Passow Uta

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  • Preprint
    Thorium speciation in seawater
    ( 2005-07) Santschi, Peter H. ; Murray, James W. ; Baskaran, Mark ; Benitez-Nelson, Claudia R. ; Guo, L. D. ; Hung, C.-C. ; Lamborg, Carl H. ; Moran, S. Bradley ; Passow, Uta ; Roy-Barman, Matthieu
    Since the 1960’s, thorium isotopes occupy a special place in the oceanographer’s toolbox as tracers for determining rates and mechanisms of oceanic scavenging, particle dynamics, and carbon fluxes. Due to their unique and constant production rates from soluble parent nuclides of uranium and radium, their disequilibrium can be used to calculate rates and time scales of sinking particles. In addition, by ratio-ing particulate 234Th (as well, in principle, other Thnuclides) to carbon (and other elements), and linking this ratio to the parent-daughter disequilibrium in the water column, it is possible to calculate fluxes of carbon and other elements. Most of these applications are possible with little knowledge of the dissolved chemical properties of thorium, other than its oxidation state (IV) and tendency to strongly sorb to surfaces, i.e., its “particle- or surface-activity”. However, the use of any tracer is hindered by a lack of knowledge of its chemical properties. Recent observations in the variability of carbon to 234Th ratios in different particle types, as well as of associations of Th(IV) with various marine organic biomolecules has led to the need for a review of current knowledge and what future endeavors should be taken to understand the marine chemistry of thorium.
  • Article
    Ocean acidification as one of multiple stressors : growth response of Thalassiosira weissflogii (diatom) under temperature and light stress
    (Inter-Research, 2015-12-15) Passow, Uta ; Laws, Edward A.
    Future shifts in phytoplankton composition and productivity are anticipated given that continuing changes are expected in environmental conditions such as temperature, the partial pressure of CO2 (pCO2) and light climate, all of which regulate phytoplankton communities and their physiology through bottom-up control. Culture experiments revealed that future (elevated) pCO2 had no effect on Thalassiosira weissflogii in the absence of environmental stressors, whereas growth rates drastically decreased under future pCO2 when cells were grown under light and temperature stress. Reduction in growth rates and a smaller decline in cellular photosynthesis under high pCO2 were associated with 2- to 3-fold increases in the production of transparent exopolymer particles (TEP) and in the cell quotas of organic carbon, as well as a similar decrease in the C:chl a ratios. Results suggest that under light- and temperature-stressed growth, elevated pCO2 led to increased energy requirements, which were fulfilled by increased light harvesting capabilities that permitted photosynthesis of acclimatized cells to remain relatively high. This was combined with the inability of these cells to acclimatize their growth rate to sub-optimal temperatures. Consequently, growth rate was low and decoupled from photosynthesis, and this decoupling led to large cell sizes and high excretion rates in future pCO2 treatments compared to ambient treatments when growth temperature and light were sub- optimal. Under optimal growth conditions, the increased energy demands required to re- equilibrate the disturbed acid-base balance in future pCO2 treatments were likely mediated by a variety of physiological acclimatization mechanisms, individually too small to show a statistically detectable response in terms of growth rate, photosynthesis, pigment concentration, or excretion.
