Week 4 Part 1 Flashcards
Do all species require the same amount of nutrients
No depending on the species they have different nutrient requirments
What is carbon and nitrogen used for
Carbon is the main component of structural compounds in plants; nitrogen is largely tied up in enzymes
What are the difference between C:N and C:N ratios and why
The C:N ratios in animals are lower than in plants because animals need to code for a lot more proteins and carbon is needed for structural tissues
What do herbivores have to do because of this ratio
Consume more food than carnivores to get enough nutrients like Nitrogen
What are all nutrients ultimately derived from
Abotic sources like rocks and gases in the atmosphere
What are the different types of weathering
Physical - wind, rain, thermal expansion and contraction, water freezing
Chemical weathering - water gases
Biological weathering - tree roots and lichnes usually works along with physical weathering
What is the order of size of soil compositon from smallest to largest and what does it determine
Clay, Silt and then Sand it determines the soils porosity the larger the particle the larger the porosity
What does clay have
Humus (organic material) have many negatively charged ions
What is the good about clay being negatively charged
Cations can bind to this site and many plants have positive charges so negative charges in soil increase its fertility
What is cation exchange capacity
The ability of a soil to hold and exchange cations related to the amount of types of clay particles present if there is more clay then there is more binding sites
What soil is better for holding onto water
Clay prevents water from getting lost where sandy soils have more drought taken up for more space for oxygen
What is Parent material
The rock or mineral material that was broken down by weathering to form a soil
What is parent material may that is deposited by glaicers
TIll
What is parent material deposited by wind
Loess
Where is soil development fastest
Warm wet conditions
Where is nutrients in soil highest
Terrestrial ecosystem than tropical forest soils because have experienced high rates of weathering and leaching for a long time are nutrient poor there is so much competition
What does decomposition do
Makes nutrients available to organisms in the ecosystem breaking them into small, soluble compounds
What is the pathway of decomposition
Starts with litter which is made up of fresh undecomposed organic matter on the soil surface
Then animals such as earthworms termites and nematodes consume the litter breaking it up into progressively finer particle in fragmentation
The fragmentation increases surface area, which facilitates chemical breakdown
Minerizaltion which chemical conversion of organic matter into inorganic nutrients
Heterotrophic organisms release enzymes into the soil that break down organic macromolecules
Where is decompostion and minerizaltion rates at the highest
Faster in warm and moist conditions
What does the graph show in refrence to ligin and decomposition
Higher values of ligin see slower decompostion rates and higher biomass remains the difference between New Hampshire and North Carolina is colder
What is denitrificaiton
Some bacteria use NO3 as an electron acceptor converting it into N2 and N20 in anoxic conditions
What is soil fertility is estimated from
Concentration of inorganic forms of nitrogen NO3 and NH4
What is Nitrification
NH3 and NH4 are converted to NO3 by chemoautotrophic bacteria in aerobic conditions so they are less ailvaliable for plants that need it in that form
What do the falling of leafs represent
Recycle some nutrients internally before the leafs fall nutrients are broken down and moved to other parts of plants because the leaves are metabolically expensive so chlorphyll is broken down to recover nutrients while other pigments remain to produce colors
What is nutrient cycling
Movment of nutrients in ecosystems as they under biological chemical and physical transformations
What is mean residence time (turnover rate) and what is the equation
Amount of time on average that a molecule spends in the pool; Mean residence time = total pool of element / rate of input
What are pools
Total amount of nutrient in a component of the ecosystem
What accounts for nutrient losses
Catchment are mostly in stream water, quantified by measuring dissolved and particulate matter in stream water also lost to the atmosphere or as organisms move out of the ecosystem
What did the study on Hawaii islands show
Nand P were added to plots in three ecosystems of different ages and growth of the dominant tree were measured in the Young N was limiting in the middle a combination was important and P was important in older communities
How can nutrients be lost
When they leach out of the root zone and into groundwater and streams or gases coverted into chemical forms that can not be used by organisms
Are nutrient inputs transferred between ecosystem components
Herbivory and predation decomposition and weathering processes
How can you measure losses
By the stream
Nutrient losses in stream flow are measured by analyzing the chemical composition of the water esitatmed by placing a V-shaped weir across the stream to gauge flow
What is the equation for measuring input
concentration element x volume of percipation = amount of element entering the catchment
What is atmospheric deposition
Includes elements in precipitation wet deposition or aresols and fine dust which is dry deposition
How do you measure nutrient losses from the air
Usually have a single drainage basin called a catchment or watershed the land area that is drained by a single is often used to define boundaries
What material was important in primary succession
There is little organic matter in the soil and little nitrogen from decomposition so nitrogen availbility should limit primary production and community composition in early stages but onece the pool of nitrogen increases limits primary production decrease
Where are nutrient pools larger
in tropical forest soils are much smaller than those in boreal forest because there is less competion in boreal forest
The turnover tare is is so much faster in tropical forest soils than in boreal forest soils
When is N and P the limiting agent
N is limiting in early succession N and P both at intermediate stages of succession and P limiting late in succession
What are nutrient inputs to a catchment
Atmospheric deposition and nitrogen fixation which are either stored in the soil in the soil or taken up by organisms
How do you measure wet deposition
Collectors open during percipitation events then close to prevent evaporation the collected the collected percipation is the analyzed for elements of intrest
How do you measure dry deposition
More diffcult to measure and is done less often usually analyzed and combined with wind speed and direction to estimate deposition on surfaces
Where can dry deposition make up the bulk of total deposition
Dry areas
What is occlusion
Solule P may combine with iron, calcium or aluminum to form insoluble compounds that are unavailable as nutrients
Where does P orginate from
Weathering of the mineral aptite
