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Katherine R. M. Mackey
Earth System Science, University of California Irvine, 3204 Croul Hall, Irvine, CA 92697, USA

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Review
Published: 19 October 2018 in Hydrology
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Submarine groundwater discharge (SGD) is a global and well-studied geological process by which groundwater of varying salinities enters coastal waters. SGD is known to transport bioactive solutes, including but not limited to nutrients (nitrogen, phosphorous, silica), gases (methane, carbon dioxide), and trace metals (iron, nickel, zinc). In addition, physical changes to the water column, such as changes in temperature and mixing can be caused by SGD. Therefore SGD influences both autotrophic and heterotrophic marine biota across all kingdoms of life. This paper synthesizes the current literature in which the impacts of SGD on marine biota were measured and observed by field, modeling, or laboratory studies. The review is grouped by organismal complexity: bacteria and phytoplankton, macrophytes (macroalgae and marine plants), animals, and ecosystem studies. Directions for future research about the impacts of SGD on marine life, including increasing the number of ecosystem assessment studies and including biological parameters in SGD flux studies, are also discussed.

ACS Style

Alanna L. Lecher; Katherine R. M. Mackey. Synthesizing the Effects of Submarine Groundwater Discharge on Marine Biota. Hydrology 2018, 5, 60 .

AMA Style

Alanna L. Lecher, Katherine R. M. Mackey. Synthesizing the Effects of Submarine Groundwater Discharge on Marine Biota. Hydrology. 2018; 5 (4):60.

Chicago/Turabian Style

Alanna L. Lecher; Katherine R. M. Mackey. 2018. "Synthesizing the Effects of Submarine Groundwater Discharge on Marine Biota." Hydrology 5, no. 4: 60.

Review
Published: 19 March 2018 in Sustainability
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The world’s oceans are a major sink for atmospheric carbon dioxide (CO2). The biological carbon pump plays a vital role in the net transfer of CO2 from the atmosphere to the oceans and then to the sediments, subsequently maintaining atmospheric CO2 at significantly lower levels than would be the case if it did not exist. The efficiency of the biological pump is a function of phytoplankton physiology and community structure, which are in turn governed by the physical and chemical conditions of the ocean. However, only a few studies have focused on the importance of phytoplankton community structure to the biological pump. Because global change is expected to influence carbon and nutrient availability, temperature and light (via stratification), an improved understanding of how phytoplankton community size structure will respond in the future is required to gain insight into the biological pump and the ability of the ocean to act as a long-term sink for atmospheric CO2. This review article aims to explore the potential impacts of predicted changes in global temperature and the carbonate system on phytoplankton cell size, species and elemental composition, so as to shed light on the ability of the biological pump to sequester carbon in the future ocean.

ACS Style

Samarpita Basu; Katherine Mackey. Phytoplankton as Key Mediators of the Biological Carbon Pump: Their Responses to a Changing Climate. Sustainability 2018, 10, 869 .

AMA Style

Samarpita Basu, Katherine Mackey. Phytoplankton as Key Mediators of the Biological Carbon Pump: Their Responses to a Changing Climate. Sustainability. 2018; 10 (3):869.

Chicago/Turabian Style

Samarpita Basu; Katherine Mackey. 2018. "Phytoplankton as Key Mediators of the Biological Carbon Pump: Their Responses to a Changing Climate." Sustainability 10, no. 3: 869.

