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Full-Text Articles in Physical Sciences and Mathematics
Reply To Comment: Controls On Turnover Of Marine Dissolved Organic Matter-Testing The Null Hypothesis Of Purely Concentration-Driven Uptake, Yuan Shen, Ronald Benner
Reply To Comment: Controls On Turnover Of Marine Dissolved Organic Matter-Testing The Null Hypothesis Of Purely Concentration-Driven Uptake, Yuan Shen, Ronald Benner
Faculty Publications
Our recent bioassay experiments indicate that molecular properties are a primary control on the microbial utilization of dissolved organic matter in the ocean. This finding is questioned by Lennartz and Dittmar who modeled our experiments and concluded that our observations could be largely explained by concentration-driven uptake independent from molecular properties. We suggest the authors' models are deficient for establishing the relative roles of molecular properties and concentration-driven uptake. Our conclusion is consistent with earlier and recent experimental results and biogeochemical observations, supporting a unified theory with molecular properties as a more prominent control than concentration-driven uptake on marine organic …
Molecular Properties Are A Primary Control On The Microbial Utilization Of Dissolved Organic Matter In The Ocean, Yuan Shen, Ronald Benner
Molecular Properties Are A Primary Control On The Microbial Utilization Of Dissolved Organic Matter In The Ocean, Yuan Shen, Ronald Benner
Faculty Publications
The global ocean sequesters a large amount of reduced carbon in dissolved organic molecules that can persist for centuries to millennia. The persistence of dissolved organic carbon (DOC) in the deep ocean has been attributed to inherently refractory molecules and to low concentrations of molecules, but the relative roles of molecular properties and molecular concentrations remain uncertain. We investigate both of these possibilities using bioas-say experiments with unfiltered seawater collected from five depths (50–1500 m) at the Bermuda Atlantic Time-Series Study site. The microbial utilization of compositionally distinct forms of seawater DOC at in situ and elevated concentrations was determined. …
Importance Of Refractory Ligands And Their Photodegradation For Iron Oceanic Inventories And Cycling, Christel Hassler, Damien Cabanes, Sonia Blanco-Ameijeiras, Sylvia G. Sander, Ronald Benner
Importance Of Refractory Ligands And Their Photodegradation For Iron Oceanic Inventories And Cycling, Christel Hassler, Damien Cabanes, Sonia Blanco-Ameijeiras, Sylvia G. Sander, Ronald Benner
Faculty Publications
Iron is an essential micronutrient that limits primary production in up to 40% of the surface ocean and influences carbon dioxide uptake and climate change. Dissolved iron is mostly associated with loosely characterised organic molecules, called ligands, which define key aspects of the iron cycle such as its residence time, distribution and bioavailability to plankton. Models based on in situ ligand distributions and the behaviour of purified compounds include long-lived ligands in the deep ocean, bioreactive ligands in the surface ocean and photochemical processes as important components of the iron cycle. Herein, we further characterise biologically refractory ligands in dissolved …
Strong Linkages Between Surface And Deep-Water Dissolved Organic Matter In The East/Japan Sea, Tae-Hoon Kim, Guebuem Kim, Yuan Shen, Ronald Benner
Strong Linkages Between Surface And Deep-Water Dissolved Organic Matter In The East/Japan Sea, Tae-Hoon Kim, Guebuem Kim, Yuan Shen, Ronald Benner
Faculty Publications
Vertical and horizontal distributions of total dissolved amino acids (TDAAs), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) were measured in the East/Japan Sea (EJS). The euphotic zone of this sea is N-limited, and the N : P ratio is ∼ 13 below 200 m depth. Elevated TDAA concentrations (137 ± 34 nM) and DOC-normalized yields (0.8 ± 0.2 % of DOC) were observed in deep waters ( ≥ 1000 m) of the EJS and compared with those in the deep North Pacific Ocean. Significantly high TDAA concentrations and yields were observed in a region of deep-water formation, indicating …
A Molecular Perspective On The Ageing Of Marine Dissolved Organic Matter, R. Flerus, O. J. Lechtenfeld, B. P. Koch, S. L. Mccallister, P. Schmitt-Kopplin, Ronald Benner, G. Kattner
A Molecular Perspective On The Ageing Of Marine Dissolved Organic Matter, R. Flerus, O. J. Lechtenfeld, B. P. Koch, S. L. Mccallister, P. Schmitt-Kopplin, Ronald Benner, G. Kattner
Faculty Publications
Dissolved organic matter (DOM) was extracted by solid-phase extraction (SPE) from 137 water samples from different climate zones and different depths along an eastern Atlantic Ocean transect. The extracts were analyzed with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with electrospray ionization (ESI). Δ14C analyses were performed on subsamples of the SPE-DOM. In addition, the amount of dissolved organic carbon was determined for all water and SPE-DOM samples as well as the yield of amino sugars for selected samples. Linear correlations were observed between the magnitudes of 43 % of the FT-ICR mass peaks and the extract Δ14C …