The carbon and nitrogen isotopic values of particulate organic material from the Florida Keys: a temporal and spatial study
The carbon and nitrogen isotopic values of particulate organic material from the Florida Keys: a temporal and spatial study
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DOI：
10.1007/s00338-007-0336-5
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发表时间：
2008-06
期刊：
影响因子：
3.5
通讯作者：
K. Lamb;P. Swart
中科院分区：
文献类型：
--
作者：
K. Lamb;P. Swart
分析了2000 ~ 2002年佛罗里达群岛35个地点的颗粒物有机物质（POM）的δ15N和δ13C值。研究区域内的地点被划分为从基韦斯特到基拉戈的九个横断面。每个样带由三到五个地点组成，从靠近礁岛一直延伸到珊瑚礁地带的边缘。POM的平均δ15N和δ13C值分别为+3.6‰（σ =±3.2‰）和- 19.9‰（σ =±0.6‰）。在研究期间，δ15N、δ13C和C:N的变化无统计学意义。大部分样品的δ13C值表现出明显的近岸（δ13C =−18.3‰，σ =±1.0‰）到近岸（δ13C =−21.4,σ =±0.9‰）梯度。相比之下，δ15N值与陆地距离没有一致的关系。近岸样品的δ13C值较高，表明近岸POM中的碳氮主要来源于海草碎屑的降解，而不是来自佛罗里达群岛的人为来源物质的输入。相比之下，外礁上的POM以海洋浮游生物为主。由于有机氮池的矿化和硝化作用是水柱中溶解无机氮的主要来源，因此佛罗里达群岛中藻类和其他底栖生物的δ15N变化不太可能与污水的输入有关。
The δ15N and δ13C values of particulate organic material (POM) were analyzed from 35 sites in the Florida Keys over the time interval 2000 to 2002. The sites within the study area were delineated into nine transects stretching from Key West to Key Largo. Each transect consisted of three to five sites extending from close to the Keys to the edge of the reef tract. The POM had mean δ15N and δ13C values of +3.6‰ (σ = ±3.2‰) and −19.9‰ (σ = ±0.6‰) respectively. Over the study period there were no statistically significant changes in δ15N, δ13C, or C:N. For the majority of the sampling dates, the δ13C values showed a distinct inshore (δ13C = −18.3‰, σ = ±1.0‰) to offshore gradient (δ13C = −21.4, σ = ±0.9‰). In contrast, the δ15N values showed no consistent patterns related to the distance from land. The more positive δ13C values of the nearshore samples suggest that the source of the carbon and the nitrogen in the POM in the nearshore was mainly derived from the degradation of seagrass detritus and not from the input of anthropogenically derived material from the Florida Keys. In contrast, the POM on the outer reef was dominated by marine plankton. As mineralization and nitrification of the organic nitrogen pool are major contributors to the dissolved inorganic nitrogen in the water column, it is unlikely that variations in the δ15N of the algae and other benthic organisms reported in the Florida Keys are related to the input of sewage.