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Werner, Iris

doi:10.1023/a:1003984327103

Cited by 22 publications

(5 citation statements)

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“…Indeed, ridges are hot spots for accumulation of sea-ice fauna (Gradinger et al, 2010) since the organisms can graze on the abundant surface-attached sea-ice algae. For example, A. glacialis, which was the most abundant ice-associated amphipod in this study, has been shown to actively feed on ice algae, which can be a main contribution to its diet (Werner, 2000;Brown et al, 2017).…”

Section: Contribution Of Fyi Ridges and Snow-ice Interfaces To Arcticmentioning

confidence: 71%

Algal Hot Spots in a Changing Arctic Ocean: Sea-Ice Ridges and the Snow-Ice Interface

et al. 2018

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During the N-ICE2015 drift expedition north-west of Svalbard, we observed the establishment and development of algal communities in first-year ice (FYI) ridges and at the snow-ice interface. Despite some indications of being hot spots for biological activity, ridges are under-studied largely because they are complex structures that are difficult to sample. Snow infiltration communities can grow at the snow-ice interface when flooded. They have been commonly observed in the Antarctic, but rarely in the Arctic, where flooding is less common mainly due to a lower snow-to-ice thickness ratio. Combining biomass measurements and algal community analysis with under-ice irradiance and current measurements as well as light modeling, we comprehensively describe these two algal habitats in an Arctic pack ice environment. High biomass accumulation in ridges was facilitated by complex surfaces for algal deposition and attachment, increased light availability, and protection against strong under-ice currents. Notably, specific locations within the ridges were found to host distinct ice algal communities. The pennate diatoms Nitzschia frigida and Navicula species dominated the underside and inclined walls of submerged ice blocks, while the centric diatom Shionodiscus bioculatus dominated the top surfaces of the submerged ice blocks. Higher light levels than those in and below the sea ice, low mesozooplankton grazing, and physical concentration likely contributed to the high algal biomass at the snow-ice interface. These snow infiltration communities were dominated by Phaeocystis pouchetii and chain-forming pelagic diatoms (Fragilariopsis oceanica and Chaetoceros gelidus). Ridges are likely to form more frequently in a thinner and more dynamic ice pack, while the predicted increase in Arctic precipitation in some regions in combination with the thinning Arctic icescape might lead to larger areas of sea ice with negative freeboard and subsequent flooding during the melt season. Therefore, these two habitats are likely to become increasingly important in the new Arctic with implications for carbon export and transfer in the ice-associated ecosystem.

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Section: Contribution Of Fyi Ridges and Snow-ice Interfaces To Arcticmentioning

confidence: 71%

Algal Hot Spots in a Changing Arctic Ocean: Sea-Ice Ridges and the Snow-Ice Interface

et al. 2018

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“…In our aquaria setting at the AAD, the krill only ever produce green or brown pellets. Here, the krill are the same age and species, so diet most likely contributes to the difference in pellet color (Werner, 2000). In the aquaria fragmentation experiment, green pellets were produced after a supply of fresh phytoplankton cells to the tank (Figure 3), and as the digestive tract of Antarctic krill is green when feeding on phytoplankton (Fuentes et al, 2016), the green pellets collected in this study for the remineralization experiments were from those feeding on phytoplankton.…”

Section: Discussionmentioning

confidence: 97%

“…Our results showed that small pellets are subjected to higher remineralization rates than larger pellets, but only when the pellets were brown in color, and thus particle size alone is not a unique driver of remineralization rates. Sinking fecal pellets collected from the ocean, including those of krill, tend to be brown or white depending on diet (Wassmann et al, 1994;Werner, 2000;Wilson et al, 2008), with whiter pellets being from those feeding on detrital food sources which are less nutritious. In our aquaria setting at the AAD, the krill only ever produce green or brown pellets.…”

Section: Discussionmentioning

confidence: 99%

Implications for the mesopelagic microbial gardening hypothesis as determined by experimental fragmentation of Antarctic krill fecal pellets

Cavan

Kawaguchi

Boyd

2020

Ecology and Evolution

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“…Some small taxa reside in the ice matrix (e.g., Nematoda, Acoela, Harpacticoida, Rotifera, Bluhm et al, 2018), while others, such as amphipods, use the bottom of the sea ice as a hard substrate and are important consumers of ice algae (abundances: few individuals to >500 ind. m −2 ) (Hop et al, 2000;Werner, 2000;Gradinger and Bluhm, 2004;David et al, 2017). In addition, analyses of lipids and isotopes showed that pelagic grazers, such as Calanus glacialis and C. hyperboreus also graze to a considerable extent on sea ice algae (Kohlbach et al, 2016).…”

Section: Abundance and Carbon Demand Of Under-ice Fauna And Zooplanktonmentioning

confidence: 99%

What Feeds the Benthos in the Arctic Basins? Assembling a Carbon Budget for the Deep Arctic Ocean

et al. 2020

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Half of the Arctic Ocean is deep sea (>1000 m), and this area is currently transitioning from being permanently ice-covered to being seasonally ice-free. Despite these drastic changes, it remains unclear how organisms are distributed in the deep Arctic basins, and particularly what feeds them. Here, we summarize data on auto-and heterotrophic organisms in the benthic, pelagic, and sympagic realm of the Arctic Ocean basins from the past three decades and put together an organic carbon budget for this region. Based on the budget, we investigate whether our current understanding of primary and secondary production and vertical carbon flux are balanced by the current estimates of the carbon demand by deep-sea benthos. At first glance, our budget identifies a mismatch between the carbon supply by primary production (3-46 g C m −2 yr −1), the carbon demand of organisms living in the pelagic (7-17 g C m −2) and the benthic realm (< 5 g C m −2 yr −1) versus the low vertical carbon export (at 200 m: 0.1-1.5 g C m −2 yr −1 , at 3000-4000 m: 0.01-0.73 g C m −2 yr −1). To close the budget, we suggest that episodic events of large, fast sinking ice algae aggregates, export of dead zooplankton, as well as large food falls need to be quantified and included. This work emphasizes the clear need for a better understanding of the quantity, phenology, and the regionality of carbon supply and demand in the deep Arctic basins, which will allow us to evaluate how the ecosystem may change in the future.

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Cited by 22 publications

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Algal Hot Spots in a Changing Arctic Ocean: Sea-Ice Ridges and the Snow-Ice Interface

Algal Hot Spots in a Changing Arctic Ocean: Sea-Ice Ridges and the Snow-Ice Interface

Implications for the mesopelagic microbial gardening hypothesis as determined by experimental fragmentation of Antarctic krill fecal pellets

What Feeds the Benthos in the Arctic Basins? Assembling a Carbon Budget for the Deep Arctic Ocean

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