Using regionalization in mapping the distribution of the diatom species<i>Didymosphenia geminata</i>(Lyngb.) M. Smith in Icelandic rivers

Jónsson, Gunnar St.; Jonsson, Ingi Runar; Björnsson, M.; Einarsson, S. M.

doi:10.1080/03680770.1998.11901249

Cited by 11 publications

(14 citation statements)

References 4 publications

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“…Other countries in Europe with recent spreads include Czech Republic (Gágyorová & Marvan, 2002a, b), Hungary (R. Tisza, Szabó et al, 2005), Serbia and Montenegro (Subakov-Simić & Cvijan, 2004;Subakov-Simić et al, 2006) and Iceland (G. S. Jónsson et al, 2000;I. R. Jónsson et al, 2008, in press).…”

Section: Europementioning

confidence: 95%

Biology of the freshwater diatom Didymosphenia: a review

2009

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Features of the colonial diatom Didymosphenia are reviewed, especially D. geminata. Although there is a long record of its occurrence in north temperate regions, mass growths have been reported much more widely in recent years. Contrary to some statements in the literature, there are also reliable older records for the southern hemisphere, though the first report of mass growth was in New Zealand in 2004. The annual cycle of morphological changes in D. geminata in northern England, and probably elsewhere, includes a winter period when motile cells are attached to the substratum followed by spring when stalks start to develop. These raise cells into the water column and provide a site for phosphatase activity. Environmental factors associated with success include absence of extreme floods, high light, pH above neutral and nutrient chemistry. D. geminata often, but not always, occurs in waters where the N:P ratio is high for much of the year, but the key factor is the ratio of organic to inorganic phosphate. D. geminata thrives where organic P is predominant and the overall P concentration is low enough for organic P to be an important P source. It is unknown whether organic N can be used. Environmental changes increasing the relative importance of organic P are likely to favour D. geminata. Likely examples are increased N:P due to atmospheric N deposition and changes in form and seasonality of P release from organic-rich soils due to climatic warming. The nutrient chemistry of deep water released from dams to rivers also needs investigation. To what extent are genetic changes occurring in response to environmental changes and are new ecotypes spreading round the world? In spite of many adverse reports about D. geminata, such as detached mats blocking water pipes, there is still doubt about the extent to which it causes problems, particularly for fish. There have been few adverse effects on migratory salmonids in Europe and North America, but at least one report of harm to a brown trout population in USA. In New Zealand, it has caused serious problems for water sports, although it remains open to question how much adverse effect it has had on fish populations. If the presence of microcystins in or associated with D. geminata, as indicated recently for two populations, proves to be widespread and at sufficiently high concentration, their possible accumulation in fish requires study. Where control is required, this could Handling editor: Pierluigi Viaroli be achieved by enhancing the ratio of inorganic to organic phosphate in the water early in the growth season. Practical ways to achieve this are suggested.

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Section: Europementioning

confidence: 95%

Biology of the freshwater diatom Didymosphenia: a review

2009

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“…1). The discovery of D. geminata in New Zealand in 2004 caused concern because D. geminata blooms had been reported from several locations in the Northern Hemisphere, including Vancouver Island, Canada (Rieberger, 1991), Iceland (Jonsson et al, 2000) and Poland (Kawecka & Sanecki, 2003). Following its introduction, which was assumed to have been 2-3 years prior to its discovery, D. geminata bloomed along 150 km of waterway in the Waiau catchment, but was not detected in other catchments for a further year.…”

Section: Introductionmentioning

confidence: 99%

The non‐indigenous diatom Didymosphenia geminata alters benthic communities in New Zealand rivers

2009

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Summary 1. Blooms of the benthic, stalked diatom Didymosphenia geminata were first observed in New Zealand in 2004. Since then, D. geminata has spread to numerous catchments in the South Island and is also spreading in its native range. The species is a rare example of an invasive alga in lotic systems. 2. Ecosystem effects may be expected as D. geminata attains unusually high biomass in rivers. We examined data from three independent studies in three South Island, New Zealand, rivers for evidence of effects on periphyton biomass and benthic invertebrate communities. 3. The combined results confirmed that the presence of D. geminata was associated with greatly increased periphyton biomass and, in most cases, increased invertebrate densities. We also recorded shifts in community composition, dominated by increased densities of Oligochaeta. Chironomidae, Cladocera and Nematoda also generally increased in density with D. geminata. Significant increases or declines in other invertebrate taxa were inconsistent among rivers. 4. In all three studies, increased spatial invertebrate community homogeneity was associated with high D. geminata biomass at the within‐river scale. However, no declines in taxon richness or diversity were detected. 5. Although ecosystem effects of D. geminata on existing periphyton biomass and invertebrate communities are measurable, no inferences can be made from the present data about effects on higher trophic levels (fish).

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“…Tömeges elszaporodása esetén a sejtek által kiválasztott kocsonyás polimerháló akár több centiméter vastag és több kilométer hosszú szőnyeget is alkothat az aljzaton (SPAULDING & ELWELL 2007, BLANCO & ECTOR 2009. A tömeges előfordulás az adott terület táplálékhálózatának felborulásához vezethet, csökkentve több élőlénycsoport (vízi makrogerinctelenek, halak) élő-és szaporodóhelyeit, alapjaiban veszélyeztetve a közösség biodiverzitását (MUNDIE & CRABTREE 1997, JÓNSSON et al 2000, BROWN 2008, BLANCO & ECTOR 2009 …”

Section: Az "éV Algájának" Jelölt Fajok 2015-benunclassified

A 2015-ös év algája szavazás jelöltjei

B‐Béres¹,

Nagy-László

T‐Krasznai³

et al. 2016

kitaibelia

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Míg a szabad szemmel látható állat-, illetve növényvilággal kapcsolatos ismeretterjesztés széleskörűvé vált, addig a mikroszkopikus világ tudományos igényű ismeretterjesztő bemutatására kevés példát találni. Hagyományteremtő céllal 2015-ben első alkalommal hirdette meg az Algológus Fórum az „Év Algája” internetes szavazást. A végső szavazásra javasolt három algafaj a Didymosphenia geminata, Haematococcus pluvialis és Prymnesium parvum voltak, melyek közül a Haematococcus pluvialis fajra érkezett a szavazatok döntő többsége. A három faj ökológiai és gazdasági vonatkozásainak, valamint hazai elterjedésük bemutatásán keresztül kívánjuk megmutatni, hogy a mikroszkopikus világ képviselői is kellően színesek és érdekesek lehetnek ahhoz, hogy nagyobb teret kapjanak a tudományos ismeretterjesztésben. Tanulmányunk felhívja a figyelmet az algák vízi ökoszisztémákban betöltött alapvető szerepére, esetleges gazdasági jelentőségükre, valamint a földi élet fenntartásában nélkülözhetetlen szerepükre.

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Using regionalization in mapping the distribution of the diatom speciesDidymosphenia geminata(Lyngb.) M. Smith in Icelandic rivers

Cited by 11 publications

References 4 publications

Biology of the freshwater diatom Didymosphenia: a review

Biology of the freshwater diatom Didymosphenia: a review

The non‐indigenous diatom Didymosphenia geminata alters benthic communities in New Zealand rivers

A 2015-ös év algája szavazás jelöltjei

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