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BIOL 2600 Chapter Notes -Silt, Symbiodinium, Hypolimnion

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BIOL 2600
Nigel Waltho

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Ecology 2006
Prof: Dr. Nigel Waltho Mon. & Wed. 10:05am
Lecture 1
Organismal Biology:
Evolutionary Biology – how individuals have evolved and adapted to their environment
through interactions with other individuals, populations and other species.
Behavioural Ecology – how an individuals behaviours contribute to their survival and
reproductive success and in turn the abundance in that population.
Physiological ecology – The study of how organisms are physiologically adapted to their
environment and how this limits their distribution patterns.
Population ecology - the study of groups of interbreeding individuals at the same place
at the same time.
Lecture 2
Freshwater Biomes: Chapter 24
Water: Is the most dense at 4’C and its least dense as ice. (increases density with salinity)
Layers of Water: (water – chapter 6)
In temperate lakes, in the summer, three layers are present (Figure 24.2c). An upper layer, called
the epilimnion, is warmed by the sun and mixed well by the wind. Below this lies a transition
zone known as the thermocline, where the temperature declines rapidly. Lower still is the
hypolimnion, a cool layer too far below the surface to be much warmed and with low light
Two types of food webs (sun driven)
1st = bentic-based macrophytic
2nd = pelagic-based microphytic
Cultural Eutrophication: (only takes a couple of years)
Biological Oxygen Demand (BOD)
Dissolved oxygen (DO): the amount of oxygen that occurs in microscopic bubbles of gas mixed
in with the water and that supports aquatic life. Oxygen enters the water directly via diffusion
from the atmosphere, from aquatic plants or algae that release it via photosynthesis, or via
waterfalls and water tumbling over rocks, which traps air.
DO = the same at all levels of the water.
Lotic (fast moving water) has a higher DO than lentic (slow moving water).
Also Temperature has an effect, cold water can hold more DO.
Air - amount of oxygen 200,000ppm (20%)
cold water - 10ppm (less in warm)
(a common water quality test, is testing the BOD
higher bod - greater likelihood DO(dissolved oxygen) depleted

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i.e. how much organic nutrients in the water
higher the bod measure, the more oxygen is required to decompose the material
once all is depleted you are left with an anoxic
anoxic = environment depleted of oxygen ( can be the result of high organic matter being broken
down by bacteri –which use O- e.g. near sewage leakage systems)
-fish and shellfish are killed when the DO drops below 2 or 3 ppm
if systems go anaerobic (lack of oxygen) the only thing able to survive in water is bacteria
(which adopts a fermentation or anaerobic respiration)
anerobic respiration releases methane (smelly!)
raw sewage BOD = 250ppm
Dissolved Oxygen: Is equal at all levels of the lake.
add nutrients (our sewage, agricultural run off, sediments etc.)
when you add nutrients, phytoplankton, algae will EXPLODE in population
algae floats on top because of photosynthesis advantage, however this provides shade for other
plants and kills them off
NOW, DO < 3ppm
^^ this sucks the oxygen out of the water, and effects bentic-based macrophytes
now, only very tolerate fish can survive, i.e. invasive species like carp
Measuring DO just place a probe in the water
Repeat sampling necessary
How to approach combating cultural Euphication:
1. address the symptoms: algae blooms, smells like sulphur,
2. AERATE the pond :) bye bye algae
3. harvest aquatic weed
4. water draw-down (lower water level to kill everything off)
2. Address the root cause: excessive inputs of nutrients
3. limiting factors, find out which nutrient needs to be lacking to suppress growth(in freshwater -
phosphate, in marine sysmtens - nitrate, or ammonium
sewage in ottawa: flushhhhh - primary treatment (clarifiers, separate fats/oils from organs
material) = clarified water
Secondary treatment - organic material - water and carbon dioxide ( C6H12O6 - H2O + CO2)
tsecondary settlement - another clarifier, gets rid of bacteria etc.
Water is then disinfected and then released
However, this still leads to eutrophication
we've dealt with carbon, but not with nitrates!

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SO, now systems are modified to oxidation and nutrient removal
process known as biological nutrient removal (BNR)
Tertiary Treatment: (Nitrates and Phosphate removal)
2 Tanks:
tank 1 - anoxic (NO3 + PO4) bacteria breaks down NO3 to get O. and release the nitrate as N and
releases it back into air as bubbles! :) yay ====== Left with, NH4 + PO4)
Tank 2 - Oxygen RIch - starts with NH4 + PO4
aerobic bacteria drawn out the phosphates
however we are still left with Nitrates, SO back into tank 1 (cycles back many times!)
= pure clean water
Riparian zones = area around lakes and rivers where vegetation taps into the lake water.
Lecture 3: Soils - Chapter 7
layers of soil:
1. O organic (fallen leaves, organic debris, partially decomposed organic)
2. Ah topsoil (humic) - mineral horizon, thin layer, (worms arthropods, so a lot of mixing, due to
their movement)
3. Ae subservice (eluvial) - in wetter well drained areas, clays, organic matter Fe & Al oxides (snow
melt off) are carried down
4. Bf Bussoil (iluvial) - accumulation mineral particles, Iron, clay, salts. redish in colour
5. C Parental Material -
6. R Bedrock –
C3: Enzyme rubisco turns CO2 into G3P
C4: Live in warmer, dryer climates than C3, When CO2 enters this plant, PEP carboxylase
bondsCO2, to a 3-carbon PEP.
CAM (Crassulacean Acid Metabolism): HOT & DRY ENVORONMENTS, similar to C3,
but only opens up stomata to do this process at night, to conserve water.
1. Temperate Grassland & the Great Depression, ALOT of type A(h) topsoil. (Annual rainfall is low,
so little leaching pushing down), therefore minerals are not drained down, they stay near
top.topsoil accumulates over time. AND since temperate temperatures, not much decomposition
(requires heat!)
2. Savvannah - Kenya for example, cattle are breaking up the o horizon, leaving just thin exposed A
horizon being picked up by the winds, eventually just rock left.
IDEAL SOIL for plant growth: mineral 45%(sand, silt, and clay), water, 25%, organic material
5%, air 25%
Q: why do most soil forming processes act from the top down?
Anoxic= oxygen deficiet/ completely gone
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