Polution and decay Flashcards
what is an indicator species for pollution
the presence or absence of these species can show whether there Is pollution or not
what are 2 indicator species for air pollution
lichen
blackspots
what are 5 indicator species for water pollution
blood worms or sludge worms
stonefly larvae
mayflies
caddisflies
how does lichen show air pollution
is a type of moss that can only grow where there is no air pollution
how does Blackspot show air pollution
is a fungus that infects roses, the fungus is damaged by sulfur dioxide in the air so where there is air pollution roses will be clear of fungus
how do bloodworms/sludge worms show water pollution
can live in water that contains little oxygen so they are found in polluted water
how do stonefly larvae, mayflies and caddisflies show water pollution
can only live in water that contains a lot of oxygen so they only grow in unpolluted water
what is the definition of decay
is the breakdown of materials by microorganisms
give 3 factors that affect the rate of decomposition
temperature
water content
oxygen availability
what is a high water content and oxygen availability crucial for decay
as microorganisms need plenty of water and oxygen to survive and decompose
what are 3 methods to prevent decay
refrigerating
salting
packing foods in nitrogen
how does refrigerating make foods last longer
the temperatures will be too cold for most microorganisms to grow quickly
how does salting make food last longer
it causes water to move out of bacterial cells by osmosis so there is not enough water for microorganisms to grow
how does packing food in nitrogen make them last longer
means there will be no oxygen for microorganisms to respire
what is the formula for the rate of decay
loss of mass in grams/time in days
