Peacock Emily E.

Last Name

Peacock

First Name

Emily E.

ORCID

0000-0003-0194-7282

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Mesoscale variability in intact and ghost colonies of Phaeocystis antarctica in the Ross Sea : distribution and abundance

( 2016-05) Smith, Walker O. ; McGillicuddy, Dennis J. ; Olson, Elise M. B. ; Kosnyrev, Valery ; Peacock, Emily E. ; Sosik, Heidi M.

Phaeocystis, a genus with a cosmopolitan distribution and a polymorphic life cycle, was observed during summer in the Ross Sea, Antarctica, where large blooms of this haptophyte regularly occur. The mesoscale vertical and horizontal distributions of colonies of P. antarctica were assessed using a towed Video Plankton Recorder (VPR). The mean size of colonies was 1.20 mm, and mean abundances within the three VPR surveys were 4.86, 1.96, and 11.5 mL-1. In addition to the typical spherical, transparent colonies, the VPR quantified an optically dissimilar form of colony that had a distinctive translucent appearance. It also measured the abundance of collapsed colonies, similar to those observed previously from cultures and mesocosms, which we called “ghost colonies”. The translucent colonial form had a different distribution than the more common colonial form, and at times was more abundant. Relative to intact colonies, the ghost colonies occurred less frequently, with mean abundances in the three surveys being 0.01, 0.08, and 0.0004 mL-1. Ghost colonies generally were found below the euphotic zone, where they often were in greater abundance than intact colonies. However, the relationship of ghost colonies to intact P. antarctica colonies was not direct or consistent, suggesting that the formation of ghost colonies from living colonies and their appearance within the water column were not tightly coupled. Given their relative scarcity and low carbon content, it is unlikely that ghost colonies contribute substantially to vertical flux; however, it is possible that we did not sample periods of major flux events, and as a result minimized the importance of ghost colonies to vertical flux. They do, however, represent a poorly documented feature of polar haptophyte life cycles.
2014 labeled IFCB images

( 2014) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
A regional, early spring bloom of Phaeocystis pouchetii on the New England continental shelf

(American Geophysical Union, 2021-01-15) Smith, Walker O. ; Zhang, Weifeng G. ; Hirzel, Andrew ; Stanley, Rachel M. ; Meyer, Meredith G. ; Sosik, Heidi M. ; Alatalo, Philip ; Oliver, Hilde ; Sandwith, Zoe O. ; Crockford, E. Taylor ; Peacock, Emily E. ; Mehta, Arshia ; McGillicuddy, Dennis J.

The genus Phaeocystis is distributed globally and has considerable ecological, biogeochemical, and societal impacts. Understanding its distribution, growth and ecological impacts has been limited by lack of extensive observations on appropriate scales. In 2018, we investigated the biological dynamics of the New England continental shelf and encountered a substantial bloom of Phaeocystis pouchetii. Based on satellite imagery during January through April, the bloom extended over broad expanses of the shelf; furthermore, our observations demonstrated that it reached high biomass levels, with maximum chlorophyll concentrations exceeding 16 µg L−1 and particulate organic carbon levels > 95 µmol L−1. Initially, the bloom was largely confined to waters with temperatures <6°C, which in turn were mostly restricted to shallow areas near the coast. As the bloom progressed, it appeared to sink into the bottom boundary layer; however, enough light and nutrients were available for growth. The bloom was highly productive (net community production integrated through the mixed layer from stations within the bloom averaged 1.16 g C m−2 d−1) and reduced nutrient concentrations considerably. Long‐term coastal observations suggest that Phaeocystis blooms occur sporadically in spring on Nantucket Shoals and presumably expand onto the continental shelf. Based on the distribution of Phaeocystis during our study, we suggest that it can have a significant impact on the overall productivity and ecology of the New England shelf during the winter/spring transition.
Long-term biological effects of petroleum residues on fiddler crabs in salt marshes

( 2007) Culbertson, Jennifer B. ; Valiela, Ivan ; Peacock, Emily E. ; Reddy, Christopher M. ; Carter, Anna ; VanderKruik, Rachel

In September 1969,the Florida barge spilled 700,000 L of No. 2 fuel oil into the salt marsh sediments of Wild Harbor (Buzzards Bay, MA). Today the aboveground environment appears unaffected, but a substantial amount of moderately degraded petroleum still remains 8 to 20 cm below the surface. The salt marsh fiddler crabs, Uca pugnax, which burrow into the sediments at depths of 5 to 25 cm, are chronically exposed to the spilled oil. Behavioral studies conducted with U. pugnax from Wild Harbor and a control site, Great Sippewissett marsh, found that crabs exposed to the oil avoided burrowing into oiled layers, suffered delayed escape responses, lowered feeding rates, and lower densities. The oil residues are therefore biologically active and affect U. pugnax populations. Our results add new knowledge about long-term consequences of spilled oil, a dimension that should be included when assessing oil-impacted areas and developing management plans designed to restore, rehabilitate, or replace impacted areas.
2011 labeled IFCB images