Journal article
Published: 19 December 2017 in Hydrology
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The Gulf of Alaska is a highly productive ecosystem that supports fisheries and subsistence harvesting of marine resources. The highly productive summer season begins with a bloom that is dominated by diatoms. Both river and submarine groundwater discharge have been recognized as substantial terrestrial nutrient (nitrate and silicate) sources to the Gulf’s coastal waters. Here, the response of in-situ phytoplankton to groundwater and river water additions was evaluated via a bioassay incubation experiment. Special attention was given to diatom genera, as previous studies have shown that submarine groundwater discharge preferentially induces growth of diatoms. The abundance of Pseudo-nitzschia spp., Chaetoceros spp., and Leptocylindrus spp. increased significantly in groundwater and river water containing treatments. Although groundwater and river water are both rich in nitrate and silicate, groundwater treatments with a higher salinity favored a higher relative abundance of Pseudo-nitzschia spp. Conversely, in the highest river water concentration treatments with lower salinity, relative abundances of Pseudo-nitzschia spp. decreased, while Chaetoceros spp. and Leptocylindrus spp. increased. Total abundances of all three genera increased in the lower salinity treatments. These findings could portend changes in the phytoplankton community composition in the Gulf of Alaska as the climate warms and river discharge increases in the coming decades. Furthermore, the findings support previous assertions that submarine groundwater discharge, with higher salinity than river water, is a preferable source of nutrients to the genus Pseudo-nitzschia.

ACS Style

Alanna L. Lecher; Katherine R. M. Mackey; Adina Paytan. River and Submarine Groundwater Discharge Effects on Diatom Phytoplankton Abundance in the Gulf of Alaska. Hydrology 2017, 4, 61 .

AMA Style

Alanna L. Lecher, Katherine R. M. Mackey, Adina Paytan. River and Submarine Groundwater Discharge Effects on Diatom Phytoplankton Abundance in the Gulf of Alaska. Hydrology. 2017; 4 (4):61.

Chicago/Turabian Style

Alanna L. Lecher; Katherine R. M. Mackey; Adina Paytan. 2017. "River and Submarine Groundwater Discharge Effects on Diatom Phytoplankton Abundance in the Gulf of Alaska." Hydrology 4, no. 4: 61.

Original research article
Published: 09 August 2017 in Frontiers in Microbiology
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Synechococcus are ubiquitous and cosmopolitan cyanobacteria that play important roles in global productivity and biogeochemical cycles. This study investigated the fine scale microdiversity, seasonal patterns, and spatial distributions of Synechococcus in estuarine waters of Little Sippewissett salt marsh (LSM) on Cape Cod, MA. The proportion of Synechococcus reads was higher in the summer than winter, and higher in coastal waters than within the estuary. Variations in the V4–V6 region of the bacterial 16S rRNA gene revealed 12 unique Synechococcus oligotypes. Two distinct communities emerged in early and late summer, each comprising a different set of statistically co-occurring Synechococcus oligotypes from different clades. The early summer community included clades I and IV, which correlated with lower temperature and higher dissolved oxygen levels. The late summer community included clades CB5, I, IV, and VI, which correlated with higher temperatures and higher salinity levels. Four rare oligotypes occurred in the late summer community, and their relative abundances more strongly correlated with high salinity than did other co-occurring oligotypes. The analysis revealed that multiple, closely related oligotypes comprised certain abundant clades (e.g., clade 1 in the early summer and clade CB5 in the late summer), but the correlations between these oligotypes varied from pair to pair, suggesting they had slightly different niches despite being closely related at the clade level. Lack of tidal water exchange between sampling stations gave rise to a unique oligotype not abundant at other locations in the estuary, suggesting physical isolation plays a role in generating additional microdiversity within the community. Together, these results contribute to our understanding of the environmental and ecological factors that influence patterns of Synechococcus microbial community composition over space and time in salt marsh estuarine waters.

ACS Style

Katherine R. M. Mackey; Kristen Hunter-Cevera; Gregory L. Britten; Leslie G. Murphy; Mitchell L. Sogin; Julie A. Huber. Seasonal Succession and Spatial Patterns of Synechococcus Microdiversity in a Salt Marsh Estuary Revealed through 16S rRNA Gene Oligotyping. Frontiers in Microbiology 2017, 8, 1496 -1496.

AMA Style

Katherine R. M. Mackey, Kristen Hunter-Cevera, Gregory L. Britten, Leslie G. Murphy, Mitchell L. Sogin, Julie A. Huber. Seasonal Succession and Spatial Patterns of Synechococcus Microdiversity in a Salt Marsh Estuary Revealed through 16S rRNA Gene Oligotyping. Frontiers in Microbiology. 2017; 8 ():1496-1496.

