Final Lecture Flashcards
1
Q
Ecosystem
A
all the organisms in a given area, along with nonliving(abiotic) factors with which they interact; a biological community and its physical environment.
Ecosystems exist at many spatial scales (e.g., from ponds to the entire biosphere)
2
Q
Ecosystem ecology
A
examines flow of energy and chemical cycling in habitats, as well as, the effects of natural and human-induced disturbances on ecosystems
(ex: air/water pollution, tree harvesting)
3
Q
Energy flow:
A
the passage of energy through the components of an ecosystem
4
Q
Chemical Cycling
A
unlike energy flow, chemical cycling involves the circular(recycling) movement of materials within the ecosystem.
5
Q
a terrarium is an example of a _______ecosystem
A
closed
6
Q
Pelagic Habitat(P-cycle)
A
Example of elemental cycling
-cycle of nutrients:
Bacteria–Protists–Zooplankton—Planktivores(fish)—Piscivores(fish)
7
Q
Abiotic Factors
A
Abiotic Inputs into the ecosystem include:
•Energy (radiant)
•Inorganic substances (CO2, N, O2, minerals)
•Organic substances (e.g., proteins, carbohydrates, humic acids)
•Water
•Energy (radiant) is an overriding factor that affects temperature, moisture, seasons, and photosynthetic energy
Note that temperature and moisture strongly influence the type of organisms present and the productivity of a given system
****organic and inorganic
8
Q
Cyanobacteria
A
consume much energy yet aren’t consumed by very many predators.
9
Q
Familiar forms of energy(4)
A
Thermal(heat)
Radiant(light)
Kinetic(motion)
Chemical
1)Energy can be converted from one form to another
2)All forms of life depend on these conversions,
For example photosynthesis:
radiant energy —> chemical energy (e.g., sugars)
10
Q
1st Law of thermodynamics and Ex
A
Energy is neither created nor destroyed
Energy may be transformed from one form or another, but the total amount of energy remains unchanged in the universe
ex: the Queen Elizabeth coal fired plant converts chemical energy in coal to electrical energy for the city of Saskatoon
11
Q
2nd law of thermodynamics
A
conversion of energy from one form or another is always accompanied by a reduction in the order of the universe
or
Energy is converted from one form to another some energy becomes unavailable to do work
12
Q
Biotic inputs (2)
A
- Organisms that move into an ecosystem (e.g., animal migrations)
- Influences from adjacent ecosystems For example, upstream ecosystems or downwind ecosystems; ocean currents.
13
Q
Radiant Energy
A
Radiant Energy
•Majority of radiant energy reaching the planet is converted to heat
Warms Earth & the Atmosphere, and in turn:
1. Drives the hydrologic (water) cycle
2. Generates air currents (winds) and ocean currents
•A small amount of radiant energy reaches photosynthetic organisms where it may be converted to photochemical energy
This photochemical energy is stored in ~170 billion metric tons of organic material produced globally per year
14
Q
What is energy
A
The capacity to do work
• Energy can only be described and measured by how it affects matter
•Energy is required to move matter in a direction it would not move if left alone
•All organisms require energy from their surroundings in order to stay alive
15
Q
Energy conversion laws(3)
A
1) Universal laws govern how one form of energy can be converted to another
2) These laws apply equally to living and non-living things
3. ) The laws governing energy conversion are called the laws of thermodynamics
16
Q
thermos=
A
heat
17
Q
dynamis=
A
power or force
18
Q
Thermodynamics
A
the study of energy transformations (conversions) that occur in a collection of matter
19
Q
Queen Elizabeth Coal fired plant
A
is an example of the 1st law of thermodynamics
energy conversion from chemical energy in coal to electrical energy for the City of Saskatoon.
20
Q
entropy(2)
A
The amount of disorder in a system = Entropy
-Energy lost in conversion
- Low Entropy-chemical form
- Vehicle combustion- 25% for movement, 75% lost
Heat can be considered a form of entropy because it represents RANDOM motion of molecules
21
Q
This photochemical energy is stored in ~______ metric tons of organic material produced globally per year
A
This photochemical energy is stored in ~170 billion metric tons of organic material produced globally per year
22
Q
PAR
A
photo- synthetically active radiation=
radiant energy is available for use by photosynthetic organisms
-falls between 400 and 700 nm.
23
Q
nm
A
nanometres
24
Q
Par falls between ___ and ____ nm
A
400 and 700
25
Autotroph(self feeders)
Autotrophs (self-feeders): an organism that makes its own food , thereby sustaining itself without eating other organisms or their molecules
•Plants, algae and photosynthetic bacteria are autotroph
26
Autotrophs
Autotrophs are the primary producers of the biosphere. They form the food base that sustain all other organisms (heterotrophs) directly or indirectly.
27
Photosynthesis
Photosynthesis: process by which photosynthetic organisms synthesize food molecules from carbon dioxide and water by using light energy.
Note, only ~1% of the PAR that reaches the autotrophs is actually converted to chemical energy (e.g. sugars)
28
Note, only ~__% of the PAR that reaches the autotrophs is actually converted to chemical energy (e.g. sugars)
1
29
Photosynthesis vs Cellular Respiration(in numbers)
Photosynthesis=
6CO(2)+6H(2)O+Energy ---> C(6)H(12)O(6)+ 6O(2)
Carbon Dioxide+Oxygen+Energy=Glucose+Oxygen Gas
Cellular Respiration=
C(6)H(12)O(6)+ 6O(2) ---> 6CO(2) + 6H(2)O + Energy
Glucose+Oxygen Gas=Energy+Oxygen+Carbon Dioxide
30
Primary Production(2)
Primary production: the rate at which photosynthetic organisms (autotrophs) convert solar energy to chemical energy (organic compounds)
-For example, the primary productivity of the biosphere is 170 billion tons of biomass per year
Types of primary production:
1. Gross Primary Production (GPP): total amount of carbon fixed per area per unit time
2. Net Primary Production (NPP): total amount of carbon fixed per area per unit time minus cellular respiration (R) by the autotrophs
- Net primary production is the carbon that is fixed and potentially available for consumers to use (e.g., herbivores).
31
Biomass or Standing Crop
Biomass or standing crop: the amount of living organic material in an ecosystem (or a subcomponent of the ecosystem, e.g., in plants)
32
For example, the primary productivity of the biosphere is ______ tons of biomass per year
170 Billion
33
Units of Measurement: Primary Production
•As above, but for a given unit of time, e.g., g C per m2 per day
34
Units of Measurement: Biomass or Standing Crop
In terrestrial environments: grams dry matter per m2 (g m-2)
In three dimensional environments (e.g., aquatic): grams dry matter per m3 (g m-3)
Or, carbon content may be substituted for dry matter, e.g., g C per m2 or m3
35
NPP
Net Primary Production (NPP): total amount of carbon fixed per area per unit time minus cellular respiration (R) by the autotrophs
Net primary production is the carbon that is fixed and potentially available for consumers to use (e.g., herbivores).
