Relating cell‐level swimming behaviors to vertical population distributions in <i>Heterosigma akashiwo</i> (Raphidophyceae), a harmful alga

Bearon, Rachel N.; Grünbaum, Daniel; Cattolico, Rose Ann

doi:10.4319/lo.2004.49.2.0607

Cited by 34 publications

(61 citation statements)

References 11 publications

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“…Note, the results are consistent with the expectation that the magnitude of the vertical velocity for Chl a concentration (representing the aggregation of many cells with variable orientation) be smaller than the swim speed potential of an individual cell. Differences between swim speed potential and the effective vertical swim speed may be attributed to random components in the swimming of flagellates as well as reorientation of cells by small-scale shear (Kessler 1986;Bearon et al 2004;Kiørboe et al 2004).…”

Section: Resultsmentioning

confidence: 99%

“…Thus, stronger swimming, or more vertically directed swimming, in the upper water column may have been occurring during the layer formation phase. The fractions of the swim potential w swim considered here are intended to account for variations in the effective vertical speed of the cells due to variably directed swimming, tumbling, and reorientation by small-scale shear (Bearon and Pedley 2000;Bearon et al 2004;Bearon and Grü mbaum 2008). Also, note that the elevated cell velocities in the upper water column produce Chl a layers that are thinner than in the field observations (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Observations of turbulent mixing in a phytoplankton thin layer: Implications for formation, maintenance, and breakdown

Steinbuck

Stacey

McManus

et al. 2009

Limnology & Oceanography

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Coincident measurements of chlorophyll a (Chl a) and temperature microstructure from Monterey Bay, California, U.S.A., are used to investigate the dynamics of a phytoplankton thin layer in the context of vertical turbulent mixing. The thin layer was situated in the thermocline of a 20.5-m water column, between a strongly turbulent surface mixed layer and a weakly turbulent stratified interior. The differential mixing established an asymmetric layer with a stronger Chl a gradient at the base of the layer than at the top. Sinking by Akashiwo sanguinea could have balanced turbulent mixing above the layer, but cannot explain the mid-column convergence needed to maintain the thin layer. Swimming by A. sanguinea directed towards a mid-column nitracline could have balanced turbulent mixing on both sides of the layer and supported the observed Chl a gradients. Results from a Eulerian advection-diffusion model suggest that cell swimming may have varied over the lifetime of the layer, with stronger or more directed swimming required for layer formation and weaker or less directed swimming needed to maintain the layer. In-layer growth is unlikely to have played a primary role in supporting the observed Chl a gradients. From the one-dimensional (vertical) observations, the role of shear-induced straining cannot be evaluated, but shear instabilities appear important to forcing elevated rates of turbulent diffusion within the layer. Finally, a Lagrangian particle-tracking model is used to explore the implications of a balance of vertical velocity and turbulent diffusion on the vertical motions of individual cells that constitute the thin layer.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Observations of turbulent mixing in a phytoplankton thin layer: Implications for formation, maintenance, and breakdown

Steinbuck

Stacey

McManus

et al. 2009

Limnology & Oceanography

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“…In marine communities, patchiness is observed at almost every scale of observation-in the zooplankton and those that feed on them, in the phytoplankton, and in the underlying physical properties of the environment. Patterns of variability across trophic levels and departures from the spectra associated with abiotic features suggest that physical features may account for the patchiness on the largest scales, but that biological features-such as swimming behaviour of zooplankton-must be invoked to explain smallerscale patchiness (Levin et al, 1989;Levin, 1992;Bearon et al, 2004). As a consequence, we should not be surprised that purely physical models often perform poorly when making predictions for dynamics that occur over the course of hours in marine ecosystems.…”

Section: Identifying Scales Associated With Biological Regularitiesmentioning

confidence: 99%

The emergence of regularity and variability in marine ecosystems: the combined role of physics, chemistry and biology

Ballantyne¹,

Schofield²,

Levin³

2011

Sci. Mar.

