@article {castillo_cieza_unusual_2024,
	title = {Unusual \textit{Hemiaulus bloom influences ocean productivity in Northeastern US Shelf waters},
	journal = {Biogeosciences},
	volume = {21},
	number = {5},
	year = {2024},
	note = {Publisher: Copernicus GmbH},
	month = {mar},
	pages = {1235{\textendash}1257},
	abstract = {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{\textendash}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{\textendash}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.},
	issn = {1726-4170},
	doi = {10.5194/bg-21-1235-2024},
	url = {https://bg.copernicus.org/articles/21/1235/2024/},
	author = {Castillo Cieza, S. Alejandra and Stanley, Rachel H. R. and Marrec, Pierre and Fontaine, Diana N. and Crockford, E. Taylor and McGillicuddy Jr., Dennis J. and Mehta, Arshia and Menden-Deuer, Susanne and Peacock, Emily E. and Rynearson, Tatiana A. and Sandwith, Zoe O. and Zhang, Weifeng and Sosik, Heidi M.}
}
@mastersthesis {mehta_spatial_2022,
	title = {Spatial and Temporal Heterogeneity in Net Community Production in the Crossshelf Direction of the Atlantic Northeastern Shelf},
	volume = {Honors in Chemistry},
	year = {2022},
	month = {04/2022},
	school = {Wellesley College},
	type = {BS},
	address = {Wellesley, MA},
	abstract = {The ocean, via physical and biological processes, absorbs 25\% of anthropogenic CO2 emissions. Climate change, however, hampers the ocean{\textquoteright}s ability to sequester carbon. The Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) project works to understand how warmer temperatures and increased environmental variability, caused by climate change, affects planktonic food webs and the productivity of the Northeast U.S. Continental Shelf ecosystem. Gas tracers, such as O2/Ar ratios and triple oxygen isotopes, are used to quantify productivity in the form of Net Community Production (NCP) and Gross Oxygen Production (GOP), respectively. NCP represents the total amount of photosynthesis minus community respiration, whereas GOP is the total amount of oxygen produced from photosynthesis. Summer and winter data from eight NES-LTER cruises between 2018-2021 enables the analysis of spatial heterogeneity and small-scale variability in productivity rates on seasonal and annual timescales . Data reveals that NCP rates are highest at mid-shelf latitudes and are smaller than expected in coastal nearshore waters of the NES. We examine temperature, salinity, transport of deeper slope waters, benthic respiration consuming oxygen, phytoplankton community structure, GOP rates, and nutrient availability to better understand cross-shelf variability in NCP. We find that, in winter, respiration from the benthic component is likely to have lowered NCP in nearshore waters, resulting in the observed peaks at mid-shelf latitudes. In summer, patterns of NCP closely follow phytoplankton biovolume, suggesting that the mid-shelf peak in NCP is related to changes in phytoplankton community abundance or structure.},
	url = {https://repository.wellesley.edu/islandora/object/ir\%3A1739/},
	author = {Mehta, Arshia}
}
@article {RN200,
	title = {A regional, early spring bloom of Phaeocystis pouchetii on the New England continental shelf},
	journal = {Journal of Geophysical Research - Oceans},
	year = {2021},
	type = {Journal Article},
	abstract = {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 {\textmu}g L-1 and particulate organic carbon levels > 95 {\textmu}mol L-1. Initially, the bloom was largely confined to waters with temperatures <6{\textdegree}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.},
	doi = {10.1029/2020jc016856},
	url = {https://app.dimensions.ai/details/publication/pub.1134619519},
	author = {Smith, Walker O. and Zhang, Weifeng and Hirzel, Andrew and Stanley, Rachel M. and Meyer, Meredith G. and Sosik, Heidi and Alatalo, Philip and Oliver, Hilde and Sandwith, Zoe and Crockford, Taylor and Peacock, Emily E. and Mehta, Arshia and McGillicuddy, Dennis J.}
}
