Three-year assessment of particulate organic carbon fluxes in Amundsen Gulf (Beaufort Sea): Satellite observations and sediment trap measurements

Forest, Alexandre; Bélanger, Simon; Sampei, Makoto; Sasaki, Hiroshi; Lalande, Catherine; Fortier, Louis

doi:10.1016/j.dsr.2009.10.002

Cited by 49 publications

(53 citation statements)

References 70 publications

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“…Here we found that ciliate and dinoflagellate taxa showed distinct seasonal patterns that could be partially explained by salinity, temperature, and nutrient changes from winter to summer (Figure 4). Specifically, the proportion of ciliate reads were generally higher under ice free conditions, when the surface waters were less saline and at the end of the spring bloom when nitrate concentrations were drawn down by photosynthetic activity (Forest et al, 2010;Tremblay et al, 2011). Although many ciliates have a wide range of salinity tolerance (Montagnes, 1996), this has not been investigated for Arctic species.…”

Section: Environmental Influences On Microzooplanktonmentioning

confidence: 99%

Seasonal and Interannual Changes in Ciliate and Dinoflagellate Species Assemblages in the Arctic Ocean (Amundsen Gulf, Beaufort Sea, Canada)

et al. 2017

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Recent studies have focused on how climate change could drive changes in phytoplankton communities in the Arctic. In contrast, ciliates and dinoflagellates that can contribute substantially to the mortality of phytoplankton have received less attention. Some dinoflagellate and ciliate species can also contribute to net photosynthesis, which suggests that species composition could reflect food web complexity. To identify potential seasonal and annual species occurrence patterns and to link species with environmental conditions, we first examined the seasonal pattern of microzooplankton and then performed an in-depth analysis of interannual species variability. We used high-throughput amplicon sequencing to identify ciliates and dinoflagellates to the lowest taxonomic level using a curated Arctic 18S rRNA gene database. DNA-and RNA-derived reads were generated from samples collected from the Canadian Arctic from November 2007 to July 2008. The proportion of ciliate reads increased in the surface toward summer, when salinity was lower and smaller phytoplankton prey were abundant, while chloroplastidic dinoflagellate species increased at the subsurface chlorophyll maxima (SCM), where inorganic nutrient concentrations were higher. Comparing communities collected in summer and fall from 2003 to 2010, we found that microzooplankton community composition change was associated with the record ice minimum in the summer of 2007. Specifically, reads from smaller predatory species like Laboea, Monodinium, and Strombidium and several unclassified ciliates increased in the summer after 2007, while the other usually summer-dominant dinoflagellate taxa decreased. The ability to exploit smaller prey, which are predicted to dominate the future Arctic, could be an advantage for these smaller ciliates in the wake of the changing climate.

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Section: Environmental Influences On Microzooplanktonmentioning

confidence: 99%

Seasonal and Interannual Changes in Ciliate and Dinoflagellate Species Assemblages in the Arctic Ocean (Amundsen Gulf, Beaufort Sea, Canada)

et al. 2017

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“…The filters were dried at 60°C for 24 h aboard the ship and analyzed in the laboratory on a Costech ECS 4010 CHN analyzer without prior acidification of the sample. Recent studies in our study area showed that particulate organic carbon (POC) represents [90% of PC concentrations in surface waters and particle interceptor traps Forest et al 2010). Therefore, we refer to POC concentrations throughout the manuscript.…”

Section: Particle Interceptor Trapsmentioning

confidence: 99%

“…The annual cycle of primary production Brugel et al 2009) and sinking export of organic material (Forest et al 2010;Juul-Pedersen et al 2010) in Table 3 Primary production and chlorophyll a (chl a) biomass integrated over the euphotic zone, daily loss rates of chl a, and particulate organic carbon (POC) at 100 m and particulate primary production exported through sinking (export ratio) Gosselin et al 2008). Upwelling events in spring-summer 2008 (Mundy et al 2009; Jean-É ric Tremblay, Laval University, pers.…”

Section: Changes Observed In Summer 2008mentioning

confidence: 99%

Summertime primary production and carbon export in the southeastern Beaufort Sea during the low ice year of 2008