Chicago/Turabian Style

Katherine R. M. Mackey; Kristen Hunter-Cevera; Gregory L. Britten; Leslie G. Murphy; Mitchell L. Sogin; Julie A. Huber. 2017. "Seasonal Succession and Spatial Patterns of Synechococcus Microdiversity in a Salt Marsh Estuary Revealed through 16S rRNA Gene Oligotyping." Frontiers in Microbiology 8, no. : 1496-1496.

Journal article
Published: 29 May 2017 in Environmental Microbiology
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Marine Synechococcus thrive over a range of light regimes in the ocean. We examined the proteomic, genomic and physiological responses of seven Synechococcus isolates to moderate irradiances (5–80 μE m−2 s−1), and show that Synechococcus spans a continuum of light responses ranging from low light optimized (LLO) to high light optimized (HLO). These light responses are linked to phylogeny and pigmentation. Marine sub-cluster 5.1A isolates with higher phycouribilin: phycoerythrobilin ratios fell toward the LLO end of the continuum, while sub-cluster 5.1B, 5.2 and estuarine Synechococcus with less phycouribilin fell toward the HLO end of the continuum. Global proteomes were highly responsive to light, with > 50% of abundant proteins varying more than twofold between the lowest and highest irradiance. All strains downregulated phycobilisome proteins with increasing irradiance. Regulation of proteins involved in photosynthetic electron transport, carbon fixation, oxidative stress protection (superoxide dismutases) and iron and nitrogen metabolism varied among strains, as did the number of high light inducible protein (Hlip) and DNA photolyase genes in their genomes. All but one LLO strain possessed the photoprotective orange carotenoid protein (OCP). The unique combinations of light responses in each strain gives rise to distinct photophysiological phenotypes that may affect Synechococcus distributions in the ocean.

ACS Style

Katherine R. M. Mackey; Anton F. Post; Matthew R. McIlvin; Mak A. Saito. Physiological and proteomic characterization of light adaptations in marineSynechococcus. Environmental Microbiology 2017, 19, 2348 -2365.

AMA Style

Katherine R. M. Mackey, Anton F. Post, Matthew R. McIlvin, Mak A. Saito. Physiological and proteomic characterization of light adaptations in marineSynechococcus. Environmental Microbiology. 2017; 19 (6):2348-2365.

Chicago/Turabian Style

Katherine R. M. Mackey; Anton F. Post; Matthew R. McIlvin; Mak A. Saito. 2017. "Physiological and proteomic characterization of light adaptations in marineSynechococcus." Environmental Microbiology 19, no. 6: 2348-2365.

Original research article
Published: 20 January 2017 in Frontiers in Marine Science
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Chinese coastal waters support vast fisheries and vital economies, but their productivity is threatened by increasingly frequent harmful algal blooms (HABs). Here we provide direct experimental evidence that atmospheric deposition, along with riverine input, opens new niches for bloom-forming dinoflagellates and diatoms in the East China Sea (ECS) by increasing the ratio of nitrogen to phosphorus (N:P), inducing severe P limitation, and altering trace metal micronutrient inventories. Remote sensing analysis of blooms in the region showed that dinoflagellate blooms were associated with increased aerosol optical thickness and decreased sea surface temperature, whereas diatom blooms were primarily associated with seasonally decreased temperature (e.g. during spring blooms). Bottle incubation experiments revealed that aerosol additions approximating 10 days of strong deposition increased iron availability and intensified P limitation, which together promoted dinoflagellate growth in offshore waters. Diatom growth was correlated with elevated trace metal and nutrient content from aerosols. Aerosols did not induce phytoplankton growth at a station within the Yangtze River plume where light was limiting, consistent with remote sensing observations that aerosol effects are stronger in offshore waters. Eutrophication and trace metal enrichment from Yangtze River discharge together with atmospheric deposition may underlie the transition from diatom-dominated spring blooms toward more frequent spring and summer dinoflagellate blooms that has occurred over the past three decades in the ECS.