36
GPP
Gross Primary Production (GPP): total amount of carbon fixed per area per unit time
37
primary production(2)
Primary production: the rate at which photosynthetic organisms (autotrophs) convert solar energy to chemical energy (organic compounds)
-For example, the primary productivity of the biosphere is 170 billion tons of biomass per year
Types of primary production:
1. Gross Primary Production (GPP): total amount of carbon fixed per area per unit time
2. Net Primary Production (NPP): total amount of carbon fixed per area per unit time minus cellular respiration (R) by the autotrophs
-Net primary production is the carbon that is fixed and potentially available for consumers to use (e.g., herbivores).
38
Biomass or Standing Crop
Biomass or standing crop: the amount of living organic material in an ecosystem (or a subcomponent of the ecosystem, e.g., in plants)
39
For example, the primary productivity of the biosphere is _____ tons of biomass per year
170 Billion
40
Units of Measurement: Primary Production
Primary production
| •As above, but for a given unit of time, e.g., g C per m2 per day
41
Units of Measurement: Biomass or Standing Crop
In terrestrial environments: grams dry matter per m2 (g m-2) In three dimensional environments (e.g., aquatic): grams dry matter per m3 (g m-3) Or, carbon content may be substituted for dry matter, e.g., g C per m2 or m3
42
Most carbon fixation occurs in the ___
open ocean
43
Primary Production in ____ is low
ocean
44
Tropical rain forest has ____ primary production
high
45
Decomposition
releases inorganic compounds
46
Piscovores
eat Planktivores
47
Difficulties with depicting the flow of energy in ecosystems in food chains (5)
Omnivory: organisms often feed on autotrophs and animals(ex:bears). Are they secondary or primary consumers?
. Some animals feed at different trophic levels at different times through their live(ex:fish)
. Matter may pass through an organism more then once. (Ex: feces of an animal eat by another, then second animal is eaten by first again)
. Some plants feed on animals( ex:pitcher plant)
. Many microorganisms make a living autotrophically and heterotrophically(ex: Euglena are capable of engulfing prey and photosynthesiszing simultaneously.
48
Food Web:
a network of interconnecting food chains that create a more realistic but complex overview of the energy transfers.
49
Duck
is a primary and secondary consumer( omnivore)
50
Most complex part of a food web?
Plankton/Detrivory/Algae portion
51
cellulose lygnen
what is some trees and plants that makes them indigestible to many species
52
Assimilation in digestion
transporting/crossing the gut lining into the body
53
egested
faeces
54
Improvement AE
mastification(chewing), digestive enzymes, symbiotic relationships, and the length and shape of gut
55
endotherms: why they can survive
PE****** slide
56
Summary of energy flow within trophic levels with Example
********
57
trophic transfer efficiency
IE x AE x PE = Trophic Transfer efficiency
58
DDT has a ___ efficiency while energy has a ____ efficiency
high, low
59
Factors influencing Algal Growth
1. Warmer water temperatures
| 2. air content of toxins
60
Once you hit a certain level of Nitrate in the water supply you can see Blue Baby syndrome when it is converted to Nitrite.
Nitrite prevents oxygen from binding by binding with red blood cells
61
Main source of Phosphate is?
weathering of rock
62
Like Nitrogen, phosphorus is often another "____ ____" restricting plant(also, algal and bacterial) production and it a common compound in fertilizers.
limiting nutrient
-Phosphorus is generally a long term limiting factor
63
Phosphorus cycle has reached a point of peak phosphorous and we will remove all of it by ____
2030
64
Saskatoon is the first city to employ Struvite. What is it?
extracting phosphorus from sewage to use for fertilizer
Also helps at sewage plant as to much phosphorus creates a cement like plaque on machinery.
8-10 mg P/L
<1 mg P/L to release in waterways
65
Pit lakes?
Pit lakes are notoriously high in metals and occur when Phosphorus is moved from pit to pit until there are no more pits to move into. Pits are creates from huge rock removal.
66
Contaminants above the Saskatchewan Surface water Quality objectives?
Cobalt
Mol
********** Phosphorus cycle section
67
If a gaseous cycle is present then the cycle is definitely _____ in it's spread.
ex:
global
Sulfur
68
Sulphur in various forms is associated with ___. Generally Sulphur is the layer above of ____.
Coal
69
DMS
Dimethylsulfide:
a major biogenic gas(biological formation) that enters the atmosphere from the ocean.
70
Biogenic Gases
are the ones that can potentially create clouds
71
shredders shred____
algae
72
Notice the _______ of the stream which allows for more sunlight and higher temps. ______ diminishes which allows for greater diversity of habitats.
_____ in the system provides most carbon
openness
Velocity
Algae
73
Notice the _______ of the stream which allows for more sunlight and higher temps. ______ diminishes which allows for greater diversity of habitats.
_____ in the system provides most carbon
openness
Velocity
Algae
74
A lot of FPOM means more prevalence of ______ feeders
filter
75
larger rivers do not depend on _____ nutrients, they actually deposit nutrients on the shore.
shore
76
order >6 can bring about the need for _______ as sandy bottoms do not support many species. Burrowers enjoy this area
specialists
77
_____ level collectors are really specialized for this area
2ND
78
____ of all water flowing to the ocean is now obstructed with dams
2/3
79
When you pools water in a dam, ______ is accelerated and therefore you lose a lot of water
evaporation
80
______ river discharge a big example of water depletion
colorado
81
California losing agricultural land because of loss of water to _____
dessert
82
Water conservation in urban and agricultural areas are the ______ and yet ______ to implement in helping water problems
cheapest, hardest
people don't want to give up watering there lawn
83
Where a dam releases it's water can affect the downstream environment.
Top of dam-
Middle-
Bottom-
Top- Warmer water that may affect wildlife
Middle-
Bottom- Colder
May affect when water can freeze, also affecting the lifecycles of species
84
Human affects: Dams
Floodplains are no longer flooded because of dams which hugely affects species that have adapted for the floods
- Often floodplains(especially in the tropics) are where fish breed
- Deltas disappear when dams are placed because sedimentation gets stuck behind the dam
85
Cottonwoods thrive when ______
flooded
86
Channelization of rivers
for decades we have been straightening out rivers and dredging them to make them deeper
-ecosystems lost because of loss of flow
87
Lentic environments
standing water: lakes and ponds
88
Saline lakes tend to develop when lakes do not...
discharge but remain stagnent
89
3 Most common processes of lake creation
1. Glaciation
2. Fluvial or Riverine- As sediment is moved around by a river, amounts of water can be cut off and develop into a lake
3. Tectonic(less common)- Lake Baikal
90
Pothole=_____ lakes
kettle
91
Deepest freshwater lake in world
Lake Baikal
92
Older lakes have much more _______ in them
biodiversity
93
Know Epilimnion, Metalimnion, and Hypolimnion!
KNOW IT
94
Level at 1% light is
lower limit of Photic zone
95
If benthos is not oxygenated then you have ______
specialists
96
Biodiversity(y axis) vs. disturbance(x-axis)
high disturbance=low biodiversity
| climax community= low biodiversity
97
Taiga= ______ forest
boreal
98
Whittaker's Classification
based on annual precipitation versus average temperature
99
Tundra can be though of as a cold _____
desert
100
Is Whittaker's classification a complete diagram?
No, there are always exceptions like soil makeup as a result of fertilizer
101
Poor soils is not a common feature of global plains
True or False?
