Department of Biology, University of Central Arkansas, Conway, AR 72035, USA
Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Philos Trans R Soc Lond B Biol Sci. 2018 Dec 3;374(1764):20180042. doi: 10.1098/rstb.2018.0042.
Secondary freshwater salinization, a common anthropogenic alteration, has detrimental, lethal and sub-lethal effects on aquatic biota. Ions from secondary salinization can become toxic to terrestrial and aquatic organisms when exposed to salinized runoff that causes periodic high-concentration pulses. Gradual, low-level (less than 1000 ppm salinity) increases in salt concentrations are also commonly documented in regions with urbanization, agriculture, drilling and mining. Despite widespread low-level salt increases, little is known about the biological and ecological consequences in coupled riparian-stream systems. Recent research indicates lethal and even sub-lethal levels of ions can subsidize or stress microbial decomposer and macroinvertebrate detritivores that could lead to alterations of three riparian-stream pathways: (i) salinized runoff that changes microbial decomposer and macroinvertebrate detritivore and algae performance leading to changes in composition and processing of detrital pools; (ii) riparian plant salt uptake and altered litter chemistry, and litterfall for riparian and aquatic detritivores and their subsequent enrichment, stimulating decomposition rates and production of dissolved and fine organic matter; and (iii) salt consumption in salinized soils could increase riparian detritivore growth, decomposition and dissolved organic matter production. Subsidy-stress and reciprocal flows in coupled riparian-stream connections provide frameworks to identify the extent and magnitude of changes in detrital processing from salinization.This article is part of the theme issue 'Salt in freshwaters: causes, ecological consequences and future prospects'.
次生淡水盐化作用是一种常见的人为改变，会对水生生物群产生有害、致命和亚致死影响。当暴露于导致周期性高浓度脉冲的盐化径流时，次生盐化作用产生的离子会对陆地和水生生物变得有毒。在城市化、农业、钻井和采矿的地区，也经常记录到盐浓度逐渐、低水平（低于 1000ppm 盐度）的增加。尽管盐度普遍增加，但对于耦合的河岸-溪流系统中的生物和生态后果知之甚少。最近的研究表明，离子的致死甚至亚致死水平可以补贴或胁迫微生物分解者和大型底栖无脊椎动物碎屑食者，这可能导致三种河岸-溪流途径的改变：（i）改变微生物分解者和大型底栖无脊椎动物碎屑食者和藻类性能的盐化径流，导致碎屑池组成和处理的变化；（ii）河岸植物的盐分吸收和改变的凋落物化学性质，以及河岸和水生碎屑食者的凋落物及其随后的富集，刺激分解速率和溶解有机物质和细粒有机物质的产生；（iii）盐化土壤中的盐分消耗可能会增加河岸碎屑食者的生长、分解和溶解有机物质的产生。耦合的河岸-溪流连接中的补贴-胁迫和相互流动提供了一个框架，用于确定碎屑处理因盐化作用而发生变化的程度和幅度。本文是主题为“淡水中的盐：原因、生态后果和未来展望”的一部分。
