scholarly journals Photosynthetic production in the Central Arctic during the record sea-ice minimum in 2012

2015 ◽  
Vol 12 (3) ◽  
pp. 2897-2945 ◽  
Author(s):  
M. Fernández-Méndez ◽  
C. Katlein ◽  
B. Rabe ◽  
M. Nicolaus ◽  
I. Peeken ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Water Column ◽  
Primary Productivity ◽  
Ice Cover ◽  
Annual Production ◽  
Ice Algae ◽  
Central Arctic Ocean ◽  
Eurasian Basin

Abstract. The ice-covered Central Arctic Ocean is characterized by low primary productivity due to light and nutrient limitations. The recent reduction in ice cover has the potential to substantially increase phytoplankton primary production, but little is yet known about the fate of the ice-associated primary production and of the nutrient supply with increasing warming. This study presents results from the Central Arctic Ocean collected during summer 2012, when sea-ice reached a minimum extent since the onset of satellite observations. Net primary productivity (NPP) was measured in the water column, sea ice and melt ponds by 14CO2 uptake at different irradiances. Photosynthesis vs. irradiance (PI) curves were established in laboratory experiments and used to upscale measured NPP to the deep Eurasian Basin (north of 78° N) using the irradiance-based Central Arctic Ocean Primary Productivity (CAOPP) model. In addition, new annual production was calculated from the seasonal nutrient drawdown in the mixed layer since last winter. Results show that ice algae can contribute up to 60% to primary production in the Central Arctic at the end of the season. The ice-covered water column has lower NPP rates than open water due to light limitation. As indicated by the nutrient ratios in the euphotic zone, nitrate was limiting primary production in the deep Eurasian Basin close to the Laptev Sea area, while silicate was the main limiting nutrient at the ice margin near the Atlantic inflow. Although sea-ice cover was substantially reduced in 2012, total annual new production in the Eurasian Basin was 17 ± 7 Tg C yr-1, which is within the range of estimates of previous years. However, when adding the contribution by sub-ice algae, the annual production for the deep Eurasian Basin (north of 78° N) could double previous estimates for that area with a surplus of 16 Tg C yr-1. Our data suggest that sub-ice algae are an important component of the ice-covered Central Arctic productivity. It remains an important question if their contribution to productivity is on the rise with thinning ice, or if it will decline due to overall sea-ice retreat and be replaced by phytoplankton.

scholarly journals Photosynthetic production in the central Arctic Ocean during the record sea-ice minimum in 2012

2015 ◽  
Vol 12 (11) ◽  
pp. 3525-3549 ◽  
Author(s):  
M. Fernández-Méndez ◽  
C. Katlein ◽  
B. Rabe ◽  
M. Nicolaus ◽  
I. Peeken ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Water Column ◽  
Primary Productivity ◽  
Ice Cover ◽  
Annual Production ◽  
Ice Algae ◽  
Central Arctic Ocean ◽  
Eurasian Basin

Abstract. The ice-covered central Arctic Ocean is characterized by low primary productivity due to light and nutrient limitations. The recent reduction in ice cover has the potential to substantially increase phytoplankton primary production, but little is yet known about the fate of the ice-associated primary production and of the nutrient supply with increasing warming. This study presents results from the central Arctic Ocean collected during summer 2012, when sea-ice extent reached its lowest ever recorded since the onset of satellite observations. Net primary productivity (NPP) was measured in the water column, sea ice and melt ponds by 14CO2 uptake at different irradiances. Photosynthesis vs. irradiance (PI) curves were established in laboratory experiments and used to upscale measured NPP to the deep Eurasian Basin (north of 78° N) using the irradiance-based Central Arctic Ocean Primary Productivity (CAOPP) model. In addition, new annual production has been calculated from the seasonal nutrient drawdown in the mixed layer since last winter. Results show that ice algae can contribute up to 60% to primary production in the central Arctic Ocean at the end of the productive season (August–September). The ice-covered water column has lower NPP rates than open water due to light limitation in late summer. As indicated by the nutrient ratios in the euphotic zone, nitrate was limiting primary production in the deep Eurasian Basin close to the Laptev Sea area, while silicate was the main limiting nutrient at the ice margin near the Atlantic inflow. Although sea-ice cover was substantially reduced in 2012, total annual new production in the Eurasian Basin was 17 ± 7 Tg C yr−1, which is within the range of estimates of previous years. However, when adding the contribution by sub-ice algae, the annual production for the deep Eurasian Basin (north of 78° N) could double previous estimates for that area with a surplus of 16 Tg C yr−1. Our data suggest that sub-ice algae are an important component of the productivity in the ice-covered Eurasian Basin of the central Arctic Ocean. It remains an important question whether their contribution to productivity is on the rise with thinning ice, or whether it will decline due to overall sea-ice retreat and be replaced by phytoplankton.

