Eutrophication and stoichiometry- nutrient pollution Flashcards
Where is the biggest dead zone caused by eutrophication?
gulf of Oman
What is eutrophication?
‘the enrichment of water by nitrogen compounds causing an accelerated growth of algae and higher
forms of plant life to produce an undesirable disturbance to the balance of organisms present in the
water and to the quality of water concerned’
by nitrates directive
What is the lake classification based on nutrient content and organic material production? (increasing)
Dystrophic- brow water lakes (peat drained)
oligotrophic- nutrient poor
mesotrophic- middle nutrient
Eutrophic- nutrient rich
Hypertrophic- very high in nutrients
What might be anthropogenic causes of eutrophication?
Sewage
Fertiliser application
NOx from car emissions
Phosphates from clothe washing
What is the biggest contributor to eutrophication?
agriculture- 3/4 (with some variation)
What type of pollution source is agriculcture?
diffuse - difficult to control (need to understand how pollutant is transported)
What type of water flow is the most problematic with eutrophication?
stagnant- pollutant can build up as fast flow disperses it
What is the problems related to sewage outlet and eutrophication?
in high situations in the sewage the dam can be flooded leading to spillage of sewage and effluent into river and coastal areas
What must also be considered along side nutrient concentration when looking at eutrophication?
stoichiometry
What nutrients are most influential in eutrophication?
N
P
What is chemical stoichiometry?
quantitative relationships to determine the amount of products/reactants in a chemical equation or composition
What is ecological stoichiometry?
study of the balance of energy and multiple chemical elements in ecological interactions
What is the Redfield ratio? (definition)
the balance of C N P nutrients in a water body
What is the Redfield ratio? (actual ratio)
C- 106
N- 16
What did the eutrophication experiment in the great lakes show was the most pivotal eutrophic nutrient?
phosphorus
What nutrient concentration ratios need to be accounted for when looking at eutrophication?
C/P
N/P
C/N
and absolute concentration
What wont have an effect on eutrophication?
adding nitrogen its the relative concentration of C/P
How have human actions affected nutrient avaliability?
nitrogen- doubled amount of reactive nitrogen
phosphorus- 5 fold increase in 50 yr in production and consumption
What are the main effects of nutrient pollution?
Hypoxia/ dead zones
Contaminated beaches
Harmful algal blooms- HABs
Contaminated drinking water
Changes in community structure
Fish kills
Poisoning - dogs and people
Increased water treatment cost
Loss of tourism
What are HABs?
harmful algal blooms
What is a dead zone?
low oxygen/ hypoxic areas
How do HABs cause hypoxia?
respiration by algae at night when they cant photosynthesise
How can you identify HABs?
oily
cant be picked up
blue/ red twinge
How can you tell is algae isnt HABs?
bubbly
can be picked up