  • Dataset
    Series 2A-2: Multiple stressor experiments on T. pseudonana (CCMP1014) – photophysiology
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-11-30) Passow, Uta ; Laws, Edward ; Sweet, Julia
    These experiments were designed to test the combined effects of temperatures and light intensity on the growth growth rate (mu) and photophysiology of the diatom Thalassiosira pseudonana CCMP 1014 in a multifactorial design. Experiments were conducted in artificial seawater supplemented with 5% sterilized seawater. Six temperatures (13.5°C, 20°C, 25°C, 29°C, 31°C, and 32.5°C), and eight light intensities (25, 50, 80, 115,190, 300, 400 and 600 µmol photons · m-2 · s-1 ) were tested during the course of these experiments. This dataset contains measurements of photophysiology using the Light curve (LC3) protocol of the Aquapen-C AP-C 100 fluorometer. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/829695
  • Dataset
    Series 2A-3: Multiple stressor experiments on T. pseudonana (CCMP1014) – Chlorophyll, particulate organic carbon and particulate organic nitrogen
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-11-30) Passow, Uta ; Laws, Edward ; Sweet, Julia
    These experiments were designed to test the combined effects of temperatures and light intensity on the growth growth rate (mu) and photophysiology of the diatom Thalassiosira pseudonana CCMP 1014 in a multifactorial design. Experiments were conducted in artificial seawater supplemented with 5% sterilized seawater. Six temperatures (13.5°C, 20°C, 25°C, 29°C, 31°C, and 32.5°C), and eight light intensities (25, 50, 80, 115,190, 300, 400 and 600 umol photons · m-2 · s-1 ) were tested during the course of these experiments.This dataset contains measurements of extracted chlorophyll, particulate organic carbon (POC), and particulate organic nitrogen (PON) made over the course of the experiments. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/829707
  • Dataset
    Continuous culture studies of possible climate change effects: Thalassiosira pseudonana CCMP1335 growth in nitrate-limited and nutrient-replete cultures
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-09-30) Laws, Edward ; Passow, Uta
    The marine diatom Thalassiosira pseudonana clone CCMP 1335 was grown in a continuous culture system on a 14:10 light-dark cycle under either nitrate-limited or nutrient-replete conditions, a photoperiod irradiance of either 50 or 300 micro-mol photons per square meter per second, partial pressures of either 400 or 1000 ppm CO2, and temperatures ranging from 5 to 32 degrees Celsius. Growth rates, photosynthetic rates, respiration rates, C:N ratios, C:Chlorophyll-a ratios, productivity indices, Fv/Fm ratios, and the initial slope and light-saturated asymptote of short-term photosynthesis-irradiance curves are reported. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/779368
  • Dataset
    Continuous culture studies of possible climate change effects: Synechococcus elongatus CCMP1629 growth in nitrate-limited and nutrient-replete cultures
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-09-30) Laws, Edward ; Passow, Uta
    The marine cyanobacterium Synechococcus elongatus clone CCMP1629 was grown in a continuous culture system on a 14:10 light-dark cycle under either nitrate-limited or nutrient-replete conditions, a photoperiod irradiance of either 50 or 300 micro-mol photons per square meter per second, partial pressures of either 400 or 1000 ppm CO2, and temperatures ranging from 20 to 45 degrees Celsius. Growth rates, photosynthetic rates, respiration rates, C:N ratios, C:Chlorophyll-a ratios, productivity indices, Fv/Fm ratios, and the initial slope and light-saturated asymptote of short-term photosynthesis-irradiance curves are reported. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/811093
  • Dataset
    Series 4A: Multiple stressor experiments on Synechococcus elongatus (CCMP1629) – pH measurements
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-08-31) Passow, Uta ; Laws, Edward ; D'Souza, Nigel
    The experiments were designed to test the combined effects of two CO2 concentrations, four temperatures, and three light intensities on growth and photophysiology of the cyanobacteria Synechococcus elongatus CCMP1629 in a multifactorial design. This dataset contains measurements of pH made over the course of the experiments. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/806998
  • Dataset
    Series 4A: Multiple stressor experiments on Synechococcus elongatus (CCMP1629) – Dissolved Inorganic Carbon (DIC)
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-08-31) Passow, Uta ; Laws, Edward ; D'Souza, Nigel
    The experiments were designed to test the combined effects of two CO2 concentrations, four temperatures, and three light intensities on growth and photophysiology of the cyanobacteria Synechococcus elongatus CCMP1629 in a multifactorial design. This dataset contains measurements of Dissolved Inorganic Carbon (DIC) made over the course of the experiments. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/807010
  • Dataset
