Distribution of lipid compounds in sediments from Conceição Lagoon, Santa Catarina Island, Brazil

Abstract

Compostos orgânicos provenientes de cinco amostras de sedimentos e um perfil com 75 cm foram coletados na Lagoa da Conceição, localizada na Ilha de Santa Catarina, com o objetivo de avaliar fontes de matéria orgânica. Os resultados que foram baseados na relação C:N:P, abundância relativa dos esteróis (com predomínio dos C 27 ), álcoois (0,2-1,2 µg g -1 ) e hidrocarbonetos lineares (0,4-5,0 µg g -1 ), e no uso do Índice Preferencial de Carbono (CPI), indicaram que a matéria orgânica é preferencialmente de origem terrestre (C/N > 10 e CPI > 2). Em todos os locais observaram-se correlações significativas entre as quantidades de fósforo (TP, média 5,20 µmol g -1 ) e carbono orgânico total (TOC, média 2,90 mmol g -1 ) com as frações de silte e argila. No perfil, que foi cronologicamente datado com o radionuclídeo 210 Pb, o intervalo de 55 a 75 cm apresentou predomínio de areia (> 50%). Entretanto, outros parâmetros, tais como TOC, TP e hidrocarbonetos também aumentaram nesse intervalo, o que sugere uma mudança na fonte de matéria orgânica.Lipid compounds from five sediment-water interface samples and a sediment core with 75 cm depth were used to assess sources of organic matter in Conceição Lagoon, located on Santa Catarina Island. The results which were based on the molar C:N:P ratios, relative abundance of sterols (dominated by the C 27 sterols), n-alkanols (0.2-1.2 µg g -1 ), n-alkanes (0.4-5.0 µg g -1 ) and the Carbon Preference Index (CPI), indicated that the organic matter is predominantly of terrestrial origin (C/N > 10 and CPI > 2). Total phosphorus (TP, average 5.20 µmol g -1 ) and organic carbon (TOC, average 2.90 mmol g -1 ) contents were well correlated with the silt and clay fractions at all locations. In the sediment core, chronologically dated with the radionuclide 210 Pb, the depth interval from 55 to 75 cm was dominated by the sand fraction (> 50%). However, parameters such as TOC, TP and n-alkane contents increased considerably at this depth suggesting a change in organic matter input sources.

Assessment and sources of nonaromatic hydrocarbons in surface sediments of three harbors in Santa Catarina State, Brazil

“…Only one location (Bab5) in the Babitonga Bay showed a concentration of OP (251.6 μg g −1 ) much higher than the IP concentration (212.7 μg g −1 ). Previous studies have indicated that the proportion of OP to IP seems to be affected by sources of phosphorus and shown that IP is usually accountable for 60% of the TP in sediments without anthropogenic input (Mater et al 2004;Silva et al 2008). …”

“…Studies on the environmental aspects of harbors are important since these environments are recipients of toxic chemical inputs from a wide variety of pollution sources and they can affect marine coastal ecosystems through sediment dredging, seawater diffusion, or advective sediment transport. There are few published studies on the characterization of organic extracts from sediments along the Santa Catarina coast (Mahiques et al 1999;Mater et al 2004;Alexandre et al 2006;Silva et al 2008). At the molecular level, little is known about the types of hydrocarbons or other compounds that may be found in the sediments of Babitonga Bay, the Itajaí-Açu River mouth, and Imbituba Harbor.…”

Geochemical markers as a tool to assess sedimentary organic matter sources of the Laguna Estuarine System, south Brazil: aliphatic and polycyclic aromatic hydrocarbons

“…[25][26][27][28][29] Concentrations and indices regarding AH and NA in our samples are summarized in Table 2. The AH concentrations varied from 12.6 to 2,267.4 µg g -1 of sediment dry weight (dw) and from 38.5 to 34,883.1 µg g -1 of organic carbon weight (OC), whereas NA concentrations ranged from 0.9 to 45.6 µg g -1 dw and from 55.1 to 7,013.5 µg g -1 OC.…”

Relationships between coal-quality and organic-geochemical parameters: A case study of the Hafik coal deposits (Sivas Basin, Turkey)

“…Biomarker analysis of soluble organic matter in the coals has contributed to our understanding of the paleoenvironment of the mires (Waples and Machihara, 1991;Silva et al, 2008). In gas chromatograms of the studied samples, n-alkanes are found in the range of C 22 -C 32 , indicating a lagoonal and/or terrestrial environment (Filley et al, 2001;Riboulleau et al, 2007;Silva et al, 2008).…”

“…In gas chromatograms of the studied samples, n-alkanes are found in the range of C 22 -C 32 , indicating a lagoonal and/or terrestrial environment (Filley et al, 2001;Riboulleau et al, 2007;Silva et al, 2008). 17α (H) -homohopane ratios are essential as a paleoclimate indicator (Waples and Machihara, 1991).…”