Second, in the calculation of the removal rate constants, the removal of tDON is assumed to be a slow process occurring at a constant rate over the timescale of river water residence time in Arctic surface waters. However, there may exist multiple tDON removal rates if tDON removal is rapid upon initial delivery to Arctic shelves and then slows with aging towards the open ocean (Tank et al., 2012). For example, riverine DOM can be rapidly removed during estuarine mixing at low salinities via flocculation; however, the removal of DOM via this
Ivacaftor physical process is small (
phototropism sea ice forms with a [DON] not significantly different from the [DON] found in surface marine water. Upon sea ice melt in summer, the addition of freshwater containing DON to the PSL only acts to lower the salinity, while leaving the observed [DON] essentially unchanged, e.g. a ~ 15% addition of sea ice melt freshwater reduces the salinity of the western Arctic PSL by > 4, while adding ~ 0.1 μM DON. This small effect is within the DON analytical error and does not significantly alter identification of end members.