Shalapyonok Alexi

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Shalapyonok
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Alexi
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  • Article
    Rapid growth and concerted sexual transitions by a bloom of the harmful dinoflagellate Alexandrium fundyense (Dinophyceae)
    (John Wiley & Sons, 2015-09-18) Brosnahan, Michael L. ; Velo-Suarez, Lourdes ; Ralston, David K. ; Fox, Sophia E. ; Sehein, Taylor R. ; Shalapyonok, Alexi ; Sosik, Heidi M. ; Olson, Robert J. ; Anderson, Donald M.
    Transitions between life cycle stages by the harmful dinoflagellate Alexandrium fundyense are critical for the initiation and termination of its blooms. To quantify these transitions in a single population, an Imaging FlowCytobot (IFCB), was deployed in Salt Pond (Eastham, Massachusetts), a small, tidally flushed kettle pond that hosts near annual, localized A. fundyense blooms. Machine-based image classifiers differentiating A. fundyense life cycle stages were developed and results were compared to manually corrected IFCB samples, manual microscopy-based estimates of A. fundyense abundance, previously published data describing prevalence of the parasite Amoebophrya, and a continuous culture of A. fundyense infected with Amoebophrya. In Salt Pond, a development phase of sustained vegetative division lasted approximately 3 weeks and was followed by a rapid and near complete conversion to small, gamete cells. The gametic period (∼3 d) coincided with a spike in the frequency of fusing gametes (up to 5% of A. fundyense images) and was followed by a zygotic phase (∼4 d) during which cell sizes returned to their normal range but cell division and diel vertical migration ceased. Cell division during bloom development was strongly phased, enabling estimation of daily rates of division, which were more than twice those predicted from batch cultures grown at similar temperatures in replete medium. Data from the Salt Pond deployment provide the first continuous record of an A. fundyense population through its complete bloom cycle and demonstrate growth and sexual induction rates much higher than are typically observed in culture.
  • Article
    Seasons of Syn
    (Wiley, 2019-11-19) Hunter-Cevera, Kristen R. ; Neubert, Michael G. ; Olson, Robert J. ; Shalapyonok, Alexi ; Solow, Andrew R. ; Sosik, Heidi M.
    Synechococcus is a widespread and important marine primary producer. Time series provide critical information for identifying and understanding the factors that determine abundance patterns. Here, we present the results of analysis of a 16‐yr hourly time series of Synechococcus at the Martha's Vineyard Coastal Observatory, obtained with an automated, in situ flow cytometer. We focus on understanding seasonal abundance patterns by examining relationships between cell division rate, loss rate, cellular properties (e.g., cell volume, phycoerythrin fluorescence), and environmental variables (e.g., temperature, light). We find that the drivers of cell division vary with season; cells are temperature‐limited in winter and spring, but light‐limited in the fall. Losses to the population also vary with season. Our results lead to testable hypotheses about Synechococcus ecophysiology and a working framework for understanding the seasonal controls of Synechococcus cell abundance in a temperate coastal system.
  • Article
    Dynamics and functional diversity of the smallest phytoplankton on the Northeast US shelf
    (National Academy of Sciences, 2020-05-15) Fowler, Bethany L. ; Neubert, Michael G. ; Hunter-Cevera, Kristen R. ; Olson, Robert J. ; Shalapyonok, Alexi ; Solow, Andrew R. ; Sosik, Heidi M.
    Picophytoplankton are the most abundant primary producers in the ocean. Knowledge of their community dynamics is key to understanding their role in marine food webs and global biogeochemical cycles. To this end, we analyzed a 16-y time series of observations of a phytoplankton community at a nearshore site on the Northeast US Shelf. We used a size-structured population model to estimate in situ division rates for the picoeukaryote assemblage and compared the dynamics with those of the picocyanobacteria Synechococcus at the same location. We found that the picoeukaryotes divide at roughly twice the rate of the more abundant Synechococcus and are subject to greater loss rates (likely from viral lysis and zooplankton grazing). We describe the dynamics of these groups across short and long timescales and conclude that, despite their taxonomic differences, their populations respond similarly to changes in the biotic and abiotic environment. Both groups appear to be temperature limited in the spring and light limited in the fall and to experience greater mortality during the day than at night. Compared with Synechococcus, the picoeukaryotes are subject to greater top-down control and contribute more to the region’s primary productivity than their standing stocks suggest.
  • Article
    Imaging FlowCytobot modified for high throughput by in-line acoustic focusing of sample particles
    (John Wiley & Sons, 2017-09-19) Olson, Robert J. ; Shalapyonok, Alexi ; Kalb, Daniel J. ; Graves, Steven W. ; Sosik, Heidi M.
