Buoyancy Regulation in Phaeocystis globosa Scherffel Colonies

Wang, Xiaodong

doi:10.2174/1874450801004010115

Cited by 11 publications

(8 citation statements)

References 52 publications

(74 reference statements)

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“…While Elementa: Science of the Anthropocene • 3: 000073 • doi: 10.12952/journal.elementa.000073 many phytoplankton species exhibit significant movement through swimming (Blasco, 1978) and/or buoyancy regulation (Walsby et al, 1997), there is no evidence that Phaeocystis exhibits capabilities for significant vertical motility. The few available laboratory studies on Phaeocystis suggest that cells are either neutrally or slightly negatively buoyant under light-limiting conditions (Wang and Tang, 2010). Although these studies were not conducted on the Antarctic species encountered during the ASPIRE and KOPRI expeditions, it appears that the rate of mixing within the upper mixed layer and not cell motility is critical to supporting the observed accumulation of phytoplankton biomass.…”

Section: Discussionmentioning

confidence: 99%

In situ phytoplankton distributions in the Amundsen Sea Polynya measured by autonomous gliders

Schofield

Miles

Alderkamp

et al. 2015

Elementa: Science of the Anthropocene

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The Amundsen Sea Polynya is characterized by large phytoplankton blooms, which makes this region disproportionately important relative to its size for the biogeochemistry of the Southern Ocean. In situ data on phytoplankton are limited, which is problematic given recent reports of sustained change in the Amundsen Sea. During two field expeditions to the Amundsen Sea during austral summer 2010-2011 and 2014, we collected physical and bio-optical data from ships and autonomous underwater gliders. Gliders documented large phytoplankton blooms associated with Antarctic Surface Waters with low salinity surface water and shallow upper mixed layers (< 50 m). High biomass was not always associated with a specific water mass, suggesting the importance of upper mixed depth and light in influencing phytoplankton biomass. Spectral optical backscatter and ship pigment data suggested that the composition of phytoplankton was spatially heterogeneous, with the large blooms dominated by Phaeocystis and non-bloom waters dominated by diatoms. Phytoplankton growth rates estimated from field data (≤ 0.10 day −1 ) were at the lower end of the range measured during ship-based incubations, reflecting both in situ nutrient and light limitations. In the bloom waters, phytoplankton biomass was high throughout the 50-m thick upper mixed layer. Those biomass levels, along with the presence of colored dissolved organic matter and detritus, resulted in a euphotic zone that was often < 10 m deep. The net result was that the majority of phytoplankton were light-limited, suggesting that mixing rates within the upper mixed layer were critical to determining the overall productivity; however, regional productivity will ultimately be controlled by water column stability and the depth of the upper mixed layer, which may be enhanced with continued ice melt in the Amundsen Sea Polynya.

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Section: Discussionmentioning

confidence: 99%

In situ phytoplankton distributions in the Amundsen Sea Polynya measured by autonomous gliders

Schofield

Miles

Alderkamp

et al. 2015

Elementa: Science of the Anthropocene

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“…Furthermore, these costs are likely to be ecological relevant, including enhanced sinking rate of colonies. P. globosa colonies in exponential phase always exhibit negative buoyancy 38 , while giant P. globosa colonies collected from Vietnamese coastal waters had sinking rates as high as 516 m d −1 33 . The high sinking rate poses a significant challenge for the colonies to maintain their population at the sea surface 33 …”

Section: Discussionmentioning

confidence: 98%

Allocation Costs Associated with Induced Defense in Phaeocystis globosa (Prymnesiophyceae): the Effects of Nutrient Availability

Wang

Yan

et al. 2015

Sci Rep

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Colony enlargement in Phaeocystis globosa has been considered as an induced defense strategy that reduces its susceptibility to grazers, but allocation costs inflicted by this plastic morphological defense are poorly understood. We conducted experiments in which P. globosa cultures were exposed to chemical cues from copepods, ciliates and heterotrophic dinoflagellates, respectively, under nutrient sufficient and deficient conditions to evaluate allocation costs associated with induced defense. Phaeocystis globosa responded to chemical cues from grazers by increasing colony diameter irrespective of nutrient conditions. We did not find trade-offs between induced defense and growth rate under nutrient sufficient conditions. Instead, induced defensive P. globosa had higher growth rates than non-induced P. globosa. When nutrient became limited, P. globosa exposed to grazing cues from copepods and dinoflagellates had significantly decreased growth rates when compared with non-induced P. globosa. We suggested that the decreased growth revealed allocation costs associated with induced defense that may influence on the trophic interactions between Phaeocystis and consumers.

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“…(Skreslet, 1988;Wang and Tang, 2010) which has become increasingly important in the phytoplankton community in Fram Strait during recent years (Nöthig et al, 2015). Unfortunately, the proposed scenario cannot be tested with the available data as PAUL's water samples were not analyzed with respect to plankton composition.…”

Section: Biogeochemical Zonesmentioning

confidence: 99%

Physical and ecological processes at a moving ice edge in the Fram Strait as observed with an AUV

Wulff

Bauerfeind

Appen

2016

Deep Sea Research Part I: Oceanographic Research Papers

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a b s t r a c tSmall-scale investigations of physical and biogeochemical parameters have been carried out with an autonomous underwater vehicle (AUV) at a moving ice edge in the Fram Strait. The AUV was equipped with various sensors to study the complex interactions between physical and ecological processes along the ice edge and the associated meltwater front. The AUV covered two cross-front sections of 9 km and recorded high resolution vertical profiles of the physical and biogeochemical properties between 0 and 50 m water depth at a horizontal station spacing of 800-1000 m.In both physical and biogeochemical terms, the measurements revealed a complex structure of the water column. The distribution of phytoplankton biomass (chlorophyll a) and nutrients was highly inhomogeneous. Chlorophyll a concentrations of 5 mg l À 1 were detected at the frontal interface in a small corridor just 2-4 km wide and only 5 m deep. Nutrients at the surface were depleted, yet, compared to previous studies of this region, were still present in the euphotic zone. Below the euphotic zone, nitrate concentrations of 8 mmol l À 1 and oxygen saturation values of 100% resulted in a "dome-like" patternsuggestive of vertical transport processes. Based on these measurements, three different zones featuring individual biogeochemical characteristics were identified in the cross-front sections. Atmospheric forcing and the presence of the melt water front are assumed to be mainly responsible for the complexity of the water column. Localized vertical transport events seem to have occurred before our investigations. Furthermore, wind driven frontogenesis likely contributed to vertical water movements. All processes had an effect on the biological processes along the observed meltwater front.

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Buoyancy Regulation in Phaeocystis globosa Scherffel Colonies

Cited by 11 publications

References 52 publications

In situ phytoplankton distributions in the Amundsen Sea Polynya measured by autonomous gliders

In situ phytoplankton distributions in the Amundsen Sea Polynya measured by autonomous gliders

Allocation Costs Associated with Induced Defense in Phaeocystis globosa (Prymnesiophyceae): the Effects of Nutrient Availability

Physical and ecological processes at a moving ice edge in the Fram Strait as observed with an AUV

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