1. 하구및 연안생태Coastal management
2016 년 가을학기

2. Nutrient patterns with depth
NH4+, PO4; increase with depth; slow upward diffusion
NO3-; 0~5 cm peak; nitrification
Decrease with depth; if water column is high
Similar trends in water column; when sediment is a major source; mixing breaks these trends

3. Chemical kinetics Rates of transformation should be known
Transformation between : organic-inorganic, oxidation state.

4. Nutrient assimilation
Photosynthesis
Various organisms compete for nutrients
Lower Ks has greater affinity
High Ks has advantage in high concentration
The Ks values are similar to the ambient concentrations of summer period of peak growth !!!

5. Nutrient assimilation
Macrophytic plants have higher Ks; transport of ions across epidermal surface; usually have roots, so high K2 is not a big problem
Plants have adapted to the respective concentration

6. Nutrient regeneration
Enzymatic decomposition by microorganisms (bacteria and fungi)
Redifield ratio release of nutrients
Silicate: dissolution of tests Si:P=15:1
Decomposition occurs in sediment rather than water column

7. Nutrient regeneration
Aerobic versus anaerobic
Exponentiall decreasing NH4 production with sediment depth
O2 is preferable
Fresh OM is readily metabolized
9 times more NH4 by O2 respiration compared to SO4 reduction
Overall deficiency NH4 released compared to O2 consumed
O:N ratio of 12
Benthic flux with chamber experiments;
NH4: 20~300 umol m-2h-1
PO43-:0~40 umol m-2h-1
20~200 % of nutrient demands for phytoplankton assimilation

8. Nutrient regeneration
Regeneration is correlated with temperature
Arrhenius type expression; other than simple temperature kinetics are involved
NH4  NO3 ; nitrification
PO4: reacts with iron and manganese and hydroxides to form insoluble precipitates in oxic; when anoxic, soluble Fe(MN)-PO4-3 complex are produced and released.
N:P release ratio 8.4: about half that is expected (16); N is lost through nitrification-denitrification
Silicon dissolution is slow compared to N, P: late summer dominance of dinoflagellate is a result of reduced Si availability (?)

9. Excretion Zooplankton (phytoplankton) excretion
N : ammonium and dissolved organic N(urea, uric acid, amino acid)
P: dissolved organic phosphorus
Si: no excretion, but uptake by zooplankton can enhance dissolution.
Metazoan zooplankton excrete through gills and antennal glands
Protozoa: cell wall

10. Excretion N, P excretion measurements
Nutrient Conc. Change with zooplankters; various nutrients at the same time; can not apply in situ; what if uptake takes place at the same time?
Isotopic tracers(33P, 32P, 15N)
Excretion rates :Directly proportional to respiration zooplankton
C:N:P=30:9:1 ; oxidation of food (phytoplankton) is not complete !!
Function of temperature
Feeding rates; increase in starvation and high feeding
Excretion rates per unit weight of zooplankton are inversely proportional to the size of individual zoo plankton; organisms associated with particulates < 32uM accounts for most of release
Excretion versus remineralization
Importance vary seasonally and inshore-offshore direction
Water-column regeneration in oceanic waters; and even 7~8 m
Excretion is important in shallow water (benthic regeneration is also important)
N, P assimilation by bacteria can be important