Premium
Influence of Seasonal Variability in Flux Attenuation on Global Organic Carbon Fluxes and Nutrient Distributions
Author(s) -
Melo Viríssimo Francisco,
Martin Adrian P.,
Henson Stephanie A.
Publication year - 2022
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2021gb007101
Subject(s) - flux (metallurgy) , attenuation , environmental science , seasonality , atmospheric sciences , carbon cycle , ecology , ecosystem , physics , chemistry , biology , organic chemistry , optics
The biological carbon pump is a key component of the marine carbon cycle. This surface‐to‐deep flux of carbon is usually assumed to follow a simple power law function, which imposes that the surface export flux is attenuated throughout subsurface waters at a rate dictated by the parameterization exponent. This flux attenuation exponent is widely assumed as constant. However, there is increasing evidence that the flux attenuation varies both spatially and seasonally. While the former has received some attention, the consequences of the latter have not been explored. Here we aim to fill the gap with a theoretical study of how seasonal changes in both flux attenuation and sinking speed affect nutrient distributions and carbon fluxes. Using a global ocean‐biogeochemical model that represents detritus explicitly, we look at different scenarios for how these varies seasonally, particularly the relative “phase” with respect to solar radiation and the “strength” of seasonality. We show that the sole presence of seasonality in the model‐imposed flux attenuation and sinking speed leads to a greater transfer efficiency compared to the non‐seasonal flux attenuation scenario, resulting in an increase of over 140% in some cases when the amplitude of the seasonality imposed is 60% of the non‐seasonal base value. This work highlights the importance of the feedback taking place between the seasonally varying flux attenuation, sinking speed and other processes, suggesting that the assumption of constant‐in‐time flux attenuation and sinking speed might underestimate how much carbon is sequestered by the biological carbon pump.