Diatom vertical migration within land-fast Arctic sea ice

Aumack, CF; Juhl, Andrew R.; Krembs, Christopher

doi:10.1016/j.jmarsys.2014.08.013

Cited by 36 publications

(27 citation statements)

References 71 publications

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“…We hypothesize that internal communities in undeformed sea ice with low snow cover form as a result of rapid bottom‐ice accretion. In this case the ice algal community cannot reposition to the ice‐water interface through vertical migration (Aumack et al, ) and gets trapped in sea ice interior layers. On the other hand, in snow‐covered sea ice, surface flooding inducing warm and permeable conditions is an alternative mechanism for the establishment of internal Chl a maxima (e.g., Meiners et al, ; Tison, Schwegmann, et al, ).…”

Section: Discussionmentioning

confidence: 99%

Chlorophyll‐a in Antarctic Landfast Sea Ice: A First Synthesis of Historical Ice Core Data

et al. 2018

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Historical sea ice core chlorophyll‐a (Chla) data are used to describe the seasonal, regional, and vertical distribution of ice algal biomass in Antarctic landfast sea ice. The analyses are based on the Antarctic Fast Ice Algae Chlorophyll‐a data set, a compilation of currently available sea ice Chla data from landfast sea ice cores collected at circum‐Antarctic nearshore locations between 1970 and 2015. Ice cores were typically sampled from thermodynamically grown first‐year ice and have thin snow depths (mean = 0.052 ± 0.097 m). The data set comprises 888 ice cores, including 404 full vertical profile cores. Integrated ice algal Chla biomass (range: <0.1–219.9 mg/m2, median = 4.4 mg/m2, interquartile range = 9.9 mg/m2) peaks in late spring and shows elevated levels in autumn. The seasonal Chla development is consistent with the current understanding of physical drivers of ice algal biomass, including the seasonal cycle of irradiance and surface temperatures driving landfast sea ice growth and melt. Landfast ice regions with reported platelet ice formation show maximum ice algal biomass. Ice algal communities in the lowermost third of the ice cores dominate integrated Chla concentrations during most of the year, but internal and surface communities are important, particularly in winter. Through comparison of biomass estimates based on different sea ice sampling strategies, that is, analysis of full cores versus bottom‐ice section sampling, we identify biases in common sampling approaches and provide recommendations for future survey programs: for example, the need to sample fast ice over its entire thickness and to measure auxiliary physicochemical parameters.

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Section: Discussionmentioning

confidence: 99%

Chlorophyll‐a in Antarctic Landfast Sea Ice: A First Synthesis of Historical Ice Core Data

et al. 2018

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“…frigida can actively move inside brine channels. It has been demonstrated that a community of unidentified pennate sea ice diatoms was able to reposition themselves inside the ice [ Aumack et al ., ]. Another possible mechanism is passive transport during brine drainage events as discussed above.…”

Section: Discussionmentioning

confidence: 99%

The seeding of ice algal blooms in Arctic pack ice: The multiyear ice seed repository hypothesis

Olsen

Laney

Duarte

et al. 2017

J. Geophys. Res. Biogeosci.

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During the Norwegian young sea ICE expedition (N‐ICE2015) from January to June 2015 the pack ice in the Arctic Ocean north of Svalbard was studied during four drifts between 83° and 80°N. This pack ice consisted of a mix of second year, first year, and young ice. The physical properties and ice algal community composition was investigated in the three different ice types during the winter‐spring‐summer transition. Our results indicate that algae remaining in sea ice that survived the summer melt season are subsequently trapped in the upper layers of the ice column during winter and may function as an algal seed repository. Once the connectivity in the entire ice column is established, as a result of temperature‐driven increase in ice porosity during spring, algae in the upper parts of the ice are able to migrate toward the bottom and initiate the ice algal spring bloom. Furthermore, this algal repository might seed the bloom in younger ice formed in adjacent leads. This mechanism was studied in detail for the dominant ice diatom Nitzschia frigida. The proposed seeding mechanism may be compromised due to the disappearance of older ice in the anticipated regime shift toward a seasonally ice‐free Arctic Ocean.

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“…Motility may be an adaptation to optimize between vertically opposing factors, such as light and nutrients, as has been suggested for some microphytobenthic diatoms [Saburova and Polikarpov, 2003]. In the present study ice algal motility was implemented in CICE based on two different paradigms: (i) assuming that vertical motion is purely random but with a realistic velocity (default value used in CICE is 4.3 cm d À1 , within the velocity ranges reported in Aumack et al [2014]), implying that ice algae may move up or down independent of any environmental gradients ("neutral model") and (ii) assuming that algae move toward the closest best conditions that minimize the impact of all limiting factors considered (light intensity, temperature, nitrate, and silicic acid concentrations), with the same velocity mentioned before ("deterministic model"). Therefore, if the minimum of all limiting factors is higher (closer to one) in a layer above or below the current layer, part of the algae migrates toward the "better" layer following an upwind scheme.…”

Section: Model Concepts and Approachesmentioning

confidence: 99%

Sea ice thermohaline dynamics and biogeochemistry in the Arctic Ocean: Empirical and model results

Duarte

Meyer

Olsen

et al. 2017

J. Geophys. Res. Biogeosci.

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Large changes in the sea ice regime of the Arctic Ocean have occurred over the last decades justifying the development of models to forecast sea ice physics and biogeochemistry. The main goal of this study is to evaluate the performance of the Los Alamos Sea Ice Model (CICE) to simulate physical and biogeochemical properties at time scales of a few weeks and to use the model to analyze ice algal bloom dynamics in different types of ice. Ocean and atmospheric forcing data and observations of the evolution of the sea ice properties collected from 18 April to 4 June 2015, during the Norwegian young sea ICE expedition, were used to test the CICE model. Our results show the following: (i) model performance is reasonable for sea ice thickness and bulk salinity; good for vertically resolved temperature, vertically averaged Chl a concentrations, and standing stocks; and poor for vertically resolved Chl a concentrations. (ii) Improving current knowledge about nutrient exchanges, ice algal recruitment, and motion is critical to improve sea ice biogeochemical modeling. (iii) Ice algae may bloom despite some degree of basal melting. (iv) Ice algal motility driven by gradients in limiting factors is a plausible mechanism to explain their vertical distribution. (v) Different ice algal bloom and net primary production (NPP) patterns were identified in the ice types studied, suggesting that ice algal maximal growth rates will increase, while sea ice vertically integrated NPP and biomass will decrease as a result of the predictable increase in the area covered by refrozen leads in the Arctic Ocean.

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Diatom vertical migration within land-fast Arctic sea ice

Cited by 36 publications

References 71 publications

Chlorophyll‐a in Antarctic Landfast Sea Ice: A First Synthesis of Historical Ice Core Data

Chlorophyll‐a in Antarctic Landfast Sea Ice: A First Synthesis of Historical Ice Core Data

The seeding of ice algal blooms in Arctic pack ice: The multiyear ice seed repository hypothesis

Sea ice thermohaline dynamics and biogeochemistry in the Arctic Ocean: Empirical and model results

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