Seasonal dynamics of the planktonic microbial community in a maritime Antarctic lake undergoing eutrophication

Butler, Helen G.

doi:10.1093/plankt/21.12.2393

Cited by 60 publications

(53 citation statements)

References 57 publications

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“…For instance, while the recent rapid recovery of Antarctic fur seal populations (Croxall, 1992 ;Guinet, Jouventin & Georges, 1994 ;Page et al, 2003), previously hunted to the verge of extinction, is generally attributed to lack of feeding competition through anthropogenic reductions in great whale populations, recent seasonal changes in distribution of this species may also be linked with regional climate warming (Quayle et al, 2003). The impact of these population changes on terrestrial and freshwater ecosystems has been drastic, with trampling and excessive nutrient input leading to the virtually complete destruction of large areas of terrestrial vegetation and the eutrophication of previously oligotrophic lake systems (Smith, 1988(Smith, , 1997Butler, 1999). Table 5 presents some likely future responses of some alien species to environmental change and their impacts on indigenous biota.…”

Section: Implications Of Climate Change (1 ) Climate Trendsmentioning

confidence: 99%

Biological invasions in the Antarctic: extent, impacts and implications

Frénot

Chown

Whinam³

et al. 2005

Biol. Rev.

613

822

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Alien microbes, fungi, plants and animals occur on most of the sub-Antarctic islands and some parts of the Antarctic continent. These have arrived over approximately the last two centuries, coincident with human activity in the region. Introduction routes have varied, but are largely associated with movement of people and cargo in connection with industrial, national scientific program and tourist operations. The large majority of aliens are European in origin. They have both direct and indirect impacts on the functioning of speciespoor Antarctic ecosystems, in particular including substantial loss of local biodiversity and changes to ecosystem processes. With rapid climate change occurring in some parts of Antarctica, elevated numbers of introductions and enhanced success of colonization by aliens are likely, with consequent increases in impacts on ecosystems. Mitigation measures that will substantially reduce the risk of introductions to Antarctica and the sub-Antarctic must focus on reducing propagule loads on humans, and their food, cargo, and transport vessels.

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Section: Implications Of Climate Change (1 ) Climate Trendsmentioning

confidence: 99%

Biological invasions in the Antarctic: extent, impacts and implications

Frénot

Chown

Whinam³

et al. 2005

Biol. Rev.

613

822

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“…Most phytoplankton surveys in Antarctic lakes lack a detailed floristic list. In many cases, taxa are identified at the generic level or, most commonly, appear as unidentified algae (LaybournParry et al 1996, 1997, Butler 1999b, Vinocur & Unrein 2000, Izaguirre et al 2001. Recent surveys conducted in the lakes of Hope Bay identified several different nanoplanktonic entities , but their precise taxonomic affiliation was difficult to achieve through conventional microscopic techniques.…”

Section: Introductionmentioning

confidence: 99%

“…We suspect that Band 11 could correspond to a heterotrophic nanoflagellate (HNF), but this suggestion cannot be confirmed. In general, the studies on the microbial plankton communities from Antarctic lakes report HNF as a 'black box' without any detailed taxonomic analysis (Laybourn-Parry et al 1996, 1997, Laybourn-Parry 1997, Bell & Laybourn-Parry 1999, Butler 1999b. This is obviously a group that needs further molecular studies in these environments.…”

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confidence: 99%

Nanoplankton assemblages in maritime Antarctic lakes: characterisation and molecular fingerprinting comparison

Unrein

Izaguirre²,

Massana³

et al. 2005

Aquat. Microb. Ecol.

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The composition of planktonic eukaryotes in the size fraction 3-20 µm of 10 maritime Antarctic lakes was studied by denaturing gradient gel electrophoresis (DGGE). Microscopic observations were also carried out to compare the results obtained by this molecular fingerprinting technique with morphological data. Six lakes from Hope Bay (Antarctic Peninsula) and 4 from the Potter Peninsula (King George Island) were sampled during the austral summer of 2003. These lakes were of different trophic status and covered a wide range of limnological features. Previous studies of the planktonic communities of these lakes revealed high nanoflagellate abundance and biomass, but their taxonomic identification was usually uncertain due to their similarity in size and shape. Here, the application of DGGE allowed both a comparison of the structure of the nanoplanktonic communities and an identification of the dominant populations through sequencing of the most prominent DGGE bands. The most important organisms in these lakes were the Chrysophyceae, represented in the DGGE gel by 5 different band positions and identified by microscopy in 5 different morphotypes, including uniflagellated and biflagellated naked organisms: 1 sequence belonged to the Chrysosphaerales, 2 closely related bands (likely 2 species from the same genus) belonged probably to the Ochromonadales (unicellular biflagellates), while the other 2 bands could not be assigned to any defined chrysophyte group. Sequences related to Chlorophyceae, Bacillariophyceae and probably Cercozoa were also retrieved. A Dictyochophyceae belonging to the order Pedinellales is reported for the first time in freshwater Antarctic ecosystems. Microscopic observations suggest that this phytoplanktonic organism most likely corresponds to Pseudopedinella. Most of the lakes shared several common sequences, such as 2 chrysophyte bands, which suggests the existence of well-adapted nanoplanktonic species dispersed throughout the Antarctic lakes. However, some sequences appeared exclusively in specific lakes, which seems to be related to the trophic status of the water bodies and probably also to the local conditions of the maritime Antarctic regions sampled. KEY WORDS: Freshwater nanoplankton · Antarctic lakes · DGGE · 18S rDNAResale or republication not permitted without written consent of the publisher Aquat Microb Ecol 40: 269-282, 2005 Signy Island, this fraction contributes between 49 and 69% of carbon fixation (Ellis-Evans 1991). In addition, bacterivory by heterotrophic nanoflagellates may remove between 0.1 and 32% of the bacterial production per day (Laybourn-Parry et al. 1995, Bell & LaybournParry 2003, while mixotrophic nanoplanktonic algae are able to remove up to 16% of the bacterial biomass, equivalent to >100% of in situ bacterial production (Bell & Laybourn-Parry 2003).Flagellated algae dominate the nanoplanktonic fraction of the phytoplankton community in Hope Bay lakes (Antarctic Peninsula) (Izaguirre et al. 1993, 2003. In particular, Chrysophyceae dominate algal...

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“…In comparison, the concentration of nitrate nitrogen in the ultra-oligotrophic Crooked Lake in the Vestfold Hills (continental Antarctica) is usually up to 10 μg/L and does not exceed 50 μg L -1 in winter. The concentration of ammonium nitrogen is mostly up to 25 μg L -1 (Butler 1999). The content of inorganic nitrogen in lake water was higher on James Ross Island than on Livingston Island in Maritime Antarctica (Toro et al 2007).…”

Section: Discussionmentioning

confidence: 94%

“…The determined pH values and conductivities of the water in the studied localities corresponded to previously published data from the Ulu Peninsula (Hawes and Brazier 1991;Nedbalová et al 2013). Generally, maximum concentrations of ammonium and nitrate nitrogen in lakes were observed under the ice; concentrations fall mainly in the upper layer of water during the summer season (Butler 1999). Moreover, the summer melting of a lake's ice cover increases the circulation of nutrients in the lake (Camacho et al 2012).…”

Section: Discussionmentioning

confidence: 99%