True, only way to distinguish grassland from desert in Australia
102
Common crop ,_____, is a type of grass
corn
103
_____ and ______ have very similar climate to Canada
| _____ even has introduced salmon
Argentina and Chile
| Chile
104
____ are a natural function to remove woody plants from plains
fire
105
Short grass prairie gets most of the rain at the ____of the summer
start-June(spring)
106
Tall Grass Prarie
.June, July August get lots of rain, allowing the prarie to grow ____
very little in Manitoba
tall
107
When Europeans arrived they called _______ grass prarie "daisyland" because of the amount of flowers
mixed
108
Most productive Prarie
Tall Grass
109
Burns were amazingly to return the environment to its natural condition
T or F
T
110
______have extra bark in order to insolate internal area from fire damage
___ degrees Celsius == dead
Burrows
60
111
Know terms like NPP
Net primary Production
112
Temperate Grassland has very little ______ yet fairly high ________
biomass-->NPP or productivity
113
Saskatchewan like the North has a lot of Organic _____ stored in the soil.
In the Tundra there is melting occurring which if oxidized will release a load of carbon from peet
Carbon
114
No till processes may allow for cultivation of food without loss of ______
carbon
115
root to shoot ratio's
___ to ____ times more roots then shoots
2, 3
116
Mean annual temp Saskatoon and tree type
2 degrees
117
Mean annual temp La Ronge tree type
0.7 degrees- Boreal Forest or Taiga
118
Boreal Forest covers ____% of Earth's land Surface
11
119
_____ is a great fiber, better for making paper
Cannabis
120
Boreal= zone of ____ _____
little sticks
121
Slow decomposition in boreal means that there is a lot of ______ _______
organic matter
122
Northern Boreal
receives most precipitation compared to north and southern neighbors
123
degrees days are
how many days that are warm enough to allow for growth
124
Saskatchewan dominated by ______.
| It is split in two=
Boreal
| Boreal(Boreal Shield and Boreal Plain) and Prairie
125
_______love well drained soils
Jack pine
ex: Athabasca plain
126
_______love well drained dry soils
Jack pine(conifer)
ex: Athabasca plain
127
_________ tree's are the R-strategists that repopulate the trees after a fire
Deciduous
128
Root to Shoot or Shoot to Root?
Root to Shoot
129
Boreal acts like a _____ not a _____ of carbon which is a good thing!
Sink not a Source
130
Impact of global warming has allowed Mountain Pine Beetle to expand its range farther north. It likes ________ but will go after ________.
lodgepole pine, Jack Pine
131
________ pine enjoys high elevations and water filled soil
lodgepole
132
______ and ______ pine hybridize in Alberta
lodgepole and jackpine
133
Jackpine is a _____ species
keystone
134
only ___% efficiency in a car
25= high entropy
135
____ in comparison to photosynthesis occurs all day
respiration
136
gpp
total amount of carbon fixed per area per unit time
137
npp
total amount of carbon fixed per area per unit time minus cellular respiration (R) by the autotrophs
138
what main factors influence primary producting in aquatic
1) Intensity and duration of sunlight 2) Temperature 3) Nutrient levels, particularly N, P and Fe in the open ocean
139
what main factors influence primary producting in terrestrial
1) Intensity and duration of sunlight 2) Temperature 3) Moisture or Precipitation 4) Nutrient levels, particularly nitrogen
140
Saskathewan has a ____ growing period
shorter
141
The influence of precipitation and temperature on terrestrial primary production is interrelated
T OR F
T
142
The ______ in plant leaves is where gases are exchanged with the atmosphere
The stomata (plural of stoma) in plant leaves is where gases are exchanged with the atmosphere
143
Loss of water through stomata is called _______
transpiration
144
photorespiration occurs in C_
C3
•Under dry hot weather •Low CO2 and high O2 concentrations in leaf •Calvin cycle uses O2 instead of CO2 and sugars are not produced
145
CAM plant?
CAM plants (Crassulacean acid metabolism), e.g., cacti
146
C__ plants avoid photorespiration by
C4
C4 plants keep stomata closed during dry & hot conditions, and use a special enzyme system to access very low internal concentrations of CO2
Note: Important C4 plants, e.g., Corn, Sugarcane and Sorghum
147
Transpiration is ____ for primary production while Evapotranspiration is _____.
bad, good
•Evapotranspiration rates are a good predictor of primary production.
•Evapotranspiration integrates the effect of temperature and moisture on primary production
In summary: warm temperatures and sufficient water (to meet the needs of transpiration) can result in great rates of primary production.
148
Bioavailability affects the primary production
Yes, many nutrients can occur at high concentrations in ecosystems, but are not bioavailable
• Nutrients may be bound in compounds that cannot be broken down and transported into biota, or they can be bound in complexes that render them inaccessible (e.g., dead organic material).
• The rate at which a nutrient may be mineralized (or become bioavailable) can be the limiting step controlling primary production
• Nutrient concentrations alone are often poor predictors of primary production
149
Potential Limiting nutrients in aquatic
Fresh Versus Marine
Marine: Nitrogen, Phosphorous, Iron and Silica
Fresh: N, P, Si
Nitrogen(Ammonium (NH4), nitrate and nitrite): For protein synthesis in phytoplankton and bacterioplankton
Phosphorus • Phosphate (PO4) is the most important bioavailable form
• For energy transfer (ATP), nucleic acid synthesis and cell membranes in algae and bacteria
Iron • Bioavailable forms: ferrous iron (Fe2+) and iron bound to organic ligands
• Used to fix nitrogen (N2) and other functions in bacteria and algae
Silica • Silicic acid H4SiO4 most important bioavailable form
• Used in the skeleton of diatoms (a major algal group)
150
Nitrogen
Nitrogen(Ammonium (NH4), nitrate and nitrite): For protein synthesis in phytoplankton and bacterioplankton
151
Phosphorous
Phosphorus • Phosphate (PO4) is the most important bioavailable form
• For energy transfer (ATP), nucleic acid synthesis and cell membranes in algae and bacteria
152
IRON
Iron • Bioavailable forms: ferrous iron (Fe2+) and iron bound to organic ligands
• Used to fix nitrogen (N2) and other functions in bacteria and algae
153
Silica
Silica • Silicic acid H4SiO4 most important bioavailable form
• Used in the skeleton of diatoms (a major algal group)
154
NPIS
NEVER PUNCH ICE SCULPTURES
| NITROGEN PHOSPHOROUS IRON SILICA
155
Classic Whole Ecosystem Case Study
fertilization of Lake 226 (ELA, Kenora, Ontario) commenced in 1969
Objective: which if any nutrients (C, N & P) were limiting primary production
Lead to the banning of P in detergents and reduction of P inputs from sewage treatment plants in Canada, the U.S. and Europe
156
Lake Winnipeg Algal Blooms caused by
N & P
157
In general, primary production in many lakes is limited by the availability of _ , as illustrated in the correlation between __-concentration and NPP in lakes from around the world
P
158
Areas with ___(small, medium, or high)intensity grazing have the highest primary production
and why?
medium
* Low grazing rates permit nutrients to be locked up in biomass in vegetation, rendering the nutrients unavailable for further plant production.
