@article{shields_bianchi_osburn_kinsey_ziervogel_schnetzer_corradino_2019, title={Linking chromophoric organic matter transformation with biomarker indices in a marine phytoplankton growth and degradation experiment}, volume={214}, ISSN={["1872-7581"]}, DOI={10.1016/j.marchem.2019.103665}, abstractNote={The production and transformation of marine chromophoric dissolved organic matter (CDOM) provides a window into the marine biological pump as it is present at all depths and can be measured both in the field and via satellite. However, outside of lignin for terrestrial DOM, few studies have linked marine CDOM characteristics with biomarker indices. In this study, we quantified five fluorescent components of marine CDOM and base-extractable particulate organic matter (BEPOM) in a growth and degradation experiment using a natural plankton assemblage, and compared those results to bacterial abundances, hydrolytic enzyme activities, and amino acid concentrations and associated diagenetic indices. Rotating glass bottles containing plankton were sampled initially (day 0), during the mid-exponential (day 13) and stationary (day 20) growth phases, and again following a dark degradation period that lasted 42 days. Protein-like fluorescence (tryptophan-like and tyrosine-like) was correlated with the total amino acid concentrations for both the DOM and BEPOM through all phases of the incubation. However, tryptophan-like fluorescence showed a stronger correlation for aromatic amino acids. The concentration of particulate organic carbon changed significantly during each phase of the experiment and this substrate correlated with hydrolytic enzyme activities and bacterial abundance. This heterotrophy diagenetically altered the POM during the stationary phase and ultimately resulted in the increased production of more humic-like CDOM after degradation in the dark. Results from this study indicate that CDOM formation and cycling may play a prominent role in the ocean's nitrogen cycle.}, journal={MARINE CHEMISTRY}, author={Shields, Michael R. and Bianchi, Thomas S. and Osburn, Christopher L. and Kinsey, Joanna D. and Ziervogel, Kai and Schnetzer, Astrid and Corradino, Gabrielle}, year={2019}, month={Aug} }
 @article{osburn_kinsey_bianchi_shields_2019, title={Formation of planktonic chromophoric dissolved organic matter in the ocean}, volume={209}, ISSN={0304-4203}, url={http://dx.doi.org/10.1016/j.marchem.2018.11.010}, DOI={10.1016/j.marchem.2018.11.010}, abstractNote={Chromophoric dissolved organic matter (CDOM) is an important fraction of the marine carbon cycle that controls most light absorption and many photochemical and biological processes in the ocean. Despite its importance, the chemical basis for the formation of oceanic CDOM remains unclear. Currently, CDOM's optical properties are best-described by an electronic interaction (EI) model of charge transfer (CT) complexes which form between electron-rich donors and electron-poor acceptors. While terrigenous compounds such as lignin best fit this model, planktonic sources of CDOM have not yet been tested. Here, we have tested CDOM formed during an incubation experiment using a natural phytoplankton assemblage and throughout active growth, stationary phase and algal biomass decomposition. Absorbance of the derived planktonic CDOM generally decreased with increasing wavelength, similar to the reference Pony Lake (PLFA) and Suwanee River (SRFA) fulvic acid solutions used as models of terrigenous CDOM. Further, after 60 d of microbial degradation in the dark, CDOM exhibited fluorescence emission maxima continuously red-shifted into the visible band, consistent with PLFA and SRFA. Reduction of carbonyl-containing groups, key to CT complex formation, with sodium borohydride (NaBH4) produced coherent results in planktonic CDOM and reference FAs. Absorption at 350 nm decreased by 50% for planktonic CDOM and by 30% for PLFA and SRFA, with corresponding increases in spectral slope (S) values, indicating preferential loss of absorption well into the visible. Fluorescence likewise responded with enhanced emission at shorter wavelengths. Apparent quantum yields (Φ) were similarly affected. Results from our work support prior observations that phytoplankton and bacteria are important sources of CDOM that color the ocean's “twilight zone”. We hypothesize that microbial processing of a variety of source substrates into more complex compounds represented as planktonic CDOM likely represents a semi-refractory pool of DOM in the ocean.}, journal={Marine Chemistry}, publisher={Elsevier BV}, author={Osburn, Christopher L. and Kinsey, Joanna D. and Bianchi, Thomas S. and Shields, Michael R.}, year={2019}, month={Feb}, pages={1–13} }
