Optics Express,
Journal Year:
2024,
Volume and Issue:
32(15), P. 25644 - 25644
Published: June 19, 2024
High
optical
complexity
caused
by
the
variability
of
marine
particles
poses
a
major
challenge
to
development
bio-optical
algorithms
for
particulate
organic
carbon
(POC)
concentration
retrievals
from
measurements
in
coastal
waters.
Here,
we
developed
particle
composition-specific
approach
estimate
POC
off
areas
Guangdong
and
eastern
Hainan
Island,
China.
The
ratio
phytoplankton
absorption
detritus
coefficient
aph(443)/ad(443)
was
used
optically
discriminate
water
types.
samples
with
≤
4.9
showed
significant
correlation
between
line
height
at
676
nm
aLH(676)
(R2
=
0.75,
n
70,
p
<
0.01).
In
contrast,
aph-dominant
>
had
high
covariance
scattering
675
bp(675)
0.85,
37,
Validation
an
independent
dataset
yielded
small
positive
bias
0.81,
APD
23.10%,
RMSE
29.01
mg
m
Journal of Geophysical Research Oceans,
Journal Year:
2024,
Volume and Issue:
129(2)
Published: Feb. 1, 2024
Abstract
Typhoons
exert
a
profound
impact
on
marine
biogeochemical
processes,
with
organic
matter
(OM)
decomposition
serving
as
key
process
in
coastal
waters
after
typhoons.
Despite
its
significance,
the
specific
contributions
of
particulate
(POM)
and
dissolved
(DOM)
to
OM
triggered
by
typhoons
remains
unclear.
In
this
study,
stable
isotopes
POM
spectral
properties
DOM
were
investigated
before
Typhoon
“Barija"
Zhanjiang
Bay,
northwestern
South
China
Sea.
The
typhoon‐induced
intrusion
high‐salinity
seawater
from
lower
bay
upper
bay,
driven
external
clockwise
wind
stress,
led
formation
an
ocean
front
middle
during
typhoon.
Notably,
induced
typhoon
(72%)
significantly
surpassed
that
(5%),
attributed
barrier
effect
increased
vertical
mixing
bay.
contrast,
removed
only
29%
net
addition
occurred
due
phytoplankton
growth
decomposition.
More
importantly,
despite
overall
larger
water
column,
inventory
(20.19
g
m
−2
)
exceeded
(16.08
).
Overall,
our
study
suggests
is
more
critical
than
typhoons,
primarily
influenced
mixing.
These
findings
contribute
clearer
understanding
post‐typhoon
dynamics
waters.
Frontiers in Marine Science,
Journal Year:
2023,
Volume and Issue:
10
Published: Jan. 24, 2023
Coastal
upwelling
around
Hainan
Island
has
a
significant
impact
on
the
physical
environment,
ecological
and
fishery
resources
of
surrounding
waters.
Based
satellite-observed
sea
surface
temperature
(SST)
from
2003
to
2021,
this
study
analyzed
interannual
variations
SST
influence
forcing
them,
with
special
attention
regions
in
Qiongdong
Qiongxi.
The
results
show
that
can
identify
three
located
west
(WS),
east
(ES),
northeast
(NES)
sides
Island.
SSTs
WS,
ES,
NES
showed
warming
trends
0.045
°C/y,
0.010
0.036
respectively.
range
low-temperature
water
gradually
shrunk
over
past
two
decades,
shrinkage
trend
was
more
prominent
WS
region
than
ES
regions.
Both
EOF
analysis
difference
between
non-upwelling
suggests
becomes
stronger
after
2013.
However,
it
seems
not
compete
overall
northwest
area
South
China
Sea.
were
affected
by
local
wind
stress
curl
summer.
Except
for
curl,
are
influenced
stratification
associated
precipitation
direction,
especially
2018.
In
addition,
variation
is
closely
related
bottom
cold
central
Gulf
Tonkin,
which
preserved
previous
winter
atmospheric
conditions.
These
helpful
understanding
ecosystem
Frontiers in Marine Science,
Journal Year:
2024,
Volume and Issue:
11
Published: May 14, 2024
The
particulate
nitrogen
(PN)
isotopic
composition
(δ
15
N
PN
)
plays
an
important
role
in
quantifying
the
contribution
rate
of
organic
matter
sources
and
indicating
water
environmental
pollution.
Estimation
δ
from
satellite
images
can
provide
significant
spatiotemporal
continuous
data
for
cycling
ecological
environment
governance.
Here,
order
to
fully
understand
dynamic
,
we
have
developed
a
machine
learning
algorithm
retrieving
.
This
is
successful
case
combining
isotopes
remote
sensing
technology.
