Fine Particulate Organic Carbon Output from Fens and Its Effect on Benthic Macroinvertebrates

Oikos ◽  
1979 ◽  
Vol 32 (3) ◽  
pp. 409 ◽  
Author(s):  
Don C. Erman ◽  
Walter C. Chouteau
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Benthic Macroinvertebrates ◽  
Fine Particulate

Stochastic modeling of fine particulate organic carbon dynamics in rivers

2014 ◽  
Vol 50 (5) ◽  
pp. 4341-4356 ◽  
Author(s):  
J. D. Drummond ◽  
A. F. Aubeneau ◽  
A. I. Packman
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Stochastic Modeling ◽  
Carbon Dynamics ◽  
Fine Particulate

The Carbon:²³⁴Thorium ratios of sinking particles in the California Current Ecosystem 2: Examination of a thorium sorption, desorption, and particle transport model

2019 ◽  
Author(s):  
Michael Stukel ◽  
Thomas Kelly
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Particulate Organic Carbon ◽  
Transport Model ◽  
California Current ◽  
In Situ Measurements ◽  
Power Law Distribution ◽  
Sinking Particles ◽  
Organic Carbon Concentration

Thorium-234 (234Th) is a powerful tracer of particle dynamics and the biological pump in the surface ocean; however, variability in carbon:thorium ratios of sinking particles adds substantial uncertainty to estimates of organic carbon export. We coupled a mechanistic thorium sorption and desorption model to a one-dimensional particle sinking model that uses realistic particle settling velocity spectra. The model generates estimates of 238U-234Th disequilibrium, particulate organic carbon concentration, and the C:234Th ratio of sinking particles, which are then compared to in situ measurements from quasi-Lagrangian studies conducted on six cruises in the California Current Ecosystem. Broad patterns observed in in situ measurements, including decreasing C:234Th ratios with depth and a strong correlation between sinking C:234Th and the ratio of vertically-integrated particulate organic carbon (POC) to vertically-integrated total water column 234Th, were accurately recovered by models assuming either a power law distribution of sinking speeds or a double log normal distribution of sinking speeds. Simulations suggested that the observed decrease in C:234Th with depth may be driven by preferential remineralization of carbon by particle-attached microbes. However, an alternate model structure featuring complete consumption and/or disaggregation of particles by mesozooplankton (e.g. no preferential remineralization of carbon) was also able to simulate decreasing C:234Th with depth (although the decrease was weaker), driven by 234Th adsorption onto slowly sinking particles. Model results also suggest that during bloom decays C:234Th ratios of sinking particles should be higher than expected (based on contemporaneous water column POC), because high settling velocities minimize carbon remineralization during sinking.

scholarly journals Exposure to chemical components of fine particulate matter and ozone, and placenta-mediated pregnancy complications in Tokyo: a register-based study

2021 ◽  
Author(s):  
Takehiro Michikawa ◽  
Seiichi Morokuma ◽  
Shin Yamazaki ◽  
Akinori Takami ◽  
Seiji Sugata ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Organic Carbon ◽  
Pregnancy Complications ◽  
Fine Particulate Matter ◽  
First Trimester ◽  
Chemical Components ◽  
Specific Chemical ◽  
Network Database ◽  
Fine Particulate ◽  
Pollutant Concentrations

Abstract Background Maternal exposure to fine particulate matter (PM2.5) was associated with pregnancy complications. However, we still lack comprehensive evidence regarding which specific chemical components of PM2.5 are more harmful for maternal and foetal health. Objective We focused on exposure over the first trimester (0–13 weeks of gestation), which includes the early placentation period, and investigated whether PM2.5 and its components were associated with placenta-mediated pregnancy complications (combined outcome of small for gestational age, preeclampsia, placental abruption, and stillbirth). Methods From 2013 to 2015, we obtained information, from the Japan Perinatal Registry Network database, on 83,454 women who delivered singleton infants within 23 Tokyo wards (≈627 km2). Using daily filter sampling of PM2.5 at one monitoring location, we analysed carbon and ion components, and assigned the first trimester average of the respective pollutant concentrations to each woman. Results The ORs of placenta-mediated pregnancy complications were 1.14 (95% CI = 1.08–1.22) per 0.51 μg/m3 (interquartile range) increase of organic carbon and 1.11 (1.03–1.18) per 0.06 μg/m3 increase of sodium. Organic carbon was also associated with four individual complications. There was no association between ozone and outcome. Significance There were specific components of PM2.5 that have adverse effects on maternal and foetal health.

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