PETROLEUM GEOCHEMISTRY

Discussion on Petroleum Geochemistry Journal



Table of Contents

Why was the Study Done?2

Have the Authors Adequately Reviewed Existing Research?3

Was there a clearly Defined Question?3

What Study Design was used?4

Was the Design Right for the Question?5

Were Measurements Free from Bias?5

Was the Study Ethical?6

Are the Conclusions Justified?7

Discussion on Petroleum Geochemistry Journal

Why was the Study Done?

This study was done to know about the deposition and transport of terrestrially derived organic matter which is also known as TOM. This is a significant phenomenon of modern global carbon cycle that is poorly understood in contemporary literature (Martin, Talbot & Wagner, 2008, Pp. 1). This study was done to understand the nature of Late Quaternary sediments from deep sea fan of Congo. This sea is at a water depth of 2Km. The samples were selected which proposed the presence of soil-specific BHP (bacteriohopanepolyol biomarkers). It also included adenosylhopane. It was found in the depth of 89 m.

Terrestrially derived organic matter (TOM) is an important component of biogeochemical cycling in river channels (Appelo, 1993, Pp. 45). Despite this, the processes regulating its export from terrestrial ecosystems to river channels and its subsequent processing within river channels remains unresolved. During transport from land to river channels, soil type is thought to be the primary controlling factor. However, the specific mechanism operating in soils that regulates TOM transport is uncertain. In the Congo basin, soils are dominated by clay-rich and sandy varieties. It is estimated that the capacity of these two soil types to retain TOM by sorption in terrestrial ecosystems and the kinetics of the sorption mechanism. The clay-rich soils absorbed TOC twice as rapidly as the sandy soils. A regression of sorption experiment results and soil properties showed that sorption correlates with both soil organic C content and mineral surface area.

Have the Authors Adequately Reviewed Existing Research?

The authors have adequately researched the existing researches in this case. TOM that is not retained in soils is transported to river channels. Studies in the Congo River basin conducted over the past three decades have suggested that most organic matter processing occurs on land, specifically in the soils. Terrestrially-derived TOM has long been recognized as an important component of biogeochemical cycling in river channels. In soils, DOM is mineralized by microbes to CO2 or becomes part of the soil organic matter pool by protection from degradation by sorption to minerals (Leedy, 2005, Pp. 89). The control of DOM transfer from land to river channels by these two processes results in the dependence on soil type of the quantity and quality of DOM exported to streams. In the Congo, McClain et al. (1997) found that differences in DOM concentration and elemental composition in streams were related to soil type. However, they did not distinguish between the extents of control by sorption compared to microbial degradation. This method used various samples of to justify the results through systematic experimentation. The researcher has clearly defined the research in a categorical way. It expounds that the Biomarkers of BHP are uniquely associated with ...