Department of Ecology and Genetics/Limnology, Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden.
Centre for Ecology and Evolution in Microbial model Systems - EEMiS, Department of Biology and Environmental Science, Linnæus University, SE-391 82, Kalmar, Sweden.
Sci Rep. 2018 Sep 7;8(1):13463. doi: 10.1038/s41598-018-31892-7.
Algal blooms occur frequently in lakes and oceans and the causes and consequences of those are often studied. In this study, we focus on a less well known type of algal bloom by the freshwater raphidophyte Gonyostomum semen. This species' abundance and occurrence is increasing, especially in brown water lakes, the most abundant lake type in the boreal zone. The aim of the study was to investigate which environmental factors are associated with G. semen by statistical evaluation of field data of 95 Swedish lakes over five years. Although we found G. semen to be associated with dark waters it was, contrary to our expectations, mainly high concentrations of iron, and only to a lesser extent high TOC (total organic carbon) concentrations, that were associated with blooms of G. semen. In addition, high phosphorus concentrations and low pH also appear to facilitate G. semen blooms. We suggest that browning of lakes caused by increased iron concentrations may decrease net heterotrophy by fostering heavy algal blooms, i.e. the opposite to commonly assumed effects of increased DOM (dissolved organic matter).
藻类水华经常发生在湖泊和海洋中，人们经常研究其成因和后果。在这项研究中，我们关注的是一种较少为人知的淡水腰鞭毛藻属藻类水华，即鱼腥藻。这种藻类的丰度和出现频率正在增加，尤其是在棕色水湖中，这是北方地区最丰富的湖类型。本研究的目的是通过对 95 个瑞典湖泊五年的现场数据进行统计评估，来研究与鱼腥藻属相关的环境因素。尽管我们发现鱼腥藻与深色水域有关，但与我们的预期相反，主要是高浓度的铁，而只有较小程度的高总有机碳（TOC）浓度与鱼腥藻的大量繁殖有关。此外，高磷浓度和低 pH 值似乎也有利于鱼腥藻属的水华。我们认为，由于铁浓度增加导致的湖泊变棕色可能会通过促进大量藻类繁殖来减少净异养作用，即与通常认为的增加 DOM（溶解有机物质）的影响相反。
