Class 11 Bottom-up Processes (Productivity and Food Webs)

Biomass

total amount of living tissue within a given trophic level

'how much "stuff" there is'

Productivity

the rate at which a biologically relevant material accumulates over time

'how much "stuff" there is over time'

Mussel ___ increases with phytoplankton ___

Mussel productivity increases with phytoplankton biomass

Tidepool _____ can also increase as _____ declines

Tidepool productivity can also increase as biomass declines

primary productivity

growth at the base of the food chain

secondary productivity

growth at higher trophic levels

food chain

A simplified, linear diagram that uses a single organism at each trophic level to illustrate the main pathway of carbon through a system

trophic level

a species or group of species that feeds on one or more other species

food web

a diagram that shows the overall feeding relationships between organisms in an ecological community

Omnivory

feeding on multiple trophic levels

Bottom-up perspective

Available biomass at the base of the food chain can determine abundances of organisms at higher trophic levels

Gross primary production (GPP)

the total amount of carbon fixed (or oxygen produced) by photosynthesis

Net primary production (NPP)

the total amount of carbon fixed (or oxygen produced) by photosynthesis minus the loss associated with respiration

Pulse Amplitude Modulated (PAM) Fluorometry

shines a light on an autroph, then measures the rate of electron transport as proxy for primary productivity

Remote sensing

measure ocean color based on satellite images to observe changes in primary productivity over time

El Nino

an irregularly occurring and complex series of climatic changes affecting the equatorial Pacific region and beyond every few years, characterized by the appearance of unusually warm, nutrient-poor water off northern Peru and Ecuador, typically in late December.

Tradewind

any of the nearly constant easterly winds that dominate most of the tropics and subtropics throughout the world, blowing mainly from the northeast in the Northern Hemisphere, and from the southeast in the Southern Hemisphere.

top-down perspective

the abundance and behavior of species at the top of the food chain can influence the populations and distribution of organisms further down the chain