Temperature 2: Sturgeon & Climate Change Flashcards
what is the degree to which temperature can vary spatially (3)
- across earth
- across ecosystems
- locally
what is the degree to which temperature can vary temporally (3)
- seasonal
- diurnal (day -> night)
- tidal
what levels does temperature affect biological organization (6)
- cell
- tissue
- organ
- organism
- population
- ecosystems
how is climate change affecting temperature (4)
- increasing the average global temperature
- less cold weathers
- more hot weathers
- new extreme hot weather experienced
what aquatic environmental factors do climate warming affect (3)
- decrease pH of water
- change salinity
- decreases O2 levels (hypoxia)
how does increasing temperatures lead to hypoxia in aquatic environments (3)
- decreased O2 solubility
- mixing of waters
- eutrophication leads to changing metabolic activities
what aspects of fish are altered in warming temperatures and aquatic hypoxia (5)
- cardiovascular function
- tolerance to stressors in general
- energy supply and demand
- growth and performance
- muscle contraction
how does warming affect the rates of biological reactions
- increases the rates of biological reactions
how does increased biological rate affect fish
- increases aerobic metabolism demand, increasing the metabolism rate
how does increased aerobic metabolism affect fish
- necessitates an increase in O2 supply to maintain energetic balance
how does warming affect available aquatic O2
- decreases available O2
why is warming so detrimental for fish (3)
- the warming necessitates an increase in oxygen supply and consumption
- warming also decreases available oxygen
- combination of both stressors will lead to loss of equilibrium and death
how will fishes cope with changing climate (3)
- leave, if possible
- acclimate
- die
acclimation (3)
- process where individual organisms adjust to a change in its environment across relatively short time periods
- generally considered reversible
- a type of plasticity
why is acclimation considered to be reversible
- phenotype will revert to its original state if environment returns to its original condition
at what levels does acclimatization occur (4)
- cell
- tissue
- organ
- organism
plasticity
- when the same genotype produces various phenotypes when exposed to different environments
when fish acclimate to warmer temperatures, what happens to their upper thermal tolerance
- upper thermal tolerance typically increases
when fish acclimate to warmer temperatures, what happens to their hypoxia tolerance
- hypoxia tolerance typically decreases, with the fish being able requiring higher levels of aquatic oxygen
cross-tolerance (2)
- phenomenon that occurs when mechanisms that are enhances to protect against one stressor also elicit protection against a second stressor
- most fishes can’t do this
what is an example of cross-tolerance
- fish that can acclimate to higher temperatures can maintain the same level of hypoxia tolerance
what is one of the largest threats to global biodiversity in regard to temperature
- heat waves, as opposed to chronic temperature increases
why are heatwaves such a large threat to global biodiversity (3)
- heat waves are rapid
- involve a magnitude of stressors
- organisms have difficulty acclimating quickly enough
how does upper thermal tolerance change during acute exposure to warm temperature
- upper thermal tolerance won’t increase as there was not sufficient time to acclimate
how does hypoxia tolerance change during acute exposure to warm temperatures
- hypoxia tolerance is severely lowered as the fish will require more oxygen to deal with stressors
what is the most endangered group of fishes on the planet
- sturgeon
how can we measure upper thermal tolerance (3)
- critical thermal maximum (CTMax)
- maximum is taken at the temperature when the fish begin to lose equilibrium/die
- loss of oxygen capacity in the water is also applied as the temperature increases
how can we measure hypoxia tolerance (2)
- incipient lethal oxygen saturation (ILOS)
- tolerance is taken at O2 water percentage when fish lose equilibrium or die
upper thermal tolerance in sturgeon not acclimated to higher temperature
- thermal tolerance was lowered in lower aquatic oxygen levels
upper thermal tolerance in sturgeon acclimated to higher temperature (2)
- thermal tolerance was higher than in non-acclimated sturgeon
- thermal tolerance was not affected by lower aquatic oxygen levels; cross-tolerance
hypoxia tolerance in sturgeon not acclimated to higher temperature
- sturgeon were able to tolerate lower aquatic oxygen levels in lower temperatures
hypoxia tolerance in sturgeon acclimated to higher temperature (2)
- sturgeon were able to tolerate lower aquatic oxygen levels than in non-acclimated sturgeon at all temperature levels
- hypoxia tolerance was less affected by temperature
how does heatwave acclimation affect individual sturgeon (2)
- increases whole organism plasticity
- induces cross-tolerance
what do increased plasticity and cross tolerance in an individual require (2)
- active molecule and physiological changes
- involve the organs, tissues, and cells
how is increase plasticity and cross tolerance achieved at the cellular level (2)
- increase in mRNA transcriptional plasticity
- increase in DNA methylation plasticity to increase transcriptional availability
