Characterization of the vertical size distribution, composition and chemical properties of dissolved organic matter in the (ultra)oligotrophic Pacific Ocean through a multi-detection approach

This work presents a multi-analytical approach for the characterization of marine dissolved organic matter (DOM). The determination carbon (DOC) was performed by size exclusion chromatography (SEC) and validated using certified reference material (CRM) as well through an intercomparison exercise. Multi-detection SEC, fluorescence electrochemical methods were used in order to describe distribution spectra, composition chemical properties DOM, (ultra)oligotrophic West Tropical South Pacific Ocean (WTSP). In this work, we defined state degradation DOC different fractions, operationally SEC. We estimated that on average 62% humic nature (0.5–10 kDa), which ~9% able complex trace elements, such iron (Fe). Our results tend support non-refractory is high molecular weight (HMW), nitrogen (N)-rich, aliphatic, has weak quantum yield enhanced binding capacity Fe. ageing DOM occurring within mesopelagic waters mainly driven microbial respiration alters these properties. Although our are agreement with paradigm describing oceanic biogeochemistry known size-reactivity continuum, 3 ?molC L?1 very HMW (> 10 kDa) still observed water mass composed Deep Waters. persistence could be explained significant content (5%) aromatic may protect from long term biodegradation.