BIOL271 Part 2 Questions With Complete Solutions
Sedimentation of coral
Sediment smothers coral. Problem near continental landmasses
and estuaries. In more turbid waters, have more zooxanthellae to
counter-act sediment - more efficient light capture
Anthropogenic impacts to coral
1. Boat accidents
2. Destructive fishing practices
3. Coral disease (increase due to pollution and climate change)
4. Nutrient enrichment
5. Sedimentation
6. Global warming
7. Ocean acidification
Coral Bleaching
Lose of symbiotic algae and/or photosynthetic pigments, caused
by environmental stress eg) global warming. 10 periods of mass
bleaching to date, annual bleaching predicted by 2040
Ocean Acidification
1. CO2 from atmosphere enters water, forms carbonic acid and
produces bicarbonate and H+
2. Water tries to buffer self from increased acidity by removing
protons using carbonate
3. Takes carbonate out of solution - if not enough carbonate,
,can't build coral skeleton
4. If reduce carbonate, coral skeletons could eventually dissolve
Increased CO2 in atmosphere causes:
Elevated CO2 concentration in the ocean and decreased pH.
Reduced saturation state of carbonate ions. Eventually skeletons
cannot be deposited and eventually dissolve
Frazil Ice
First ice that's formed - little turbulence and gloopy surface
Grease Ice
Slight waves and ice bring frazil ice together in clumps
Sheet Ice
From grease ice in calm conditions
Nilas sheet ice
Low wind/wave action. Forms overnight. 10s of cm thick
Finger rafted sheet ice
Sheet ice that overlaps
Pancake ice
Wind-driven. Have raised rims from constant collisions
Fast ice
Attached to land, ~2m thick
Pressure ridges
Build up of ice on ice shelf by glacier
,Sea ice formation
When ice formed, brine/salt excreted in brine channels. Brine
channels up to 150ppt and expelled into water.
Colder it is, the saltier it is due to brine exclusion (warmer
conditions = less salt) - salt sinks to bottom (is heavy and dense)
Antarctic Convergence/Polar Front
Nutrient poor. Sudden change in temperature - big change over
very small distance, a boundary some organisms can't cross =
very low diversity.
Antarctic divergence
Nutrient rich - high productivity from upwelling.
Katabatic Winds
Gravity-driven winds. Cold dense air that forms over polar
plateau and 'falls' downhill towards coast. Strong and persistent
Polynyas
Area of open ocean surrounded by pack ice. Katabatic winds
push ice offshore, exposing water which refreezes and is pushed
away.
Coastal polynya
Briney water comes off ice shelf, making it harder to freeze in
combination with katabatic winds
Open ocean polynya
Driven by warm, salty water upwelling from below, melting the
ice.
, Ross Sea Polynya
Maintained by Katabatic winds. Has greater light and nutrient
availability not limited by sea ice, creates large phytoplankton
blooms
B-15 iceberg
Iceberg calved off of Ross Sea Ice Shelf. Broke up and stuck on
side of Ross Island - prevented polynya formation. lead to great
loss of primary production, delayed sea ice breakout, restricted
penguin feeding ground and delayed phytoplankton blooms.
Productivity of marine phytoplankton
95% (40% of total planet production)
Southern Ocean Primary Production
1. Highest in coastal waters (upwelling)
2. Patchy production - productivity varies with region
3. Limited by light
4. High phosphate and nitrate but low production in some places
Main limitations of primary production in Antarctic
Iron deficiencies - phytoplankton extremely sensitive to iron,
can't grow without it. Limits phytoplankton growth in many
nutrient-rich areas.
SOIREE - Southern Ocean Iron Release Experiment
1999 added 10 tons of iron to patch of ocean - increased
phytoplankton growth. However, 1-2 orders magnitude lower
than maximum possible yield - a lot less carbon sequestered than
theoretically possible with amount of iron added
Sedimentation of coral
Sediment smothers coral. Problem near continental landmasses
and estuaries. In more turbid waters, have more zooxanthellae to
counter-act sediment - more efficient light capture
Anthropogenic impacts to coral
1. Boat accidents
2. Destructive fishing practices
3. Coral disease (increase due to pollution and climate change)
4. Nutrient enrichment
5. Sedimentation
6. Global warming
7. Ocean acidification
Coral Bleaching
Lose of symbiotic algae and/or photosynthetic pigments, caused
by environmental stress eg) global warming. 10 periods of mass
bleaching to date, annual bleaching predicted by 2040
Ocean Acidification
1. CO2 from atmosphere enters water, forms carbonic acid and
produces bicarbonate and H+
2. Water tries to buffer self from increased acidity by removing
protons using carbonate
3. Takes carbonate out of solution - if not enough carbonate,
,can't build coral skeleton
4. If reduce carbonate, coral skeletons could eventually dissolve
Increased CO2 in atmosphere causes:
Elevated CO2 concentration in the ocean and decreased pH.
Reduced saturation state of carbonate ions. Eventually skeletons
cannot be deposited and eventually dissolve
Frazil Ice
First ice that's formed - little turbulence and gloopy surface
Grease Ice
Slight waves and ice bring frazil ice together in clumps
Sheet Ice
From grease ice in calm conditions
Nilas sheet ice
Low wind/wave action. Forms overnight. 10s of cm thick
Finger rafted sheet ice
Sheet ice that overlaps
Pancake ice
Wind-driven. Have raised rims from constant collisions
Fast ice
Attached to land, ~2m thick
Pressure ridges
Build up of ice on ice shelf by glacier
,Sea ice formation
When ice formed, brine/salt excreted in brine channels. Brine
channels up to 150ppt and expelled into water.
Colder it is, the saltier it is due to brine exclusion (warmer
conditions = less salt) - salt sinks to bottom (is heavy and dense)
Antarctic Convergence/Polar Front
Nutrient poor. Sudden change in temperature - big change over
very small distance, a boundary some organisms can't cross =
very low diversity.
Antarctic divergence
Nutrient rich - high productivity from upwelling.
Katabatic Winds
Gravity-driven winds. Cold dense air that forms over polar
plateau and 'falls' downhill towards coast. Strong and persistent
Polynyas
Area of open ocean surrounded by pack ice. Katabatic winds
push ice offshore, exposing water which refreezes and is pushed
away.
Coastal polynya
Briney water comes off ice shelf, making it harder to freeze in
combination with katabatic winds
Open ocean polynya
Driven by warm, salty water upwelling from below, melting the
ice.
, Ross Sea Polynya
Maintained by Katabatic winds. Has greater light and nutrient
availability not limited by sea ice, creates large phytoplankton
blooms
B-15 iceberg
Iceberg calved off of Ross Sea Ice Shelf. Broke up and stuck on
side of Ross Island - prevented polynya formation. lead to great
loss of primary production, delayed sea ice breakout, restricted
penguin feeding ground and delayed phytoplankton blooms.
Productivity of marine phytoplankton
95% (40% of total planet production)
Southern Ocean Primary Production
1. Highest in coastal waters (upwelling)
2. Patchy production - productivity varies with region
3. Limited by light
4. High phosphate and nitrate but low production in some places
Main limitations of primary production in Antarctic
Iron deficiencies - phytoplankton extremely sensitive to iron,
can't grow without it. Limits phytoplankton growth in many
nutrient-rich areas.
SOIREE - Southern Ocean Iron Release Experiment
1999 added 10 tons of iron to patch of ocean - increased
phytoplankton growth. However, 1-2 orders magnitude lower
than maximum possible yield - a lot less carbon sequestered than
theoretically possible with amount of iron added
