Publication Date:
2019-07-17
Description:
Bivalve suspension-feeding can produce horizontal gradients of particulate suspended matter, or seston, which
may impair bivalve growth among other impacts to the coastal ecosystem. We proposed a method to assess the
concentration of seston at different locations along a shellfish farm by means of measurements of the depth-averaged diffuse attenuation coefficient of downwelling irradiance at 490 nm, , from at least two autonomous
buoys equipped with a vertical array of irradiance sensors. Two approaches were compared. First, horizontal gradients of chlorophyll plus phaeopigments (Chl) were calculated from using an empirical algorithm derived
from water samples. In the second approach, gradients of particulate suspended matter were calculated after correcting for the attenuation due to water and riverine colored dissolved organic matter (CDOM), estimated
from continuous in situ measurements of salinity. The method was assessed in a mussel farm in Ship Harbour
(Nova Scotia, Canada). The proposed method is relatively insensitive to the angular distribution of downwelling irradiance, biofouling, frame-shading, and wave focusing; but it cannot be easily applied in places with strong and sustained sediment resuspension. This method can complement and validate current modeling studies of seston depletion, and it can assist managerial activities and legislative requirements of shellfish aquaculture. This method can also be used to assess gradients of other ecologically relevant substances (i.e., CDOM, phytoplankton,and seston) in applications associated with sewage discharges, river runoff, harmful algal blooms, suspension-feeding invasive bivalves, and other horizontally variable phenomena in the coastal ocean.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
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