 @article{tyssebotn_kinsey_kieber_kiene_rellinger_motard-cote_2017, title={Concentrations, biological uptake, and respiration of dissolved acrylate and dimethylsulfoxide in the northern Gulf of Mexico}, volume={62}, ISSN={["1939-5590"]}, DOI={10.1002/lno.10495}, abstractNote={AbstractThe abundant marine organosulfur compound, dimethylsulfoniopropionate (DMSP) can be degraded to acrylate and dimethylsulfide (DMS), with some DMS further oxidized to dimethylsulfoxide (DMSO). Despite intensive study of DMSP and DMS in a variety of marine settings, the processes affecting acrylate and DMSO concentrations in marine waters are poorly known, particularly their loss from the dissolved phase through biological uptake. We measured the concentrations of dissolved acrylate (acrylated) and DMSO (DMSOd) in coastal and open‐ocean waters of the northern Gulf of Mexico during non‐bloom conditions and quantified the rates and kinetics of their biological uptake using 14C labeled substrates. Acrylated concentrations and uptake rates ranged from 0.8–2.1 nmol L−1 and 0.07–1.8 nmol L−1 d−1, respectively. Somewhat higher uptake rates were observed for DMSOd (0.27–3.9 nmol L−1 d−1) owing to higher DMSOd concentrations (5.5–14 nmol L−1). Both compounds were taken up by the microbial community with high affinity uptake systems, with similar Ks and Vmax values to those for other well‐studied biological substrates including amino acids and monosaccharides. However, median turnover times were relatively slow, 4.8 d for acrylated and 7.4 d for DMSOd. The slow acrylated turnover points to low supply rates of this compound to the dissolved phase, a finding consistent with previous observations that the microbial DMSP lyase pathway accounts for only a small fraction of dissolved DMSP degradation (and therefore acrylate production) in the Gulf of Mexico.}, number={3}, journal={LIMNOLOGY AND OCEANOGRAPHY}, author={Tyssebotn, Inger Marie B. and Kinsey, Joanna D. and Kieber, David J. and Kiene, Ronald P. and Rellinger, Alison N. and Motard-Cote, Jessie}, year={2017}, month={May}, pages={1198–1218} }
 @article{netburn_kinsey_bush_djurhuus_fernandez_hoffman_mcveigh_twing_bagge_2018, title={First HOV Alvin study of the pelagic environment at Hydrographer Canyon (NW Atlantic)}, volume={150}, ISSN={["1879-0100"]}, DOI={10.1016/j.dsr2.2017.10.001}, abstractNote={Continental slope canyons off the United States Atlantic coast remain poorly studied, and in particular, the distributions of pelagic organisms in waters overlying these unique environments are not well documented. During the Early Career Scientist Deep Submergence Training cruise, AT36-EAGER, the distribution of organisms in the water column overlying Hydrographer Canyon, which cuts through the northwestern Atlantic continental margin, was investigated through daytime midwater observations using HOV Alvin (AD4831) at three depths. Mixed swarms of krill and Themisto sp. amphipods were observed at all depths surveyed. Observations centered at 250 m were also dominated by chaetognaths, copepods, and Phronima sp. amphipods, while at 500 and 750 m, the assemblages were dominated by the fishes in the families Paralepididae, Nemichthyidae, and Mytophidae. Additionally, measurements of methane, nitrous oxide, optical properties (absorbance and fluorescence), dissolved organic carbon, and base-extracted particulate organic carbon were made to better characterize the hydrography and biogeochemistry over Hydrographer Canyon. This study was aided by the use of telepresence to communicate between ship and shore-based researchers, and the expedition marks the first use of SMS messaging to communicate between the submersible and the ship. This study demonstrates the capabilities and utility of using Alvin for conducting water column science.}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Netburn, Amanda N. and Kinsey, Joanna D. and Bush, Stephanie L. and Djurhuus, Anni and Fernandez, Julianne and Hoffman, Colleen L. and McVeigh, Doreen and Twing, Katrina I. and Bagge, Laura}, year={2018}, month={Apr}, pages={30–40} }
