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22 Cards in this Set
- Front
- Back
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Gross Production |
Total amount of carbon fixed by phytoplankton (DIC to DOC) per unit time; expressed per unit volume or area |
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Net production |
Total carbon fixed minus carbon respired by phytoplankton (GPP-DIC from respiration) |
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Recycled production |
Fraction of net production for which the nutrients are supplied/recycled from within the given area |
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New production |
Fraction of net production for which nutrients are supplied from outside the given area where production occurs |
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Export production |
Fraction of net production that is not consumed and regenerated within the area, but is transported out of the region (sinking particles, harvest fish) At stead state, export production = new production |
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Net primary production in the oceans |
Low production in the Sargasso Sea (and other central gyres), high production along western coast of South America
Most marine organisms are captive to/characteristic of the seawater in which they live |
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Organic matter from rivers |
Average DOC for all rivers is 5.75 mg/L Avg POC is 3.86 mg/L Total discharge is ~1% of the total net primary production of basin |
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Organic matter from atmosphere |
Atmosphere contributes 0.05 Gt/yr Emissions around N Atlantic have Dec but inc around N pacific (inc in Pb as indicator is not due to age of water mass, since Pb is particle reactive and doesn’t accumulate with age) Precipitation over ocean contains pollen, etc Also from black carbon (incomplete combustion from sores and engines) |
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Fate of primary production |
Net primary production expressed in units of C as g/m2/yr 10% of net PP sinks before 200 m 90% is consumed through the water column 0.3% accumulates in sediment (less than 1% of original C reaches sea floor) Microbial loop is more important to energy cycling in Pacific/low nutrient regions where picoplankton dominate; particle settling in Atlantic where large diatoms dominate |
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Organic carbon: vitamins |
Biotin and thiamine are synthesized by bacteria and algae B12 only made by bacteria; largest and most complex molecular identified dissolved in seawater Always present in seawater |
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Organic carbon: volatiles (hydrocarbons) |
Small unsaturated hydrocarbons are more common Some (unsaturated) may be produced photochemically Ex: propene increases in spring/summer with inc in UV Cycloalkanes and aromatic hydrocarbons also in seawater |
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Organic carbon: oxides and sulfides |
Carbon monoxide:biologically produced, found in gas bladders Dimethylsulfide: may be used by phytoplankton to regulate osmotic pressure Carbonyl sulfide: formed by photochemical processes at surface; most abundant sulfur-carbon compound in atm |
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Halocarbons |
Chlorinated, brominates, iodinated compounds made bh algae High conc of dobromomethane in shallow water near coasts suggests source is benthic biota is shallows—produced by attached macroalgae to deter herbivores |
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Fatty acids |
Consist of carboxyl group (COOH) and long hydrocarbon tail Components of fats, oils, phospholipids when esterified to glycerol Unsaturated fatty acids found in oils Phytol tail of chlorophyll is source of isoprenoid fatty acids, hydrocarbons in the sea Fatty acids from recent biological sources usually have even numbered carbon chain High ratio of C16+C18indicstes recent bio source vs diagenetic source (petroleum) Unsaturated fatty acids are easily degraded, presence indicates recent source |
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Alkenones |
Long chain hydrocarbons with a ketone unit Found in multimillion year old ocean sediments, made by a few species of algae Role in membrane structure and lipid storage Ratio (uk-37) of more saturated alkenones increases with temperature Don’t degrade, can be used to infer temperature of surface waters over millions of years |
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Humic acids |
High molecular weight, contain many functional groups Formation possibly activated by UV light and catalysis by transition metals Pathway is polyunsaturated lipids cross linked to form dulcimer acid or humic acid (degradation of organic matter) |
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Radioactive decay schemes |
Beta- emission: emission of a negative electron Beta+ emission: emission of a positive electron Electron capture Alpha decay: emission of a particle with 2 N and 2 P |
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Isotope |
Form of an element with variable number of neutrons Isotopic nuclei are unstable and will spontaneously transform to reach stable nuclear state, release a detectable amount of energy |
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Decay of K-40 |
Decays to Ca-40 and Ar-40 (by three pathways) Amount of Ar to K remaining gives age since mineral formation Most radioactivity in sea from K40 |
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Branching ratio |
Ratio of two products produced by transformation of certain radionuclei Ex: K40 to Ca40 and Ar40 |
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Conservative radionuclides |
K40, Rb87, U238,234,235 Primordial (except U234) - part of the earth during initial formation |
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Non-conservative radionuclides |
Produced by cosmic rays, decay of primordial uranium, nuclear explosions in atmosphere Ex: Th234, H3, C14 |