    Imaging FlowCytobot, a submersible instrument that measures optical properties and captures images of nano- and microplankton-sized particles, has proved useful in plankton studies, but its sampling rate is limited by the ability of hydrodynamic focusing to accurately position flowing sample particles. We show that IFCB's sampling rate can be increased at least several-fold by implementing in-line acoustic focusing upstream of the flow cell. Particles are forced to the center of flow by acoustic standing waves created by a piezo-electric transducer bonded to the sample capillary and driven at the appropriate frequency. With the particles of interest confined to the center of the sample flow, the increased size of the sample core that accompanies increased sample flow rate no longer degrades image and signal quality as it otherwise would. Temperature affects the optimum frequency (through its effect on the speed of sound in water), so a relationship between sample temperature and optimum frequency for acoustic focusing was determined and utilized to control the transducer. The modified instrument's performance was evaluated through analyses of artificial particles, phytoplankton cultures, and natural seawater samples and through deployments in coastal waters. The results show that large cells, especially dinoflagellates, are acoustically focused extremely effectively (which could enable, for example, > 10-fold increased sampling rate of harmful algal bloom species, if smaller cells are ignored), while for nearly all cell types typically monitored by IFCB, threefold faster data accumulation was achieved without any compromises. Further increases are possible with more sophisticated software and/or a faster camera.
  • Dataset
    Martha's Vineyard Coastal Observatory 2024
    (Woods Hole Oceanographic Institution, 2025-02-27) Cinquino, Eve ; Batchelder, Sidney ; Fredericks, Janet J. ; Sisson, John D. ; Faluotico, Stephen M. ; Popenoe, Hugh ; Sandwith, Zoe O. ; Crockford, E. Taylor ; Peacock, Emily E. ; Shalapyonok, Alexi ; Sosik, Heidi M. ; Kirincich, Anthony R. ; Edson, James B. ; Trowbridge, John H.
    Martha's Vineyard Coastal Observatory (MVCO) is a leading research and engineering facility operated by Woods Hole Oceanographic Institution. MVCO has been collecting ocean and atmospheric data at 3 sites on and near Martha's Vineyard since 2001. A meteorological mast (met mast) on South Beach in Edgartown, MA collected atmospheric data from May 31, 2001 to Dec 18, 2023. An Air Sea Interaction Tower (ASIT) has been collecting atmospheric and subsurface oceanic data since August 5, 2004. A seafloor node (12m node) collected oceanic data from the seafloor from June 14, 2001 to September 5, 2018. This dataset encompasses the core data (wind speed and direction, air pressure, temperature and relative humidity, water temperature and salinity, and wave data) that has been collected during this period. To learn more about the facility and see additional data collected during short term deployments, visit the MVCO Website (https://mvco.whoi.edu/).
  • Dataset
    Martha's Vineyard Coastal Observatory 2022
    (Woods Hole Oceanographic Institution, 2023-01-31) Cinquino, Eve ; Batchelder, Sidney ; Fredericks, Janet J. ; Sisson, John D. ; Faluotico, Stephen M. ; Popenoe, Hugh ; Sandwith, Zoe O. ; Crockford, E. Taylor ; Peacock, Emily E. ; Shalapyonok, Alexi ; Sosik, Heidi M. ; Kirincich, Anthony R. ; Edson, James B. ; Trowbridge, John H.
    Martha's Vineyard Coastal Observatory (MVCO) is a leading research and engineering facility operated by Woods Hole Oceanographic Institution. MVCO has been collecting ocean and atmospheric data at 3 sites on and near Martha's Vineyard since 2001. A meteorological mast (met mast) on South Beach in Edgartown, MA has collected atmospheric data since May 31 2001. An Air Sea Interaction Tower (ASIT) has been collecting atmospheric and subsurface oceanic data since August 5, 2004. A seafloor node (12m node) has been collecting oceanic data from the seafloor since June 14, 2001. This dataset encompasses the core data (wind speed and direction, air pressure, temperature and relative humidity, water temperature and salinity, and wave data) that has been collected during this period. To learn more about the facility and see additional data collected during short term deployments, visit the MVCO Website (https://mvco.whoi.edu/).
  • Dataset
    Martha’s Vineyard Coastal Observatory
    (Woods Hole Oceanographic Institution, 2021-10-15) Cinquino, Eve ; Batchelder, Sidney ; Fredericks, Janet J. ; Sisson, John D. ; Faluotico, Stephen M. ; Popenoe, Hugh ; Sandwith, Zoe O. ; Crockford, E. Taylor ; Peacock, Emily E. ; Shalapyonok, Alexi ; Sosik, Heidi M. ; Kirincich, Anthony R. ; Edson, James B. ; Trowbridge, John H.
    Martha's Vineyard Coastal Observatory (MVCO) is a leading research and engineering facility operated by Woods Hole Oceanographic Institution. MVCO has been collecting ocean and atmospheric data at 3 sites on and near Martha's Vineyard since 2001. A meteorological mast (met mast) on South Beach in Edgartown, MA has collected atmospheric data since May 31 2001. An Air Sea Interaction Tower (ASIT) has been collecting atmospheric and subsurface oceanic data since August 5, 2004. A seafloor node (12m node) has been collecting oceanic data from the seafloor since June 14, 2001. This dataset encompasses the core data (wind speed and direction, air pressure, temperature and relative humidity, water temperature and salinity, and wave data) that has been collected during this period. To learn more about the facility and see additional data collected during short term deployments, visit the MVCO Website (https://mvco.whoi.edu/).
