L29: Ocean Acidification and Eutrophication
No description yet. This curated deck is ready for daily study.
Card preview (24)
what are the 2 ways the Anthropocene can be defined?
-as a ‘new’ geological period of time (subdivision of the Holocene), -as an informal cultural time,
what is the controversy surrounding the Anthropocene?
been rejected as it is time transgressive so cannot be defined as an accurate period of geological time
what are the different forms that marine carbon exists in?
-organic/inorganic, -dissolved/particulate form (solid),
what does organic marine carbon look like?
black and soft
what does inorganic marine carbon look like?
white, skeletal calcium carbonate
what are the 3 chemical forms that carbon occurs in ocean in?
-dissolved CO2 which reacts with sea water to form carbonic acid, H2CO3 (ocean acidification), -Bicarbonate, HCO3, -Carbonate, CO3 2-,
what happens when atmospheric CO2 levels increase?
dissolved CO2 in surface oceans increases, causing an increase in carbonic acid and resulting in the ocean acidifying as PH decreases
what follows the decrease in carbonate ions?
calcification is inhibited and the abundance of marine calcifies drop
what is the chemical equation that represents the formation of bicarbonate ions?
CO2 + H20 + CO3 2- —–> HCO3 (carbonate) (bicarbonate)
is the change in PH consistent across the whole globe?
no
what ocean is seeing the greatest change and highest reductions in alkilinity?
the North Atlantic
what oceans are seeing little change in ocean PH?
the Pacific and Indian ocean
what impact does ocean acidification have on the carbonate compensation depth (CCD)?
causes it to shoal (get shallower)
what does a shallowing of the CCD cause?
causes a dissolution of carbonate deposits on the sea bed
what are a couple examples of impacts ocean acidification may have on marine organisms?
inhibits the ability of calcifying organisms to grow their shell and can even cause the dissolution of shells
what does the presence of deep ocean red clay indicate?
that the lysocline moves and shoals
where is deep ocean red clay derived from?
the land
why is deep ocean red clay red in appearance?
the lots of free oxygens oxidise giving a rusty appearance
where does the word eutrophication derive from?
the Greek word eutrophs meaning ‘well-nourished’
what is the process of eutrophication?
the ecosystem becomes enriched with nutrients e.g. nitrate, phosphate and organic materials causing enhanced productivity. this increases respiration, removing oxygen from the system leading to anaerobic conditions.
can eutrophication be a naturally occurring phenomenon?
yes
what is an Oligotrophic?
nutrient depleted system (very acidic- can reach PH 4)
what is an example of a Oligotrophic environment?
Blanket Bog, Scotland
what is a eutrophic fen?
a base rich and alkaline environment which are eutrophic