scholarly journals Contrasting trends in sea ice and primary production in the Bering Sea and Arctic Ocean

2012 ◽  
Vol 69 (7) ◽  
pp. 1180-1193 ◽  
Author(s):  
Zachary W. Brown ◽  
Kevin R. Arrigo
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Bering Sea ◽  
Net Primary Productivity ◽  
Remote Sensing Data ◽  
Ice Cover ◽  
The Arctic ◽  
Light Limitation ◽  
The Bering Sea

Abstract Brown, Z. W., and Arrigo, K. R. 2012. Contrasting trends in sea ice and primary production in the Bering Sea and Arctic Ocean. – ICES Journal of Marine Science, 69: . Satellite remote sensing data were used to examine recent trends in sea-ice cover and net primary productivity (NPP) in the Bering Sea and Arctic Ocean. In nearly all regions, diminished sea-ice cover significantly enhanced annual NPP, indicating that light-limitation predominates across the seasonally ice-covered waters of the northern hemisphere. However, long-term trends have not been uniform spatially. The seasonal ice pack of the Bering Sea has remained consistent over time, partially because of winter winds that have continued to carry frigid Arctic air southwards over the past six decades. Hence, apart from the “Arctic-like” Chirikov Basin (where sea-ice loss has driven a 30% increase in NPP), no secular trends are evident in Bering Sea NPP, which averaged 288 ± 26 Tg C year−1 over the satellite ocean colour record (1998–2009). Conversely, sea-ice cover in the Arctic Ocean has plummeted, extending the open-water growing season by 45 d in just 12 years, and promoting a 20% increase in NPP (range 441–585 Tg C year−1). Future sea-ice loss will likely stimulate additional NPP over the productive Bering Sea shelves, potentially reducing nutrient flux to the downstream western Arctic Ocean.

An Improved Chamber for in situ Measurement of Primary Productivity by Sea Ice Algae

1982 ◽  
Vol 39 (3) ◽  
pp. 522-524 ◽  
Author(s):  
G. C. Schrader ◽  
R. Horner ◽  
G. F. Smith
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Primary Productivity ◽  
In Situ Measurement ◽  
Carbon Uptake ◽  
Ice Algae ◽  
Sea Ice Algae ◽  
Scuba Divers ◽  
Ice Conditions

A modified chamber was designed for in situ measurement of carbon uptake of micro-algae growing on the underside of sea ice. The chamber, operated by SCUBA divers, accommodates a wider range of ice conditions, has better holding capability, and reduces sample loss during retrieval.Key words: Arctic Ocean, sea ice algae, primary productivity

scholarly journals Ice-Associated Amphipods in a Pan-Arctic Scenario of Declining Sea Ice

2021 ◽  
Vol 8 ◽  
Author(s):  
Haakon Hop ◽  
Mikko Vihtakari ◽  
Bodil A. Bluhm ◽  
Malin Daase ◽  
Rolf Gradinger ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Time Span ◽  
The Arctic ◽  
Ice Algae ◽  
Central Arctic Ocean ◽  
Ice Drift ◽  
Landfast Ice ◽  
Landfast Sea Ice ◽  
Important Habitat

Sea-ice macrofauna includes ice amphipods and benthic amphipods, as well as mysids. Amphipods are important components of the sympagic food web, which is fuelled by the production of ice algae. Data on the diversity of sea-ice biota have been collected as a part of scientific expeditions over decades, and here we present a pan-Arctic analysis of data on ice-associated amphipods and mysids assimilated over 35 years (1977–2012). The composition of species differed among the 13 locations around the Arctic, with main differences between basins and shelves and also between communities in drift ice and landfast sea ice. The sea ice has been dramatically reduced in extent and thickness during the recorded period, which has resulted in reduced abundance of ice amphipods as well as benthic amphipods in sea ice from the 1980’s to the 2010’s. The decline mainly involved Gammarus wilkitzkii coinciding with the disappearance of much of the multiyear sea ice, which is an important habitat for this long-lived species. Benthic amphipods were most diverse, and also showed a decline over the time-span. They had higher abundance closer to land where they are associated with landfast ice. However, they also occurred in the Central Arctic Ocean, which is likely related to the origin of sea ice over shallow water and subsequent transport in the transpolar ice drift. Recent sampling in the waters east and north of Svalbard has found continued presence of Apherusa glacialis, but almost no G. wilkitzkii. Monitoring by standardized methods is needed to detect further changes in community composition of ice amphipods related to reductions in sea-ice cover and ice type.

