Intense stratification leads to phytoplankton nutrient limitation and reduced microzooplankton grazing in the southeastern Bering Sea

Strom, Suzanne L.; Fredrickson, Kerri A.

doi:10.1016/j.dsr2.2008.04.008

Cited by 83 publications

(98 citation statements)

References 51 publications

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“…On 15 and 16 September, the abundance of the centric diatoms C. convolutes and L. danicus increased (phase 2). This sudden increase in diatom abundance in phase 2, which exceeded the range reported for diatom growth (0.35-0.4 day −1 ) in this region (Strom and Fredrickson, 2008;Sherr et al, 2009), could not be explained by cell division growth within the same water masses. Accordingly, as an alternative cause, reported that the displacement of the ice-melt seawater during this period caused the horizontal movement of water masses, which, in turn, may have led to the sudden increase in diatoms during this phase.…”

Section: Short-term Changes In the Microplankton Communitymentioning

confidence: 80%

“…Regarding temporal changes in the microplankton community, seasonal comparisons with 3-to 4-month sampling intervals (Sukhanova et al, 2009) and year-round changes with 8-day intervals were reported (Sherr et al, 2003). As microplankton grow rapidly (Strom and Fredrickson, 2008;Sherr et al, 2009), fine temporal resolution (every day) is required to evaluate detailed temporal changes in their community. However, such high-frequency sampling of microplankton has not been conducted previously.…”

Section: Introductionmentioning

confidence: 99%

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Short-term changes in a microplankton community in the Chukchi Sea during autumn: consequences of a strong wind event

et al. 2016

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Abstract.Recent studies indicate an increase in atmospheric turbulence in the Chukchi Sea due to the recent drastic sea-ice reduction during summer months. The importance of the effects of this atmospheric turbulence on the marine ecosystem in this region, however, is not fully understood. To evaluate the effects of atmospheric turbulence on the marine ecosystem, high-frequency sampling (daily) from five layers of the microplankton community between 0 and 30 m at a fixed station in the Chukchi Sea from 10 through 25 September 2013 was conducted. During the study period, a strong wind event (SWE) was observed on 18 and 19 September. The abundance of microplankton was 2.6 to 17.6 cells mL −1 , with a maximum abundance being reported at 20 m on 22 September, while diatoms were the most dominant taxa throughout the study period. The abundance of diatoms, dinoflagellates and ciliates ranged between 1.6 and 14.1, 0.5 and 2.4 and 0.1 and 2.8 cells mL −1 , respectively. Diatoms belonging to 7 genera consisting of 35 species (Cylindrotheca closterium and Leptocylindrus danicus were dominant), dinoflagellates belonging to 7 genera consisting of 25 species (Prorocentrum balticum and Gymnodinium spp. were dominant) and ciliates belonging to 7 genera consisting of 8 species (Strobilidium spp. and Strombidium spp. were dominant) were identified. Within the microplankton species, there were 11 species with abundances that increased after the SWE, while there was no species with an abundance that decreased following the SWE. It is conjectured that atmospheric turbulences, such as that of an SWE, may supply sufficient nutrients to the surface layer that subsequently enhance the small bloom under the weak stratification of the Chukchi Sea Shelf during the autumn months. After the bloom, the dominant diatom community then shifts from centric-dominated to one where centric/pennate are more equal in abundance.

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Section: Short-term Changes In the Microplankton Communitymentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Short-term changes in a microplankton community in the Chukchi Sea during autumn: consequences of a strong wind event

et al. 2016

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“…For example, higher grazing rate on smaller phytoplankton has been reported accounting for the larger-sized phytoplankton dominance in eutrophic waters (e.g. Strom et al, 2007), but no such pattern was found in other studies (Lie and Wong, 2010;Safi et al, 2007;Strom and Fredrickson, 2008;Zhou et al, 2011). In contrast, Zhou et al (2015a) found that microzooplankton selectively grazed on nano-phytoplankton (3-20 µm) in the oligotrophic waters of the SCS in summer, and proposed that the size-selective grazing on nano-phytoplankton contributes to the pico-phytoplankton dominance there.…”