* However, under moderate grazing nutrients are rapidly released back to the environment (e.g., through egestion, excretion and decomposition) for re-uptake into vegetation, stimulating further plant production.
* However, overgrazing reduces vegetation biomass to such low levels that autotrophs cannot increase biomass in the ecosystem rapidly (low production)
* For example, if plant biomass doubles every week (production), then a field with 200 kg of biomass is going to produce more biomass in a week than a field that had been grazed down to 1 kg of biomass
159
Primary Producer ecosystems: Best, Worst
Tropical rainforest, extreme desert
160
All consumers participate in the breakdown of _______ compounds into ______ compounds
Decomposition releases ______ compounds (e.g., CO2, NH4, PO4, etc) that can be reused by producers (this maintains ecosystem productivity
organic to inorganic
inorganic
161
food web
a network of interconnecting food chains
Food webs provide more detailed information about trophic relationships or “who eats who” and therefore, are more realistic, but complex.
What type of consumer is the duck?
162
secondary production
Secondary production: the rate of accumulation of biomass by heterotrophic or consumer organisms
Secondary production may be expressed in similar units as primary production, e.g., •Terresterial habitats: g C m-2 day-1 •Aquatic habitats: g C m-3 day-1 •Or units of energy may be used, e.g., kJ m-2 day-
163
In general ecosystem with high primary production tend to have _____ secondary production
high
164
3 Fundamental efficiencies of energy transfer
1. Ingestion or consumption efficiency
2. Assimilation efficiency
3. Production efficiency
165
IE for herbivores
_% in forests, __% in grasslands and __% in phytoplankton dominated communities.
5,25,50
166
adaptions of prey(3)
•Prevent easy detection (e.g., cryptic coloration), •Some prey are difficult to subdue (e.g., spines), •And some prey may not be completely consumable (e.g., shell of a turtle).
=lower ingestion efficiency of carnivores
167
Carnivores have a ______ AE
higher
168
The relative ease of assimilating prey is referred to as
food quality
169
predator adaptions to counter bad food quality
in mastication, digestive enzymes, symbiotic relationships, and the length and shape of the gut represent features that can be modified through evolution to improve AE
170
Endotherms use about __% of their assimilated energy in respiration and only __% to secondary production
98
| 2
171
__x __ x __= trophic transfer efficiency
IE x AE x PE = trophic transfer efficiency
•Energy transfers between trophic levels generally occur with a ~10% trophic transfer efficiency
172
_____ _____ HAS AN INVERTED BIOMASS PYRAMID
OPEN OCEAN= MORE HERBIVORES THEN PP
173
Production of one kg (2.2 lbs) of beef requires:
1) 20,000 litres of water 2) 15 kg of grain 3) 32 kg of topsoil 4) 8 litres of gasoline
174
Solutions for a cultivated planet
• Crops that require less energy, fertilizer/manure and biocides are essential to:
-reduce greenhouse gas emissions -water pollution for fertilizers and biocides
• Better transportation and storage of food is required:
-reduce retail and household waste in developed world -improve transportation and storage in developing world
175
Cold Condensation theory
Many of these POPs are still in use in agricultural settings in the tropics
In the tropics, at warm temperatures, POPs vaporize into the air and are carried thousands of kilometres in air currents
If they reach cold environments, they condense, collect in snow and ice and melt out in spring to eventually enter Arctic food webs
176
Biogeochemical Cycles
processes by which matter cycles from the living world to the nonliving physical environment and back again
177
Carbon Cycle
•Carbon is present as carbon dioxide, carbonate (CO3-2) and bicarbonate (HCO3-)
and
as dissolved organic matter (DOM) in aquatic systems & soil
•Plants and algae remove inorganic carbon (e.g., CO2) from their environment and fix it into organic carbon compounds (e.g., glucose)
•Many of these compounds are used as fuel for cellular respiration by the producers that created them, or by consumers, or by decomposers
•Cellular respiration returns CO2 back to the abiotic environment (e.g., atmosphere or dissolved in water)
•Plants and algae remove inorganic carbon (e.g., CO2) from their environment and fix it into organic carbon compounds (e.g., glucose)
•Large quantities of inorganic carbon are also stored in limestone rock (CaCO3) for millions of years
•Combined with fossil fuels, this represents the largest reservoir
.Most is in ocean
•Photosynthesis and respiration are the two opposing processes that drive the global carbon cycle in the biosphere •Historically the lithosphere played only a minor role; fossil fuels were dormant reservoirs of carbon until humans started mining and burning them.
178
Greenhouse affect?
* CO2 in the atmosphere traps heat and creates the greenhouse effect
* Normally, the greenhouse effect is beneficial because it moderates temperature in the biosphere (our insulation from the cold temperatures of outer space)
* How? Incident radiation is absorbed by the earth’s surface and transmitted back to the atmosphere at longer wavelengths •These longer wavelengths are absorbed by CO2, other greenhouse gases, and water vapour and then converted to heat •This prevents the radiant energy from escaping from the atmosphere back into space
179
3 Major green house gases
Major greenhouse gases: CO2, CH4 and N2O
Carbon Dioxide, Methane, Nitrogen Oxide
180
•Methane is __x more effective than CO2 as a greenhouse gas
Nitrous oxide (N2O) is ___x more effective than CO2 as a greenhouse gas
sources?
20
300
•N2O sources: • fertilizer and manure • industrial (e.g., nylon) • sewage • soil nitrification processes • deforestation
181
•The IPCC now predicts a __ degree rise in average global temperature by 2100
3
•The 20th century saw a 0.7* degree rise
•Many scientists believe we have already undergone a one degree increase
182
British Columbia ______ glaciers are losing _____ cubic metres of water annually
17,000
| 22 billion
183
Nitrogen Cycle?
•___% of the atmosphere is molecular nitrogen
* Nitrogen is needed to produce many biomolecules (e.g., amino acids, proteins, & nucleic acids)
* All nitrogen found in living organisms has ultimately come from the atmosphere
* The atmosphere is a large reservoir for nitrogen (4 x 109 Mt)
* 78% of the atmosphere is molecular nitrogen N2 •However, N2 is very stable and does not readily combine with other elements, e.g., carbon
* Therefore, N2 must be split before it can combine with other elements
* Nitrogen largely enters the ecosystem through microbial fixation, but some also enters through geologic reservoirs.
* Nitrogen leaves ecosystems through denitrification (back to the atmosphere) and through burial and sedimentation
184
5 steps of Nitrogen cycle
1) Nitrogen fixation: the conversion of N2 to NH3 (O2 free environment required)
Certain cyanobacteria and soil bacteria can fix nitrogen with the enzyme nitrogenase (some free living, others in symbiotic relationships with plants)
Wild plants with symbiotic nitrogen fixers are often colonizers of poor soils (e.g., alders). Cultivated legumes have nitrogen fixers
2) Nitrification: the conversion of ammonia (NH3) or ammonium (NH4+) to nitrate (NO3-)
As in the N fixation step, nitrification is also accomplished by a series of bacteria (e.g., Nitrosomonas sp., and Nitrobacter sp.)
