Protists in the marine ice of the Amery Ice Shelf, East Antarctica

Roberts, D; Craven, Mike; Cai, Minghong; Allison, Ian; Nash, Geraldine V.

doi:10.1007/s00300-006-0169-7

Cited by 30 publications

(29 citation statements)

References 32 publications

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“…Based on this study, the results show that F. cylindrus is able to acclimate to the new salinity and temperature conditions more rapidly than the other 2 species, potentially giving it a competitive advantage in the marine environment. This strongly supports its wide distribution as a generalist species and its prevalence throughout the Antarctic marine ecosystem (Lizotte 2001, Kopczynska et al 2007, Roberts et al 2007, Beans et al 2008. In contrast, Pseudonitzschia subcurvata showed a particular adaptation to meltwater characteristics, with a much lower level of photosynthetic plasticity for changes in salinity, temperature and light, perfectly matching the geographical environment where the species is known to be most abundant (Almandoz et al 2008).…”

supporting

confidence: 61%

Photosynthesis and net primary productivity in three Antarctic diatoms: possible significance for their distribution in the Antarctic marine ecosystem

Petrou¹,

Ralph²

2011

Mar. Ecol. Prog. Ser.

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Photosynthesis and net primary productivity were measured in 3 Antarctic diatoms, Fragilariopsis cylindrus, Pseudo-nitzschia subcurvata and Chaetoceros sp., exposed to rapid changes in temperature and salinity representing a range of conditions found during a seasonal cycle. Measured differences in fluorescence-derived photosynthetic activity and oxygen evolution suggested that some alternative electron cycling activity was present under high irradiances. F. cylindrus displayed the highest rates of relative electron transport and net primary productivity under all salinity and temperature combinations and showed adaptive traits towards the sea-icelike environment. P. subcurvata displayed a preference for low saline conditions where production rates were greatest. However, there was evidence of photosynthetic sensitivity to the lowest temperatures and highest salinities, suggesting a lack of adaptation for dealing with sea-ice-like conditions. Chaetoceros sp. showed high plasticity, acclimating well to all conditions but performing best under pelagic conditions. The study shows species-specific sensitivities to environmental change, highlighting photosynthetic capacity as a potentially important mechanism in ecological niche adaptation. When these data were modelled over different seasons, integrated daily net primary production was greatest under summer pelagic conditions. The findings from this study support the general observations of light control and seasonal development of net primary productivity and species succession in the Antarctic marine ecosystem. KEY WORDS: Net primary productivity · Antarctic diatoms · Ecological niche adaptation · Chl a fluorescence Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 437: [27][28][29][30][31][32][33][34][35][36][37][38][39][40] 2011 display high photoprotective capabilities. However, it is unknown whether differences in photoprotective capacity among Antarctic diatom species can be linked with specific niche environments.Antarctic marine phytoplankton are exposed to large changes in ecosystem conditions during an annual cycle (Fig. 1). In winter, phytoplankton are rapidly incorporated into the sea ice matrix where they are confined to tiny brine channels (salinities up to 145) at freezing temperatures . Initially incoming solar irradiance is very high in the developing sea ice, as a result of being constrained close to the surface, but as the ice thickens, irradiance declines, often to levels of less than 1% surface irradiance (Palmisano et al. 1987). In the austral spring, the ice begins to melt, and the microalgae are washed out of the brine channels into a surface lens of hyposaline water. The meltwater environment, characterised by low salinities (typically below 33), a stable water column and shallow mixed layer, forms an ideal environment for the development of phytoplankton blooms (Dierssen et al. 2002). In summer, the Southern Ocean mixes phytoplankton from the surface waters to the deep, delivering ...

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supporting

confidence: 61%

Photosynthesis and net primary productivity in three Antarctic diatoms: possible significance for their distribution in the Antarctic marine ecosystem

Petrou¹,

Ralph²

2011

Mar. Ecol. Prog. Ser.

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“…Although sympagic communities show a high biodiversity, there is also overlap between species found in landfast and pack ice. Some species, like Polarella glacialis (Montresor et al, 2003;Thomson et al, 2006) and Fragilariopsis cyclindrus (Roberts et al, 2007, and references therein; Poulin et al, 2011), are distributed in both polar regions, which supports the hypothesis that many ice-algal species living in sea ice are in fact pelagic phytoplankton species (see Table 2 in Garrison, 1991, for an extensive species list). A similar correspondence in Comparing landfast and pack-ice surface communities, the composition of heterotrophic protists also appears remarkably similar in two separate and remote sites in Antarctica (Archer et al, 1996).…”