Section: Size-selective Grazing Contributes To the Pico-phytoplanktonmentioning

confidence: 83%

Seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in the southern South China Sea under the influence of the East Asian monsoon

et al. 2015

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Abstract.To examine seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in oligotrophic tropical waters under the influence of seasonal reversing monsoon, dilution experiments were conducted during the summer of 2009 (21 May to 9 June) and winter 2010 (9 to 18 November) in the southern South China Sea (SSCS). The results showed that environmental variables, phytoplankton biomass, phytoplankton growth rate (µ), microzooplankton grazing rate (m), and correlationship (coupling) between the µ and m, rather than the microzooplankton grazing impact on phytoplankton (m/µ) significantly varied between the two seasons. Higher relative preference index (RPI) for the larger-sized (> 3 µm) phytoplankton than pico-phytoplankton (< 3 µm), indicating significant size-selective grazing by microzooplankton on the larger-sized phytoplankton, were also observed. The µ and m were significantly correlated with seawater salinity and temperature, and phytoplankton biomass, which indicated that salient seasonal variations in the phytoplankton growth and microzooplankton grazing in the SSCS were closely related to the environmental variables under the influence of the East Asian monsoon. We propose that intermittent arrivals of the northeast winter monsoon could lead to the low µ and m, and the decoupling between the µ and m in the SSCS, through influencing nutrient supply to the surface water, and inducing surface seawater salinity decrease. The low m/µ (< 50 % on average) indicates low remineralization of organic matter mediated by microzooplankton and mismatch between the µ and m, and thus probably accounts for part of the high vertical biogenic particle fluxes in the prevailing periods of the monsoons in the SSCS. The size-selective grazing suggests that microzooplankton grazing partially contributes to the pico-phytoplankton dominance in the oligotrophic tropical waters such as that of the SSCS.

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“…Decreased sea ice thickness, less snow cover, and an earlier ice break-up during spring will result in higher ambient irradiances during algal spring blooms (Nicolaus et al 2012). Also, the stratification of surface waters is supposed to increase, as a result of less saline and warmer surface waters (Strom and Fredrickson 2008). It is generally assumed that increased light availability will result in a higher annual primary production in this area (Sakshaug 2004;Arrigo et al 2008;Pabi et al 2008).…”

Section: Introductionmentioning

confidence: 99%

A (too) bright future? Arctic diatoms under radiation stress

2016

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Decreasing Arctic sea ice cover and increasing stratification of ocean surface waters make the exposure of pelagic microalgae to high irradiances more likely. Apart from light being a necessary prerequisite for photosynthesis, rapidly changing and/or high irradiances are potentially detrimental. An in situ study was performed in the high Arctic (79°N) to determine the effect of high irradiances in general, and ultraviolet radiation (UVR, 280-400 nm) in particular, on cell concentrations, fatty acid composition, and photoprotective pigments of three diatom species isolated from seawater around Svalbard. Unialgal cultures were exposed in situ at 0.5-and 8 m-depth. After 40 h, cell concentrations of Synedropsis hyperborea and Thalassiosira sp., were lower at 0.5 than at 8 m, and the content of the photoprotective xanthophyll-cycle pigment diatoxanthin in all species (S. hyperborea, Thalassiosira sp., Porosira glacialis) was higher in the 0.5 m exposure compared to 8 m. In S. hyperborea, growth was additionally inhibited by UVR at 0.5-m depth. In situ radiation conditions led, furthermore, to a significant decrease in polyunsaturated fatty acids (PUFAs) in all three species, but UVR had no additional effect. Hence, we conclude that natural radiation conditions close to the surface could reduce growth and PUFA concentrations, but the effects are species specific. The diatoms' potential to acclimate to these conditions over time has to be evaluated.

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Intense stratification leads to phytoplankton nutrient limitation and reduced microzooplankton grazing in the southeastern Bering Sea

Cited by 83 publications

References 51 publications

Short-term changes in a microplankton community in the Chukchi Sea during autumn: consequences of a strong wind event

Short-term changes in a microplankton community in the Chukchi Sea during autumn: consequences of a strong wind event

Seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in the southern South China Sea under the influence of the East Asian monsoon

A (too) bright future? Arctic diatoms under radiation stress

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