3) Assimilation: Plants (via roots), bacteria & algae can absorb NH3, NH4+ NO3- and NO2- and incorporate the nitrogen into organic compounds
These organic N compounds may then move up the food web through consumers
4) Ammonification: the breakdown of organic nitrogen compounds into ammonia (NH3) or ammonium (NH4+)
Decomposers (e.g. bacteria and fungi) are important in the breaking down of nitrogenous waste to ammonium
This ammonium can be recycled back to plants and algae for re-assimilation
This recycling within the food web is a major process in most ecosystems
5) Denitrification: the reduction of nitrate (NO3-) to gaseous nitrogen (N2)
Denitrifying bacteria complete the cycle by converting NO3- to gaseous N2
Requires a low O2 environment
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Human processes with nitrogen?
Human processes now outweigh natural nitrogen
Human processes include: industrial (fertilizer production), fossil fuel, and agricultural fixation (planting of legumes)
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Cultural eutrophication
•Indirect human fertilization of surface waters is called cultural eutrophication
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blue baby syndrome
nitrogen is converted to nitrite, binds red blood cells causing anoxia
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Phosphorous cycle
•Phosphorus is a component in many biomolecules (e.g., ATP), cellular structures (e.g., cell membranes) and morphological structures (bones of vertebrates)
•Phosphate (PO4-3) is the form of phosphorus taken up by organisms from the abiotic environment
•Unlike nitrogen and carbon, phosphorus does not have a gaseous atmospheric phase in the biosphere
•However, it does travel in the atmosphere as dust
•Phosphate comes from the weathering of rock
•The P cycle is less complex than the N cycle
PO4 becomes available to the ecosystems as it is weathered from rock
PO4 is lost from ecosystems when it becomes deeply buried in soils or aquatic sediments
Like nitrogen, phosphorus is often another “limiting nutrient” restricting plant (also, algal and bacterial) production and is a common compound in fertilizers
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Saskatoon Phosphorous removal
Sewage typically has 10-20 mg P/l
| Regulations require P to be at ~1 mg/l before being discharged into the river
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Bioremediation at DJX pit
•Phosphorus fertilizations resulted in algal growth •P-fertilizations resulted in overall reduced surface water contaminant concentrations •Reduced surface water contaminant concentration was a result of sedimentation of algae to the bottom •The greater the P-load to the mesocosm, the greater the sedimentation of contaminants from the surface waters
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Sulphur Cycle
* Sulfur is an important element in some amino acids (cysteine & methionine)
* Sulfate (SO4) is the form used by plants, however, many compounds of sulfur are reduced and oxidized by microorganisms (bacteria and algae)
* The S cycle includes gaseous, liquid and solid phases, permitting S to circulate on a global scale
* Largest reservoirs of S are in sedimentary rock, marine sediments, and in the oceans
* S cycle is complex and least understood of the cycles considered
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Dimethylsulphide
* Dimethylsulfide (DMS) is a major biogenic gas (biological formation) that enters the atmosphere from the ocean
* Created from decomposition of plankton (algae) in ocean surface waters
* DMS is oxidized to sulfate aerosols which are involved in the formation of cloud condensation nuclei (water droplets)
* Clouds have a pronounced effect on climate (cooling effect)
* Therefore, DMS production may provide a partial solution to offset global warming
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Lotic System
Streams and Rivers
•Steep gradient lotic systems (e.g., alpine systems) are characterized by high velocities (50 cm s-1) and downward erosion into the streambed
•Low gradient lotic systems (e.g., floodplain rivers) are characterized by low velocities and lateral erosion (river banks).
•Low gradient systems may deposit sediment loads eroded from upstream locations
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Riffles
are zones of fast moving (rapids), shallow, and turbulent water, these are erosional zones, where only moderate to large stones (rubble) may remain without being washed downstream
•Riffles are zones of intense primary production by periphyton (algae growing on rock surfaces)
•These are also zones of great secondary production (aquatic insect larvae)
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Bottom of streams and rivers is called
benthic zone
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_______ (~6-25 cm in diameter) provides the best environment for primary & secondary production
(Same)____in fast flowing streams provides the most surface area for algal attachment, and the most crevices for insects to occupy
cobble
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The wet subsurface sediments make-up the ______
hyporheic zone
•This zone is an ecotone between ground water and stream water
•Water moves in and out (via upwelling and downwelling) of the hyporheic zone resulting in an exchange of nutrients and dissolved organic matter (DOM)
•During low flow conditions invertebrates (e.g. insects) will migrate into the hyporheic sediments
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A small headwater stream without any tributaries is a ____ order stream
FIRST
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Headwater streams are order
orders 1-3
.Considered heterotrophic systems
Large energy and nutrient subsidies enter lotic systems from the terrestrial environment
•High velocity, cold, forested, & shaded
•Shading by riparian vegetation restricts autotrophic production
•90% of organic production comes from input of riparian vegetation (strongly heterotrophic)
•Dominant organisms: shredders that process CPOM and collectors that process FPOM
•Grazers are low in abundance due to little autotrophic (algal) production
Gross primary production to respiration ratio (P/R) is < 1
•Predators include large invertebrates (e.g., stoneflies) and small cold water fish: sculpins, darters and trout
•Organisms of headwater streams are adapted to: • narrow temperature range, • low nutrients, • and maintaining their position in turbulent water
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Medium Sized Streams are order
4-6
•The importance of riparian vegetation and detrital (leaf) inputs diminishes
•Increased sunshine entering stream (less shading) results in higher water temperatures (solar warming)
•Velocity diminishes & a greater # of habitats are created, and this results in greater biodiversity of organisms
•Fish tolerate higher temperatures and lower O2 concentrations
•More light, higher temperatures and less terrestrial input = switch to autotrophy, P/R >1,
•Algal and macrophyte production is greater
•Little CPOM, so shredders are not as prevalent
•Collectors feeding on FPOM (processed upstream) become dominant
•Grazers become dominant with the increase in algal production
•Predator abundance remains unchanged
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Rivers are order
>6
•River channel is wider and deeper
•Velocity declines and material is being deposited out of the water column (sandy or silt bottom)
•Influence of riparian inputs decline due to size of river, and autotrophic production also declines due to turbidity, river shifts back to heterotrophy P/R <1
•FPOM is the dominant source of energy used by bottom dwelling collectors (e.g., chironomids)
•River is becoming more lake-like
• Pelagic organisms start to appear
• Phytoplankton
• Zooplankton community
•Encounter warm water fish that tolerate low O2 and consume plankton
Throughout the downstream continuum organisms take advantage of inefficient feeding upstream.
