Climate change Flashcards
Hvad er et parameter man ofte kigger på ift. havet - når man snakker om klimaforandringer
Temperatur
Forklar Global pattern for thermal adaptation in marine phytoplankton
De er adapterede til at have temp optimum til der hvor de er. Når de er optimeret til enderne (meget koldt, meget varmt) kan deres temp optimum ikke rykke sig så meget som det kan for dem mere i midten.
Forklar Fish communities change ift climate change og højere temp. Migration.
Ved højere temp skifter fiske communities i områder. De skubbes højere.
Hvad forårsager local extinctions? Hvor sker det mest ?
Local extinction: Havene bliver varmere og i nogle områder mindre fyldt med ilt. Det forårsager lokale extictions. Der er faktisk flest i verdens varme områder - de har ikke mulighed for at rykke sig lige så meget og konsekvenserne ved højere varme er mere dødelige.
Hvorfor er ice cover godt rundt omkring?
Snow cover: Det beskytter isen nedenunder fra at smelte.
Derudover reflekterer sne og is solen væk - ellers absorberer det nedenunder varmen.
Hvad sker der ved loss of ice?
Loss of ice: Loss of ice communities. Fx diatoms. Som er en food source for birds. Loss of ice er også loss of habitat for top predators (fx valrosser, isnjørne som ikke kan chille).
Forklar om Sea ice and primary production.
Sea ice and primary production: Less ice means more open water period. More light. More phytoplankton growth. For a longer time. The spring bloom starts earlier (when there is enough light and not by the break up of sea ice as before ). This means PP will increase. PP is then used by the next tropic level (zooplankton).
MEN hvis zooplankton kommer for sent til blooms - så er det ikke godt.
Forklar korte fødekæder i Arktis
Short food web in Arctic: Fytoplankton er ikke så lipid rich. Men zooplankton i arktis er lipid rich. Dvs. i de første trofiske steps stiger lipid med 10-20%. Nå man kommer op til zooplankton fx Calanus, så stiger det med 50-70%. Zooplankton og især Calanus er nogle af de største copepods i verden.
Fytoplankton og reduced / increased melt-water stratification.
Some areas with reduced meltwater stratification experience less phytoplankton, other areas with more meltwater experience increase.
Forklar poleward species migration
Poleward species migration (can change biodiversity, increase food web complexity) global ocean system.
Forklar Shift in species size in the Arktis.
Large shift in species size (for example a shift to smaller less lipid rich copepods - reduced overall productivity)
Coral reefs are especially sensitive to changes in ..
They are also severely impacted by other multiple stressors such as…
pH and temperature
overfishing, destructive fishing, pollution, sedimentation, nutrient overenrichment, and invasive species
What does rising temperatures do to corals
cause bleeching
Genetic diversity in hosts and symbionts leads to a diversity of responses to mild temperature increases, but severe temperature anomalies almost always lead to widespread bleaching and death
Hvad er coral bleeching og hvad er effekterne på korallen fra moderate coral bleeching og bleeching
Coral bleaching, a state in which the tissues of the coral become colorless because of the loss of the zooxanthellae, the symbiotic dinoflagellates that through their photosynthesis fuel the growth of their coral hosts
Moderate bleaching results in stress that causes reduced growth rates and reproductive
output, whereas severe bleaching results in coral death
Bleaching also appears to make corals
more vulnerable to disease, so that some death occurs after a time lag
Bleaching also appears to make corals
more vulnerable to disease, so that some death occurs after a time lag
Hvis der bliver ved med at komme højere temperaturer - hvilke coraller / symbiotiske forhold mellem dem og deres zooxanteallae vil der findes i fremtiden?
Reefs are likely to become dominated in the future by symbiotic associations with warm-tolerant
zooxanthellae, allowing some corals to survive moderate temperature increases. However, these
more robust zooxanthellae may be less suitable as partners from the perspective of other aspects
of coral health, such as growth
Hvad er ocean acidification?
Ocean acidification refers to a reduction in the pH of the ocean over an extended period of time, caused primarily by uptake of carbon dioxide (CO2) from the atmosphere.
Ocean acidification occurs when carbon dioxide (CO2) is absorbed rapidly into the ocean. It reacts with water molecules (H2O) to form carbonic acid (H2CO3). This compound then breaks down into a hydrogen ion (H+) and bicarbonate (HCO3-). These hydrogen ions decrease seawater pH
How does ocean acidification affect corals?
Ocean acidification makes it more difficult for corals to secrete and maintain their skeleton.
Some coral species lose their skeletons altogether.
and skeletal growth of recent recruits can be disrupted.
Growth rates of adult corals may be reduced, or their skeletons may be less dense (which would make storm
damage more serious). However, as with zooxanthellae and temperature, some coral species are likely to be more resistant to the effects of low pH
What is eutrophication - how does it occur
Eutrophication starts with fertilisers, which are rich in nutrients like nitrate and phosphate, are washed into the river or lake system. This leads to an increase in nutrient concentrations in the water. The nutrients are food for algae. The algae grow and reproduce quickly, forming a thick green bloom in the water. This algal bloom will absorb sunlight shining on the water so the sunlight can’t reach the bottom. Plants who need this light to photosynthesis will die. The algae will also start to die when they eat up all of the nutrients and run out of food.
Next, bacteria start to breakdown the dead plants and algae. That releases more nutrients back into the water continuing the Algal Bloom Cycle. The bacteria, with a continuing supply of food, reproduce into much larger numbers consuming oxygen as they grow and respire.
There is not much oxygen in the water to begin with so when the bacteria consume it quickly it might run out completely. Water without oxygen is called Anoxic. If the water turns anoxic, all non-bacterial life in the water, including fish and other animals, will die.
So, eutrophication happens when nutrients are added to water which causes an algal bloom, cutting off sunlight and feeding bacteria. The bacteria use up oxygen in the water which becomes an anoxic, causing everything living in the water to die.
Eutrophication is one reason why we need to be careful with fertilisers when we are growing crops.
