Biogeography and ecology of freshwater chrysophyte cysts in Finland

Korkonen, Sanna; Weckström, Jan; Korhola, Atte

doi:10.1007/s10750-019-04112-0

Cited by 8 publications

(9 citation statements)

References 62 publications

(91 reference statements)

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“…The composition of phytoplankton was assessed by the abundances of cyanobacteria and golden alga (Chrysophytes). Cyanobacteria are assumed to benefit from warmer temperatures and become dominant in higher nutrient concentrations, whereas Chrysophyceae are assumed to prefer colder and less eutrophic conditions [41,[61][62][63]. Their abundances were weighted by taxa biovolume (considered as fixed) in order to calculated their respective biomass (Cyano_Biovolume and Chryso_Biovolume), and expressed in cubic millimeters per liter (mm 3 /L).…”

Section: Biological Characterizationmentioning

confidence: 99%

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How Do Eutrophication and Temperature Interact to Shape the Community Structures of Phytoplankton and Fish in Lakes?

Bouraï

Logez

Laplace-Treyture

et al. 2020

Water

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Freshwater ecosystems are among the systems most threatened and impacted by anthropogenic activities, but there is still a lack of knowledge on how this multi-pressure environment impacts aquatic communities in situ. In Europe, nutrient enrichment and temperature increase due to global change were identified as the two main pressures on lakes. Therefore, we investigated how the interaction of these two pressures impacts the community structure of the two extreme components of lake food webs: phytoplankton and fish. We modelled the relationship between community components (abundance, composition, size) and environmental conditions, including these two pressures. Different patterns of response were highlighted. Four metrics responded to only one pressure and one metric to the additive effect of the two pressures. Two fish metrics (average body-size and biomass ratio between perch and roach) were impacted by the interaction of temperature and eutrophication, revealing that the effect of one pressure was dependent on the magnitude of the second pressure. From a management point of view, it appears necessary to consider the type and strength of the interactions between pressures when assessing the sensitivity of communities, otherwise their vulnerability (especially to global change) could be poorly estimated.

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Section: Biological Characterizationmentioning

confidence: 99%

“…The ratio of the biomasses of large taxa on the biomasses of small taxa in each lake was then calculated. This metric (phytoplankton size class) allows us to see, as with ichthyofauna, whether the size structure of the phytoplankton community is affected by thermal and/or eutrophic stress [41,42,62,65,66].…”

Section: Biological Characterizationmentioning

confidence: 99%

How Do Eutrophication and Temperature Interact to Shape the Community Structures of Phytoplankton and Fish in Lakes?

Bouraï

Logez

Laplace-Treyture

et al. 2020

Water

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show abstract

“…That transition was also marked by an increase in the total abundance of diatoms and relative abundances of S. parvus and A. islandica (group 4), and a decrease in the relative abundance of chrysophyte cysts (Fig. 6), which are typically more abundant in nutrient-poor lakes with low EC (Tammelin and Kauppila 2018;Korkonen et al 2020).…”

Section: Onset and Changes In Varve Preservationmentioning

confidence: 97%

Human actions were responsible for both initiation and termination of varve preservation in Lake Vesijärvi, southern Finland

et al. 2021

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The influence of lake restoration efforts on lake bottom-water conditions and varve preservation is not well known. We studied varved sediments deposited during the last 80 years along a water-depth transect in the Enonsaari Deep, a deep-water area of the southernmost Enonselkä Basin, Lake Vesijärvi, southern Finland. For the last few decades, the Enonselkä Basin has been subject to ongoing restoration efforts. Varve, elemental, and diatom analyses were undertaken to explore how these actions and other human activities affected varve preservation in the Enonsaari Deep. In contrast to most varved Finnish lakes, whose water columns have a natural tendency to stratify, and possess varve records that span thousands of years, varve formation and preservation in Lake Vesijärvi was triggered by relatively recent anthropogenic stressors. The multi-core varve analysis revealed that sediment in the Enonsaari Deep was initially non-varved, but became fully varved in the late 1930s, a time of increasing anthropogenic influence on the lake. The largest spatial extent of varves occurred in the 1970s, which was followed by a period of less distinguishable varves, which coincided with diversion of sewage from the lake. Varve preservation weakened during subsequent decades and was terminated completely by lake aeration in the 2010s. Despite improvements in water quality, hypolimnetic oxygen depletion and varve preservation persisted beyond the reduction in sewage loading, initial aeration, and biomanipulation. These restoration efforts, however, along with other human actions such as harbor construction and dredging, did influence varve characteristics. Varves were also influenced by diatom responses to anthropogenic forcing, because diatoms form a substantial part of the varve structure. Of all the restoration efforts, a second episode of aeration seems to have had the single most dramatic impact on profundal conditions in the basin, resulting in replacement of a sediment accumulation zone by a transport or erosional zone in the Enonsaari Deep. We conclude that human activities in a lake and its catchment can alter lake hypolimnetic conditions, leading to shifts in lake bottom dynamics and changes in varve preservation.

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“…Dispersal of scaled chrysophytes at the end of the vegetative period by current in the form of thick-walled stomatocysts is highly likely [8,24,28], while their germination can be delayed for several years [8,[67][68][69][70].…”

Section: Fundingmentioning

confidence: 99%

Small Organisms in a Large River: What Provides the High Diversity of Scaled Chrysophytes in the Ob River?

Bessudova,

Likhoshway,

Firsova

et al. 2023

Water

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Currents are one of the main factors favoring the dispersal of microscopic planktic organisms over inland lakes and rivers. Large rivers of the northern hemisphere, flowing from south to north, can increase the diversity of northern latitudes with boreal species, while high water levels and floods expand the range of ecotopes and the biodiversity of rivers. We studied the distribution of the taxonomic structure and species richness of scaled chrysophytes downstream of the Ob river—a large river in West Siberia—at the end of the high-water period (June). Methods of scanning and transmission microscopy allowed the determination of a high taxonomic richness of these organisms, 67 species in total. The species were unevenly distributed by stations, with the maximum number of species (54) occurring in a shallow still bay without current and with minimum turbidity and a small number of diatoms. The species diversity in the main current was represented mainly by ubiquitous and cosmopolitan species.Water level fall usually coincides with the end of the vegetation of many scaled chrysophytes and the formation of stomatocysts. The stomatocysts of different species may drift downstream and then germinate when they find suitable conditions at theappropriatetime. Large rivers that are subject to significant changes in water level during their hydrologicalperiodsare able to host ahigh diversity of microscopic planktic organisms. Studying this capacity may reinforce the hypothesis of an omnipresence, i.e., that “everything is everywhere”.

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Biogeography and ecology of freshwater chrysophyte cysts in Finland

Cited by 8 publications

References 62 publications

How Do Eutrophication and Temperature Interact to Shape the Community Structures of Phytoplankton and Fish in Lakes?

How Do Eutrophication and Temperature Interact to Shape the Community Structures of Phytoplankton and Fish in Lakes?

Human actions were responsible for both initiation and termination of varve preservation in Lake Vesijärvi, southern Finland

Small Organisms in a Large River: What Provides the High Diversity of Scaled Chrysophytes in the Ob River?

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