ACS Style

Katherine R. M. Mackey; Maria Kavanaugh; Fujiang Wang; Ying Chen; Fei Liu; David M. Glover; Chia-Te Chien; Adina Paytan. Atmospheric and Fluvial Nutrients Fuel Algal Blooms in the East China Sea. Frontiers in Marine Science 2017, 4, 1 .

AMA Style

Katherine R. M. Mackey, Maria Kavanaugh, Fujiang Wang, Ying Chen, Fei Liu, David M. Glover, Chia-Te Chien, Adina Paytan. Atmospheric and Fluvial Nutrients Fuel Algal Blooms in the East China Sea. Frontiers in Marine Science. 2017; 4 ():1.

Chicago/Turabian Style

Katherine R. M. Mackey; Maria Kavanaugh; Fujiang Wang; Ying Chen; Fei Liu; David M. Glover; Chia-Te Chien; Adina Paytan. 2017. "Atmospheric and Fluvial Nutrients Fuel Algal Blooms in the East China Sea." Frontiers in Marine Science 4, no. : 1.

Journal article
Published: 27 July 2015 in Proceedings of the National Academy of Sciences
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MarineSynechococcusare some of the most diverse and ubiquitous phytoplankton, and iron (Fe) is an essential micronutrient that limits productivity in many parts of the ocean. To investigate how coastal and oceanic AtlanticSynechococcusstrains acclimate to Fe availability, we compared the growth, photophysiology, and quantitative proteomics of twoSynechococcusstrains from different Fe regimes.Synechococcusstrain WH8102, from a region in the southern Sargasso Sea that receives substantial dust deposition, showed impaired growth and photophysiology as Fe declined, yet used few acclimation responses. Coastal WH8020, from the dynamic, seasonally variable New England shelf, displayed a multitiered, hierarchical cascade of acclimation responses with different Fe thresholds. The multitiered response included changes in Fe acquisition, storage, and photosynthetic proteins, substitution of flavodoxin for ferredoxin, and modified photophysiology, all while maintaining remarkably stable growth rates over a range of Fe concentrations. Modulation of two distinct ferric uptake regulator (Fur) proteins that coincided with the multitiered proteome response was found, implying the coastal strain has different regulatory threshold responses to low Fe availability. Low nitrogen (N) and phosphorus (P) availability in the open ocean may favor the loss of Fe response genes when Fe availability is consistent over time, whereas these genes are retained in dynamic environments where Fe availability fluctuates and N and P are more abundant.

ACS Style

Katherine R. M. Mackey; Anton F. Post; Matthew R. McIlvin; Gregory Cutter; Seth G. John; Mak A. Saito. Divergent responses of Atlantic coastal and oceanicSynechococcusto iron limitation. Proceedings of the National Academy of Sciences 2015, 112, 9944 -9949.

AMA Style

Katherine R. M. Mackey, Anton F. Post, Matthew R. McIlvin, Gregory Cutter, Seth G. John, Mak A. Saito. Divergent responses of Atlantic coastal and oceanicSynechococcusto iron limitation. Proceedings of the National Academy of Sciences. 2015; 112 (32):9944-9949.

Chicago/Turabian Style

Katherine R. M. Mackey; Anton F. Post; Matthew R. McIlvin; Gregory Cutter; Seth G. John; Mak A. Saito. 2015. "Divergent responses of Atlantic coastal and oceanicSynechococcusto iron limitation." Proceedings of the National Academy of Sciences 112, no. 32: 9944-9949.