Based
on
field
observation
Zhanjiang
Bay
May
September
2016,
three
retrieval
models
(Back
Propagation
Neural
Network,
Random
Forest
Multiple
Linear
Regression)
were
constructed
using
optical
indicators
composed
situ
reflectance
as
input
variable
output
variable.
Through
comparative
analysis,
it
was
found
that
Back
Network
(BPNN)
model
had
better
performance.
BPNN
applied
quasi-synchronous
Ocean
Land
Color
Imager
(OLCI)
onboard
Sentinel-3.
determination
coefficient
(R
2
),
root
mean
square
error
(RMSE)
absolute
percentage
(MAPE)
satellite-ground
matching
point
based
0.63,
1.63‰,
20.10%,
respectively.
From
results,
be
inferred
value
good
consistency
with
measured
In
addition,
independent
datasets
used
validate
model,
which
showed
accuracy
retrieval,
effective
has
been
built
algorithm.
However,
enhance
performance,
need
strengthen
information
collection
covering
diverse
coastal
bodies
optimize
variables
indicators.
study
provides
technical
support
large-scale
long-term
understanding
biogeochemical
processes
matter,
well
new
management
strategy
quality
monitoring.
Frontiers in Marine Science,
Journal Year:
2022,
Volume and Issue:
9
Published: Sept. 28, 2022
Mass
coral
bleaching
is
a
severe
threat
to
reefs
in
the
era
of
global
warming,
and
upwelling
areas
may
serve
as
thermal
refugia
for
by
mitigating
effects
heating
anomalies.
This
study
seeks
examine
impact
Qiongdong
(QDU)
on
coastal
Hainan
Island.
The
environmental
variables
(i.e.,
physiochemical
parameters,
land
use)
differed
significantly
non-upwelling
areas.
In
particular,
presence
colder
more
saline
water
was
important
indicator
upwelling.
QDU,
turf
algae
macroalgae
dominated
communities,
but
habitat-specific
environment
development
contributed
lower
calcified
algae,
larvae
replenishment
live
corals
cover.
Lower
abundance
fishes
could
be
attributed
disappearance
corals,
increase
coverage,
low
habitat
complexity
strong
wave
exposure
at
stations.
Upwelling-related
exposure,
use
potential
local
stressors
were
revealed
major
driving
factors
related
significant
spatial
changes
stony
fish
communities.
Overall,
present
findings
suggest
that
has
provide
refuge
reefs,
severely
affected
anthropogenic
activities.
Ecological Indicators,
Journal Year:
2023,
Volume and Issue:
146, P. 109852 - 109852
Published: Jan. 2, 2023
With
a
high
species
diversity
of
coral
reefs,
Wuzhizhou
(WZZ)
is
tropical
marine
ranch
built
by
China.
In
the
present
study,
we
investigated
structure
and
function
reef
food
webs
on
WZZ
in
Sanya
to
understand
how
climate
change
human
activities
affected
ecosystems.
Using
carbon
nitrogen
stable
isotopes
Bayesian
mixture
models,
assessed
major
organic
matter
pathways
causes
seasonal
variation
fauna
isotope
values
delineate
ecosystem
function.
Macroalgae
benthic
microalgae
were
primary
sources
feeding
this
web,
while
there
also
some
notable
variations.
Nutrient
changes
caused
temperature,
upwelling,
cyclones
might
be
reasons
for
consumer
community
composition
or
isotopes.
Seasonal
environmental
did
not
affect
stability
nutrient
web
WZZ.
Journal of Geophysical Research Oceans,
Journal Year:
2021,
Volume and Issue:
127(1)
Published: Dec. 23, 2021
Abstract
Few
systematic
investigations
use
isotopic
compositions
(δ
18
O
and
δD)
of
seawater
together
with
water
temperature
salinity
to
trace
the
dynamic
processes
in
upwelling
area.
This
study
presents
depth‐specific
δ
O,
δD,
(S),
data
samples
collected
from
northwestern
South
China
Sea
(NWSCS)
during
spring
summer
2018
other
oceanic
physical
processes.
Strong
is
observed
southwestern
area
NWSCS
both
based
on
distribution
temperature.
In
spring,
lower
has
generally
higher
δD
values
than
studied
areas,
while
this
phenomenon
not
summer.
indicates
different
hydrodynamic
conditions
these
seasons.
The
eastward
advection
upwelled
contributes
phenomenon,
which
can
be
supported
by
O‐S
relationships.
regression
line
slope
that
spring.
Five
masses
are
defined
west
NWSCS,
offshore
upper
(OUW)
mainly
formed
mixing
coastal
deep
(ODW).
We
principle
mass
conservation
estimate
relative
contributions
ODW
O.
40%
OUW,
it
69%.
method
using
stable
isotopes
event
quantifies
contribution
obtains
more
information
compared
traditional
hydrological
observations.
