Tracing organic matter sources in the estuarine sediments of Vanga, Kenya, and provenance implications

2021 ◽  
pp. 107636
Author(s):  
Amon Kimeli ◽  
Shawlet Cherono ◽  
Bonface Mutisya ◽  
Fredrick Tamooh ◽  
Judith Okello ◽  
...  
Keyword(s):  
Organic Matter ◽  
Estuarine Sediments ◽  
Organic Matter Sources

scholarly journals Benthic fluxes of dissolved organic nitrogen in the lower St. Lawrence estuary and implications for selective organic matter degradation

2013 ◽  
Vol 10 (11) ◽  
pp. 7609-7622 ◽  
Author(s):  
M. Alkhatib ◽  
P. A. del Giorgio ◽  
Y. Gelinas ◽  
M. F. Lehmann
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Bottom Water ◽  
Estuarine Sediments ◽  
Internal Source ◽  
Lawrence Estuary ◽  
Element Partitioning ◽  
Sediment Porewaters ◽  
St Lawrence Estuary

Abstract. The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment porewaters was determined at nine locations along the St. Lawrence estuary and in the gulf of St. Lawrence. In a previous manuscript (Alkhatib et al., 2012a), we have shown that this study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, and benthic respiration rates. Based on the porewater profiles, we estimated the benthic diffusive fluxes of DON and DOC in the same area. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1). DON fluxes were positively correlated with sedimentary POM reactivity and varied inversely with sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30 to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange, a result that is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. In contrast to DON, DOC fluxes out of the sediments did not show any significant spatial variation along the Laurentian Channel (LC) between the estuary and the gulf (2100 ± 100 μmol m−2 d−1). The molar C / N ratio of dissolved organic matter (DOM) in porewater and the overlying bottom water varied significantly along the transect, with lowest C / N in the lower estuary (5–6) and highest C / N (> 10) in the gulf. Large differences between the C / N ratios of porewater DOM and POM are mainly attributed to a combination of selective POM hydrolysis and elemental fractionation during subsequent DOM mineralization, but selective adsorption of DOM to mineral phases could not be excluded as a potential C / N fractionating process. The extent of this C- versus N- element partitioning seems to be linked to POM reactivity and redox conditions in the sediment porewaters. Our results thus highlight the variable effects selective organic matter (OM) preservation can have on bulk sedimentary C / N ratios, decoupling the primary source C / N signatures from those in sedimentary paleoenvironmental archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

GDGTs as indicators for organic-matter sources in a small subtropical river-estuary system

2021 ◽  
pp. 104180
Author(s):  
Zhangyu Cheng ◽  
Fengling Yu ◽  
Xiaoyan Ruan ◽  
Peng Cheng ◽  
Nengwang Chen ◽  
...  
Keyword(s):  
Organic Matter ◽  
River Estuary ◽  
Organic Matter Sources

scholarly journals Efektivitas Kompos Limbah Jagung Menggunakan Dekomposer Bakteri dan Cendawan pada Tanaman Jagung

JURNAL PANGAN ◽  
2018 ◽  
Vol 27 (2) ◽  
pp. 129-140
Author(s):  
Faesal Pate
Keyword(s):  
Organic Matter ◽  
Grain Yield ◽  
Agricultural Land ◽  
Block Design ◽  
Organic Fertilizer ◽  
The Other ◽  
Organic Matter Sources ◽  
Green House ◽  
Randomized Block Design ◽  
K Fertilizer

Utilization of maize waste as the organic matter sources in agricultural land couldn’t be directly applied, caused by late decomposition prosess. An effort to accelerate of maize waste decomposting needed bioactivator. The research was conducted in green house and Bajeng Research Intallation from March to August 2015. The research was arranged in randomized block design using isolate bacteria and fungus just one or theier combining ie: three bacteria  (B7.1,E7.7and E7.11), three fungus (M7, O5, P7), and four bacteria-fungus combining(B7.1+O5, B7.1+M7, E7.7+P7, B7.1+E7.7+O5), EM4 and N,P,K fertilizer(200,45,60) ha-1as the check treatment. Just one isolate fertilized by 75 percent N,P,K while combine isolate fertilized by 50 percent N,P,K recommended. The results indicated that just one decomposer E7.7 produced high enouugh grain yield not siqnificantly different by N,P,K (200,45,60) and five other just one treatment (E7.11,B7.1,M7 and O5), however siqnificantly different with combining decomposer (B7.1+O5, E7.11+M7, E7.7+P7, B7.1+E7.7+O5 and EM4). This mean that using stalk plus leaf waste maize compost could be subtitution in organic fertilizer untill 25 percent. Meanwhile combining decomposer was good enough for composting stalk and leaf of maize waste ie. isolate B7.1+O5 and E7.7+P7 although not significntly different with the other combine isolate including EM4. Thise case related by applied 50 percent N,P,K inorganic recommended fertilizer did not sufficient to supporting maize nutrient.Key Words: Decomposer, Bacteria, Fungus, Composting,Maize waste

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