( 2011) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
2007 labeled IFCB images

( 2007) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
2013 labeled IFCB images

( 2013) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
2006 labeled IFCB images

( 2006) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
2010 labeled IFCB images

( 2010) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
2012 labeled IFCB images

( 2012) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
Parasitic infection of the diatom Guinardia delicatula, a recurrent and ecologically important phenomenon on the New England Shelf

(Inter-Research, 2014-04-29) Peacock, Emily E. ; Olson, Robert J. ; Sosik, Heidi M.

Plankton images collected by Imaging FlowCytobot from 2006 to 2013 at the Martha’s Vineyard Coastal Observatory (Massachusetts, USA) were used to identify and quantify the occurrence of the diatom Guinardia delicatula and of a parasite that seems specific to this host. We observed infection with morphological stages that appear similar to the parasite Cryothecomonas aestivalis. Our results show that events during which infection rates exceed 10% are recurrent on the New England Shelf and suggest that the parasites are an important source of host mortality. We document a significant negative relationship between bloom magnitude and parasite infection rate, supporting the hypothesis that the parasites play a major role in controlling blooms. While G. delicatula is observed during all seasons, the infecting stages of the parasite are abundant only when water temperature is above 4°C. The anomalously warm water and small G. delicatula bloom during the winter of 2012 provided evidence that parasites can be active through winter if temperatures remain relatively high. As climate change continues, winter periods of water below 4°C may shorten or disappear in this region, suggesting that parasite effects on species such as G. delicatula may increase, with immediate impacts on their population dynamics.
2009 labeled IFCB images

( 2009) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
2008 labeled IFCB images

( 2008) Sosik, Heidi M. ; Peacock, Emily E. ; Brownlee, Emily F.
Temperature regulates Synechococcus population dynamics seasonally and across the continental shelf

(Association for the Sciences of Limnology and Oceanography, 2023-05-12) Stevens, Bethany L. F. ; Crockford, E. Taylor ; Peacock, Emily E. ; Neubert, Michael G. ; Sosik, Heidi M.

Hourly, year‐round flow cytometry has made it possible to relate seasonal environmental variability to the population dynamics of the smallest, most abundant phytoplankton on the Northeast US Shelf. To evaluate whether the insights from these data extend to Synechococcus farther from shore, we analyze flow cytometry measurements made continuously from the underway systems on 21 cruises traveling between the Martha's Vineyard Coastal Observatory (MVCO) and the continental shelf break. We describe how seasonal patterns in Synechococcus , which have been documented in detail at MVCO, occur across the region with subtle variation. We find that the underlying relationship between temperature and division rate is consistent across the shelf and can explain much of the observed spatial variability in concentration. Connecting individual cell properties to annual and regional patterns in environmental conditions, these results demonstrate the value of autonomous monitoring and create an improved picture of picophytoplankton dynamics within an economically important ecosystem.
Temperature dependence of parasitoid infection and abundance of a diatom revealed by automated imaging and classification

(National Academy of Sciences, 2023-07-03) Catlett, Dylan ; Peacock, Emily E. ; Crockford, E. Taylor ; Futrelle, Joe ; Batchelder, Sidney ; Stevens, Bethany L. F. ; Gast, Rebecca J. ; Zhang, Weifeng Gordon ; Sosik, Heidi M.

Diatoms are a group of phytoplankton that contribute disproportionately to global primary production. Traditional paradigms that suggest diatoms are consumed primarily by larger zooplankton are challenged by sporadic parasitic “epidemics” within diatom populations. However, our understanding of diatom parasitism is limited by difficulties in quantifying these interactions. Here, we observe the dynamics of Cryothecomonas aestivalis (a protist) infection of an important diatom on the Northeast U.S. Shelf (NES), Guinardia delicatula, with a combination of automated imaging-in-flow cytometry and a convolutional neural network image classifier. Application of the classifier to >1 billion images from a nearshore time series and >20 survey cruises across the broader NES reveals the spatiotemporal gradients and temperature dependence of G. delicatula abundance and infection dynamics. Suppression of parasitoid infection at temperatures <4 °C drives annual cycles in both G. delicatula infection and abundance, with an annual maximum in infection observed in the fall-winter preceding an annual maximum in host abundance in the winter-spring. This annual cycle likely varies spatially across the NES in response to variable annual cycles in water temperature. We show that infection remains suppressed for ~2 mo following cold periods, possibly due to temperature-induced local extinctions of the C. aestivalis strain(s) that infect G. delicatula. These findings have implications for predicting impacts of a warming NES surface ocean on G. delicatula abundance and infection dynamics and demonstrate the potential of automated plankton imaging and classification to quantify phytoplankton parasitism in nature across unprecedented spatiotemporal scales.
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.
Unusual Hemiaulus bloom influences ocean productivity in Northeastern US Shelf waters