 @article{gali_kieber_romera-castillo_kinsey_devred_perez_westby_marrase_babin_levasseur_et al._2016, title={CDOM Sources and Photobleaching Control Quantum Yields for Oceanic DMS Photolysis}, volume={50}, ISSN={["1520-5851"]}, DOI={10.1021/acs.est.6b04278}, abstractNote={Photolysis is a major removal pathway for the biogenic gas dimethylsulfide (DMS) in the surface ocean. Here we tested the hypothesis that apparent quantum yields (AQY) for DMS photolysis varied according to the quantity and quality of its photosensitizers, chiefly chromophoric dissolved organic matter (CDOM) and nitrate. AQY compiled from the literature and unpublished studies ranged across 3 orders of magnitude at the 330 nm reference wavelength. The smallest AQY(330) were observed in coastal waters receiving major riverine inputs of terrestrial CDOM (0.06-0.5 m3 (mol quanta)-1). In open-ocean waters, AQY(330) generally ranged between 1 and 10 m3 (mol quanta)-1. The largest AQY(330), up to 34 m3 (mol quanta)-1), were seen in the Southern Ocean potentially associated with upwelling. Despite the large AQY variability, daily photolysis rate constants at the sea surface spanned a smaller range (0.04-3.7 d-1), mainly because of the inverse relationship between CDOM absorption and AQY. Comparison of AQY(330) with CDOM spectral signatures suggests there is an interplay between CDOM origin (terrestrial versus marine) and photobleaching that controls variations in AQYs, with a secondary role for nitrate. Our results can be used for regional or large-scale assessment of DMS photolysis rates in future studies.}, number={24}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Gali, Marti and Kieber, David J. and Romera-Castillo, Cristina and Kinsey, Joanna D. and Devred, Emmanuel and Perez, Gonzalo L. and Westby, George R. and Marrase, Celia and Babin, Marcel and Levasseur, Maurice and et al.}, year={2016}, month={Dec}, pages={13361–13370} }
 @article{kinsey_kieber_2016, title={Microwave preservation method for DMSP, DMSO, and acrylate in unfiltered seawater and phytoplankton culture samples}, volume={14}, ISSN={["1541-5856"]}, DOI={10.1002/lom3.10081}, abstractNote={AbstractA microwave‐preservation method was developed to quantify total dimethylsulfoniopropionate (DMSPT), dimethylsulfoxide (DMSOT), and acrylate (acrylateT) concentrations in unfiltered samples to alleviate problems associated with the acidification method when applied to samples containing Phaeocystis. Microwave‐ and acid‐preservation methods were compared using batch cultures of Phaeocystis antarctica and 11 other marine phytoplankton species for DMSPT, batch P. antarctica cultures for DMSOT and acrylateT, and unfiltered Delaware Estuary water samples for DMSPT to demonstrate the general applicability of this method. Acidification of P. antarctica culture samples resulted in the underestimation of DMSPT (42–69%) and overestimation of dimethylsulfide (DMS) (2156–3819%), DMSOT (9–101%), and acrylateT (71–249%). By comparison, DMSPT concentrations in microwaved samples agreed with non‐microwaved, non‐acidified controls. In contrast to P. antarctica results, the microwave‐ and acid‐preservation methods yielded DMSPT concentrations that were statistically indistinguishable for 11 other marine phytoplankton species and Delaware Estuary samples. Unfiltered samples stored frozen following microwave treatment or stored at room temperature if acidified after the microwaving step, resulted in no change in DMSPT or acrylateT; DMSOT concentrations increased slightly (∼ 15%) when they were not sparged to remove DMS prior to acidification and room temperature storage. Based on these findings, we propose microwaving small sample volumes (≤ 7 mL) of unfiltered seawater or culture samples as a general approach to preserve samples for subsequent DMSPT, DMSOT, and acrylateT analyses, especially when the phytoplankton composition of the samples is unknown.}, number={3}, journal={LIMNOLOGY AND OCEANOGRAPHY-METHODS}, author={Kinsey, Joanna D. and Kieber, David J.}, year={2016}, month={Mar}, pages={196–209} }