Week 7 Flashcards
MAR 6
Impacts on Natural Ecosystems
Photosynthesis and CO2
*
Response to elevated Co2 related to Photosynthetic type
(there are 3 pathways)
1
2
3
The process:
CO2 + water + light –> carbohydrates + oxygen
* Temperature is also important b/c most metabolic processes speed up with higher temperature - more CO2 to a plant = photosynthesize faster] (& water and nutrients)
1 - C3 (most plants on the planet are C3 ~90%) ex rice
2 - C4 (many of the plants that are C4 are very important crops - tropical and sub-tropical grasses + corn/maize, sugar cane, sorghum and millet
: CO2 enters via the stoma - enters and grabbed by enzyme Rubisco then enters Calvin-Benson cycle
Passive process for C3 plants - very responsive to how much CO2 there is
C4 are different… they have a helping aid (Co2 pump) so no matter what Co2 conc in atmosphere is - they don’t care as much - CO2 pump means C4 plants are less responsive to elevated CO2
CO2 benefits crops differently dependent on photosynthesis process
CON’D
CO2 fertilization
for C3:
C4:
Carbon fertilization
–>
C3: gradually increases - at about 700ppm becomes really impacted / At very low CO2 - plants suffer (C3)
C4: plateaus / C4 plants are in general relatively unresponsive to elevation of atmospheric CO2 above current ambient levels
–> Elevated CO2 could benefit agri and forestry
Problem with people thinking this….
In a natural environment (vs chamber experiment) - cannot control water and nutrients… if elevated CO2 Aka changing climate: higher precip or dryer climate
HOWEVER, negative impacts of climate change will likely outweigh the “greening” from CO2 fertilization
(negative impacts: drought, floods, extreme weather, shifting seasons, increases ranges of weeds, invasive species and plant pests)
Impacts on Natural Ecosystems
MOVE, ADAPT or DIE
IPCC quote
“Without urgent and deep emissions reductions,
some species and ecosystems, especially those in
polar and already-warm areas, face temperatures
beyond their historical experience in the next
decades (e.g., >20% of species on some tropical
landscapes and coastlines at 1.5°C global warming).
Unique and threatened ecosystems are expected
to be at high risk in the very near term at 1.2°C
global warming levels (very high confidence) due to mass tree mortality, coral reef bleaching, large
declines in sea-ice dependent species, and mass
mortality events from heatwaves.”
MOVE…
Range Shifts:
-
-
Insects:
Plants:
*Very resourceful animal:
Birds:
: results of a meta-analysis
- Species have moved 16.9 km per decade away from the equator (b/c moving too much)
More so more data for northern hemisphere
- Will drive food security, patterns of disease transmission and processes of carbon sequestration are all altered by changes in species distribution
Insects: are particular good at moving with shifting climate
Impact of climate change on shifting pest infestation problems
Plants: (esp fast growing plants) are also capable of moving with shifting climate
Might be a good thing (ability to grow different crops) but it might also be a bad thing in terms of invasive plant species
Concerned about Maple trees: certain type of nutrients and water - not just temperature
*Very resourceful animal: Mice and Rats (Rodents) - doing okay in climate change - borrowing animal and may be beneficial for them
Birds: North ward shift
Change in center of abundance of about 40 miles North (over 40 years) - WINTER temperatures that impact this most
MAR 4
“Greening” of the Arctic and Antarctic
–> Begins with Glacier retreat
- seeing more and taller native shrubs in the Arctic
Satellites can bombard…
Satellites can bombard - use Infrared & amount that bounces off indicates the color (green specifically)
[more plant growth = more carbon sequestration ALTHOUGH….]
Melting permafrost (speed up decomposition process (which produces CO2 and CH4) - left with bog like substance which anaerobic causes methane
ADAPT…
Adaptation of organisms
Phenotype vs Genotype =
-
-
Evolutionary Changes
Evolutionary adaptation =
- microevolution
Geno = genetic makeup of an organism (evolutionary response)
Phen = physical characteristics of an organism
- Phenotypic plasticity
- Plasticity = changeable
Phenotypic plasticity = changes in an organism over the course of its lifetime (organisms features can be influenced by its environment)
- developmental (ex; organism grows larger when lots of food vs smaller when less),
- behavioral (ex; polar bears - seals are their main source but will eat goose eggs when no sea ice to hunt) and
- physical changes (ex; rabbits - brown in summer and white in winter)
= natural selection (changes in gene frequencies to improve the function of a trait)
- Experienced by whole populations over many generations
- Microevolution (changes over shorter periods of time) - already seeing this in response to a changing climate - specifically will organisms with rapid reproduction
Series of Studies:
–> Coral reef exploratory research
–> Salmon
–> Tawny Owl
–> Squirrel
–> Precipitation and Natural Selection
Changes to phenology
–> Earlier timing of spring events, such as leaf-unfolding, bird migration and egg-laying
Can get “synchronization” issues when species are affected differently
EXAMPLES:
–> Migration ex with wood warbler species bird
–> Hibernation ex with ground squirrel
–> Breeding mismatch ex with bird and mosquitos
–> Fatal competition btw two bird species
DIE…
Vulnerable species are those that cannot escape or adapt to the changing climate THUS at risk of extinction
- Primates and marsupials
- Birds
- Rodents
- Polar Bears
Estimated that 47% of terrestrial threatened mammals (out of 873 species) and 23.4% of threatened birds (out of 1,272 species) may have already been negatively impacted by climate change
- Primates and marsupials are at particular risk: (already in warm climate & slow reproductive rates, restricted environmental tolerances)
-Birds in cold mountain regions are at particular risk (already live at the tops of these mountains, fewer opp to move and synchronization issues (timing of chick feeding and peak food avail)
- Rodent and insect are thought to benefit - eat anything, fast reproducers, living in borrows may mean they can insulate to changing temps
- Loss of arctic sea-ice threat to polar bears
Summer arctic sea ice extent is shrinking by 12.6% per decade as result of global warming
Australian rodent named 1st mammal to go extinct due to human changed climate change
-
Red list of threatened species
Drivers;
:
- Tropical areas particularly susceptible
- Animals more susceptible than plants
Drivers:
Land use changes
Direct exploitation
Climate change
Pollution
Invasive species
Amphibians at 41% risk
