Inadvertent alkalization of a Florida lake caused by increased ionic and nutrient loading to its watershed     

Thomas J. Whitmore  Mark Brenner  Keith V. Kolasa  William F. Kenney  Melanie A. Riedinger-Whitmore  Jason H. Curtis  Joseph M. Smoak 《Journal of Paleolimnology》2006,36(4):353-370

We evaluate the effects of land-use change since c.1890 on Little Lake Jackson in south-central Florida, USA. The lake currently is alkaline despite the prevalence of acidic lakes in the region. Watershed soils are acidic and poorly drained, but are underlain by limestone bedrock. Limnetic pH inferences, based on weighted-averaging tolerance regression of sedimented diatoms, indicate that Little Lake Jackson became significantly alkalized during the 1900s. Two driving forces that appear to be responsible for water-quality change are increased ionic loading and increased nutrient loading. Golf courses and residential lawns in the watershed receive substantial applications of lime, fertilizer, and irrigation with alkaline waters from deep wells, some of which reaches the lake in channelized runoff. Stormwater runoff and septic leachate also contribute to nutrient and solute loading. Sedimentary total P accumulation increased 5-fold and total N accumulation increased 3-fold since c. 1890. δ¹⁵N values suggest agricultural and septic sources for N loading. Sedimented pigments, inferred limnetic chlorophyll a values, and δ¹³C values of organic matter indicate that increased primary productivity occurred. Surface and subsurface inflow is nutrient-rich but low in hardness. Increased cation deposition in sediments indicates that ionic input might have reduced the lake’s natural resistance to alkalization. Lake waters remain low in ionic content, which suggests that the addition of base from carbonate sources is not responsible for all of the observed alkalization. Acid neutralization might have been facilitated by phosphate loading that led to increased base generation through greater nitrate assimilation. Inadvertent alkalization might occur commonly in regions where poorly buffered lakes are subject to significant ionic and nutrient loading from agriculture, turfgrass, and septic sources in their watersheds.  相似文献   

Testing the application of the Systems Approach Framework (SAF) for the management of eutrophication in the Ria Formosa     

《Marine Policy》2014

The SAF (Systems Approach Framework) encompasses the ecological, social and economic components of coastal zones and aims to establish a permanent dialogue between scientists, stakeholders and policy makers working within European coastal zones for developing effective ICZM (Integrated Coastal Zone Management). The objective of the present study is to test the application of the SAF for defining eutrophication management options in the Ria Formosa, Portugal. Stakeholders were identified and the issue of eutrophication was agreed upon. Having defined the virtual system, the conceptual model of the Ria Formosa was developed. The formulation of the conceptual model into a mathematical model representing the ecological, social and economic components of the system is then discussed. The linking variable of the three components within the simulation model, as well as the scenarios to be run are then explored. The role of scientists as facilitators within the deliberation process is discussed, and a format by which the final output package could be disseminated is suggested. This case study demonstrates how the SAF could successfully be applied to the management of eutrophication in the Ria Formosa. It also suggests ways in which this approach may be adapted to address unique coastal systems with specific system characteristics.  相似文献   

基于模糊综合评价的桑沟湾增养殖区富营养化水平分析          下载免费PDF全文

刘缵延 《海洋开发与管理》2016,33(3):43-47

文章简要回顾海洋水体富营养化评价方法,探索建立海水养殖区富营养化水平模糊综合评价模型,并就桑沟湾海水养殖区的化学需氧量、无机氮(硝酸盐、亚硝酸盐和氨氮之和)、活性磷酸盐、溶解氧、pH值、叶绿素a等指标进行了不同时段、不同时空的综合评价,系统分析综合评价结果的合理性,与其他富营养化评价方法进行了比较,得出用模糊综合评价方法取得的结果更有利于指导海水养殖生产的结论。  相似文献   

Structuring problems in sustainability science: The multi-level DPSIR framework   总被引：2，自引：0，他引：2  

Barry Ness  Stefan Anderberg  Lennart Olsson 《Geoforum》2010,41(3):479-488

Sustainability science needs approaches that allow for the integration of knowledge across disciplines and scales. This paper suggests an approach to conceptualize problems of unsustainability by embedding the Drivers-Pressure-State-Impact-Response (DPSIR) scheme within a multi-level institutional framework represented by Hägerstrand’s system of nested domains. The proposed taxonomy helps to decipher and to better understand key casual chains and societal responses at the appropriate spatial levels for particular sustainability problem areas. To illustrate the scheme more concretely the example of recent problem-solving efforts for Baltic Sea eutrophication driven by Swedish agriculture is examined. The discussion focuses on how the scheme fulfills the four research strategy requirements within the field of sustainability science and how the scheme is distinct from alternative approaches.  相似文献   

近海营养盐和微量元素的大气沉降   总被引：3，自引：1，他引：2  

陈莹  庄国顺  郭志刚 《地球科学进展》2010,25(7):682-690

受气候变化和人类活动的影响,传输和沉降到全球近海的大气污染物急剧增加.1997年后对近海营养盐和微量元素大气沉降的众多研究表明,通过大气沉降至近海的氮和磷分别为13～73 mmol N/(m2·a)和0.11～1.6 mmol P/(m2·a),微量元素的沉降通量具有显著的时空变化特征,在不同海区最高可相差3个数量级.对于很多近海包括东海(East China Sea)和黄海(Yellow Sea),大气沉降的营养盐和部分微量元素可能超出了其河流输入量.大气沉降除了对近海富营养化有重要贡献之外,其事件性特征可使初级生产力在短期内大幅度增加,从而影响赤潮发生.微量元素沉降还可能抑制某些藻类生长,对初级生产力和生态系统结构产生更为复杂的影响.未来研究重点是准确估算近海各物质的大气沉降通量,了解其对浮游植物生长的影响机制.  相似文献