Holocene variability in sea ice cover, primary production, and Pacific-Water inflow and climate change in the Chukchi and East Siberian Seas (Arctic Ocean)

2017 ◽  
Vol 32 (3) ◽  
pp. 362-379 ◽  
Author(s):  
Ruediger Stein ◽  
Kirsten Fahl ◽  
Inka Schade ◽  
Adelina Manerung ◽  
Saskia Wassmuth ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Ice Cover ◽  
Water Inflow ◽  
Pacific Water

scholarly journals Ice-Tethered Profiler Measurements of Dissolved Oxygen under Permanent Ice Cover in the Arctic Ocean

2010 ◽  
Vol 27 (11) ◽  
pp. 1936-1949 ◽  
Author(s):  
M.-L. Timmermans ◽  
R. Krishfield ◽  
S. Laney ◽  
J. Toole
Keyword(s):  
Sea Ice ◽  
Dissolved Oxygen ◽  
Arctic Ocean ◽  
Water Column ◽  
Ocean Circulation ◽  
Oxygen Sensor ◽  
Ice Cover ◽  
The Arctic ◽  
Surface Mixed Layer ◽  
The Arctic Ocean

Abstract Four ice-tethered profilers (ITPs), deployed between 2006 and 2009, have provided year-round dissolved oxygen (DO) measurements from the surface mixed layer to 760-m depth under the permanent sea ice cover in the Arctic Ocean. These ITPs drifted with the permanent ice pack and returned 2 one-way profiles per day of temperature, salinity, and DO. Long-term calibration drift of the oxygen sensor can be characterized and removed by referencing to recently calibrated ship DO observations on deep isotherms. Observed changes in the water column time series are due to both drift of the ITP into different water masses and seasonal variability, driven by both physical and biological processes within the water column. Several scientific examples are highlighted that demonstrate the considerable potential for sustained ITP-based DO measurements to better understand the Arctic Ocean circulation patterns and biogeochemical processes beneath the sea ice.

scholarly journals Recent Arctic Ocean Surface Air Temperatures in Atmospheric Reanalyses and Numerical Simulations

2020 ◽  
Vol 33 (10) ◽  
pp. 4347-4367
Author(s):  
Allison B. Marquardt Collow ◽  
Richard I. Cullather ◽  
Michael G. Bosilovich
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Ice Cover ◽  
The Arctic ◽  
Central Arctic Ocean ◽  
Mean Values ◽  
Weather Forecasts ◽  
Air Temperatures ◽  
Autumn And Winter

AbstractSurface air temperatures have recently increased more rapidly in the Arctic than elsewhere in the world, but large uncertainty remains in the time series and trend. Over the data-sparse sea ice zone, the retrospective assimilation of observations in numerical reanalyses has been thought to offer a possible, but challenging, avenue for adequately reproducing the historical time series. Focusing on the central Arctic Ocean, output is analyzed from 12 reanalyses with a specific consideration of two widely used products: the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), and the European Centre for Medium-Range Weather Forecasts interim reanalysis (ERA-Interim, hereafter ERA-I). Among the reanalyses considered, a trend of 0.9 K decade−1 is indicated but with an uncertainty of 6%, and a large spread in mean values. There is a partitioning among those reanalyses that use fractional sea ice cover and those that employ a threshold, which are colder in winter by an average of 2 K but agree more closely with in situ observations. For reanalyses using fractional sea ice cover, discrepancies in the ice fraction in autumn and winter explain most of the differences in air temperature values. A set of experiments using the MERRA-2 background model using MERRA-2 and ERA-I sea ice and sea surface temperature indicates significant effects of boundary condition differences on air temperatures, and a preferential warm bias inherent in the MERRA-2 model sea ice representation. Differences between experiments and reanalyses suggest the available observations apply a significant constraint on reanalysis mean temperatures.

scholarly journals Diazotroph Diversity in the Sea Ice, Melt Ponds, and Surface Waters of the Eurasian Basin of the Central Arctic Ocean

2016 ◽  
Vol 7 ◽  
Author(s):  
Mar Fernández-Méndez ◽  
Kendra A. Turk-Kubo ◽  
Pier L. Buttigieg ◽  
Josephine Z. Rapp ◽  
Thomas Krumpen ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Surface Waters ◽  
Central Arctic Ocean ◽  
Ice Melt ◽  
Melt Ponds ◽  
Eurasian Basin
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