DOC, DON, DOP Cycling and Composition

Organic Carbon, Nitrogen, and Phosphorus Cycles and the composition of marine phytoplankton 1. C, N, P cycles 2. Major biochemicals in marine phytoplankton 3. Introduction to dissolved organic carbon TOC in the N. Passic Particulate organic carbon (POC) and Dissolved organic carbon (DOC) - - PARTICULATE w BACTERIA DlSSOLVED -MESO. MICRO. NANO. PICO- PtANKTON COLLOlDAL I I I 3 1OOmm From Peltzw and Hayward. 1996 IOmm - 1mm i 100nm IOnm 0.fmm 0.3 nm .O.OOl mm 0 1 POC IiDOC TOA -e THE NITROGEN CYCLE Nitrogen Cycle Fixation -2 NH4+ Norg N2 Fixation (lightning) N2 N2O +1 Denitrification Bacteria in Nodules N Fixing Bacteria Nitrate Bacteria Fertilizer Factory NO3 Plants Animals Decay and waste NO2 Nitrite Bacteria n +5 NO2- atio +4 c rifi +3 NO nit +2 Nitrification 0 N reduction -1 De Oxidation state of Nitrogen -3 NO3- NH4+ Decomposers GLOBAL NITROGEN FIXATION (GT N/YR) Industrial 0.05 Fossil Fuel Combustion 0.02 Lightning 0.01 Agriculture 0.09 Forests, etc. 0.05 Ocean 0.04 THE NITROGEN CYCLE (Tg N/year) Denitrification 30 Outgassing 1 Atmosphere NOx Dep 36 N2 Fix 150 NH3 Dep 89 N2fix 40 Ind Fix Microb NH3 NOx 40 Denit Vol 8 147 122 NH3 Dep 23 Terrestrial Weathering 5 Crust Rivers 34 NOx Dep 11 Ocean Sedimentation 14 Dissolved Nitrogen (pM) at HOTS ,... . . 0 ni lo 20 30 40 SO I + Nitrate Dissolved organic Nitrogen Preservoirs and Cycling in the Ocean Atmospheric Input: 1 x 1010 mol p yr-1 Riverine Input (TDP): 10 -1 3.15 x 10 mol p yr SNP Protozoa Bacteria Microbial Food Web Euphotic Zone SRP Zooplankton 0-150 m Fish Phytoplankton Aggregation and Sinking of Particulate Organic Matter Occanic P Reservoir 3.2 x1011mol P Upwelling Sedimentary P Reservoir 1.3 x1011mol P 150-6000 m 10 -1 P Burial: 11-34.1 x 10 mol P Yr The pre-anthropogeric marine Pcycle. see text for detaills on fluxes. Chlorophyceae (green algae) Tetraselrnis rnaculata Dunaliela salina Chrysophyceae (golden brown algae) Monochrysis lutheri Syracosphae ra carterae Protein 72 58 53 70 Bacillariophyceae (brown algae, diatoms) Chaetoceros sp. 68 Skeletonerna costaturn 58 Coscinodjscz~ssp. 74 Phaeodac tylurn tricornu turn 49 Dynophyceae (dinoflagellates) Arnphidiniurn carteri Exuriella sp. 35 37 Average 57 Carbohydrate Lipid Ash Proteins proreins serve as eminyes and structural compomtsof cells CH2 H2C O CH fixes RUBISCO in photsynthesis CH CH RUBISCO fixes CO2 in photsynthesis C C H CH2 O C N H C H N CH2 Methionine S CH2 amino acid R-C-COOH I NH2 O C C H O C N H O CH2 H C H N C CH2 HC HC C C OH CH CH C H N H O Tyrosine PEPTIDE polymers OCW. of amino acids Figure by MIT UN = 4, 80% of all nitrogen in marine algae 250% clf the carbon Amino Add Cmpdtlaa wf A l p hCowynmdCnmkr~l%6) Picture removed due to copyright restrictions. Palysaccharide analysis Polysaccharide Analysis 2 3 1 O H+ 1 2 3 0 O 2 Fructose, Glucose 3 Sucrose 4 hydrolysis 56 7 4 Minutes 8 O H+ hydrolysis Lipid biosynthesis occurs via two pathways 1) polyketide polymerization of acetate I(CH3000H). products usually have an even number of carbons 2) imprenoid polymerization of isoprene a five carbon H C Products have 10,15,20,rarbns (head) Terrestrial Plant organic components Lignin is a complex structural polymer of hydroxycinnamyl alcohols that are linked together in a number of different linkages and patterns Lignin and cellulose make up a large percentage of the carbonin woody and nonwoody tissues of higher plants. DIN vs DIP,and TDN vs TDP at station ALOHA Nitrogen (µM) 30 20 10 0 0 0.4 0.8 1.2 1.6 2 Phosphorus (µM) Nitrogen versus phosphorus correlations for samples collected in the upper 0-400 m of the water column at Sta. ALOHA during the period October 1988 to December 1997. The bottom line is for nitrate plus nitrite (N+N) versus soluble reactive phosphorus (SRP) concentrations and the top line is for total