English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

: The goal of this thesis is to investigate three different areas relating to the characterization of dissolved organic matter (DOM). The first section used periodate over-oxidation to analyze the previously unidentified fraction of HMWDOM. The majority of the carbon in two HMWDOM samples was over-oxidation, including 70% of the aliphatic NMR signal, with a high degree of branching. Based on the HNMR spectra data, it was concluded that 6-deoxysugars were the primary compounds in the unidentified fraction of HMWDOM. In the second section, a new method was presented for the purification of individual underivatized amino acids hydrolyzed from HMWDOM, using cation exchange chromatography and high-pressure liquid chromatography (HPLC) with C18 and strong cation exchange (SCX) columns. Six amino acids were isolated from HMWDOM with sufficient purity and quantity for radiocarbon analysis. These amino acids had a range of delta(exp 14) C values, from 121% to -454%. The final section investigates biological controls on dissolved organic nitrogen (DON). Total hydrolyzable amino acids (THAA), and nucleic acids were measured for four incubations: a control, a grazer added, a zero virus, and a 10 times virus. Comparison to the control showed THAA and nucleic acid release were influenced by viruses but not grazers.

Chemical characterization of dissolved organic matter (DOM) in seawater : structure, cycling, and the role of biology