In:
Ocean Science, Copernicus GmbH, Vol. 18, No. 2 ( 2022-04-07), p. 455-468
Abstract:
Abstract. There have been considerable efforts to understand the hydrography
of Storfjorden (Svalbard). A recurring winter polynya with large
sea ice production makes it an important region of dense water formation at
the scale of the Arctic Ocean. In addition, this fjord is seasonally
influenced by freshwater inputs from sea ice melt and the surrounding
islands of the Svalbard archipelago, which impacts the hydrography. However,
the understanding of factors controlling the optical properties of the
waters in Storfjorden are lacking and are crucial for the development of more
accurate regional bio-optical models. Here, we present results from the
first detailed optical field survey of Storfjorden conducted in early summer
of 2020. Our observations are based on spectrometric analysis of water
samples and in situ vertical profiles with an absorption and attenuation
meter, a fluorometer, and a conductivity, temperature, and depth (CTD) sensor.
In addition to the expected seasonal contribution from phytoplankton, we
find that in early summer waters in Storfjorden are optically complex with a
significant contribution from coloured dissolved organic matter (CDOM,
33 %–64 % of the non-water absorption at 443 nm) despite relatively low
CDOM concentrations and in the nearshore or near the seabed from non-algal
particles (up to 61 % of the non-water absorption at 550 nm). In surface
waters, the spatial variability of light attenuation was mainly controlled
by inorganic suspended matter originating from river runoff. A distinct
subsurface maximum of light attenuation was largely driven by a subsurface
phytoplankton bloom, controlled by stratification resulting from sea ice
melt. Lastly, the cold dense bottom waters of Storfjorden from winter sea
ice production periodically overflows the sill at the mouth of the fjord and
can thus reach the Fram Strait. It contained elevated levels of both
non-algal particles and dissolved organic matter, which are likely caused by
the dense flows of the nepheloid layer interacting with the sea bed.
Type of Medium:
Online Resource
ISSN:
1812-0792
DOI:
10.5194/os-18-455-2022
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2022
detail.hit.zdb_id:
2183769-7
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