(European Geosciences Union, 2024-03-13) Cieza, S. Alejandra Castillo ; Stanley, Rachel H. R. ; Marrec, Pierre ; Fontaine, Diana N. ; Crockford, E. Taylor ; McGillicuddy Jr., Dennis J. ; Mehta, Arshia ; Menden-Deuer, Susanne ; Peacock, Emily E. ; Rynearson, Tatiana A. ; Sandwith, Zoe O. ; Zhang, Weifeng Gordon ; Sosik, Heidi M.

Because of its temperate location, high dynamic range of environmental conditions, and extensive human activity, the long-term ecological research site in the coastal Northeastern US Shelf (NES) of the northwestern Atlantic Ocean offers an ideal opportunity to understand how productivity shifts in response to changes in planktonic community composition. Ocean production and trophic transfer rates, including net community production (NCP), net primary production (NPP), gross oxygen production (GOP), and microzooplankton grazing rates, are key metrics for understanding marine ecosystem dynamics and associated impacts on biogeochemical cycles. Although small phytoplankton usually dominate phytoplankton community composition and Chl a concentration in the NES waters during the summer, in August 2019, a bloom of the large diatom genus Hemiaulus, with N2-fixing symbionts, was observed in the mid-shelf region. NCP was 2.5 to 9 times higher when Hemiaulus dominated phytoplankton carbon compared to NCP throughout the same geographic area during the summers of 2020–2022. The Hemiaulus bloom in summer 2019 also coincided with higher trophic transfer efficiency from phytoplankton to microzooplankton and higher GOP and NPP than in the summers 2020–2022. This study suggests that the dominance of an atypical phytoplankton community that alters the typical size distribution of primary producers can significantly influence productivity and trophic transfer, highlighting the dynamic nature of the coastal ocean. Notably, summer 2018 NCP levels were also high, although the size distribution of Chl a was typical and an atypical phytoplankton community was not observed. A better understanding of the dynamics of the NES in terms of biological productivity is of primary importance, especially in the context of changing environmental conditions due to climate processes.
Toward a synthesis of phytoplankton communities composition methods for global-scale application

(Association for the Sciences of Limnology and Oceanography (ASLO), 2024-02-23) Kramer, Sasha J. ; Bolanos, Luis M. ; Catlett, Dylan ; Chase, Alison P. ; Behrenfeld, Michael J. ; Boss, Emmanuel S. ; Crockford, E. Taylor ; Giovannoni, Stephen J. ; Graff, Jason R. ; Haentjens, Nils ; Karp-Boss, Lee ; Peacock, Emily E. ; Roesler, Collin S. ; Sosik, Heidi M. ; Siegel, David A.

The composition of the marine phytoplankton community has been shown to impact many biogeochemical processes and marine ecosystem services. A variety of methods exist to characterize phytoplankton community composition (PCC), with varying degrees of taxonomic resolution. Accordingly, the resulting PCC determinations are dependent on the method used. Here, we use surface ocean samples collected in the North Atlantic and North Pacific Oceans to compare high-performance liquid chromatography pigment-based PCC to four other methods: quantitative cell imaging, flow cytometry, and 16S and 18S rRNA amplicon sequencing. These methods allow characterization of both prokaryotic and eukaryotic PCC across a wide range of size classes. PCC estimates of many taxa resolved at the class level (e.g., diatoms) show strong positive correlations across methods, while other groups (e.g., dinoflagellates) are not well captured by one or more methods. Since variations in phytoplankton pigment concentrations are related to changes in optical properties, this combined dataset expands the potential scope of ocean color remote sensing by associating PCC at the genus- and species-level with group- or class-level PCC from pigments. Quantifying the strengths and limitations of pigment-based PCC methods compared to PCC assessments from amplicon sequencing, imaging, and cytometry methods is the first step toward the robust validation of remote sensing approaches to quantify PCC from space.
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/).
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/).

Peacock Emily E.

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