Land-Use and Climate Influences on Lake Tanganyika Floor Sediments and Ecosystems

该项目的目标是确定坦噶尼喀湖岸的农业和城市发展活动对海底栖息和筑巢生物的影响程度。坦噶尼喀湖被广泛认为是研究进化和生态过程的“天然实验室”，因为许多生物在湖中进化和多样化。这一生态宝藏正受到威胁。许多研究集中在开放水域渔业或流域（沉积和污染）问题上，因为这些问题影响到四个沿岸国的健康和财富。然而，坦噶尼喀湖浅水区（10-30米）内的巨大贝壳床却很少受到关注，尽管这些死贝壳堆积是坦噶尼喀湖的独特栖息地，并拥有多种特有的动物，包括大量的鲷鱼。这些死蜗牛壳的堆积无处不在，但在同一栖息地似乎没有活蜗牛。如果没有活蜗牛，那么这意味着要么是自然环境变化，要么是严重的人为影响。因此，如果测量正确，这些壳层可以提供一种评估自然和人为引起的环境变化的手段。研究人员将在俄克拉荷马大学为中学生开设的课程和夏令营中使用这项工作的结果。首席研究员还领导以非洲湖泊保护和资源为主题的海外学习课程。该小组将在科学和大众媒体上发表研究结果，并将通过在相关网站（例如慈鲷爱好者）上张贴和通过在博客上记录实地经验来开展公众宣传，使美国和非洲的理科生都能接触到这些研究结果。研究小组将比较和对比坦噶尼喀湖浅水区的三个地点，这些地点由贝壳床覆盖，但在土地利用方面有所不同（高度受干扰，中度受干扰和对照地点）。收集的数据将包括：每个地点湖底的性质，包括贝壳的年龄和特征以及混合沉积物的质地和组成；地点内某些底栖生物的多样性和丰度；从每个地点采集的岩心数据推断沉积物随时间的变化；以及根据每个地点的地球物理（地震）数据推断出的沉积模式随时间的变化。对不同地点的数据进行比较，将使调查人员能够确定贝壳的积累是否记录了整个湖泊或区域的变化，以及利用贝壳床作为栖息地的现代生物的分布是否因土地利用的变化而变化。这些结果将影响对坦噶尼喀湖和其他现代和古代热带湖泊的生物多样性、保护和进化史感兴趣的研究人员。拟议的活动将在一个综合研究计划中培养一名博士生和六名本科生。这项研究将涉及俄克拉荷马大学、亚利桑那大学和伦敦国家博物馆。与美国地质调查局和北亚利桑那大学的合作也将加强接触和跨学科研究。该小组与坦桑尼亚渔业研究所的合作将为他们的科学家提供更多研究底栖生态的经验，研究结果将使政府和其他利益相关者，如保护团体，掌握管理这些关键生态系统的知识。

The goal of this project is to determine the degree to which agricultural and urban development activities on the shores of Lake Tanganyika affect the bottom-dwelling and -nesting organisms.Lake Tanganyika is widely considered a "natural laboratory" for the study of evolutionary and ecological processes, because many of the organisms have evolved and diversified within the lake itself. This ecological treasure is under threat. Numerous studies have focused either on open-water fisheries or on watershed (sedimentation and pollution) issues as these affect the health and wealth of the four riparian countries. However, the vast shell beds within the shallow (10-30 m) regions of Lake Tanganyika have received much less attention, even though these accumulations of dead shells are a unique habitat to Lake Tanganyika and host a diverse, endemic fauna, including numerous Cichlid fish. These accumulations of dead snail shells are pervasive, but appear to contain no living snails in the same habitat. If living snails are absent, then it implies either natural environmental change or acute anthropogenic impacts. Thus, these shell beds, if measured correctly, may provide a means of assessing natural and human-induced environmental change. The researchers will use the results of this work in courses and within a summer science camp for middle school students taught at the University of Oklahoma. The chief investigator also leads study abroad courses in which the topics of conservation and resources of African lakes are featured. The team will publish the results of the research in both scientific and popular press venues, and will carry out public outreach through posting to related web sites (e.g. Cichlid fish hobbyists) and through blogging of the field experience to make it accessible to both American and African science students.The research team will compare and contrast three sites within shallow regions of Lake Tanganyika that are floored by shell beds, but that vary in terms of their land-use (highly disturbed, moderately disturbed, and a control site). Data to be collected will include: the nature of the lake bottom at each site, including the age and character of the shells as well as the texture and composition of the intermixed sediment; the diversity and abundance of certain bottom-dwelling organisms among the sites; changes in sedimentation over time inferred from data from core collected at each site; and changes in sedimentation patterns over time as inferred by geophysical (seismic) data from each site. Comparison of the data among the sites will allow the investigators to determine whether the accumulation of the shells record lake-wide or regional changes and whether the distribution of modern organisms using the shell beds as a habitat vary as a result of land-use changes. These results would impact researchers interested in the biodiversity, conservation and evolutionary history of Lake Tanganyika and other modern and ancient tropical lakes. The proposed activity will train one PhD student and six undergraduates within an integrated research program. This research would involve the University of Oklahoma, the University of Arizona, and the National Museum, London. Work with the United States Geological Survey and Northern Arizona University would also enhance exposure and interdisciplinary research. The team's collaboration with Tanzanian Fisheries Research Institute would provide their scientists with increased experience in studying benthic ecology, and the results would vest governments and other stakeholders, such as conservation groups, with knowledge to manage these critical ecosystems.