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heterotrophic system?
heterotrophic systems (ecosystem respiration, R, exceeds primary production, P)
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riparian(____)
riparian (streamside) vegetation
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CPOM VS FPOM VS DOM
* Inputs > 1 mm = coarse particulate organic matter (CPOM)
* Inputs < 1 mm = fine particulate organic matter (FPOM), e.g., leaf fragments, insect faeces
* Inputs < 0.5 μm = dissolved organic matter (DOM) e.g., dissolved materials leaching in from the surrounding landscape in groundwater ex: Leaf
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Shredders
* The presence of these microbes on the leaf, render the leaf more nutritional to specialized invertebrate shredders
* The shredders assimilate ~40% of the material that they ingest, the rest is egested as faeces back to the stream as FPOM
* CPOM and FPOM are also produced from physical breakdown of the leaves as they move downstream
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Collectors
•Invertebrates that specialize in collecting FPOM through filtering and gathering (termed collectors) extract further nutrition from the microbial laden FPOM
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Scrapers
* Other invertebrates, called scrapers feed on the algae on rock surfaces
* Their scraping activities loosen material off rock surfaces, and what is not ingested contributes to the FPOM pool (travelling downstream)
* Some scrapers have unique adaptations for living in fast water (of the riffle)
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drift
This downstream benthic material is called drift and subsidizes downstream environments with energy and nutrients
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Physical Retention
-Physical retention concerns the storage of the nutrient, i.e., in leaf packs or debris dams, or in wood detritus such as logs
refers to the uptake & storage in living organisms
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longitudinal spiral
Tight versus loose spiral
All these processes (e.g., uptake, transformation & release downstream) are described by lotic ecologists with a
Tight: important for retaining nutrients in fast waters
Possible cause: abundant debris dams
Loose: less retention of nutrients
Possible cause: e.g., flood waters
•The longer the spiral length, the less efficient the system is in retaining nutrients •Physical structure in the stream, e.g., boulders & debris dams, slow the water & create habitat for microbes that will take up nutrients and shorten the spiraling lengt
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river continuum concept
was a major advance in viewing lotic systems as “longitudinally integrated” ecosystems
•Lotic systems are intimately linked to their drainage basins
•And downstream functioning is strongly tied to processes occurring further upstream
The RCC links stream size, organic matter inputs (energy), the processing of organic matter, and the structuring of invertebrate communities from the headwaters to the mouth of lotic systems
RCC was developed from a synthesis of research on small forested temperate streams of Eastern North America
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Human impacts on lotic system
| •_______(fraction)of all water flowing to the ocean is now obstructed with dams
* Two thirds of all water flowing to the ocean is now obstructed with dams
* Most large rivers are dammed except in Canada and Russia
* Majority of dammed water is used for irrigation
* Humans return water to rivers in a polluted form
* Much of dammed water is lost to evaporation
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Upstream Affects of a Dam
•Sediment load in river settles in reservoir & displaces benthic biota •Flooded terrestrial vegetation decomposes and O2 is lost •Anoxia may become prevalent in reservoir •Rise in nutrients & metals & increases in algal production •Anoxia & poor water quality prevail •Some metals are toxic (e.g., mercury) •Migration of biota up & downstream is impeded •organisms cannot migrate and are lost from the upstream system (e.g., salmon)
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Downstream Affects of a Dam
Lake Diefenbaker reservoir, ~__% of useable water evaporates in a typical year
•Reduction in water & loss of habitat •Water evaporates •Water is removed for irrigation and other uses
Lake Diefenbaker reservoir, ~15% of useable water evaporates in a typical year
•Thermal regimes of river water are modified: •Bottom draw from a dam is often colder & has low O2 •Surface draw is often warmer
•Loss of floodplains and associated vegetation and fauna •Without floods, connection between river and surrounding floodplain is reduced
•Disappearance of floodplain deltas (e.g., Nile delta) •Sediments are held behind dams and do not replace eroded sediments downstream in delta
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• __% of Colorado Rivers' water is used for irrigation
70
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Cheapest and Most expensive ways to save water
Water conservation and SEAWater Desalination
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Lake or _____ systems
Lentic
Lakes and ponds: basins in the landscape that collect water (size: < 1 ha to large seas)
Lakes are formed by a variety of processes (over 70 processes)
Major processes include: glacial (74%), fluvial or riverine (10%), and tectonic (5%)
glacial: Glacial Canadian Shield lake,Glacial tarn or cirque lake ,Glacial prairie pothole lakes.
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3 Worlds biggest collection of Freshwater
•Lake Baikal 20% •Laurentian Great Lakes 20% •Tanganyika 20%
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Saskatchewan has ______ freshwater lakes
100,000
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Fluvial lakes
lakes that are alongside rivers that were cutoff in the past
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Thermal Structure of a lake in summer:3
Thermal Structure of a Deep Lake in Summer
Epilimnion: warm , well mixed, well lit surface water
Metalimnion: region of rapid temperature & density change between warm epilimnetic waters and cold hypolimnetic waters, slow mixing
Hypolimnion: cold, oxygen-poor, dark zone that lies below the metalimnion, zone of little mixing
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Thermal Structure of Lake over full year:A,B,C,D
A. Winter stratification
•Low density 0C water lies at surface under ice
•Denser 4C water is at bottom
B. Spring turnover
•Ice melts, water completely mixes top to bottom with the help of wind
•Temperature is similar throughout (~4C, isothermal)
C. Summer stratification
•Surface waters warm with increasing solar radiation
•Low density warm surface water sits on the cold dense water below
•Epilimnion, metalimnion and hypolimnion become established
D. Fall overturn
•Surface water cools
•Vertical differences in water density diminish
•Lake proceeds to mix top to bottom with wind events (isothermal temp. pattern)
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Lentic Systems: Light Gradient
* Photic zone: upper lit waters that extend down to 1% remaining light intensity
* Photosynthesis and respiration occur in the photic zone
* Aphotic zone: dark region below the photic zone, where only respiration occurs
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Littoral Zone
near shore region (extends out from shore to a depth where only 1% surface light remains on bottom)
•Aquatic rooted plants (macrophytes) are common (cattails, lily pads, reeds, etc.) providing habitat for many organisms •Littoral zone fish (e.g., pike, walleye) and aquatic insects will be present •Bottom of the littoral may contain thick productive algal mats
•Macrophytes and algae extend from the shore to the 1% light level depth (~ where P=R)
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Pelagic Zone
Plankton: organisms (bacteria to arthropods) that are unable to maintain their position in the water column independent of water currents, unlike fish
Phytoplankton: algae, primary producers (Diatoms, Chrysophytes, Cyanobacteria, Chlorophytes, etc). Most are microscopic
•Zooplankton: feed on phytoplankton, include protists (flagellates & ciliates), & metazoans (rotifers, crustaceans & insects)
•Pelagic fish: feed on zooplankton, include lake trout, perch, white fish, etc.
