Grazing behavior and winter phytoplankton accumulation

Freilich, Mara; Mignot, Alexandre; Flierl, Glenn R.; Ferrari, Raffaele

doi:10.5194/bg-18-5595-2021

Cited by 6 publications

(4 citation statements)

References 80 publications

(119 reference statements)

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“…In addition, following Freilich et al. (2021), the deepening MLD dilutes the volume concentration through wintertime (Equation ). Whereas when MLD shallows in the growing season, material detrained, but the volumetric concentration in the mixed layer will remain almost unchanged.…”

Section: The Ross Ice Shelf Polynya Ecosystem Modelmentioning

confidence: 96%

“…In Equation 16, the shear rate (sh) is set to 0.8 s −1 and the value of the minimum sinking rate of phytoplankton ( 𝐴𝐴 𝐴𝐴 B ) is presented in Table 2. In addition, following Freilich et al (2021), the deepening MLD dilutes the volume concentration through wintertime (Equation 17). Whereas when MLD shallows in the growing season, material detrained, but the volumetric concentration in the mixed layer will remain almost unchanged.…”

Section: Fementioning

confidence: 99%

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Iron Limitation and Uneven Grazing Pressure on Phytoplankton Co‐Lead the Seasonal Species Succession in the Ross Ice Shelf Polynya

Zhang

Wei

et al. 2023

JGR Oceans

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The Ross Sea continental shelf is considered as the most productive area of the Southern Ocean (Arrigo, vanDijken, & Bushinsky, 2008). In particular, the Ross Ice Shelf Polynya (RISP), occupying half of the shelf area (Figure 1a) (Smith et al., 2012;Wang et al., 2021), sustains an annual productivity (166 g C m −2 ) comparable to that of the entire shelf (Smith & Kaufman, 2018). The large increase in size of this persistent polynya in austral spring and summer facilitates the occurrence of a large phytoplankton bloom (Arrigo & van Dijken, 2004), which is driven by decreased ice coverage, increasing irradiance, and shoaling mixed layer depths (MLDs) (

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Section: The Ross Ice Shelf Polynya Ecosystem Modelmentioning

confidence: 96%

Section: Fementioning

confidence: 99%

Iron Limitation and Uneven Grazing Pressure on Phytoplankton Co‐Lead the Seasonal Species Succession in the Ross Ice Shelf Polynya

Zhang

Wei

et al. 2023

JGR Oceans

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“…We do not explicitly represent the grazing by zooplankton. Instead, we consider nutrient limitation and a quadratic loss term which increases the mortality to account for phytoplankton biomass losses due to higher-trophic level predation (Freilich et al, 2021) and to enhance the phytoplankton response to sporadic nutrient uptake (Freilich and Mahadevan, 2019). Lastly, the ammonium is initialized as zero.…”

Section: P Zmentioning

confidence: 99%

Mixed layer eddies supply nutrients to enhance the spring phytoplankton bloom

Simoes-Sousa

Tandon²,

Pereira³

et al. 2022

Front. Mar. Sci.

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Mixed layer eddies resulting from baroclinic instability of fronts convert horizontal buoyancy gradients into vertical stratification, shoaling the mixed layer. In light-limited regimes – high-latitudes – this process can initiate phytoplankton blooms prior to the springtime warming. The question is whether mixed layer eddies can enhance the spring bloom by delivering nutrients from beneath the mixed layer. We couple a submesoscale-resolving model (SUB) with a simple ecosystem model and examine the role of mixed layer eddies on the development of the spring bloom. We compare the SUB simulation to two coarser resolution (10 km) simulations, one that includes a mixed layer eddy parameterization (MLE) and another that prescribes the restratification from SUB and advects the biogeochemical tracers using geostrophic velocities (NVF). The MLE simulates restratification of the mixed layer and bloom onset, but the spring bloom has a deficit of 10–13% in the new production compared to SUB. The NVF has the same restratification as SUB, and with no vertical flux of nutrients, leads to a spring bloom with a 32–40% new production deficit compared to SUB. Submesoscale processes lead to exchange across the mixed layer base, which is not represented in coarse resolution model simulations, even with mixed layer eddy parameterizations. Our results show that nutrients supplied by mixed layer eddies are important to enhance the spring bloom.

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“…In particular, the dynamics of small phytoplankton (< 10 µm) are tightly coupled with those of microzooplankton grazers due to their fast ingestion and growth rates (Hansen et al, 1997;Haraguchi et al, 2018), allowing them to consume most phytoplankton primary production in the ocean, including coastal habitats (Calbet and Landry, 2004). Also, a Holling III functional response seems to best describe the grazing behavior of microzooplankton (Liu et al, 2021), which might be key at low winter food concentrations to allow phytoplankton biomass to accumulate (Freilich et al, 2021). At Stonehaven, we observed that small phytoplankton dominated the winter community biomass, as also occurs in other temperate oceanic and coastal areas (see for instance Haraguchi et al, 2018;Bolaños et al, 2020).…”

Section: Effect Of Light On the Spring Bloom Onsetmentioning

confidence: 99%

The onset of the spring phytoplankton bloom in the coastal North Sea supports the Disturbance Recovery Hypothesis

González-Gil

Banas

Bresnan

et al. 2021

Preprint

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Abstract. The spring phytoplankton bloom is a key event in temperate and polar seas, yet the mechanisms that trigger it remain under debate. Some hypotheses claim that the spring bloom onset occurs when light is no longer limiting, allowing phytoplankton division rates to surpass a critical threshold. In contrast, the Disturbance Recovery Hypothesis (DRH) proposes that the onset responds to an imbalance between phytoplankton growth and loss processes, allowing phytoplankton biomass to start accumulating, and this can occur even when light is still limiting. Although many studies have shown that the DRH explains the spring bloom onset in oceanic waters, it is less certain whether and how it also applies to coastal areas. To address this question at a coastal location in the Scottish North Sea, we combined 21 years (1997–2017) of weekly in situ data with meteorological information. The onset of phytoplankton biomass accumulation occurred around the same date each year, 16 ± 11 days (mean ± SD) after the winter solstice, when light limitation for growth was strongest. Also, negative and positive biomass accumulation rates (r) occurred respectively before and after the winter solstice at similar light levels. The seasonal change from negative to positive r was mainly driven by the rate of change in light availability rather than light itself. Our results support the validity of the DRH for the studied coastal region and suggest its applicability to other coastal areas.

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Grazing behavior and winter phytoplankton accumulation

Cited by 6 publications

References 80 publications

Iron Limitation and Uneven Grazing Pressure on Phytoplankton Co‐Lead the Seasonal Species Succession in the Ross Ice Shelf Polynya

Iron Limitation and Uneven Grazing Pressure on Phytoplankton Co‐Lead the Seasonal Species Succession in the Ross Ice Shelf Polynya

Mixed layer eddies supply nutrients to enhance the spring phytoplankton bloom

The onset of the spring phytoplankton bloom in the coastal North Sea supports the Disturbance Recovery Hypothesis

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