Glossary of terms Flashcards
(110 cards)
1
Q
Adsorbed
A
Attached to the outside of a mineral particle (as opposed to absorbed, going into the particle).
2
Q
Albedo
A
The light that is bounced off the surface of the lake; a surface (such as snow) with higher albedo reflects more light from the lake surface.
3
Q
Alkaline phosphatases
A
Enzymes put outside an algal cell to chemically separate limiting PO4 from organic molecules in a lake
4
Q
Alkalinity
A
The capacity of the water to neutralize acid, using the anions of carbonates, bicarbonates and occasionally hydroxides
5
Q
Allochthonous
A
Sources of nutrients and food produced outside the system
6
Q
Amictic
A
A lake that is permanently frozen, and therefore never mixes
7
Q
Ammonification
A
The various bacterial processes that convert dead organisms (detritus) into ammonium
8
Q
Anion
A
A negatively charged ion (e.g. HCO3-)
9
Q
Anoxic
A
Lacking oxygen
10
Q
Aphotic zone
A
The part of a lake below the compensation depth; plant growth is not possible here due to low light levels
11
Q
Aquifer
A
An underground geologic formation that contains water
12
Q
Aufwuchs
A
A slimy layer of bacteria, fungi and algae found on the surface of rocks and wood in streams and lakes
13
Q
Autochthonous
A
Sources of nutrients and food produced inside the system
14
Q
Autotroph
A
An organism whose course of carbon (“food”) is inorganic carbon dioxide (e.g. a plant)
15
Q
Bathymetric map
A
A map of a lake showing depth contours
16
Q
Benthic
A
Pertaining to the bottom of lakes and streams. Usually used to describe algae, invertebrates and fish living there.
17
Q
Blooms
A
Explosive increases in numbers of phtoplankton (algae). During an algal bloom population growth is from asexual reproduction
18
Q
Cation
A
A positively charged ion (e.g. Na+)
19
Q
Chemocline
A
The zone of sudden change in concentration of a chemical (e.g., oxygen or nitrate) with depth (usually corresponds to the thermocline depth).
20
Q
Chemotrophs
A
Organisms that get their energy from chemicals
21
Q
Clinograde oxygen curve
A
an oxygen curve in which oxygen levels are depleted below the thermocline. This curve is typical of eutrophic lakes.
22
Q
Cold monomictic
A
Lakes in which ice melts on the lake, but the water never gets warmer than 4 degrees C
23
Q
Compensation depth
A
The depth at which the rate of food production by plants (photosynthesis) equals the rate of food consumption (respiration)
24
Q
Conductivity
A
A measure of the flow of electrons through water (units are microsiemens per centimeter (uS/cm)).
25
Coriolis force
A force, caused by rotation of the earth, which causes currents to move at a 45degree angle to the wind direction.
26
Covalent bond
A strong chemical bond formed by the sharing of electrons by the atoms in a molecule. E.g. a covalent bond holds together the oxygen and hydrogen atoms in the water molecules.
27
Crater lake
A lake formed by water filling the crater left from a past volcanic eruption
28
Currents
The net unidirectional flow of water in a water body
29
Dendritic
Any highly branched pattern (e.g. the highly branched shape of a reservoir)
30
Denitrification
The process of converting nitrate (NO3-) to nitrogen gas (N2). The conversions are made by bacteria under anaerobic (or at least very low oxygen) conditions.
31
Density currents
Currents produced when cold river water (e.g. from snow melt) enters a lake; the cold water, being denser than the warmer lake water, sinks to the depth in the lake where it encounters water of equal density.
32
Diel
Following a 24hr cycle. Activity during the day is diurnal, while activity at night is nocturnal
33
Dimictic
A lake with both spring and fall mixing period
34
Discharge
The volume of water which passes a point in a river. Discharge is the product of velocity and stream cross-sectional area.
35
Ekman spirals
Water movement in lakes in which water moves at an increasing angle to the wind as you go deeper in the lake; responsible for horizontal, not vertical mixing of water.
