CAS ES 142 Study Guide - Fall 2018, Comprehensive Midterm Notes - Sediment, Phytoplankton, Fish
12 Oct 2018
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CAS ES 142
MIDTERM EXAM
STUDY GUIDE
Fall 2018
10/21: Primary Production
Primary production is a RATE (how much is produced (biomass) per unit time)
Which phytoplankton are made out of cellulose? – dinoflagellates
What phytoplankton requires silica? – diatoms
Justus von Liebig
- wanted to increase the amount of food available for humans on earth
- we can grow more crops by figuring out what limits their growth
o primary production is limited by nutrients available
- created agricultural model (called Liebig’s Law of the Minimum) that is used today
o for freshwater, phosphorus is the limiting nutrient
o for land and oceans, nitrogen is the limiting nutrient
o other limiting nutrients include iron and silicon
o these are major limiting nutrients – big amounts are needed
- types of nutrients available dictate the type of phytoplankton available
o ex: lots of silica, lots of diatoms
What are some sources of nutrients?
- weathering of continents
- runoff of farm fertilizers
- wastewater treatment plants
Phytoplankton suck up CO2 from the atosphere look at leture slide titled priary produtio y
phytoplakto
Respiration
- opposite of photosynthesis
- aerobic (requires oxygen)
- organic matter + O2 = CO2 + NO3 + PO4 + H2O
o produces inorganic matter
- also called remineralization, regeneration, or degradation
o consumes oxygen
o produces carbon dioxide
o regenerates nutrients
Marine snow
- made from fecal pellets, dead organic matter (diatoms, coccolithophores)
- a lot found in dysphotic zones
find more resources at oneclass.com
find more resources at oneclass.com
- carries carbon and nutrients in the deep ocean
- can capture in a sediment trap to examine
- sequesters CO2 and remineralizes through respiration by bacteria to regenerate nutrients
What would a profile of oxygen with depth look like? – look at slide
- depth (m) on y axis
- oxygen concentration on x axis
- euphotic zone
o surface waters, oxygen is produced by photosynthesis
o respiration is also occurring but at a lesser degree
making more oxygen (through photosynthesis)than consuming oxygen (through
respiration)
i.e. a build-up of oxygen
- at end of euphotic zone (100 m), can no longer photosynthesize (not enough light) so respiration
takes over
o oxygen concentration declines
respiration consumes oxygen
o respiration outpaces production of oxygen
o oxygen minimum zone – lowest amount of oxygen
- after around 1000 m, the concentration of oxygen goes up as get deeper in ocean
o due to thermohaline circulation
cold water holds more gases than warm water
• collects oxygen as gets colder and colder
as it descends in the ocean, carries high concentration of oxygen with it
LOTS of deep water circulation
o also low rate of respiration in deep water because not a lot to eat
not consuming oxygen
- summary of oxygen concentration
o highest at surface
o decreases after euphotic
o increases after 1000 m
Nitrogen concentrations
- exact opposite of oxygen levels
o because nitrogen is on the other side of the reaction in respiration
as oxygen is consumed, nitrogen is produced
- summary of nitrogen concentration
o lowest at surface
o increases after euphotic – nutrient maximum at 1000 meters
o decreases after 1000 m
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Primary production is a rate (how much is produced (biomass) per unit time) Wanted to increase the amount of food available for humans on earth. Weathering of continents runoff of farm fertilizers. Phytoplankton suck up co2 from the at(cid:373)osphere (cid:894)look at le(cid:272)ture slide titled (cid:862)pri(cid:373)ary produ(cid:272)tio(cid:374) (cid:271)y phytopla(cid:374)kto(cid:374)(cid:863)(cid:895) Organic matter + o2 = co2 + no3 + po4 + h2o: produces inorganic matter also called remineralization, regeneration, or degradation, consumes oxygen, produces carbon dioxide regenerates nutrients. Oxygen concentration on x axis euphotic zone: surface waters, oxygen is produced by photosynthesis respiration is also occurring but at a lesser degree. As it descends in the ocean, carries high concentration of oxygen with it. Lots of deep water circulation: also low rate of respiration in deep water because not a lot to eat. Not consuming oxygen summary of oxygen concentration: highest at surface, decreases after euphotic increases after 1000 m.
