Sea ice microbial communities. VII. Changes in under-ice spectral irradiance during the development of Antarctic sea ice microalgal communities

Palmisano, AC; SooHoo, JB; Moe, RL; Sullivan, Cornelius W.

doi:10.3354/meps035165

Cited by 87 publications

(40 citation statements)

References 11 publications

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“…Strong inverse relationships between snow cover thickness and ice algal biomass have been reported from both Antarctic and Arctic fast ice habitats in previous studies (e.g. Palmisano et al 1987, Mundy et al 2007). We interpret the lack of correlation between snow cover and ice algal biomass in our pack ice dataset to be a result of high snow cover dynamics in the Weddell Sea and East Antarctica, i.e.…”

Section: Discussionmentioning

confidence: 90%

Algorithms to estimate Antarctic sea ice algal biomass from under-ice irradiance spectra at regional scales

Melbourne-Thomas¹,

Meiners²,

Mundy³

et al. 2015

Mar. Ecol. Prog. Ser.

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The presence of algal pigments in sea ice alters under-ice irradiance spectra, and the relationship between these variables can be used as a non-invasive means for estimating iceassociated algal biomass on ecologically relevant spatial and temporal scales. While the influence of snow cover and ice algal biomass on spectra transmitted through the snow-ice matrix has been examined for the Arctic, it has not been tested for Antarctic sea ice at regional scales. We used paired measurements of sea ice core chl a concentrations and hyperspectral-transmitted under-ice irradiances from 59 sites sampled off East Antarctica and in the Weddell Sea to develop algorithms for estimating algal biomass in Antarctic pack ice. We compared 4 approaches that have been used in various bio-optical studies for marine systems: normalised difference indices, ratios of spectral irradiance, scaled band area and empirical orthogonal functions. The percentage of variance explained by these models ranged from 38 to 79%, with the best-performing approach being normalised difference indices. Given the low concentrations of integrated chl a observed in our study compared with previous studies, our statistical models performed surprisingly well in explaining variability in these concentrations. Our findings provide a basis for future work to develop methods for non-invasive time series measurements and medium-to large-scale spatial mapping of Antarctic ice algal biomass using instrumented underwater vehicles.KEY WORDS: Sea ice algae · Chl a · Bio-optics · Normalised difference index · Weddell Sea · East Antarctica Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 536: [107][108][109][110][111][112][113][114][115][116][117][118][119][120][121] 2015 ice coring (Meiners et al. 2012). Recent circumpolar estimates of ice algal biomass for Antarctica are limited to records from historical ice core data that are unevenly distributed in space and time (Meiners et al. 2012) and model-based estimates that may underestimate internal communities (Saenz & Arrigo 2014). Improved in situ data on temporal and spatial patterns of ice algal biomass distribution are needed for quantitative evaluation of sea ice primary production models and an improved understanding of the role of ice algae in Antarctic marine ecosystem function.Antarctic pack ice provides a habitat for iceassociated algae, which form distinct surface, interior and bottom communities (Arrigo et al. 2010, Meiners et al. 2012. Surface communities are promoted by snow loading, surface flooding by seawater and brine, and subsequent snow-ice formation (Ackley et al. 2008). Interior communities can form either through the rafting and ridging of ice floes or by scavenging of phytoplankton during ice formation (i.e. the uptake of algal cells from the water column as ice crystals form; Arrigo et al. 2010). Bottom communities thrive in the lowermost porous parts of sea ice floes, where brine salinities and high nutrient availability favour algal gr...

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Section: Discussionmentioning

confidence: 90%

Algorithms to estimate Antarctic sea ice algal biomass from under-ice irradiance spectra at regional scales

Melbourne-Thomas¹,

Meiners²,

Mundy³

et al. 2015

Mar. Ecol. Prog. Ser.

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“…Ice ablation in spring and autumn resulted in strong horizontal gradients and reduced vertical mixing seaward of the ice edge, conditions which persisted even after the ice edge became stationary (Nelson et al 1989). Furthermore, removal of snow and ice cover significantly increased the photic zone depth (Palmisano et al 1987). Thus spring and autumn were seasons during which ice melt and longer photoperiod dramatically improved the irradiance regime seaward of the ice edge.…”

Section: Seasonal Mesoscale Spatial Zonationmentioning

confidence: 90%

“…Also, due to the wide longitudinal spacing of the cover about 20 million km2 of the Southern Ocean in transects, it was unclear i f the Scotia Front was a conwinter (Zwally et al 1983), and attenuate about 99% of tinuous east-west feature at this tlme. incident irradiance (Palmisano et al 1987). The influThe study region was dominated by mesoscale ence of ice coverage on photosynthetic organisms was eddies and/or meanders, typically anticyclonic warm demonstrated by significantly lower chl a standing core features.…”

