Sample acidification has a predictable effect on isotopic ratios of particulate organic matter along the Chilean coast

Knowledge of carbon and nitrogen isotopic ratios in organic matter and their changes is important when studying nutrient cycles in aquatic ecosystems. Relationships between δ13C and δ15N values of suspended particulate organic matter (POM), water temperature, salinity, pH, redox potential, chlorophyll a concentration, primary production, and biomasses of different taxonomic groups of phytoplankton in the Neva Estuary were statistically analyzed. We tested the hypothesis that the studied physicochemical and biogeochemical characteristics, as well as the species composition of phytoplankton and its productivity, can be significant predictors of changes in the isotopic ratios of suspended particulate organic matter in estuaries. In the Neva Estuary, δ13CPOM (−16.8–−27.6‰) and δ15NPOM (2.3–7.3‰) changed synchronously. Statistical analysis showed that for both isotopes, the photosynthetic activity and taxonomic composition of phytoplankton are important. For 13CPOM, the second most important factor was water salinity, which was apparently associated with the transition of algae from CO2 to HCO3 consumption during photosynthesis in estuarine waters. For 15NPOM changes, the most important abiotic factor was pH. The study showed that the dependences of POM isotopic ratios on environmental variables obtained for continental and oceanic waters are also valid in transitional zones such as the Neva Estuary.

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Relating particulate organic matter-nitrogen (POM-N) and non-POM-N with pulse crop residues, residue management and cereal N uptake

Agronomie ◽

10.1051/agro:2002056 ◽

2002 ◽

Vol 22 (7-8) ◽

pp. 777-787 ◽

Cited By ~ 8

Author(s):

Graeme D. Schwenke ◽

Warwick L. Felton ◽

David F. Herridge ◽

Dil F. Khan ◽

Mark B. Peoples

Keyword(s):

Organic Matter ◽

Particulate Organic Matter ◽

Crop Residues ◽

N Uptake ◽

Residue Management ◽

Pulse Crop

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Macrophyte-derived detritus in shallow coastal waters contributes to suspended particulate organic matter and increases growth rates of Mytilus edulis

Marine Ecology Progress Series ◽

10.3354/meps13314 ◽

2020 ◽

Vol 644 ◽

pp. 91-103

Author(s):

D Bearham ◽

MA Vanderklift ◽

RA Downie ◽

DP Thomson ◽

LA Clementson

Keyword(s):

Organic Matter ◽

Mytilus Edulis ◽

Particulate Organic Matter ◽

Coastal Waters ◽

Gill Tissue ◽

Suspension Feeder ◽

Food Sources ◽

Suspension Feeders ◽

Blue Mussels ◽

Suspended Particulate

Benthic suspension feeders, such as bivalves, potentially have several different food sources, including plankton and resuspended detritus of benthic origin. We hypothesised that suspension feeders are likely to feed on detritus if it is present. This inference would be further strengthened if there was a correlation between δ13C of suspension feeder tissue and δ13C of particulate organic matter (POM). Since detritus is characterised by high particulate organic matter (POC):chl a ratios, we would also predict a positive correlation between POM δ13C and POC:chl a. We hypothesised that increasing depth and greater distance from shore would produce a greater nutritional reliance by experimentally transplanted blue mussels Mytilus edulis on plankton rather than macrophyte-derived detritus. After deployments of 3 mo duration in 2 different years at depths from 3 to 40 m, M. edulis sizes were positively correlated with POM concentrations. POC:chl a ratios and δ13C of POM and M. edulis gill tissue decreased with increasing depth (and greater distance from shore). δ13C of POM was correlated with δ13C of M. edulis. Our results suggest that detritus comprised a large proportion of POM at shallow depths (<15 m), that M. edulis ingested and assimilated carbon in proportion to its availability in POM, and that growth of M. edulis was higher where detritus was present and POM concentrations were higher.

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Staining particulate organic matter with DTAF--a fluorescence dye for carbohydrates and protein:a new approach and application of a 2D image analysis system

Marine Ecology Progress Series ◽

10.3354/meps171077 ◽

1998 ◽

Vol 171 ◽

pp. 77-88

Author(s):

R Schumann ◽

D Rentsch

Keyword(s):

Image Analysis ◽

Organic Matter ◽

Particulate Organic Matter ◽

Image Analysis System ◽

New Approach ◽

Fluorescence Dye ◽

Analysis System

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Hydrolysis of organic wastewater particles in laboratory scale and pilot scale biofilm reactors under anoxic and aerobic conditions

Water Science & Technology ◽

10.2166/wst.1998.0805 ◽

1998 ◽

Vol 38 (8-9) ◽

pp. 179-188 ◽

Cited By ~ 4

Author(s):

K. F. Janning ◽

X. Le Tallec ◽

P. Harremoës

Keyword(s):

Organic Matter ◽

Mass Balance ◽

Particulate Organic Matter ◽

Removal Rate ◽

Pilot Scale ◽

Laboratory Scale ◽

Synthetic Wastewater ◽

Aerobic Conditions ◽

Biofilm Reactors ◽

Hydrolysis Of

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.

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