36
Electronegative
Refers to an atom in a molecule that has a very strong attraction for electrons e.g. O2 atoms in H2O molecle take an uneven share of the electrons compared to the H atoms in the molecule
37
Ephemeral ponds
Temporary ponds that only fill during large rain events
38
Epilimnion
The upper, warm layer of a lake above the thermocline
39
Eukaryotic
Organisms having their genetic material enclosed in a nucleus in their cells
40
Eutrophic lake
Lake having very high levels of nutrients, typically shallow, and are depleted of O2 at their bottom
41
Evapo-transpiration
The process of water loss to the atmosphere from trees and other vegetation
42
Fluviatile forces
The forces of moving water in rivers, which form lakes. E.g. oxbow lakes
43
Frustules
The silica-based cell walls of diatoms, which fit together like a petrie dish
44
Fungi
A group of organisms that include molds and mushrooms, responsible for the decomposition of dead plant and animal matter
45
Graben lake
A lake formed in the depression formed between two raised blocks on either side of fault lines
46
hardness
Water hardness is caused by calcium and magnesium cations in the water; hard water makes it difficlt to generate lather when washing
47
heterotroph
an organism whose source of C ("food") is a preformed organic carbon compound (e.g. the body of a plant or animal)
48
Holomictic
Lakes in which the entire water column is mixed- top to bottom
49
humic acids
major components of natural organic matter, most commonly found in acidic bogs. Humic acids often turn the water a tea colour
50
Hydraulic residence time
the amount of time to fill a lake; calculated by dividing the volume of a lake by the inflow or outflow rate
51
hydrogen bond
A weak chemical bond formed when the positive and negative charges on atoms of adjacent molecules are attracted to each other. E.g. H bonds hold together the molecules making up water
52
Hydrograph
A plot of discharge over time for a river
53
Hyetograph
A graph plotting discharge at one point on a river on the X-axis against precipitation (rain or snow) per hour on the Y-axis.
54
Hypolimnion
The cold bottom layer of a lake below the thermocline
55
Intensity
The number of photons ( or quanta) per unit area of light (the "brightness" of light)
56
Internal loading
The recycling of a nutrient (eg phosphorous) from the large sediment pool of a water body; comes from both organic and inorganic sources
57
internal seiches
Long-wavelength standing waves that form at the thermocline of a lake; responsible for Kelvin-Helmholtz mixing which brings hypolimnetic water up into the epilimnion.
58
Langmuir spirals
A series of clockwise and counterclockwise rotating cells of water which cause areas of vertical upwelling and downwelling in lakes
59
Lentic
Water bodies such as lakes and ponds that lack unidirectional flow (contrast with lotic water bodies).
60
Littoral zones
The shallow margins of lake bottom extending from the shore at the top of the wave spray zone to that depth where light is barely sufficient to grow rooted plants
61
Lotic
Water bodies such as rivers and streams that have unidirectional flow (contrast with lentic water bodies)
62
Luxury consumption
Algal storage of phosphorous in granules in the spring for later use in summer
63
Meromictic
Lakes that only partially mix, as the hypolimnion is too dense, due to salt water or some other chemical stratification
64
Mesotrophic lake
A lake having an intermediate levels of nutrients, plants and animals (probably the most common type).
65
Metalimnion
The middle later of a lake that contains a zone of rapid temperature change (the actual temperature gradient in called the thermocline)
66
Morphometry
Measurements of the size and shape of a lake. examples include lake surface area and maximum length.
67
Negative heterograde oxygen curve
An oxygen curve in which oxygen levels are lowered at the thermocline
68
Nephelometric turbidity units (NTU)
The units of turbidity, which reflects how much a beam of light is scattered y particles in the water sample
69
Nitrification
The process of converting ammonium (NH4+) to nitrate (NO3-). The conversions are made by bacteria under aerobic conditions.
70
Nitrogen fixation
The process of converting nitrogen gas (N2) to ammonium (NH4+). The conversion is made by a few Cyanobacteria ("Blue Green Algae") and bacteria. The process requires anaerobic conditions.
71
Nutrient spiraling
The cycling of nutrients in a stream from the dissolved, inorganic form through organisms and back to the inorganic form
72
Oligotrophic
Lakes that are low in nutrients, and hence also contain low numbers of animals and plants
73
Orthograde
An oxygen curve in which oxygen levels are relatively constant from top to bottom of the lake. this curve is typical of oligotrophic lakes.