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Ecosystem within the Lentic System
Littoral Zone
Pelagic Zone
Benthic Zone
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Benthic Zone
The benthic region underlying the pelagic is often an anoxic zone with very few invertebrates; however, if the benthic zone is oxic, the invertebrates can become abundant
Ex: Freshwater clam
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Lake Productivity Levels(3)
As a result of the strong relationship between algal biomass & phosphorus, the trophic status (or productive capacity) of a lake can be classified according to the quantity of phosphorus in a lakes water column
.Input of P from benthic sediments, terrestrial litter & stream inflows
Oligotrophic <10 P CONCENTRATION
Mesotrophic 10-30 P
Eutrophic >30 P
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Marine Ecosystems: 4 depth layers
•Largest ecosystems covering __% of the Earth’s surface
•Contain __% of the Earth’s water
•Pronounced effect on Earth’s climate and weather & biogeochemical cycles
* Largest ecosystems covering 75% of the Earth’s surface
* Contain 97% of the Earth’s water
* Pronounced effect on Earth’s climate and weather & biogeochemical cycles
Epipelagic <200 M
Mesopelagic 200-1000
Bathypelagic 1000-4000
Abyssopelagic 4000-6000
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Highest rate of production in Marine system
Bacterial production (photosynthetic and heterotrophic)
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Marine Ecosystem open ocean pp and pc
* Phytoplankton (prokaryotic and eukaryotic are the primary producers in photic zone (top 200 m)
* However, 80% of light energy is absorbed in the first 10 m
* Water column is as bright as a star-lit night at 600 m; majority of the ocean is dark
* Zooplankton (copepods) are the primary consumers
* Both zooplankton and phytoplankton drift with the currents
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Open Ocean
However, due to their vastness, the oceans account for __% global carbon fixation (or __% of the air we breath comes from the oceans)
However, due to their vastness, the oceans account for 50% global carbon fixation (or 50% of the air we breath comes from the oceans)
* Majority of ocean is N or P limited, and there has been a debate about which nutrient over the long term controls primary production
* This has immediate relevance to the carbon cycle and global warming
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•Tyrrell (1999) illustrated with a mathematical model that P ultimately controls primary production
WHY? Potential explanation…recall your N and P cycles
* There is an endless supply of gaseous nitrogen (N2) that diffuses into the water
* This N2 can be fixed readily by Cyanobacteria when N03 and NH4 concentrations become limiting in the water column
* When P concentrations become limiting, a gaseous supply of P does not exist
* Therefore, additional forms of P cannot enter the water column and be fixed into biomolecules by phytoplankton, or bacteria.
* Hence, these organisms are restricted in biomass by the amount of P available in the water column (over the long term)
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Kelp: Growing issues of overuse
* Kelp are brown algae that grow on rocky shorelines
* Kelp forests can reach 60 m heights, and form complex habitat
* Coral reefs & kelp forests have high biodiversity & are very productive
* Corals and kelp exist in low nutrient waters
* High rates of productivity are maintained by rapid recycling and retention of nutrients within the biotic components of the ecosystem
* This is similar to tropical rainforests
* >600,000 tonnes of Kelp are exploited annually for alginate for many uses (e.g., food, thickeners, cosmetics etc)
* Kelp forests are fast growing and over- exploitation is not a problem (yet?)
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Zooxanthellae photosynthetic dinoflagellates
* Zooxanthellae are photosynthetic dinoflagellates (algae) that form symbiotic relationships with reef forming corals (hard corals)
* Calcification in hard corals is much more rapid when light is present
* Zooxanthellae are photosynthesizing and producing glycerol for the coral
* When corals get “stressed” they lose their zooxanthellae, or zooxanthellae lose their pigments
* This results in the loss of color of many corals and is called coral bleaching
* This may occur from extreme temperatures, lack of sunlight (turbid water), or from acidification of the surrounding water
* The corals may die, but often regain their symbiont within a few months
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Estuaries
•Estuaries are found where rivers meet the ocean
•Estuarine organisms are posed with two problems: -Maintaining their position as tides and river water moves in the estuary -Adjusting to changing salinity as freshwater dilutes saltwater
•Most estuarine organisms are tolerant of salinity changes
•However, zonation of clams and other benthic organisms does occur down the estuary based on salinity preferences
Structure
•Freshwater floats on saltwater in a seaward direction
•Freshwater sediment & organic matter settles & crosses the pycnocline
•A brackish* bottom water countercurrent carries this nutrient laden material back upstream and creates a sediment trap
•Fertile tidal marshes and mudflats are created
* Estuaries have soft muddy bottoms, unlike the hard substratum of the rocky intertidal
* These muds will be nutrient rich, and support a large biomass of organisms, but biodiversity is relatively low in estuaries
* High nutrient inputs create excess algal production and result in anoxic zones or “dead zones” that are becoming more prevalent globally
* For example, Gulf of Mexico, Gulf of St. Lawrence, Baltic Sea, Black Sea, Chesapeake Bay, all have major “dead zones”
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grassland definition
land covered with herbaceous plants with <10% tree & shrub cover
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grasslands
| Once covered __% of Earth’s land surface
Once covered 42% of Earth’s land surface
•High rates of evaporation
•Severe droughts on seasonal or multi-year scales
•Prairie soil is among the most fertile worldwide (e.g., 12 x the humus layer of a typical forest soil)
•Rainfall between 250-750 mm y-1 (too light for extensive forest, but too heavy for desert)
•Dominated by grazing and burrowing animals
•Requires periodic fires to be maintained (to remove woody plants)
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Two grass growth forms of Grasslands
* Sod grasses: develop a solid mat above the soil
* Bunchgrasses: grow in clumps. Other non-grass plants (e.g., forbs) may grow between these clumps
* Roots may reach to a depth >2 m
* Some sod grasses will take on a bunchgrass form under different environmental conditions (e.g. dry soils)
* Most grasses have rhizomes or underground stems for new plant propagation, and food storage
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Short Grass Prarie
. High moisture June
• Found in Saskatchewan (south west) and Alberta • Kindersely marks its northern distribution
• Associated with the drier sections of the Canadian Prairie
• Annual precipitation below 350 mm:
• Mean annual temperatures below 3oC
• Moisture usually plentiful only in spring
• Very dry summers
•Grasses are typically under 50 cm in height
•Dense sod grasses (few forbs, but some can exist, e.g., asters)
•This region has more “natural” cover than mixed- and tall-grass regions
•Typically used for ranching (too dry for crops, unless irrigated)
•Overgrazing has shifted vegetation to shorter grasses, or to sage brush, or to cacti
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Mixed Grass Prarie
Bordered by the short-grass region to the south and the aspen parkland region to the north (found in all three plains provinces)
•The mixed-grass region is more humid and experiences lower mean annual temperatures, resulting in less water stress (e.g., due to evaporation)
•Precipitation: 350 to 650 mm annually:
•Mixture of sod and bunch grasses
•Plants may attain heights of 1.5 m
•Taller grasses occupy lowlands, and shorter grasses occupy higher elevations
•Highly variable precipitation results in year to year variation in the type of grass cover:
• Wet years, taller grasses dominate • Dry years, short grasses
•Most of the mixed-grass prairie has been converted to cropland
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Tall-Grass Prarie
• Most eastern part of the grasslands in Canada • Located in the Red River basin of central Manitoba • Majority of tall-grass prairie is found in the United States
.Annual precipitation: ~500 to ~1000 mm
• Moisture available well into the summer, unlike the shortgrass and mixed grass zones
• Most productive of the three North American Grasslands
• Soil moisture in the Red River basin persists later into the summer
• This promotes the dominance of late maturing tall grasses
• Grasses on well drained sites can reach heights of 2-3 m
• Although restoration efforts are underway, only a few small patches of tallgrass prairie (i.e., <4 km2) remain in southern Manitoba
• Tall-grass prairie is susceptible to tree invasion due to higher rainfall
• Tree establishment results in losses to grassland biodiversity
• Natural fires once every three to ten years would keep tree establishment to a minimum in the tall- grass prairie
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Temperate Grassland Ecosystems
Temperate Grassland Ecosystems:
•Contain less biomass •Store considerable organic matter •And have moderate rates of net primary production
Grasslands 20 to 55% productivity efficiency
.higher temp negatively affects grasland
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Carbon Pools in grasslands
* Organic and inorganic carbon stored in grasslands is estimated at 770-880 Pg (Pg = 1015 g) of carbon globally
* This is equal to 20-25% of all carbon stored in terrestrial ecosystems
* However, they release large quantities when cultivated, or tilled
* Tilling breaks up soil and provides better access to decomposers to previously unavailable carbon compounds
* Many grasslands lose up to 50% of carbon stocks in first year of cultivation
* Cultivated grasslands or rangelands can take 50-100 years to regain lost carbon.
