Journal of Physical Oceanography,
Journal Year:
2022,
Volume and Issue:
unknown
Published: Aug. 29, 2022
Abstract
Previous
in-situ
observations
have
suggested
that
bottom
water
temperature
variations
in
shelf
seas
can
drive
significant
ocean
heat
flux
(BHF)
by
conduction.
The
BHF-driven
variations,
however,
been
overlooked
general
circulation
models.
In
this
study,
we
established
a
sea-sediment
fully
coupled
model
through
incorporating
the
BHF.
included
sediment
module/model,
and
BHF
was
calculated
based
on
content
variations.
Meanwhile,
applied
temporally
varying
calculation
of
temperature,
which
further
determined
temperature.
two-way
process
presents
more
complete
physically
reasonable
budget
synchronously
profile.
validated
using
one-dimensional
test
case,
then
it
domain
covering
Bohai
Yellow
Seas.
results
suggest
when
strong
thermocline
exists,
change
than
1°C
because
effects
are
limited
to
within
shallow
layer.
However,
column
is
well
mixed,
changes
entire
column,
transported
across
boundary
ventilated
atmosphere.
Thus,
has
less
effect
may
directly
affect
air-sea
flux.
interactions
dampen
amplitude
propose
calling
seabed
d
ampening
h
eat
variation
mechanism
(SDH).
Journal of Marine Science and Engineering,
Journal Year:
2025,
Volume and Issue:
13(2), P. 359 - 359
Published: Feb. 15, 2025
Monitoring
bottom
dissolved
oxygen
(DO)
is
crucial
for
understanding
hypoxia,
a
threat
to
marine
ecosystems
and
fisheries.
However,
traditional
observations
are
limited
in
spatiotemporal
coverage,
while
numerical
models
consume
tremendous
computing
resources.
This
study
develops
an
interpretable
machine
learning
framework
simulate
the
DO
distribution
on
East
China
Sea
(ECS)
shelf
explore
its
potential
driving
mechanisms.
By
integrating
remote
sensing,
situ
observations,
model
outputs,
generates
high-resolution
(4
km)
estimates
from
1998
2024.
Validation
against
independent
datasets
confirms
improved
accuracy
spatial
resolution,
with
RMSE
below
1
mg/L.
The
results
reveal
persistent
decline
DO,
strongly
linked
rising
sea
surface
temperature
(SST),
underscoring
role
of
warming
water
deoxygenation.
Model
interpretability
further
identifies
SST
bathymetry
as
key
factors.
provides
robust
tool
assessing
trends,
their
ecological
impacts,
supporting
future
monitoring
management
ECS
shelf.
Frontiers in Marine Science,
Journal Year:
2022,
Volume and Issue:
9
Published: May 20, 2022
Details
of
the
development
coastal
hypoxia
in
response
to
passage
Typhoon
Bavi
(2020)
East
China
Sea
were
reconstructed
by
numerical
modeling
using
a
three-dimensional
coupled
physical–biogeochemical
model.
The
model
was
validated
via
repeated
surveys
along
transect
across
submerged
river
valley
off
Changjiang
Estuary
before
and
after
Bavi.
Before
Bavi’s
arrival,
survey
data
indicated
that
had
formed
Estuary.
However,
not
eliminated
but
instead
migrated
aggravated
observed
typhoon
passage.
This
phenomenon
cannot
be
attributed
typhoon-induced
mixing.
Simulation
results
reveal
spatial
migration
mainly
controlled
oceanic
advection.
Results
show
stimulated
regional
quasi-barotropic
cyclonic
loop
circulation
downwelling
reversing
general
summer
patterns.
onshore
transport
warmer
shelf
water
subsequent
resulted
warming
water.
southward
current
induced
also
led
hypoxic
zone.
Meanwhile,
massive
resuspended
planktonic
detritus
from
steep
inner
shallow
bank
toward
occurred.
study
reveals
typhoon-driven
currents
can
play
an
important
role
redistribution
deposited
organic
matter
seas,
which
may
have
both
short-
long-term
effects
on
marine
biogeochemical
environment.
Frontiers in Marine Science,
Journal Year:
2022,
Volume and Issue:
9
Published: Oct. 4, 2022
Global
estuarine
hypoxia
is
among
the
most
acute
environmental
issues,
yet
recognition
of
variability
remains
patchy.
