Stream Bio Unit 1

watershed/drainage basin/catchment

the area of land where all the water drains out of the same pour point

network scale

the full watershed scale

section scale

defined by a common landform (e.g. a section of the river within a mountain range)

reach scale

most common scale; homogenous units 100-1000m w/ similar hydrology and no tributaries

channel unit

a section of the river with similar depth (e.g. pools, riffles, glides)

active channel shelf/bankfull width

the land around a channel where the water covers when it rises

flood plain

the area where a river could reach, should a large rising event occur, but not as common as the channel shelf

hill slope

the slope outside the floodplain where water can drain into the river from but cannot flow into

river continuum concept

a set of predictions for how up, mid, and downstream reaches should look in a forested network

fluvial geomorphology

the location and shape of river channels, determined through complex interactions of hydrology, geology, topography, and vegetation

riffle

water is shallow and fast

pool

water is deeper and slow

thalweg

the line of maximum depth and fastest water as you move downstream (not always the center of the stream)

sinuosity

quantifiying the level of meandering; channel distance / straight downvalley distance

dynamic equilibrium

even streams that are in equilibrium (no change in the valley/climate) change through time due to processes of erosion and deposition

avultion

a “jumping channel” that can occur when streams morph and connect two dramatic meanders, creating an oxbow lake with the meander that is “cut off”

washload

particles that entered the river channel during a high-flow event

bedload

materials that were already in the channel but not moving until after a storm event

flow-sediment balance

the channel shape and sediments within are in a sort of equilibrium; if characteristics of one change, we will see the other change to bring the river back to that equilibrium

cation

ion with a positive charge

anion

ion with a negative charge; contribute to alkalinity, esp. carbonate and bicarbonate

pH

concentration of protons; low value = more H+

alkalinity

conc. of ions that can neutralize acid

hardness

concentration of Mg (2+) and Ca (2+)

total dissolved solids (TDS)

mass of all positive and negative ions

conductivity

capacity to carry electrical charge due to +/- ions (aka specific conductance)

nutrient

inorganic material necessary for life; generally used to build structures and metabolic machinery

macronutrients

needed in greater amounts; includes C, N, and O in every organism and Si, K, S, Ca, Mg, and other sin come organisms

micronutrients

needed in smaller quantities; includes Fe, Mn, Mo, Zn, Cu, Cl, etc.

transformation

a change from one chemical form to another; moat are biologically mediated, reversible, and involve microbes

pools (cycling)

compartments where nutrients are stored

fluxes (cycling)

transport of nutrients between pools

assimilation

the uptake in inorganic N into biological tissuses; impoartnat for animo acids

nitrogen fixation

conversion of nitrogen gas to ammonium; done naturally by cyanobacteria, legumes, lightning; foundation of Haber-Bosch process

denitrification

multi-step process converting nitrate to gaseous nitrogen; reductive process facilitated by anaerobic bacteria; occurs in absence of oxygen by respiring nitrate

nitrification

ammonium to nitrate w/ a nitrite intermediate; oxidative process done by chemoautotrphoic; requires oxygen; use chemical energy stored in ammoium rather than aolar energ to ix carbon dioxide

sorptino

abiotic process by which nitrogne compounds adhere to particles; difficult for biota to access; ammonium is sticky for soils while but nitrate is not

phosphorus assimilation

uptake inorganic phosphate into in biological tissues; used for ATP, DNA, RNA; decomposition of organic material returns P to inorganic forms

phosphorus assimilation

uptake of inorganic P into biological tissues; done by algae, fungi, and microbes; released from tissues by decomposition

phosphorus sorption

phosphate “sticking” to particles or sediments; primarily sorbs to iron oxides and CaCO3 and can be reversible if conditions change

conservative ions

ions not readily used by biota or altered by the abiotic process

reactive ions

ion transport downstream is slowed by biotic uptake, transformation, or sorption

nutrient spiraling

downstream movement of water in streams stretched cycles into spirals; relationship between uptake length (Sw) and velocity towards stream bed (Vf)

nutrient uptake saturation

high ambition nutrient concentration can slow nutrient removal efficiency

impervious surface

parking lots, roads, rooftops, etc that do not allow infiltration

thermal surge

freshwater salinitation synditrome

many human activities are acumulatively increase salinity in freshwater streams and groundwater; caused by road salt, human-accelerated weathering, hydrologic modifications, soil disturbances, biological alkalinization