BIO 341 Exam 2

lake outflow

when a lotic system originates from a lake

perennial

system that flows all the time and never dries up, below the water table

intermittent

systems that flow occasionally, at water table

ephermal

systems that flow occasionally, above water table

watershed

all of the land, water, and material that drains to a certain point

Strahler ordering

way of ordering lotic systems where 1 is lowest with no tributaries and 1+1 = 2, 1+2 = 2, 2+2 = 3, 3+3 = 4 and so on

nile

the world's longest river; flows northward through eastern Africa into the Mediterranean

amazon

the largest river in terms of discharge

discharge

volume of water per unit time

hydrograph

a graph of discharge v. time

flow regime

magnitude, frequency, duration, timing, and rate of change of a system

floodplain

land next to the stream that is modified by floods that occur less frequently than average flood discharges

active channel

Area of the channel being actively modified by average stream discharge

wetted channel

area of a wetted stream bed, part of the active channel

straight

channel usually associated with constrained or channelized reaches (canyons, agriculture)

sinuous

channel that meanders back and forth or braids

sinuosity

measured as the thalweg length/valley length, determines magnitude of meandering

stream slope/gradient

elevation change between two points divided by the length of the stream, expressed as a percent (1:1 = 100%)

pool

channel unit with low gradient and little surface turbulence

riffles

channel unit with moderate gradient and turbulent water

rapids

channel unit with high gradient and turbulent water

runs

channel unit with slow moving water

upwelling

water exchanging from groundwater to surface water

downwelling

water exchanging from surface water to groundwater

hyporheic zone

exchange area between groundwater and surface/stream water located directly below the stream

parafluvial zone

the subsurface water lateral of stream; the region of the active channel without surface water

boulder

sediment >25.6 cm

cobble

sediment 6.4 - 25.6 cm

gravel

sediment 0.2 - 6.4 cm

sand

sediment 0.006 - 0.2 cm

silt

sediment 0.004 - 0.006 cm

clay

sediment <0.004 cm

embededness

degree to which larger particles are buried by finer sediments, decreases biological activity

tracer study

study where we inject a know amount of a measurable substance into a stream and measure concentrations downstream, can measure time of travel, discharge, water movement, and nutrient dynamics

advection

location of a tracer changes

dispersion

concentration of tracer changes

transient storage

when the water is held up temporarily, often on the sides of channels

rhodamine

non-toxic visual dye often used in studies, red-orange in color

conservative tracer

tracers that do not degrade of significantly react with the substrate, includes dyes, ions, and gases

reactive tracer

tracer that reacts somehow with substrate or biota

filter feeder

aquatic invertebrate that filter out suspended material from water column

collector/gatherer

aquatic invertebrate that browse sediment for food

scraper

aquatic invertebrate that removes periphyton from rocks and other substrates

shredders

aquatic invertebrate that break apart and consume large detritus

oligotrophic

a _______ lake contains ~500,000 bacteria per mm

mesotrophic

a _______ lake contains ~1,000,000 bacteria per mm

eutrophic

a _______ lake contains ~3,700,000 bacteria per mm

heterocyst

the site of nitrogen fixation in cyanobacteria, N2 --> NH3

phycobilin

the unique light-harvesting pigments found in red algae and cyanobacteria

gelatinous covering

cyanobacteria is difficult to eat for most predators due to its _______

cyanobacteria

toxic blooms in freshwater are always caused by ________

cyanotoxin

phosphatase blocker toxin found in cyanobacteria

microbial loop

how microbes link the food chain between bacteria and zooplankton, most important in oligotrophic systems

algae

single-celled photosynthetic organisms with various morphology, lack vascular systems, have chlorophyll a

cyanidium

genus of extremophile red algae

Shelford's law of tolerance

states populations have optimal survival conditions within critical and maximal thresholds

chrysophyceae

mixotrophic golden brown algae with two unequal flagella, one hairy and one smooth

cryptophyceae

single cellular asymmetrical algae with two near equal flagella

epivalve

flattened part of a diatom that is larger

hypovalve

flattened part of a diatom that is smaller

epitheca

epivalve and associated girdle bands

hypotheca

hypovalve and associated girdle bands

cingulum

group of girdle bands

puncta

hole in valve face to allow materials to pass in and out of diatom

striae

linear or near linear rows of puncta

raphe

slit along valve face of diatom where slime is emitted to slide over surfaces

centric

diatom morphology with radial symmetry

pennate

diatom morphology with bilateral symmetry

dinoflagellates

mixotrophic unicellular algae with cellulose plates containing symbiotes that assist in feeding, accountable for most harmful algal blooms

euglenoid

marine and freshwater green or colorless flagellate organism, few are planktonic

chlorophyceae

algae distinguished chiefly by having flagella and clear green color, their chlorophyll being masked little if at all by other pigments, will form mother and daughter colonies

competitive exclusion

principle that states no two species can exist with the same niche in the same area, violated by "the paradox of the plankton"

the paradox of the plankton

predators, microhabitats, constant change, and varying nutrient requirements are all explanations of _________________

phosphorus

in high N:P environments, _____ is the limiting resource

nitrogen

in low N:P environments, _____ in the limiting resource

cyanobacteria

can fix their own nutrients and are not as affected by low N:P environments

epiphytic

growing on other plants (macrophytes)

epilithic

growing on stone

epipelic

growing on mud

episammic

growing on sand

epixylic

growing on wood

periphyton

algae, bacteria, fungi, and protozoans in a polysaccharide matrix, described as a "chef salad" for grazing organisms

chytridiomycosis/chytrid fungus

infectious fungal disease of amphibians

bryophytes

nonvascular mosses and liverworts

vascular plants

can be dominant producers in many wetlands and can be used to classify systems

macrophytes

can reduce erosion and resuspension, provide habitat, increase nutrient and gas transport

porifera

phylum including sponges, often green, brown, or colorless in freshwater systems

bryozoa

invertebrates with ciliated tentacles for filtering seston

cnidaria

phylum of jellyfish, rare in freshwater , often the size of a dime

platyhelminthes

phylum of flatworms that can be parasites or free-living

nemotoda

unsegmented roundworm, one of the least studied

annelida

segmented worms: earthworms; lugworms; leeches

tardigrada

water bears found in lots of habatats, well studies

rotifer

often confused with protozoa, most abundant soft bodied metazoan

cyclomorphosis

change in the morphology to prevent predation (like the production of spines) seen in rotifers and daphnia

cyclical parthenogenesis

combination of sexual and asexual production

halploid

rotifer males are _______

diploid

rotifer females are _______

mullusca

phylum of clams (bivalvia) and snails (gastropoda)

arthropoda

diverse phylum of arachnida, entognatha, and insecta. defined by segmented body parts