Two chemically distinct pools of organic nitrogen accumulate in the ocean

Science

Volumn 308, Issue 5724, 2005, Pages 1007-1010

  Aluwihare, Lihini I ^a   Repeta, Daniel J ^b   Pantoja, Silvio ^c   Johnson, Carl G ^b  

^a GEOSCIENCES RESEARCH DIVISION   (United States)

^b WOODS HOLE OCEANOGRAPHIC INSTITUTION   (United States)

^c UNIVERSITY OF CONCEPCIÓN   (Chile)

Author keywords

[No Author keywords available]

Indexed keywords

DEGRADATION; HYDROLYSIS; MOLECULAR WEIGHT; NITROGEN; ORGANIC ACIDS; ORGANIC CHEMICALS; POLYSACCHARIDES; SURFACE WATERS;

AMIDE BONDS; DISSOLVED ORGANIC NITROGEN (DON); HIGH MOLECULAR WEIGHT (HMW) DON; SURFACE ACCUMULATION;

OCEANOGRAPHY;

AMIDE; ORGANIC NITROGEN;

ORGANIC NITROGEN; SEAWATER;

ARTICLE; BINDING AFFINITY; BIODEGRADATION; HYDROLYSIS; MOLECULAR DYNAMICS; MOLECULAR WEIGHT; PRIORITY JOURNAL; SEA; SEA SURFACE WATERS;

AMIDES; AMINO ACIDS; ATLANTIC OCEAN; BACTERIA; HYDROLYSIS; MAGNETIC RESONANCE SPECTROSCOPY; MOLECULAR WEIGHT; MURAMIC ACIDS; NITROGEN; PEPTIDOGLYCAN; POLYSACCHARIDES; PROTEINS; SEAWATER;

EID: 18644372636     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.1108925     Document Type: Article

References (33)

1. J. Abell, S. Emerson, P. Renaud, J. Mar. Res. 58, 203 (2000).
2. M. J. Church, H. W. Ducklow, D. M. Karl, Limnol. Oceanogr. 47, 1 (2002).
3. P. Libby, P. Wheeler, Deep-Sea Res. 44, 345 (1997).
4. N. J. Antia, P. J. Harrison, L. Oliveira, Phycologia 30, 1 (1991).
5. T. Berman, D. A. Bronk, Aquat. Microb. Ecol. 31, 279 (2003).
6. D. A. Bronk, in Biogeochemistry of Marine Dissolved Organic Matter, D. A. Hansell, C. A. Carlson, Eds. (Academic Press, San Diego, CA, 2002), pp. 163-247.
7. HMWDON is defined here as the fraction of DON retained by an ultrafiltration membrane with a pore size of 1 nm. This fraction is expected to have a nominal molecular weight of >1 kD.
8. M. D. McCarthy, T. Pratum, J. I. Hedges, R. A. Benner, Nature 390, 150 (1997).
9. M. D. McCarthy, J. I. Hedges, R. A. Benner, Science 281, 231 (1998).
10. L. I. Aluwihare, D. J. Repeta, R. F. Chen, Deep-Sea Res. II 49, 4421 (2002).
11. L. I. Aluwihare, D. J. Repeta, R. F. Chen, Nature 387, 166 (1997).
12. S. Henrichs, P. M. Williams, Mar. Chem. 17, 141 (1985).
13. 15N-NMR spectroscopy. Under these hydrolysis conditions, no muramic acid (deacetytated) or amino sugar monomers were detected.
14. D. B. Albert, C. S. Martens, Mar. Chem. 56, 27 (1997).
15. M. Zhao, J. L. Bada, J. Chromatogr. A. 690, 55 (1995).
16. The percentage of N in each sample represented by N-AAPs, hydrolyzable protein, and nonhydrolyzable amide was calculated as follows: Because 1 mol of N-AAP sugar is de-acetylated for every mole of acetic acid released, we assumed that μmoles of acetic acid were equal to μmoles of N in N-AAPs; hydrolyzable protein N was calculated on the basis of the recoveries of amino acid N after strong acid hydrolysis (12); nonhydrolyzable amide was determined after strong acid hydrolysis (Table 1). Higher amino acid yields were obtained when HMWDON was hydrolyzed with strong acid. As a result, after strong acid hydrolysis, only 2.2 (29% of total N) and 5.5 μmol (71% of total N) of amide-N remained unhydrolyzed in the Woods Hole and MAB samples, respectively. In order to quantify the amount of amide-N remaining after strong acid hydrolysis, the sum Σacetic acid (mild) + amino acids (strong) was first determined and then subtracted from the initial amide content of the HMWDON sample (before hydrolysis). In all cases, percentages are expressed relative to total N in each sample. We calculated the amount of N-AAP carbon with the C/N ratio in HMWDOM (Table 1) and assumed 8 μmol of C per μmol of N-AAP (e.g., N-acetyl glucosamine).
17. J. J. Boon, V. A. Klap, T. I. Eglinton, Org. Geochem. 29, 1051 (1998).
18. J. A. Leenheer, T. I. Noyes, C. E. Rostad, M. L. Davisson, Biogeochemisty 69, 125 (2004).
19. K. Kaiser, R. Benner, Anal. Chem. 72, 2566 (2000).
20. D. L. Popham, J. Helin, C. E. Costello, P. Setlow, J. Bacteriol. 178, 6451 (1996).
21. We modified the method provided in (20) and hydrolyzed samples (in 4 N HCl) overnight at 90°C. We recovered no muramic acid and only small amounts of glucosamine and galactosamine from surface samples. This modified hydrolysis method was tested on chitin oligomers, peptidoglycan (from Bacillus subtilus), and bacterial cells (mixed laboratory culture) to ensure the quantitative (>90%) recovery of glucosamine and de-acetylated muramic acid. We assessed amino sugar recoveries by high-performance liquid chromatography and fluorescence detection of o-phthaldialdehyde-derivatized samples (15) or gas chromatography after derivatizing to alditol acetates (10).
22. J. I. Hedges et al., Org. Geochem. 31, 945 (2000).
23. O. Hadja, Anal. Biochem. 60, 512 (1974).
24. Y. Nagata, T. Fujiwara, K. Kawaguchinagata, Y. Fukumori, T. Yamanaka, Biochim. Biophys. Acta 1379, 76 (1998).
25. J. S. Martinez et al., Science 287, 1245 (2000).
26. B. Palenik, S. E. Henson, Limnol. Oceanogr. 42, 1544 (1997).
27. M. T. Cottrell, D. L. Kirchman, Appl. Environ. Microbiol. 66, 1692 (2000).
28. A. L. Svitil, D. L. Kirchman, Microbiol. 144, 1299 (1998).
29. M. T. Cottrell, D. N. Wood, L. Yu, D. L. Kirchman, Appl. Environ. Microbiol. 66, 1195 (2000).
30. H. Knicker, P. G. Hatcher, Naturwissenschaften 84, 231 (1997).
31. R. G. Keil, D. L. Kirchman, Mar. Chem. 45, 187 (1994).
32. E. Tanoue, S. Nishiyana, M. Kamo, A. Tsugita, Geochim. Cosmochim. Acta 59, 2643 (1995).
33. 15N-NMR spectroscopy: M. Pullin and D. Albert for assistance in the determination of acetic acid; and the staff at the Natural Energy Laboratory in Kona, Hawaii, and E. Smith for assistance in sample collection. Supported by the Chemical and Biological Oceanography Programs at the National Science Foundation; the Carbon Sequestration Program at the U.S. Department of Energy; the Rhinehart Coastal Research Center of the Woods Hole Oceanographic Institution; and the Fundadon Andes, Chile.