摘要
波罗的海本体的富营养化已导致水质的破坏,这一点已得到例如夏季黄金假期中蓝藻细菌的大量繁殖以及深水中严重缺氧等的证实。通过减少磷(P)的供应量持续改善水质将需要几十年时间才能充分生效,原因是储存在流域土壤中,水体中以及波罗的海本体海底沉积物中的磷量很大。本文表明,利用大规模的生态工程方法有可能在几年内实现水质的大辐度改善。过去几十年中,波罗的海本体中天然变化已经证实如何能够实现水质的迅速改善。本文描述了波罗的海本体磷、有机质以及氧的基本动力学。文章还简要地讨论了旨在使波罗的海本体从富营养化影响中恢复的不同种类的生态工程方法的利弊。初步的计算表明,如果每秒向深水上部供应100kg氧,那么,几年内磷含量可能会减半。这将需要100个泵站,每个泵站从约50向125m的深度每秒输送100m^3富氧的所谓冬季水被作为浮动急流释放。每个泵站需要0.6MW的动力供应。海上风力发电技术似乎已成熟到足以提供泵站所需的动力。在约125m的深度安装100个风力发电泵站(每个泵站的动力为0.6MW)的成本约为2亿欧元。
Eutrophication of the Baltic proper has led to impaired water quality, demonstrated by,e.g.,extensive blooming of cyanobacteria during the premium summer holiday season and severe oxygen deficit in the deepwater.Sustainable improvements in water quality by the reduction of phosphorus (P) supplies will take several decades before giving full effects because of large P storages both in soils in the watershed and in the water column and bottom sediments of the Baltic proper.In this article it is shown that drastically improved water quality may be obtained within a few years using large-scale ecological engineering methods.Natural variations in the Baltic proper during the last decades have demonstrated how rapid improvements may be achieved.The present article describes the basic dynamics of P,organic matter,and oxygen in the Baltic proper. It also briefly discusses the advantages and disadvantages of different classes of methods of ecological engineering aimed at restoring the Baltic proper from eutrophication effects.Preliminary computations show that the P content might be halved within a few years if about 100 kg O_2 s^(-1) are supplied to the upper deepwater.This would require 100 pump stations, each transporting about 100 m^3 s^(-1) of oxygen-rich so-called winter water from about 50 to 125 m depth where the water is released as a buoyant jet. Each pump station needs a power supply of 0.6 MW.Offshore wind power technology seems mature enough to provide the power needed by the pump stations.The cost to install 100 wind-powered pump stations,each with 0.6 MW power,at about 125-m depth is about 200 million Euros.