Section: (Dis)similarities In the Biodiversity Of Microalgae In Variomentioning

confidence: 59%

Microalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis

Leeuwe

Tedesco

Arrigo

et al. 2018

Elementa: Science of the Anthropocene

122

128

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van Leeuwe, MA, et al. 2018 Microalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis. Elem Sci Anth, 6: 4. DOI: https://doi.org/10.1525/elementa.267 IntroductionSea ice is one of the largest biomes on earth. The area covered by Arctic (15.6 × 10 6 km 2 ) and Antarctic (18.8 × 10 6 km 2 ) sea ice is roughly 4 and 5% of the global ocean surface (361.9 × 10 6 km 2 ) at their respective maximum extents (Meier, 2017;Stammerjohn and Maksym, 2017). Sea ice is a very diverse and potentially very productive habitat, with primary production estimated to amount to 2-24% of total production in sea-ice covered marine areas (Arrigo, 2017). Sea ice is especially productive in spring and summer when, locally, carbon biomass can be ten times higher in the bottom ice than in the seawater, with values greater than 3 mg chlorophyll a) in bottom layers (e.g., Corneau et al., 2013). On some occasions, ice algae may contribute up to 50-60% of total primary production McMinn et al., 2010; Fernandez-Mendez et al., 2015). Sympagic (ice-associated) microalgae (see Horner et al., 1992, for terminology) are REVIEWMicroalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis Sea ice is one the largest biomes on earth, yet it is poorly described by biogeochemical and climate models. In this paper, published and unpublished data on sympagic (ice-associated) algal biodiversity and productivity have been compiled from more than 300 sea-ice cores and organized into a systematic framework. Significant patterns in microalgal community structure emerged from this framework. Autotrophic flagellates characterize surface communities, interior communities consist of mixed microalgal populations and pennate diatoms dominate bottom communities. There is overlap between landfast and pack-ice communities, which supports the hypothesis that sympagic microalgae originate from the pelagic environment. Distribution in the Arctic is sometimes quite different compared to the Antarctic. This difference may be related to the time of sampling or lack of dedicated studies. Seasonality has a significant impact on species distribution, with a potentially greater role for flagellates and centric diatoms in early spring. The role of sea-ice algae in seeding pelagic blooms remains uncertain. Photosynthesis in sea ice is mainly controlled by environmental factors on a small scale and therefore cannot be linked to specific ice types. Overall, sea-ice communities show a high capacity for photoacclimation but low maximum productivity compared to pelagic phytoplankton. Low carbon assimilation rates probably result from adaptation to extreme conditions of reduced light and temperature in winter. We hypothesize that in the near future, bottom communities will develop earlier in the season and develop more biomass over a shorter period of time as light penetration increases due to the thinning of sea ice. The Arctic is already witnessing changes. The shift forward in time of the algal bloom can resu...

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“…Unfortunately, we conducted only duplicate incubations in each experiment and were thus unable to calculate differences between the experiments. However, growth of HD in the water column was always positive except for 18 January, where a value of 0 d -1 for HD< 20 µm indicated that HD were reproducing in the water column (Table 4), while some of the HD found in the water column may have originated from sea ice (Buck et al 1990, Garrison et al 2005, Roberts et al 2007). The growth rates of HD> 20 µm and < 20 µm may also have been underestimated, since their mortality was not considered.…”

Section: Growth Of Hdmentioning

confidence: 99%

“…We previously reported that Fragilariopsis kerguelensis, Porosira pseudodenticulata, Pseudo-nitzschia cf. turgiduloides, and Thalassiosira australis, which are recognized as ice-associated species that are found in and close to the sea ice (Palmisano & Garrison 1993, Scharek et al 1994, Garrison et al 2005, Scott & Thomas 2005, Roberts et al 2007, were dominant among the diatom assemblage in the austral summer of 2005 to 2006 (Ichinomiya et al 2008a,b). Following the predominance of these diatoms, the microalgal populations shift to phytoflagellates, e.g.…”

Section: Introductionmentioning

confidence: 99%

Role of heterotrophic dinoflagellates in the fate of diatoms released from fast ice in coastal water of Lützow-Holm Bay, East Antarctica

Ichinomiya¹,

Nakamachi²,

Honda³

et al. 2009

Mar. Ecol. Prog. Ser.

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Protists in the marine ice of the Amery Ice Shelf, East Antarctica

Cited by 30 publications

References 32 publications

Photosynthesis and net primary productivity in three Antarctic diatoms: possible significance for their distribution in the Antarctic marine ecosystem

Photosynthesis and net primary productivity in three Antarctic diatoms: possible significance for their distribution in the Antarctic marine ecosystem

Microalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis

Role of heterotrophic dinoflagellates in the fate of diatoms released from fast ice in coastal water of Lützow-Holm Bay, East Antarctica

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