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SUMMARY: Marine ecosystems play an integral role in the functioning of life on earth. To predict how they will respond to global changes, and to effectively manage and maintain services upon which humans rely, we must understand how biological processes at the cellular level generate macroscopic patterns in the oceans. Here, we discuss how physics and biogeochemistry influence and constrain marine ecosystem structure and function, and outline key regularities and patterns of variability that models should aim to reproduce. We identify unanswered questions regarding how size-dependent physiological and ecological processes are linked to turbulent mixing, dealing specifically with how size structure is related to mixing over a range of spatial scales and how it is linked to the fate of primary production in the sea.Keywords: variability, turbulence, scaling, abundance, trophic interactions, modelling. RESUMEN: La aparición de regularidades y variabilidad en ecosistemas marinos: el papel combinado de la física, la química y la biología. -Los ecosistemas marinos juegan un papel integral en el funcionamiento de la vida sobre la Tierra. Para predecir cómo van a responder a cambios globales y para mantener los servicios de los cuales los humanos dependemos, tenemos que comprender cómo los procesos biológicos a nivel celular generan patrones macroscópicos en el océano. Examinamos cómo la física y la biogeoquímica afectan y limitan la estructura y función de los ecosistemas marinos, y exponemos importantes regularidades y patrones de variabilidad que los modelos deberían reproducir. Identificamos aspectos sin resolver sobre la relación entre procesos fisiológicos y ecológicos y la mezcla turbulenta. En concreto, cómo la estructura de tamaños está relacionada con la mezcla en un rango de escalas espaciales y cómo está conectada con el destino de la producción primaria en el mar.

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“…Moreover, recent observations indicate that this behavior may be deceptively sophisticated (Kamykowski and Yamazaki 1997;Bearon et al 2004;Clegg et al 2004b). For example, in an investigation of the behavioral response of five phylogenetically contrasting species of flagellates, significant preferences for light (Clegg et al 2003a), temperature (Clegg et al 2003b), and chemical gradients (Clegg et al 2004a) were described.…”

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confidence: 99%

Behavioral response as a predictor of seasonal depth distribution and vertical niche separation in freshwater phytoplanktonic flagellates

Clegg

Maberly

Jones

2007

Limnology & Oceanography

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The distribution of phytoplanktonic flagellates in aquatic ecosystems has been widely attributed to a number of driving factors. In this study, we evaluated the influence of behavior on the daytime, seasonal depth distribution and vertical niche separation of five phylogenetically contrasting species of freshwater flagellates. A model predicting distribution was formulated using the dominant behavioral preferences for light, oxygen, and carbon dioxide, previously quantified in laboratory experiments, and was subsequently applied to the physical and chemical conditions measured in a small, strongly stratifying, hypertrophic lake. This model predicted the daytime depth distributions of natural populations of flagellates well, with an average areal fit of above 56% for all species; above 74% for Ceratium furcoides, Chlamydomonas sp., and Dinobryon sertularia; and of up to 93% during stratification. Regression analyses showed no significant variation from a 1 : 1 relationship between the predicted and observed average depths of species in the water column. The model also predicted the constriction into discrete vertical niches upon stratification and delineated the progression from Plagioselmis nannoplanctica in surface waters, through C. furcoides and D. sertularia, to Chlamydomonas sp. and Euglena gracilis deeper in the water column. Changes in observed distributions could not be directly correlated with other members of the plankton community or explained by the segregation of nutrients. The model's wider, transferable applicability suggested that behavioral response to environmental gradients may predict many patterns of distribution, particularly during stratification. In addition to known physiological and biochemical influences, this investigation emphasized the importance of behavioral response in the functional ecology of phytoplanktonic flagellates.Phytoplanktonic flagellates are a diverse group of unicellular or colonial eukaryotic microorganisms characterized by controlled motility combined with an ability to photosynthesize. Commonly occurring in both freshwater and marine habitats, they form an important functional component of the phytoplankton community (Salonen et al. 1984;Stone et al. 1993) and are frequently the principal contributor to harmful algal blooms and red tides (Smayda 1997). The spatial and temporal distributions of flagellates in aquatic ecosystems have been attributed to a large number of driving factors such as physiological response (e.g., Harris et al. 1979), competitive interactions (Riegman et al. 1996), succession (Gasol et al. 1992), the changing distribution of resources (Klausmeier and Litchman 2001), differential predation (Elser and Carpenter 1988), and regimes of turbulent mixing propagated by wind or wave action (Kamykowski 1995). In much the same way, cell motility is also widely considered to be an important influence on distribution; however, to date and due to its complexity, the full ecological significance of active behavioral response still remains uncertai...

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Relating cell‐level swimming behaviors to vertical population distributions in Heterosigma akashiwo (Raphidophyceae), a harmful alga

Cited by 34 publications

References 11 publications

Observations of turbulent mixing in a phytoplankton thin layer: Implications for formation, maintenance, and breakdown

Observations of turbulent mixing in a phytoplankton thin layer: Implications for formation, maintenance, and breakdown

The emergence of regularity and variability in marine ecosystems: the combined role of physics, chemistry and biology

Behavioral response as a predictor of seasonal depth distribution and vertical niche separation in freshwater phytoplanktonic flagellates

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