“Industrial-era decline in subarctic Atlantic productivity”, by Osman, Das, et al


Marine phytoplankton have a crucial role in the modulation of marine-based food webs [1], fishery yields [2] and the global drawdown of atmospheric carbon dioxide [3]. However, owing to sparse measurements before satellite monitoring in the twenty-first century, the long-term response of planktonic stocks to climate forcing is unknown. Here, using a continuous, multi-century record of subarctic Atlantic marine productivity, we show that a marked 10 ± 7% decline in net primary productivity has occurred across this highly productive ocean basin over the past two centuries. We support this conclusion by the application of a marine-productivity proxy, established using the signal of the planktonic-derived aerosol methanesulfonic acid, which is commonly identified across an array of Greenlandic ice cores. Using contemporaneous satellite-era observations, we demonstrate the use of this signal as a robust and high-resolution proxy for past variations in spatially integrated marine productivity. We show that the initiation of declining subarctic Atlantic productivity broadly coincides with the onset of Arctic surface warming [4], and that productivity strongly covaries with regional sea-surface temperatures and basin-wide gyre circulation strength over recent decades. Taken together, our results suggest that the decline in industrial-era productivity may be evidence of the predicted [5] collapse of northern Atlantic planktonic stocks in response to a weakened Atlantic Meridional Overturning Circulation [6–8]. Continued weakening of this Atlantic Meridional Overturning Circulation, as projected for the twenty-first century [9,10], may therefore result in further productivity declines across this globally relevant region.

(Emphasis added.)

Article about the investigation at WHOI.

The paper using a technique devised by Chaudhuri and Marron called SiZer.

There is an R package for it.

Hannig and Marron published a more recent article, and Marron has studied its applications extensively.

The figure below is from

N. J. Abram, et al, “Early onset of industrial-era warming across the oceans and continents”, Nature, 2016, 536, with corrigendum in 2017.

where SiZer is used in a geophysical application cited by Osman, Das, et al.

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