2011

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Following the extreme low ice year of 2007, primary production and the sinking export of particulate and gel-like organic material, using short-term particle interceptor traps deployed at 100 m, were measured in the southeastern Beaufort Sea during summer 2008. The combined influence of early ice retreat and coastal upwelling contributed to exceptionally high primary production (500 ± 312 mg C m -2 day -1 , n = 7), dominated by large cells ([5 lm, 73% ± 15%, n = 7). However, except for one station located north of Cape Bathurst, the sinking export of particulate organic carbon (POC) was relatively low (range: 38-104 mg C m -2 day -1 , n = 12) compared to other productive Arctic shelves. Estimates indicate that 80% ± 20% of the primary production was cycled through large copepods or the microbial food web. Exopolymeric substances were abundant in the sinking material but did not appear to accelerate POC sinking export. The use of isotopic signatures (d 13 C, d 15 N) and carbon/nitrogen ratios to identify sources of the sinking material was successful only at two stations with a strong marine or terrestrial signature, indicating the limitations of this approach in hydrographically and biologically complex Arctic coastal waters such as in the Beaufort Sea. At these two stations influenced by either coastal upwelling or erosion, the composition and magnitude of particulate sinking fluxes were markedly different from other stations visited during the study. These observations underscore the fundamental role of mesoscale circulation patterns and hydrodynamic singularities on the export of particulate organic material on Arctic shelves.

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“…Wassmann et al (2011) highlighted that climate change has already resulted in clearly discernable changes in marine Arctic ecosystems, but the number of well-documented changes in planktonic and benthic systems was surprisingly low. Although total primary production in the Arctic Ocean will likely increase (Arrigo et al 2008), its reduced seasonal variability and increased pelagic remineralisation might result in a general decrease in the vertical flux of fresh organic matter to the bottom (Piepenburg 2005;Forest et al 2010;. There is still controversy about the actual scope and direction of future changes in primary production and vertical flux patterns (Wassmann et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Spring-to-summer changes and regional variability of benthic processes in the western Canadian Arctic

et al. 2011

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Seasonal dynamics in the activity of Arctic shelf benthos have been the subject of few local studies, and the pronounced among-site variability characterizing their results makes it difficult to upscale and generalize their conclusions. In a regional study encompassing five sites at 100-595 m water depth in the southeastern Beaufort Sea, we found that total pigment concentrations in surficial sediments, used as proxies of general food supply to the benthos, rose significantly after the transition from ice-covered conditions in spring (March-June 2008) to open-water conditions in summer (June-August 2008), whereas sediment Chl a concentrations, typical markers of fresh food input, did not. Macrobenthic biomass (including agglutinated foraminifera [500 lm) varied significantly among sites (1.2-6.4 g C m -2 in spring, 1.1-12.6 g C m -2 in summer), whereas a general spring-to-summer increase was not detected. Benthic carbon remineralisation also ranged significantly among sites (11.9-33.2 mg C m -2 day -1 in spring, 11.6-44.4 mg C m -2 day -1 in summer) and did in addition exhibit a general significant increase from spring-to-summer. Multiple regression analysis suggests that in both spring and summer, sediment Chl a concentration is the prime determinant of benthic carbon remineralisation, but other factors have a significant secondary influence, such as foraminiferan biomass (negative in both seasons), water depth (in spring) and infaunal biomass (in summer). Our findings indicate the importance of the combined and dynamic effects of food supply and benthic community patterns on the carbon remineralisation of the polar shelf benthos in seasonally ice-covered seas.

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Three-year assessment of particulate organic carbon fluxes in Amundsen Gulf (Beaufort Sea): Satellite observations and sediment trap measurements

Cited by 49 publications

References 70 publications

Seasonal and Interannual Changes in Ciliate and Dinoflagellate Species Assemblages in the Arctic Ocean (Amundsen Gulf, Beaufort Sea, Canada)

Seasonal and Interannual Changes in Ciliate and Dinoflagellate Species Assemblages in the Arctic Ocean (Amundsen Gulf, Beaufort Sea, Canada)

Summertime primary production and carbon export in the southeastern Beaufort Sea during the low ice year of 2008

Spring-to-summer changes and regional variability of benthic processes in the western Canadian Arctic

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