74
Oxbow lake
A lake formed when a large meander loop of a river is cut off from the main channel by silt deposition
75
Pelagic zone
That part of a lake past the littoral zone towards the middle of the lake, but in open water, not associated with the bottom of the lake
76
Percent saturation (of oxygen)
The actual amount of oxygen in water divided by the potential amount of oxygen water can hold at that temperature
77
Permanent hardness
Permanent hardness is the concentration of cations of calcium and magnesium combined with non-carbonates (eg SO42-, Cl-). The hardness is permanent because it cannot be removed by boiling.
78
Photic zone
The upper part of a lake extending from the surface to that depth where light is 1% of light levels at the lake's surface
79
Photoautotroph
An organism that uses light energy and carbon dioxide to make food
80
Photosynthesis
The production of food (eg the sugar glucose) by plants, using light
81
photosynthetically active radiation PAR
The range of wavelengths of light useful to plants for photosynthesis
82
Phototrophs
Organisms that get their energy from sunlight in photosynthesis e.g. algae
83
Phytoplankton
Tiny plants (algae) that float in the water column of lakes and large rivers
84
Polymictic
A lake that mixes frequently (every few days, or daily)
85
Pools
Slow, deep sections of streams having fine substrates, and where the water surface is not broken by rocks
86
Positive heterograde oxygen curve
An oxygen curve, in which oxygen levels are elevated at the thermocline
87
Profundal zone
The deeper areas of a lake below the littoral zone (no light is present here)
88
RAHOD, (Relative Areal Hypolimnial Oxygen Deficit)
The amount of oxygen used up in the hypolimnion of a lake due to decomposition. The higher the RAHOD the more productive the lake.
89
Recycle
The passing of nutrients through a system again for further use
90
Redox potential
The REDuction/OXidation potential of a metal or other chemical, determined by the oxygen level in the lake water or sediments
91
Respiration
Cellular respiration is the process by which plants and animals burn up food (eg. glucose) to produce energy. Oxygen is consumed in the process.
92
Retention time
The amount of time a chemical, such as the nutrient phosphorous, spends in a lake. Compare this to hydraulic residence time
93
Riffles
The fast, shallow sections of streams having coarse substrates and rocks that break the surface of the water.
94
Rift lake
a lake formed in a single, tilted fault line
95
Riparian
The area of land along the edge of a river or lake. The term is usually used to refer to the vegetation growing there.
96
Secchi depth
A relative measure of light penetration in a lake, determined by lowering a secchi disc (a disc 20cm in diameter that is marked into black and white quadrants) until it is no longer visible
97
Sinuosity
The "curviness" of a river, defined as the distance water travels in the river divided by the straight-line distance down the river's valley
98
Specific heat
The capacity of water to store heat
99
Stream order
Stream classification based on the pattern of branching. E.g. a 3rd order stream is one formed by the joining of two 2nd order streams
100
Substrate
The mineral particles on the bottom of a stream or lake. Particles range from fine silt to boulders
101
Surface tension
A measure of the strength of the surface film of a liquid
102
Surfactants
Chemicals, often naturally produced, that reduce surface tension
103
Tectonic forces
Lake-forming forces caused by the folding, thrusting and buckling of the earth's crust. E.g. graben and rift lakes
104
Temporary hardness
Temporary hardness in the concentration of Ca2+ and Mg2+ that have combined with carbonates and bicarbonates. It is referred to as temporary hardness because it can be removed by boiling the water
105
Thermocline
A layer of water in a lake containing a rapid temperature change from the warmer, upper water to the colder, deeper water. Often used interchangeably with metalimnion
106
Total dissolved solids (TDS)
Total concentration of cations and anions dissolved in water
107
Total suspended solids (TSS)
Total concentration of suspended (ie particulate) solids in water
108
Travertine
Deposits of CaCO3 ("marl") found on rocks in hardwater streams
109
Trophic status
The amount of nutrients, plants and animals produced in a lake. Oligotrophic lakes have low nutrients, while eutrophic lakes have high nutrients
110
Turbidity
The decrease in transparency of water due primarily to suspended particles, but also to dissolved substances, which cause light to be scattered, reflected, or absorbed (as opposing to passing through the water)
