modeling

the practice of constructing and testing models that aim to explain and predict how ecological systems function

ecosystem

all organisms and nonliving entities that occur and interact in a particular area at the same time, includes abiotic and biotic components

ecosystem services

services provided by the planet's systems. (soil formation, water and air purification, pollination, breakdown of some pollutants and waste, quality of life issues - inspiration / spiritual renewal, nutrient cycling)

ecotone

transitional zones between 2 ecosystems. elements of each system mix

emergent properties

system characteristics not evident in the components alone, the whole is more than the sum of its parts

eutrophication

nutrient over enrichment. blooms of algae, increased production of organic matter, decomposition and hypoxia. (can take place in both freshwater and saltwater systems)

evaporation

the conversion of a liquid to a gaseous form; water moves from aquatic and land systems into the atmosphere. warm temperatures, long exposure time, and strong winds speed rates of evaporation.

feedback loop

a circular process in which a system's output serves as input to the same system

flux

the rate at which materials move between pools. can change over time, is influenced by human activities

geographic information systems (GIS)

common tool for research in conservation ecology. consists of computer software that takes multiple types of data (geology, hydrology, vegetation, animal population, and human infrastructure)

gross primary production (GPP)

assimilation of energy by autotrophs

groundwater

water found underground beneath layers of soil

Haber-Bosch process

production of fertilizers by combining Nitrogen and Hydrogen to synthesize ammonia. humans overcame the limits on crop productivity

homeostasis

a system maintains constant (stable) internal conditions

hydrologic cycle

the flow of water - in liquid, gaseous, and solid forms - through our biotic and abiotic environment

hydrosphere

liquid, solid, or vapor water

hypoxia

low concentration of dissolved oxygen (in water) - from fertilizer, fossil fuel emissions, runoff, sewage

landscape ecology

studies how landscape structure affects the abundance, distribution, and interaction of organisms. helpful for sustaining regional development

lithosphere

rock and sediment

metapopulation

network of subpopulations where members stay in their respective patches but some move among or mate with other patch members

model

a simplified representation of a complex natural process, designed by scientists to help understand how the process occurs and to make predictions

mosaic

a spacial configuration of patches arrayed across a landscape

negative feedback loop

input and output neutralize each other's efforts, stabilizing the system (ex: predator prey relationships, most systems in nature)

net primary poduction (NPP)

energy remaining after respiration which is used to generate biomass, available for consumption by heterotrophs

net primary productivity

high for ecosystems whose plants convert solar energy to biomass rapidly (highest = freshwater wetlands, tropical forests, coral refs, and algal beds. lowest = deserts, tundra, and open ocean). increases with temperature, precipitation, light, and availability of nutrients.

nitrification

bacteria convert ammonium ions first into nitrite ions then into nitrate ions. plants can take up these ions

nitrogen cycle

describes the routes that Nitrogen atoms take through the environment. (Nitrogen gas can't be used by organisms)

nitrogen fixing bacteria

bacteria that live mutualistic relationships with many plants (including soybeans and other legumes), providing them nutrients by converting Nitrogen to a usable form

nutrient cycles

see biogeochemical cycles

nutrients

elements and compounds that organisms consume and require for survival

patches

form the landscape, are spread spatially in complex patterns. (ie forested patches within an agricultural landscape, widely spread patches endanger organisms)

phosphorus cycle

a major nutrient cycle consisting of the routes that phosphorus atoms take through the nested networks of environmental systems

pool

"reservoirs." where nutrients reside for varying amounts in time. oceans are the main reservoirs.

positive feedback loop

input and output drive the system further to an extreme (ex: exponential growth in population, cancer, melting glaciers and sea ice, natural systems affected by human impact)

precipitation

water that condenses out of the atmosphere and falls to Earth in droplets or crystals

productivity

rate at which ecosystems generate biomass

reservoir

see pool

residence time

in a biogeochemical cycle, the amount of time a nutrient remains in a given pool before moving to another

runoff

the water from precipitation that flows into streams, rivers, lakes, and ponds, and (in many cases) eventually to the ocean

sink

a pool that accepts more than it receives. we have increased the flux of Nitrogen from the atmosphere to reservoirs on the Earth's surface, and shifted the flux of Carbon in the opposite direction

source

a pool that releases more material than it accepts

system

a network of relationships among a group of parts, elements, or components that interact with and influence one another through the exchange of energy, matter, and / or information

transpiration

release of water vapor by plants

water cycle

the cycle of processes by which water circulates between the earth's oceans, atmosphere, and land, involving precipitation as rain and snow, drainage in streams and rivers, and return to the atmosphere by evaporation and transpiration

watershed

the entire area of land from which water drains into a given river

water table

the upper limit of ground water in an aquifer, water may be ancient (thousands of years old)

nitrogen fixation

lightning or Nitrogen fixing bacteria combine (fix) Nitrogen with Hydrogen to form ammonium, which can be used in plants