    Series 2A-1: Multiple stressor experiments on T. pseudonana (CCMP1014) – cell abundance and cell size in experiments
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-11-30) Passow, Uta ; Laws, Edward ; Sweet, Julia
    These experiments were designed to test the combined effects of temperatures and light intensity on the growth growth rate (mu) and photophysiology of the diatom Thalassiosira pseudonana CCMP 1014 in a multifactorial design. Experiments were conducted in artificial seawater supplemented with 5% sterilized seawater. Six temperatures (13.5°C, 20°C, 25°C, 29°C, 31°C, and 32.5°C), and eight light intensities (25, 50, 80, 115,190, 300, 400 and 600 umol photons · m-2 · s-1 ) were tested during the course of these experiments. This dataset contains measurements of cell abundances and cell size expressed as forward scatter (FSC) as well as in equivalent spherical diameter (ESD) in microns. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/829675
  • Dataset
    Series 1B-3: Multiple stressor experiments on T. pseudonana (CCMP1335) – computed data from the LC3 protocol for samples at 4 temperatures, 15-26C
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-11-30) Passow, Uta ; Laws, Edward ; Sweet, Julia
    Four follow-up experiments on the combined effect of light and temperature changes on the growth rate (mu) and photophysiology of Thalassiosira pseudonana CCMP 1335 were conducted to supplement / repeat series 1A experiments. This was necessary because doubt existed regarding the growth during 1A experiments. 1A experiments were conducted in artificial seawater. 1B experiments were conducted in artificial seawater supplemented with 5% sterilized seawater. The experiments were designed to test the combined effects of four temperatures, and eight light intensities on the growth and photophysiology of the diatom T. pseudonana CCMP1335 in a multifactorial design. This dataset contains measurements of photophysiology using the Light curve (LC3) protocol of the Aquapen-C AP-C 100 fluorometer. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/829009
  • Dataset
    Series 3A: Multiple stressor experiments on T. pseudonana (CCMP1014) - Chlorophyll, particulate organic carbon and particulate organic nitrogen.
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-06-29) Passow, Uta ; Laws, Edward ; D'Souza, Nigel
    The experiments were designed to test the combined effects of CO2, temperatures, and light on growth and photophysiology of the diatom T. pseudonana CCMP1014 in a multifactorial design. This dataset contains measurements of extracted chlorophyll, particulate organic carbon (POC), and particulate organic nitrogen (PON) made over the course of the experiments. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/771594
  • Dataset
    Series 4A: Multiple stressor experiments on the cyanobacteria Synechococcus elongatus CCMP1629 - raw fluorescence readings for photophysiology computations
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-08-31) Passow, Uta ; Laws, Edward ; D'Souza, Nigel
    The experiments were designed to test the combined effects of two CO2 concentrations, four temperatures, and three light intensities on growth and photophysiology of the cyanobacteria S. elongatus CCMP1629 in a multifactorial design. This dataset contains raw fluorescence measurements for computing photophysiology using the Light curve (LC3) protocol of the Aquapen-C AP-C 100 fluorometer. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/808174
  • Article
    Biogeochemical processes affecting the fate of discharged Deepwater Horizon gas and oil new insights and remaining gaps in our understanding
    (Oceanography Society, 2021-06-03) Farrington, John W. ; Overton, Edward B. ; Passow, Uta
    Research funded under the Gulf of Mexico Research Initiative provided new insights into the biogeochemical processes influencing the fate of petroleum chemicals entering the Gulf of Mexico from the Deepwater Horizon (DWH) accident. This overview of that work is based on detailed recent reviews of aspects of the biogeochemistry as well as on activities supported by the US Natural Resource Damage Assessment. The main topics presented here are distribution of hydrocarbons in the water column; the role of photo-oxidation of petroleum compounds at the air-sea interface; the role of particulates in the fate of the DWH hydrocarbons, especially marine oil snow (MOS) and marine oil snow sedimentation and flocculent accumulation (MOSSFA); oil deposition and accumulation in sediments; and fate of oil on beaches and in marshes. A brief discussion of bioaccumulation is also included. Microbial degradation is addressed in a separate paper in this special issue of Oceanography. Important future research recommendations include: conduct a more robust assessment of the mass balance of various chemical groupings and even individual chemicals during specific time intervals; seek a better understanding of the roles of photo-oxidation products, MOS, and MOSSFA and their relationships to microbial degradation; and determine the fates of the insoluble highly degraded and viscous oil residues in the environment.