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Factors Affecting Primary Production
•However, unlike forested ecosystems, grassland production is inversely related to temperature
•This is a result of the effect of temperature on water and nutrient availability
1. High temperatures increase evapotranspiration and can result in water stress in grassland plants
Cooler grassland regions in North America have lower water losses due to evapotranspiration and therefore, lower water stress
2. Nutrient mineralization is greater in soils with greater moisture, compared to dry soils
Therefore, nutrients may be more accessible in cooler regions, where more moisture is present in the soil
. Grazing positive affect
. Fire: (burns in the fall, winter and spring are beneficial)
* Grasslands of moderate rainfall have been replaced with arable annual crops of wheat, oats, corn, rye and barley
* Cultivation of drier grasslands is not economical and these have been converted to meat and milk production
* Natural grazers (i.e., bison & pronghorn in North America, and ungulates in Africa) have been replaced with cattle, sheep and goats
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Approximately, __% of natural grasslands remain in North America
__% have been converted to croplands and another __% have converted to urban areas
Approximately, 9% of natural grasslands remain in North America
71% have been converted to croplands and another 20% have converted to urban areas
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Boreal Forest(Taiga)
(World’s Largest Terrestrial Biome)
.La Ronge
•Predominantly coniferous forest
•Most of which lies in Canada, Alaska, and Siberia with smaller sections in Europe
•Covers 11% of the Earth’s land surface or 6.7 million km2
•Includes 1/3 of the World’s forested land and 14% of World’s forest biomass
•Boreal may have been more extensive, centuries of harvesting may have reduced size of this biome
•Dominant forest cover in Canada
•Stretches from the Yukon, through south central Canada and the Great Lake States of the USA into maritime region
•Bordered on the North by Tundra and to the south by prairie and temperature deciduous forest in the east
•Associated worldwide with recently deglaciated areas, humid climates, and low evaporation rates
•As a result, region contains many lakes & wetlands
•Fire is the predominant form of disturbance, unlike grasslands, much of the boreal forest still undergoes natural burns
•Often mineral poor soils that are thin and acidic (especially those directly on the granitic Precambrian Shield )
•But yields vast quantities of lumber and pulp (for paper products)
•World’s primary source of industrial wood and wood fibre
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Boreal Forest Climate
•However, outside of coastal regions, the climate is generally continental (i.e., cold winters and hot summers with moderate rainfall ~400 to 700 mm)
•Siberia has the most continental of climates (e.g., a range of 100 degrees celsius in a single year has been noted, -70 to +30oC)
•The unifying criterion is that the prevailing climate promotes conifers over broadleaf deciduous trees.
•Soil decomposition is slow (low temperatures) and leads to the accumulation of peatlands
Most northerly and southerly parts of boreal have lower annual precipitation
Range in Precipitation & Degree Days • Range in Mean annual precipitation ~250 to 450 mm
• Cool temperatures keep the moisture balance high
• Some permafrost is present in extremely northerly sections of Boreal
•Hardwoods (deciduous trees) are sensitive to low winter temperatures and short growing seasons
•Softwoods or conifers are adapted to cold winters and short growing seasons
•Four coniferous genera dominate worldwide • Spruce (Picea), e.g. black spruce • Fir (Abies), e.g., balsam fir • Pine (Pinus), e.g. jack pine • and larch (Larix), e.g., tamarack
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4 Dominant species of coniferous trees in boreal
* Four coniferous genera dominate worldwide
* Spruce (Picea), e.g. black spruce
* Fir (Abies), e.g., balsam fir
* Pine (Pinus), e.g. jack pine
* and larch (Larix), e.g., tamarack
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Boreal divided into two in Saskatchewan
Boreal Shield and Boreal Plain
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Athabasca Plain
located in boreal shield
.Jack pine dominate
Soils are very dry due to good drainage (through sand), this creates pine meadows instead of dense forests (insufficient water to support dense forests)
Soils are also very infertile
A variety of endemic plants exist in this dune area
In deeper soils, deciduous trees may be more prevalent such as white birch and aspens
Lowlands contain lakes or peatlands
Southern Boreal Plain:
•Increase in broadleaf (deciduous) trees and forest productivity from north to south
•Trees reach heights of 25 or 30 m in south
•Greater diversity of vegetation
WHY?
•Longer & warmer growing season
•Soils are more fertile
Note
•Southern boreal across Canada is the main commercial forest region
•Timber harvesting in some regions replaces fire as the main disturbance
•Coarse textured and dry soils favour jack pine (coarse sands)
•Wet soils with low nutrients favour black spruce
•In south, spruce only dominate in peatlands
•In the most southerly region (Boreal Transition Zone), the vegetation becomes more like Aspen Parkland
•Here, conifers are still present, but at decreasing abundance, and pure aspen stands are common
•Some of this observed decline may also be associated with logging in earlier times (conifers have not re-established)
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Southern Succesional plan saskatchewan
* Aspen can quickly regenerate after a burn and dominate the landscape for decades
* Aspens have a thin canopy, and the extra light that passes to the forest floor permits a lush ground cover of shrubs and herbs
* Spruce slowly develop in underbrush
* In 80 to 100 years aspen die-off, and longer lived spruce push up through the canopy and eventually dominate
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The Boreal Ecosystem-Atmosphere Study (BOREAS)
to investigate large scale vegetation- atmosphere interactions
•~40% of NPP occurs below ground (compare with grasslands > 50%
•According to BOREAS study the Boreal forest is still a sink for carbon
The turnover* of soil organic matter and nutrients in the Boreal forest is very slow compared to other ecosystems
This is likely a function of the short growing season, cooler temperatures and the type of organic material (recalcitrant to breakdown)
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Orca's in the North
seem to be expanding there reach into the north
. disappearance of ice allowing them in farther
.traditional knowledge needed from hunters and elders
.marine mammals the prey
.small groups of whales coordinate like wolves in packs hunting narwhales
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Woody shrubs podcast creeping in on tallgrass prairie
Flint Hills region-where remaining tall grass prairie is
| . Maintained by disturbance
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limnetic
open water
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eutrophic versus oligotrophic
high nutrient rich lake versus nutrient poor lakes
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Dystrophic lakes
receive high ammounts of human organic matter
259
gougers
invertebrates that burrow into water logged limbs
260
Anadromous Fish
live most of their lives in salt water, returning to spawn in frwsh
261
2 main divisions of body of water
pelagic zone and benthic
262
benthic is:
| benthos:
benthic refers to the floor of the sea
| benthos refers to the organisms that live there
263
Mean annual temperature determines
| Mean Annual percipitation
```
species composition(tropical,temperate, boreal)
growth form(trees,shrubs,forbs)
```
