Pugh Tracy L.

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Pugh
First Name
Tracy L.
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  • Dataset
    Southern Cape Cod Bay hypoxia data
    (Woods Hole Oceanographic Institution, 2022-01-14) Scully, Malcolm E. ; Pugh, Tracy L. ; Geyer, W. Rockwell ; Costa, Amy ; Nichols, Owen C.
    This project investigated the distribution of low dissolved oxygen bottom waters (hypoxia) in southern Cape Cod Bay. Hypoxia was documented for the first time in late summer 2019 and 2020 despite extensive monitoring for the past decade. The data include: 1) measurements of bottom dissolved oxygen collected in 2019 by the Massachusetts Division of Marine Fisheries (MDMF) and the Center for Coastal Studies (CCS) ; 2) full water column profiles of temperature, salinity, chlorophyll fluorescence, dissolved oxygen concentration and optical backscatter collected in late summer 2020 by the Woods Hole Oceanographic Institution (WHOI); 3) monthly water quality data including CTD with dissolved oxygen and chlorophyll fluorescence and discrete bottom samples analyzed for dissolved nutrients collected by the CCS for the period 2011-2020; 4) inorganic nutrients from discrete surface and bottom samples collected monthly for the period 2006-2020; 5) bottom temperature data collected the Wreck of Mars location by the MDMF over the period 1991-2021. There are four separate data sets included: 1) MDMF and CCS bottom dissolved oxygn from 2019; 2) CTD and ancillary data collected by WHOI in 2019; 3) CCS monthly survey data from 2011-2020; and 4) bottom temperature data collected by MDMF for 1991-2021. 1) MDMF/CCS dissolved oxygen data was collected from ship-based surveys using an YSI 6920 V2-2 data sonde; 2) WHOI CTD data was collected from vertical casts made from a small research vessel using an RBR CTD; 3) CCS CTD data was collected from vertical casts made from a small research vessel using a SeaBird Electronics CTD; 4) MDMF temperature data was collected from a bottom mounted temperature logger. Related Publications: Scully, M.E., W.R. Geyer, D. Borkman, T.L. Pouch, A. Costa, and O.C. Nichols, in press. Unprecedented summer hypoxia in southern Cape Cod Bay: An ecological response to regional climate change? Biogeosciences.
  • Dataset
    Understanding the cause of low dissolved oxygen in Cape Cod Bay and initiating a hypoxia warning system for the lobster fishery
    (Woods Hole Oceanographic Institution, 2024-12-13) Scully, Malcolm E. ; Geyer, W. Rockwell ; Pugh, Tracy L. ; Costa, Amy ; Nichols, Owen C.
    Bottom hypoxia was observed in late summer 2019 and 2020 in southern Cape Cod Bay, resulting in significant benthic mortality of lobsters, scallops and some fish species. To investigate and better understand what caused this unprecedented hypoxia, these data were collected with funding the NOAA Sea Grant American Lobster Initiative . Data consist of vertical profiles collected with a CTD equipped with dissolved oxygen sensor, chlorophyll fluorometer and optical backscatter sensor. Data collection focused on late summer when physical conditions conducive to hypoxia are most common and included 2020, 2021, 2022, and 2023.
  • Article
    Unprecedented summer hypoxia in southern Cape Cod Bay: an ecological response to regional climate change?
    (European Geosciences Union, 2022-07-28) Scully, Malcolm E. ; Geyer, W. Rockwell ; Borkman, David ; Pugh, Tracy L. ; Costa, Amy ; Nichols, Owen C.
    In late summer 2019 and 2020 bottom waters in southern Cape Cod Bay (CCB) became depleted of dissolved oxygen (DO), with documented benthic mortality in both years. Hypoxic conditions formed in relatively shallow water where the strong seasonal thermocline intersected the sea floor, both limiting vertical mixing and concentrating biological oxygen demand (BOD) over a very thin bottom boundary layer. In both 2019 and 2020, anomalously high sub-surface phytoplankton blooms were observed, and the biomass from these blooms provided the fuel to deplete sub-pycnocline waters of DO. The increased chlorophyll fluorescence was accompanied by a corresponding decrease in sub-pycnocline nutrients, suggesting that prior to 2019 physical conditions were unfavorable for the utilization of these deep nutrients by the late-summer phytoplankton community. It is hypothesized that significant alteration of physical conditions in CCB during late summer, which is the result of regional climate change, has favored the recent increase in sub-surface phytoplankton production. These changes include rapidly warming waters and significant shifts in summer wind direction, both of which impact the intensity and vertical distribution of thermal stratification and vertical mixing within the water column. These changes in water column structure are not only more susceptible to hypoxia but also have significant implications for phytoplankton dynamics, potentially allowing for intense late-summer blooms of Karenia mikimotoi, a species new to the area. K. mikimotoi had not been detected in CCB or adjacent waters prior to 2017; however, increasing cell densities have been reported in subsequent years, consistent with a rapidly changing ecosystem.