  • Dataset
    Series 1B: Four follow-up experiments on the combined effect of light and temperature changes on the growth rate (mu) of Thalassiosira pseudonana CCMP 1335 conducted to supplement series 1A experiments
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-08-31) Passow, Uta
    This dataset reports supplemental experiments that were conducted to investigate the combined effect of light and temperature changes on the growth rate (mu) of Thalassiosira pseudonana CCMP 1335. Experiments were conducted at three temperatures and two light levels. Optical density measurements, dark-adapted Instantaneous Chlorophyll Fluorescence, and the quantum yield and cell concentrations were determined daily. Particulate organic carbon and nitrogen as well as Chl a were measured when volume allowed. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/745492
  • Dataset
    Series 1A: Two-stressor effects on Tp-1335: Experiments to investigate the combined effect of light and temperature changes on the growth rate of Thalassiosira pseudonana CCMP
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-08-31) Passow, Uta
    Series 1A: Two-stressor effects on Tp-1335: Experiments were conducted to investigate the combined effect of light and temperature changes on the growth rate (mu) of Thalassiosira pseudonana CCMP 1335. This is the first series, consisting of 5 experiments For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/714528
  • Dataset
    Series 4A: Multiple stressor experiments on Synechococcus elongatus (CCMP1629) – nutrients
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-08-31) Passow, Uta ; Laws, Edward ; D'Souza, Nigel
    The experiments were designed to test the combined effects of two CO2 concentrations, four temperatures, and three light intensities on growth and photophysiology of the cyanobacteria Synechococcus elongatus CCMP1629 in a multifactorial design. This dataset contains measurements of nutrients (phosphate, nitrate, and nitrate + nitrite) made over the course of the experiments. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/807026
  • Dataset
    Series 3A: Multiple stressor experiments on T. pseudonana (CCMP1014) – cell abundance by flow cytometry
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-06-29) Passow, Uta ; Laws, Edward ; D'Souza, Nigel
    The experiments were designed to test the combined effects of three CO2 concentrations, four temperatures, and three light intensities on growth of the diatom T. pseudonana CCMP1014 in a multifactorial design. This dataset contains measurements of cell abundances measured by forward scatter. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/771421
  • Dataset
    Experimental results of nitrate-limited or nitrate-replete continuous culture studies of Thalassiosira pseudonana at 5 temperatures with either high or low pCO2 and irradiance
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-09-30) Laws, Edward ; Passow, Uta
    Thalassiosira pseudonanana were grown in nitrate limited culture at five temperatures, 400 umol photons m–2 s­–1, and 1000 ppm CO2 and irradiance levels of 50 and 300 umol photons m-2 s-1. Growth rates, photosynthetic rates, respiration rates, C:N ratio, C:Chlorophyll-a ratio, maximum quantum yield are reported. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/746398
  • Dataset
    Series 1B-4: Multiple stressor experiments on T. pseudonana (CCMP1335) – Chlorophyll, particulate organic carbon and particulate organic nitrogen
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-11-30) Passow, Uta ; Laws, Edward ; Sweet, Julia
    Four follow-up experiments on the combined effect of light and temperature changes on the growth rate (mu) and photophysiology of Thalassiosira pseudonana CCMP 1335 were conducted to supplement / repeat series 1A experiments. This was necessary because doubt existed regarding the growth during 1A experiments. 1A experiments were conducted in artificial seawater. 1B experiments were conducted in artificial seawater supplemented with 5% sterilized seawater. The experiments were designed to test the combined effects of four temperatures, and eight light intensities on the growth and photophysiology of the diatom T. pseudonana CCMP1335 in a multifactorial design.This dataset contains measurements of extracted chlorophyll, particulate organic carbon (POC), and particulate organic nitrogen (PON) made over the course of the experiments. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/829025
  • Dataset
    Series 3A: Multiple stressor experiments on T. pseudonana (CCMP1014) - Phosphate, silicate, and nitrate plus nitrite measurements
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-06-29) Passow, Uta ; Laws, Edward ; D'Souza, Nigel
    The experiments were designed to test the combined effects of three CO2 concentrations, four temperatures, and three light intensities on growth and photophysiology of the diatom T. pseudonana CCMP1014 in a multifactorial design. This dataset contains measurements of nutrients (phosphate, silicate, and nitrate plus nitrite) made over the course of the experiments. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/771370