  • Dataset
    Martha's Vineyard Coastal Observatory 2023
    (Woods Hole Oceanographic Institution, 2024-10-28) Cinquino, Eve ; Batchelder, Sidney ; Fredericks, Janet J. ; Sisson, John D. ; Faluotico, Stephen M. ; Popenoe, Hugh ; Sandwith, Zoe O. ; Crockford, E. Taylor ; Peacock, Emily E. ; Shalapyonok, Alexi ; Sosik, Heidi M. ; Kirincich, Anthony R. ; Edson, James B. ; Trowbridge, John H.
    Martha's Vineyard Coastal Observatory (MVCO) is a leading research and engineering facility operated by Woods Hole Oceanographic Institution. MVCO has been collecting ocean and atmospheric data at 3 sites on and near Martha's Vineyard since 2001. A meteorological mast (met mast) on South Beach in Edgartown, MA collected atmospheric data from May 31, 2001 to Dec 18, 2023. An Air Sea Interaction Tower (ASIT) has been collecting atmospheric and subsurface oceanic data since August 5, 2004. A seafloor node (12m node) collected oceanic data from the seafloor from June 14, 2001 to September 5, 2018. This dataset encompasses the core data (wind speed and direction, air pressure, temperature and relative humidity, water temperature and salinity, and wave data) that has been collected during this period. To learn more about the facility and see additional data collected during short term deployments, visit the MVCO Website (https://mvco.whoi.edu/).
  • Dataset
    Martha's Vineyard Coastal Observatory 2021
    (Woods Hole Oceanographic Institution, 2022-06-24) Cinquino, Eve ; Batchelder, Sidney ; Fredericks, Janet J. ; Sisson, John D. ; Faluotico, Stephen M. ; Popenoe, Hugh ; Sandwith, Zoe O. ; Crockford, E. Taylor ; Peacock, Emily E. ; Shalapyonok, Alexi ; Sosik, Heidi M. ; Kirincich, Anthony R. ; Edson, James B. ; Trowbridge, John H.
    Martha's Vineyard Coastal Observatory (MVCO) is a leading research and engineering facility operated by Woods Hole Oceanographic Institution. MVCO has been collecting ocean and atmospheric data at 3 sites on and near Martha's Vineyard since 2001. A meteorological mast (met mast) on South Beach in Edgartown, MA has collected atmospheric data since May 31 2001. An Air Sea Interaction Tower (ASIT) has been collecting atmospheric and subsurface oceanic data since August 5, 2004. A seafloor node (12m node) has been collecting oceanic data from the seafloor since June 14, 2001. This dataset encompasses the core data (wind speed and direction, air pressure, temperature and relative humidity, water temperature and salinity, and wave data) that has been collected during this period. To learn more about the facility and see additional data collected during short term deployments, visit the MVCO Website (https://mvco.whoi.edu/).
  • Article
    Distinct responses to warming within picoplankton communities across an environmental gradient
    (Wiley, 2024-05-20) Stevens, Bethany L. F. ; Peacock, Emily E. ; Crockford, E. Taylor ; Shalapyonok, Alexi ; Neubert, Michael G. ; Sosik, Heidi M.
    Picophytoplankton are a ubiquitous component of marine plankton communities and are expected to be favored by global increases in seawater temperature and stratification associated with climate change. Eukaryotic and prokaryotic picophytoplankton have distinct ecology, and global models predict that the two groups will respond differently to future climate scenarios. At a nearshore observatory on the Northeast US Shelf, however, decades of year-round monitoring have shown these two groups to be highly synchronized in their responses to environmental variability. To reconcile the differences between regional and global predictions for picophytoplankton dynamics, we here investigate the picophytoplankton community across the continental shelf gradient from the nearshore observatory to the continental slope. We analyze flow cytometry data from 22 research cruises, comparing the response of picoeukaryote and Synechococcus communities to environmental variability across time and space. We find that the mechanisms controlling picophytoplankton abundance differ across taxa, season, and distance from shore. Like the prokaryote, Synechococcus, picoeukaryote division rates are limited nearshore by low temperatures in winter and spring, and higher temperatures offshore lead to an earlier spring bloom. Unlike Synechococcus, picoeukaryote concentration in summer decreases dramatically in offshore surface waters and exhibits deeper subsurface maxima. The offshore picoeukaryote community appears to be nutrient limited in the summer and subject to much greater loss rates than Synechococcus. This work both produces and demonstrates the necessity of taxon- and site-specific knowledge for accurately predicting the responses of picophytoplankton to ongoing environmental change.