210Pb Atmospheric Flux and Growth Rates of a Microbial Mat from the Northwestern Mediterranean Sea (Ebro River Delta)

详细信息    查看全文

• 作者：Joan-Albert Sanchez-Cabeza ; Pere Masqué ; Maira Martí ; nez-Alonso ; Joan Mir ; and Isabel Esteve
• 刊名：Environmental Science & Technology
• 出版年：1999
• 出版时间：November 1, 1999
• 年：1999
• 卷：33
• 期：21
• 页码：3711 - 3715
• 全文大小：77K
• 年卷期：v.33,no.21(November 1, 1999)
• ISSN：1520-5851

文摘

Environmental archives are needed to study the variabilityof natural systems and the impact of man on them.Microbial mats, modern homologues of stromatolites, canbe found in extreme environments such as the EbroRiver Delta and were studied as potential environmentalarchives of atmospheric deposition. ²¹⁰Pb, a radiotracer widelyused in geochronology studies, was used both to determinethe growth rates of a microbial mat from this environmentand to estimate the ²¹⁰Pb atmospheric flux in the northwesternMediterranean Sea. The ²¹⁰Pb profile showed the presenceof three distinct peaks related to low growth-rate periods.This variability indicated the sensitivity of the system toexternal forcing. The annual atmospheric flux of ²¹⁰Pbwas 81.2 ± 1.4 Bq m^-2 yr^-1, which is similar to other valuesfound in the literature. The age profile showed twolayers of differing growth rates, being 0.99 ± 0.10 mmyr^-1 from the surface down to 10 mm depth. The accumulatedmass profile showed a change at about 9 mm depth,corresponding to year 1983 ± 1. It is noteworthy that thisis coincident with a strong El Niño Southern Oscillationevent during 1982-1983, which has been shown to affectother ecosystems, including some in the Mediterraneanarea.