Lapointe ​​Brian E.

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Last Name
Lapointe
First Name
​​Brian E.
ORCID
0000-0002-6187-1913

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Now showing 1 - 2 of 2
  • Article
    Nutrient content and stoichiometry of pelagic Sargassum reflects increasing nitrogen availability in the Atlantic Basin
    (Nature Research, 2021-05-24) Lapointe, ​​Brian E. ; Brewton, Rachel A. ; Herren, Laura W. ; Wang, Mengqiu ; Hu, Chuanmin ; McGillicuddy, Dennis J. ; Lindell, Scott ; Hernandez, Frank J. ; Morton, Peter L.
    The pelagic brown macroalgae Sargassum spp. have grown for centuries in oligotrophic waters of the North Atlantic Ocean supported by natural nutrient sources, such as excretions from associated fishes and invertebrates, upwelling, and N2 fixation. Using a unique historical baseline, we show that since the 1980s the tissue %N of Sargassum spp. has increased by 35%, while %P has decreased by 44%, resulting in a 111% increase in the N:P ratio (13:1 to 28:1) and increased P limitation. The highest %N and δ15N values occurred in coastal waters influenced by N-rich terrestrial runoff, while lower C:N and C:P ratios occurred in winter and spring during peak river discharges. These findings suggest that increased N availability is supporting blooms of Sargassum and turning a critical nursery habitat into harmful algal blooms with catastrophic impacts on coastal ecosystems, economies, and human health.
  • Article
    Nutrient and arsenic biogeochemistry of Sargassum in the western Atlantic
    (Nature Research, 2023-10-05) McGillicuddy Jr., Dennis Joseph ; Morton, Peter Lynn ; Brewton, Rachel Aileen ; Hu, Chuanmin ; Kelly, Thomas Bryce ; Solow, Andrew Robert ; Lapointe, Brian Edward
    The oceanographic ecology of pelagic Sargassum, and the means by which these floating macroalgae thrive in the nutrient-poor waters of the open ocean, have been studied for decades. Beginning in 2011, the Great Atlantic Sargassum Belt (GASB) emerged, with Sargassum proliferating in the tropical Atlantic and Caribbean where it had not previously been abundant. Here we show that the nutritional status of Sargassum in the GASB is distinct, with higher nitrogen and phosphorus content than populations residing in its Sargasso Sea habitat. Moreover, we find that variations in arsenic content of Sargassum reflect phosphorus limitation, following a hyperbolic relationship predicted from Michaelis-Menten nutrient uptake kinetics. Although the sources of nutrients fueling the GASB are not yet clear, our results suggest that nitrogen and phosphorus content of Sargassum, together with its isotopic composition, can be used to identify those sources, whether they be atmospheric, oceanic, or riverine in origin.