A multiproxy study involving bulk (TOC, δ¹³C_org, grain size) and molecular (n-alkane biomarkers) analyses is used to investigate surface sediments from the Mandovi estuary in Goa, west coast of India to determine the origin, distribution and composition of organic matter (OM). The δ¹³C_org and n-alkane based indices (terrigenous/aquatic ratio (TAR) and P_aq) indicate higher terrigenous OM accumulation in the river dominated upper reaches of the estuary. The presence of unresolved complex mixture (UCM), n-alkane indices (carbon preference index (CPI), average chain length (ACL), natural n-alkanes ratio (NAR)) and diagnostic isoprenoid ratios (pristane/phytane (Pr/Ph), Pr/n-C_17, Ph/n-C₁₈) helped to characterise intense human activity in the lower estuary. This conclusion is further supported by relatively high concentration of hopanes indicating petroleum contamination in the lower estuary. Furthermore, the study also highlights the important role of grain size on the distribution of OM along coastal margins, and provides detailed understanding of the variations in OM distribution/accumulation forced by natural processes and anthropogenic activities. The results of this study have significant implications for identifying natural and anthropogenic OM sources in estuarine systems especially in the context of increasing anthropogenic activities.

一项涉及体积（TOC、δ ¹³ C_组织、粒度）和分子（正烷烃生物标志物）分析的多代理研究用于调查印度西海岸果阿曼多维河口的表层沉积物，以确定其起源、分布和组成有机质 (OM)。基于δ ¹³ C _org和n-烷烃的指数（陆源/水生比(TAR) 和P _aq）表明在河口上游占主导地位的河流中陆源OM 积累量较高。存在未解析的复杂混合物 (UCM)、正烷烃指数（碳偏好指数 (CPI)、平均链长 (ACL)、天然n-烷烃比值 (NAR)) 和诊断类异戊二烯比值（草烷/植烷 (Pr/Ph)、Pr/ n -C _17、 Ph/ n -C ₁₈) 有助于表征下河口的强烈人类活动。这一结论得到了相对高浓度的藿烷的进一步支持，表明下游河口有石油污染。此外，该研究还强调了粒度对 OM 沿沿海边缘分布的重要作用，并提供了对自然过程和人为活动强迫的 OM 分布/积累变化的详细理解。这项研究的结果对于识别河口系统中的自然和人为 OM 来源具有重要意义，尤其是在人为活动增加的背景下。