Study on Settling Model of Suspended Organic Matter in Coastal Region

AbstractIn Jeju Island, multiple land-based aquafarms were fully operational along most coastal region. However, the effect of effluent on distribution and behaviours of dissolved organic matter (DOM) in the coastal water are still unknown. To decipher characteristics of organic pollution, we compared physicochemical parameters with spectral optical properties near the coastal aquafarms in Jeju Island. Absorption spectra were measured to calculate the absorption coefficient, spectral slope coefficient, and specific UV absorbance. Fluorescent DOM was analysed using fluorescence spectroscopy coupled with parallel factor analysis. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were measured using high-temperature catalytic oxidation. The DOC concentration near the discharge outlet was twice higher than that in natural groundwater, and the TDN concentration exponentially increased close to the outlet. These distribution patterns indicate that aquafarms are a significant source of DOM. Herein, principal component analysis was applied to categorise the DOM origins. There were two distinct groups, namely, aquaculture activity for TDN with humic-like and high molecular weights DOM (PC1: 48.1%) and natural biological activity in the coastal water for DOC enrichment and protein-like DOM (PC2: 18.8%). We conclude that the aquafarms significantly discharge organic nitrogen pollutants and provoke in situ production of organic carbon. Furthermore, these findings indicate the potential of optical techniques for the efficient monitoring of anthropogenic organic pollutants from aquafarms worldwide.

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Exploring the application of TEX86 and the sources of organic matter in the Antarctic coastal region

Organic Geochemistry ◽

10.1016/j.orggeochem.2021.104288 ◽

2021 ◽

pp. 104288

Author(s):

Ana Lúcia L. Dauner ◽

B. David A. Naafs ◽

Richard D. Pancost ◽

César C. Martins

Keyword(s):

Organic Matter ◽

Coastal Region ◽

The Antarctic

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Dissolved and suspended organic matter dynamics in the Cape Verde Frontal Zone (NW Africa)

Progress In Oceanography ◽

10.1016/j.pocean.2021.102727 ◽

2021 ◽

pp. 102727

Author(s):

S. Valiente ◽

B. Fernández-Castro ◽

R. Campanero ◽

A. Marrero-Díaz ◽

A. Rodríguez-Santana ◽

...

Keyword(s):

Organic Matter ◽

Frontal Zone ◽

Cape Verde ◽

Suspended Organic Matter ◽

Organic Matter Dynamics

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Sources and export of particle-borne organic matter during a monsoon flood in a catchment of northern Laos

Biogeosciences ◽

10.5194/bg-12-1073-2015 ◽

2015 ◽

Vol 12 (4) ◽

pp. 1073-1089 ◽

Cited By ~ 10

Author(s):

E. Gourdin ◽

S. Huon ◽

O. Evrard ◽

O. Ribolzi ◽

T. Bariac ◽

...

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Total Organic Carbon ◽

Particulate Organic Matter ◽

Rainy Season ◽

Overland Flow ◽

Specific Yield ◽

Main Stream ◽

Δ13c And Δ15n ◽

Suspended Organic Matter

Abstract. The yields of the tropical rivers of Southeast Asia supply large quantities of carbon to the ocean. The origin and dynamics of particulate organic matter were studied in the Houay Xon River catchment located in northern Laos during the first erosive flood of the rainy season in May 2012. This cultivated catchment is equipped with three successive gauging stations draining areas ranging between 0.2 and 11.6 km2 on the main stem of the permanent stream, and two additional stations draining 0.6 ha hillslopes. In addition, the sequential monitoring of rainwater, overland flow and suspended organic matter compositions was conducted at the 1 m2 plot scale during a storm. The composition of particulate organic matter (total organic carbon and total nitrogen concentrations, δ13C and δ15N) was determined for suspended sediment, soil surface (top 2 cm) and soil subsurface (gullies and riverbanks) samples collected in the catchment (n = 57, 65 and 11, respectively). Hydrograph separation of event water was achieved using water electric conductivity and δ18O measurements for rainfall, overland flow and river water base flow (n = 9, 30 and 57, respectively). The composition of particulate organic matter indicates that upstream suspended sediments mainly originated from cultivated soils labelled by their C3 vegetation cover (upland rice, fallow vegetation and teak plantations). In contrast, channel banks characterized by C4 vegetation (Napier grass) supplied significant quantities of sediment to the river during the flood rising stage at the upstream station as well as in downstream river sections. The highest runoff coefficient (11.7%), sediment specific yield (433 kg ha−1), total organic carbon specific yield (8.3 kg C ha−1) and overland flow contribution (78–100%) were found downstream of reforested areas planted with teaks. Swamps located along the main stream acted as sediment filters and controlled the composition of suspended organic matter. Total organic carbon specific yields were particularly high because they occurred during the first erosive storm of the rainy season, just after the period of slash-and-burn operations in the catchment.

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