Section: Hydrographymentioning

confidence: 99%

“…Total daily irradiances and oblique sun angle limit both the irradiance and photoperiod within the water column (Kirk 1983, Sakshaug & Holm-Hansen 1984. Ice cover, which is at its seasonal maximum, diminishes wind driven mixing (Carmack 1986), alters the heat flux out of the ocean (Maykut 1986), and has a high albedo that limits available irradiance and alters its spectral quality in the underlying waters (Maykut & Grenfell 1975, Palmisano et al 1987, Arrigo et al 1991. These factors are expected to have a profound seasonal influence on microbial rates and processes both in open-water and in the water column underneath the ice.…”

Section: Introductionmentioning

confidence: 99%

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Spatial distribution of bacterioplankton biomass and production in the marginal ice-edge zone of the Weddell-Scotia Sea during austral winter

Cw¹,

Dm²,

Cw³

1995

Mar. Ecol. Prog. Ser.

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Recent investigations in the marginal ice-edge zone (MIZ) of the western Weddell and Scotia Seas revealed similar distributions of primary and microbial production in spring and autumn. Yet, little is known about the distributions of bacterial biomass and production in winter, and how these distributions may be influenced by local physical oceanographic features or interrelated to other chemical and biological distributions in the M1Z. To help elucidate the ecological and biogeochemical significance of bacterial production in winter, we examined the distributions of bacterial biomass and production in the MIZ of the Weddell-Scotia Sea in austral w~nter 1988 as part of the Antarctic Marine Ecosystem Research at the Ice-edge Zone (AMERIEZ) program. Measurements were made along 3 rapid transects providing a synoptic view of the MIZ. Transects were oriented normal to the ice edge with stations extending up to 100 km into the pack and several hundred km seaward of the ice edge. Winter distributions of bacterial biomass and production were more closely related to local hydrography than to microalgal distributions or the proximity of the ice edge Bacterial characteristics were highest within or in the proximity of warm-core eddies, enrichments which may have resulted from prior ice melt or from advection of more productive waters. Microalgal characteristics and bacterial production were at their seasonal minimum during the winter cruise; however, bacterial biomass was essentially invariant seasonally and was not as greatly influenced by the location of the ice edge as previously demonstrated for phytoplankton. Sirmlar reports for micrograzers suggest that steady-state conditions apply to much of the microbial food web throughout the year. Bacterial production did not dominate ammonium remineralization processes in winter; instead, ammonium maxima under the ice and near the ice edge were attributed to protozooplankton and higher trophic organisms.

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“…Surface communities are most often associated with thin ice (<0.4 m) (Meiners et al, 2012) and as such, could become more prominent in the future. Increased albedo caused by greater snow cover on the ice would also limit light transmission through the ice, reducing ice algal productivity in internal and bottom communities (Grossi et al, 1987;Palmisano et al, 1987).…”

Section: Seasonal Sea Ice Zonementioning

confidence: 99%

Southern Ocean Phytoplankton in a Changing Climate

2017

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Phytoplankton are the base of the Antarctic food web, sustain the wealth and diversity of life for which Antarctica is renowned, and play a critical role in biogeochemical cycles that mediate global climate. Over the vast expanse of the Southern Ocean (SO), the climate is variously predicted to experience increased warming, strengthening wind, acidification, shallowing mixed layer depths, increased light (and UV), changes in upwelling and nutrient replenishment, declining sea ice, reduced salinity, and the southward migration of ocean fronts. These changes are expected to alter the structure and function of phytoplankton communities in the SO. The diverse environments contained within the vast expanse of the SO will be impacted differently by climate change; causing the identity and the magnitude of environmental factors driving biotic change to vary within and among bioregions. Predicting the net effect of multiple climate-induced stressors over a range of environments is complex. Yet understanding the response of SO phytoplankton to climate change is vital if we are to predict the future state/s of the ecosystem, estimate the impacts on fisheries and endangered species, and accurately predict the effects of physical and biotic change in the SO on global climate. This review looks at the major environmental factors that define the structure and function of phytoplankton communities in the SO, examines the forecast changes in the SO environment, predicts the likely effect of these changes on phytoplankton, and considers the ramifications for trophodynamics and feedbacks to global climate change. Predictions strongly suggest that all regions of the SO will experience changes in phytoplankton productivity and community composition with climate change. The nature, and even the sign, of these changes varies within and among regions and will depend upon the magnitude and sequence in which these environmental changes are imposed. It is likely that predicted changes to phytoplankton communities will affect SO biogeochemistry, carbon export, and nutrition for higher trophic levels.

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Sea ice microbial communities. VII. Changes in under-ice spectral irradiance during the development of Antarctic sea ice microalgal communities

Cited by 87 publications

References 11 publications

Algorithms to estimate Antarctic sea ice algal biomass from under-ice irradiance spectra at regional scales

Algorithms to estimate Antarctic sea ice algal biomass from under-ice irradiance spectra at regional scales

Spatial distribution of bacterioplankton biomass and production in the marginal ice-edge zone of the Weddell-Scotia Sea during austral winter

Southern Ocean Phytoplankton in a Changing Climate

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