7.7. Questions and Tasks
139
modified to incorporate changes in the N0 3
- inventory driven by Fe availability by adding a sink and source term sensitive to surface Fe concentrations. Increasing the Fe flux to surface water has the potential to effect the
relative rates of nitrogen fixation and denitrification . These interactions
have been hypothesized to regulate the oceanic inventory of oxidized nitrogen on geologic time scales (Falkowski 1997). In essence, an increase in
Fe and the concomitant increase in nitrogen fixation would have the eventual effect of increasing the upwelling concentration of N0 3
- in the world 's
oceans. This creates another potential positive feedback between iron supply and primary production. If, on the other hand, the relative ratio of nitrogen fixation/denitrification decreases, N0 3
- is consumed and the maximum potential for primary production decreases.
The parameterizations of the model simplify the complexity of some
smaller-scale chemical and ecological processes, and limit the model's applicability over large temporal and spatial scales. As a consequence, the
model only approximates the dynamics of the atmosphere-ocean carbon
cycle and the biogeochemical behavior of N and Fe in an oligotrophic marine ecosystem on geologic time scales (10,000-100,000). The model may
serve as a tool for understanding the ocean carbon cycle and its effect on
regulating atmospheric pe0l' The model demonstrates in simple form the
regulation of carbon sequestration to the deep ocean by N0 3
- and Fe, and
shows alternative peo 2 changes in response to changes in the Fe flux.
7.7. Questions and Tasks
a) a) l lO OO Ox x d de ec cr re ea as se e in in the the solu solubil bility ity of of CO CO 2 2 in in w wate ater r ; ;
b) b) No No d de ee ep p- -o oc ce ea an n mixin mixing g w with ith t th he e s su ur rfa fac ce e l layer ayer; ;
c) c) No No e eff ffe ect ct of of Fe Fe o on n rate rate o of f i in nc co or rp po or ra at ti io on n of of N N int into o org orga an ni ic c m matter atter; ;
d) 100x increase in V
- .
Now, introduce these changes into the model and see whether your predictions agree with the results.
2. How is the chemistry of CO 2 in seawater different from that of 0/ Why
is that important for the ocean's ability to sequester inorganic carbon
from the atmosphere?
a) a) 1 1 pH pH uni unit t d de ec cr re ea as se e in in th the e se seawater? awater?
b) b) 1 1 pH pH uni unit t in inc cre rea as se e in in the the s seaw eawater? ater?
4. If a new organism invaded the ocean and had a C : N ratio of 1000, how
would this affect the global carbon cycle?
139
modified to incorporate changes in the N0 3
- inventory driven by Fe availability by adding a sink and source term sensitive to surface Fe concentrations. Increasing the Fe flux to surface water has the potential to effect the
relative rates of nitrogen fixation and denitrification . These interactions
have been hypothesized to regulate the oceanic inventory of oxidized nitrogen on geologic time scales (Falkowski 1997). In essence, an increase in
Fe and the concomitant increase in nitrogen fixation would have the eventual effect of increasing the upwelling concentration of N0 3
- in the world 's
oceans. This creates another potential positive feedback between iron supply and primary production. If, on the other hand, the relative ratio of nitrogen fixation/denitrification decreases, N0 3
- is consumed and the maximum potential for primary production decreases.
The parameterizations of the model simplify the complexity of some
smaller-scale chemical and ecological processes, and limit the model's applicability over large temporal and spatial scales. As a consequence, the
model only approximates the dynamics of the atmosphere-ocean carbon
cycle and the biogeochemical behavior of N and Fe in an oligotrophic marine ecosystem on geologic time scales (10,000-100,000). The model may
serve as a tool for understanding the ocean carbon cycle and its effect on
regulating atmospheric pe0l' The model demonstrates in simple form the
regulation of carbon sequestration to the deep ocean by N0 3
- and Fe, and
shows alternative peo 2 changes in response to changes in the Fe flux.
7.7. Questions and Tasks
a) a) l lO OO Ox x d de ec cr re ea as se e in in the the solu solubil bility ity of of CO CO 2 2 in in w wate ater r ; ;
b) b) No No d de ee ep p- -o oc ce ea an n mixin mixing g w with ith t th he e s su ur rfa fac ce e l layer ayer; ;
c) c) No No e eff ffe ect ct of of Fe Fe o on n rate rate o of f i in nc co or rp po or ra at ti io on n of of N N int into o org orga an ni ic c m matter atter; ;
d) 100x increase in V
- .
Now, introduce these changes into the model and see whether your predictions agree with the results.
2. How is the chemistry of CO 2 in seawater different from that of 0/ Why
is that important for the ocean's ability to sequester inorganic carbon
from the atmosphere?
a) a) 1 1 pH pH uni unit t d de ec cr re ea as se e in in th the e se seawater? awater?
b) b) 1 1 pH pH uni unit t in inc cre rea as se e in in the the s seaw eawater? ater?
4. If a new organism invaded the ocean and had a C : N ratio of 1000, how
would this affect the global carbon cycle?