The
Changjiang
(Yangtze
River)
Estuary
(CE)
well
known
as
one
largest
hypoxic
systems.
However,
mechanisms
controlling
spatial
and
heterogeneity
summer
have
been
rarely
examined
in
this
region.
Based
on
observational
data
2013,
essential
linkages
between
physical-biogeochemical
processes
were
revealed
off
CE.
generally
occurred
a
transitional
region
CE,
presenting
to
be
spatially
variable
heterogeneous
its
distribution
intensity.
river
plume,
stratification,
front,
upwelling
localized
high
phytoplankton
biomass
combine
shape
morphology
scope
hypoxia.
magnitude
horizontal
direction
mainly
regulated
by
intensity
stratification
blooms.
position
bottom
front
formed
offshore
Taiwan
Warm
Current
(TWC)
coastal
water
under
tidal
mixing
controls
shoreward
boundary
zone,
while
plume
front-dominated
outer
edge
blooms
upper
layers
plays
role
determining
seaward
limit
reach
depth
controlled
governs
top
hypoxia,
shapes
vertical
zone.
We
contextualize
drivers
conceptual
diagram.
findings
would
considerably
contribute
our
understanding
plume-upwelling-front
coupled
systems,
providing
sound
basis
for
prediction
simulation
anticipated
future
conditions.
Frontiers in Marine Science,
Journal Year:
2023,
Volume and Issue:
9
Published: Jan. 13, 2023
The
summer
hypoxia
off
the
Changjiang
Estuary
is
one
of
largest
coastal
hypoxic
systems
in
world
and
has
displayed
spatial
heterogeneity
recent
years.
Based
on
observation
data
2014,
was
identified
both
bottom
mid-layers.
Except
for
typical
submarine
canyon,
subsurface
oxygen
minima
(SOM)
were
captured
mid-layer
10~15
m,
with
lower
dissolved
than
at
(30–50
m).
This
SOM
phenomenon
located
boundary
pycnocline
above
Taiwan
warm
current
(TWC)
Kuroshio
water
(KSSW).
Due
to
southern
expansion
diluted
(CDW),
a
high
phytoplankton
biomass
(the
maximum
chlorophyll
25
μg
L
−1
,
pH
8.6,
DO
11
mg
)
band
occupied
surface
area
along
123°E.
By
analyzing
24-h
continuous
high-resolution
profile
data,
we
revealed
that
predominantly
controlled
by
remineralization
bottom-flushing
effects.
Fast
local
consumption
occurred
near
layer,
while
lateral
transport
oxygen-rich
ambient
replenished
deficit
from
south
north.
We
summarize
contextualize
three
hot
spots
into
conceptual
diagram
emphasize
influences
advection,
mixing,
respiration
their
location
severity.
Overall,
compared
discussion
about
low
background
TWC/KSSW,
this
research
highlights
flushing
effects
TWC/KSSW
will
reshape
structure
alleviate
severity
Estuary.
Journal of Geophysical Research Oceans,
Journal Year:
2024,
Volume and Issue:
129(8)
Published: July 31, 2024
Abstract
The
frequency
of
riverine
floods
is
predicted
to
increase
in
East
Asia.
However,
the
response
coastal
hypoxia
(<63
μmol
L
−1
)
has
not
been
well
understood.
In
summer
2020,
characterized
by
one
most
significant
Changjiang
water
fluxes
three
decades,
we
conducted
a
cruise
during
flood
period
on
China
Sea
inner
shelf.
Our
observations
revealed
severe
bottom
with
maximum
spatial
coverage
∼11,600
km
2
and
minimum
dissolved
oxygen
concentration
(DO)
21
.
surface
layer,
relationships
between
salinity
nitrate,
inorganic
carbon
(DIC)
indicated
organic
matter
production,
validated
high‐Chlorophyll‐
(Chl
patch
(>5
μg
).
Furthermore,
relationship
apparent
utilization
DIC
deep
waters
reveals
that
decomposition
primarily
drove
period.
Episodic
wind
events
also
influenced
DO
DIC,
transporting
deep.
Multiple‐years
data
set
shows
average
nitrate
flux
years
about
1.4
times
non‐flood
years.
mix
estuarine
waters,
forming
high‐nutrient
plume
which
expanded
farther
offshore
While
high
turbidity
remained
confined
estuary.
Consequently,
high‐Chl
area
significantly
expanded,
exacerbated
hypoxia.