dissolved nitrogen (TDN) versus total dissolved phosphorus (TDP). Model II linear regression analyses: N+N (µM) = 14.62 [14.58 to 14.66] SRP (µM) -1.08 [-1.10 to -1.06], r = 0.996, n = 3299 and TDN (µM) = 14.57 [14.45 to 14.69] TDP (µM) + 1.50 [1.44 to 1.56], r = 0.981, n = 2060. Values in brackets indicate the 95% confidence intervals of the respective slope and intercept values. DON and DOP at station ALOHA,HOTS 0 2 8 10 0 100 100 300 300 500 Depth (m) Depth (m) 0 DON (µM) 4 6 500 700 700 900 900 1100 1100 0 0.1 DON (µM) 0.2 0.3 0.4 N/P ratios at station ALOHA, HOTS 0 0 N:P (mol:mol) 10 15 5 0 N:P (mol:mol) 10 20 10 N:P (mol:mol) 15 20 25 30 200 Depth (m) 400 600 800 Inorganic Total 1000 Nitrogen-to-phosphorus (N:P) ratios versus water depth for samples collected at Sta. ALOHA during the period Oct. 1988 to Dec. 1997. (Left) Molar N:P ratios for dissolved inorganic pools calculated as nitrate plus nitrite (N + N): soluble reactive phosphorus (SRP). (Center) Molar N:P ratios for the "corrected" total dissolved matter pools. (Right) Molar N:P ratios for total dissolved matter pools, including both inorganic and organic compounds, calculated as total dissolved nitrogen (TDN) : total dissolved phosphorus (TDP). As a point for reference, the vertical dashed line in each graph is the Redfield-Ketchum-Richards molar ratio 16N:1P. Global inventory of DOC DOC measured by high temperature catalytic oxidation (HTCO) method. Global inventory was measured by International JGOFS program (680 GT C). Depth pretty much the same everywhere, with high surface water values (40-80 uM C) and low deep water values (40 uM C). Deep sea concentrations are nearly constant. Solar Variability Solar Variability Cosmic Rays Geomagnetic Field Intensity 14CO 2 Producfi~n ∆ 14C14C Cycle 14C Distribution among Production C reservoirs Distribution among C reservoirs Atm Surf Surf Bio/Soils CaCO3 Seds CaC6, Seds Deep I Deep Radiocarbon Age of Dissolved Organic Carbon ACID DO1'C and 0Ii4Cin the Atlantic Ocean r Sargassa Sea DOC L SaTgaw Sea DIG D0I4Cm d D114Cin the Atlantic and Pacific Ocean I Sergarraa Sea WC r Sam8 Sea DIG Paclflc Ocaan aOC A PactflcOceen MC Radiocarbon measurements show that the average age of deep sea DOC is > 5000 yr. If the global inventory is 700 GT C, then the annual flux of C to maintain the system at steady state can be calculated as: 700 GT/ 5000 yr = 0.14 GT C yr-1 The annual input of DOC from rivers is 0.2-0.4 GT C yr-1, While annual marine primary production is 60-75 GT Cyr-1 Either source adds enough C per year to maintain the system. So what is the source of oceanic DOC? Origin of DOC from stable carbon isotopes Wrap up The elemental composition (C, N, P, S) of marine and terrestrial organisms is a reflection of their biochemical composition at the molecular level. Marine organisms (in terms of their carbon) are made of proteins > carbohydrates > lipids > nucleic acids. In terms of N, 70-80% is in proteins. The remaining is distributed between nucleic acids, carbohydrates, pigments, etc. The proportions of biochemicals are variable and reflect both environmental factors And physiological status. N and P are limiting nutrients in the euphotic zone. Most of the N and P in the euphotic zone occur as DON and DOP. It is not known why these reservoirs of organic nutrients exist. Is the ocean N or P limited??? DOC is the largest reservoir of organic carbon in seawater. >98% of organic carbon in the ocean is DOC. It has high concentrations In the euphotic zone indicating net production or at least input. Values at depth are low (about half surface water values) and nearly Constant. Radiocarbon values of DOC are highly depleted, consistent with An average residence time of 5000-6000 years. Several ocean Mixing cycles!!! No one knows why, but surely this impacts Organic nutrients.