Original research article
Published: 21 January 2015 in Frontiers in Microbiology
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Atmospheric deposition is a major source of trace metals in marine surface waters and supplies vital micronutrients to phytoplankton, yet measured aerosol trace metal solubility values are operationally defined and there are relatively few multi-element studies on aerosol-metal solubility in seawater. Here we measure the solubility of aluminum (Al), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) from natural aerosol samples in seawater over a 7 day period to (1) evaluate the role of extraction time in trace metal dissolution behavior and (2) explore how the individual dissolution patterns could influence biota. Dissolution behavior occurs over a continuum ranging from rapid dissolution, in which the majority of soluble metal dissolved immediately upon seawater exposure (Cd and Co in our samples), to gradual dissolution, where metals dissolved slowly over time (Zn, Mn, Cu, and Al in our samples). Additionally, dissolution affected by interactions with particles was observed in which a decline in soluble metal concentration over time occurred (Fe and Pb in our samples). Natural variability in aerosol chemistry between samples can cause metals to display different dissolution kinetics in different samples, and this was particularly evident for Ni, for which samples showed a broad range of dissolution rates. The elemental molar ratio of metals in the bulk aerosols was 23,189Fe: 22,651Al: 445Mn: 348Zn: 71Cu: 48Ni: 23Pb: 9Co: 1Cd, whereas the seawater soluble molar ratio after 7 days of leaching was 11Fe: 620Al: 205Mn: 240Zn: 20Cu: 14Ni: 9Pb: 2Co: 1Cd. The different kinetics and ratios of aerosol metal dissolution have implications for phytoplankton nutrition, and highlight the need for unified extraction protocols that simulate aerosol metal dissolution in the surface ocean.

ACS Style

Katherine Rose Marie Mackey; Chia-Te Chien; Anton F. Post; Mak A. Saito; Adina Epaytan. Rapid and gradual modes of aerosol trace metal dissolution in seawater. Frontiers in Microbiology 2015, 5, 794 .

AMA Style

Katherine Rose Marie Mackey, Chia-Te Chien, Anton F. Post, Mak A. Saito, Adina Epaytan. Rapid and gradual modes of aerosol trace metal dissolution in seawater. Frontiers in Microbiology. 2015; 5 ():794.

Chicago/Turabian Style

Katherine Rose Marie Mackey; Chia-Te Chien; Anton F. Post; Mak A. Saito; Adina Epaytan. 2015. "Rapid and gradual modes of aerosol trace metal dissolution in seawater." Frontiers in Microbiology 5, no. : 794.

Original research article
Published: 20 November 2014 in Frontiers in Microbiology
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Coastal California is a dynamic upwelling region where nitrogen (N) and iron (Fe) can both limit productivity and influence biogeochemistry over different spatial and temporal scales. With global change, the flux of nitrate from upwelling is expected to increase over the next century, potentially driving additional oceanic regions toward Fe limitation. In this study we explored the effect of changes in Fe/N ratio on native phytoplankton from five currently Fe-replete sites near the major California upwelling centers at Bodega Bay and Monterey Bay using nutrient addition incubation experiments. Despite the high nitrate levels (13-30 M) in the upwelled water, phytoplankton at three of the five sites showed increased growth when 10 M nitrate was added. None of the sites showed enhanced growth following addition of 10 nM Fe. Nitrate additions favored slow sinking single-celled diatoms over faster sinking chain-forming diatoms, suggesting that future increases in nitrate flux could affect carbon and silicate export and alter grazer populations. In particular, solitary cells of Cylindrotheca were more abundant than the toxin-producing genus Pseudonitzschia following nitrate addition. These responses suggest the biogeochemistry of coastal California could change in response to future increases in nitrate, and multiple stressors like ocean acidification and hypoxia may further result in ecosystem shifts.

ACS Style

Katherine R. M. Mackey; Chia-Te Chien; Adina Paytan. Microbial and biogeochemical responses to projected future nitrate enrichment in the California upwelling system. Frontiers in Microbiology 2014, 5, 632 .

AMA Style

Katherine R. M. Mackey, Chia-Te Chien, Adina Paytan. Microbial and biogeochemical responses to projected future nitrate enrichment in the California upwelling system. Frontiers in Microbiology. 2014; 5 ():632.

Chicago/Turabian Style

Katherine R. M. Mackey; Chia-Te Chien; Adina Paytan. 2014. "Microbial and biogeochemical responses to projected future nitrate enrichment in the California upwelling system." Frontiers in Microbiology 5, no. : 632.