Authorea (Authorea),
Journal Year:
2024,
Volume and Issue:
unknown
Published: July 31, 2024
Dispersion
coefficients
and
the
average
solute
transport
velocity
are
pivotal
for
groundwater
modeling.
Accurately
efficiently
determining
these
parameters
is
challenging
due
to
difficulties
in
directly
correlating
them
with
pore-space
structure.
To
address
this
issue,
we
introduced
Physics-enhanced
Convolutional
Neural
Network-Transformer
(PhysenCT-Net),
an
innovative
model
designed
concurrently
estimate
longitudinal
dispersion
coefficient
three-dimensional
porous
media.
PhysenCT-Net
exhibited
excellent
predictive
performance
on
unseen
testing
datasets
significantly
reduced
computational
demands.
Comprehensive
evaluations
confirmed
its
robust
generalization
across
various
flow
conditions
pore
structures.
Notably,
predictions
closely
align
established
empirical
relationships
involving
Péclet
number,
affirming
model's
physical
interpretability
potential
aid
simulating
phenomena
Frontiers in Marine Science,
Journal Year:
2024,
Volume and Issue:
11
Published: May 14, 2024
Research
on
the
impact
of
seawater
intrusion
nitrogen
(N)
cycling
in
coastal
estuarine
ecosystems
is
crucial;
however,
there
still
a
lack
relevant
research
conducted
under
in-situ
field
conditions.
The
effects
elevated
salinity
N
processes
and
microbiomes
were
examined
situ
experiments
from
2019
to
2021
Nakdong
River
Estuary
(South
Korea),
where
an
dam
regulates
tidal
hydrodynamics.
After
opening
Dam
(seawater
event),
density
difference
between
freshwater
resulted
varying
degrees
trapping
at
topographically
deep
stations.
Bottom-water
oxygen
conditions
had
been
altered
normoxia,
hypoxia,
weak
hypoxia
due
different
2019,
2020,
2021,
respectively.
Denitrification
mostly
dominated
nitrate
(NO
3
-
)
reduction
process,
except
2020
after
intrusion.
However,
denitrification
rates
decreased
because
reduced
coupled
nitrification
dissolved
limitation
2020.
Dissimilatory
ammonium
(DNRA)
immediately
increased
replacing
as
dominant
pathway
NO
process.
enhanced
DNRA
rate
was
mainly
abundant
organic
matter
associated
with
invasion
more
reducing
environment
(maybe
sulfide
enhancement
effects)
high
seawater-trapping
during
hypoxia;
did
not
change.
Small
caused
no
overall
normoxic
condition,
though
slight
shift
observed.
Metagenomic
analysis
revealed
decrease
denitrification-associated
genes
response
while
DNRA-associated
gene
abundance
increased.
In
intrusion,
microbial
increased,
that
change
significantly.
These
changes
align
alterations
transformation
rates.
summary,
ecological
(N
retention
or
release,
is,
eutrophication
deterioration
mitigation)
depend
degree
underlying
conditions,
which
constitute
extent
seawater-trapping.
Scientific Reports,
Journal Year:
2024,
Volume and Issue:
14(1)
Published: Feb. 17, 2024
Abstract
This
study
investigates
the
impact
of
water
levels
and
soil
texture
on
migration
transformation
nitrate
(NO
3
−
-N)
ammonium
(NH
4
+
within
a
column.
The
concentrations
NO
-N
gradually
decreased
from
an
initial
concentration
34.19
±
0.86
mg/L
to
14.33
0.77
day
70,
exhibiting
fluctuations
influenced
by
texture.
Higher
were
associated
with
concentrations,
while
lower
resulted
in
increased
concentrations.
retention
absorption
capacity
for
highest
fine
sand
soil,
followed
medium
coarse
sand,
highlighting
significance
movement
retention.
analysis
variance
(ANOVA)
confirmed
statistically
significant
variations
pH,
dissolve
oxygen
oxidation–reduction
potential
across
columns
(p
<
0.05).
Fluctuating
-N,
distinct
patterns
observed
different
textures.
Water
level
also
impacted
NH
higher
resulting
Among
types
considered,
exhibited
-N.
These
findings
underscore
roles
levels,
texture,
type
migration,
transformation,
nitrogen
compounds
columns.
results
contribute
better
understanding
dynamics
under
varying
environmental
conditions,
providing
valuable
insights
into
small-scale
column
experiments.
Groundwater for Sustainable Development,
Journal Year:
2023,
Volume and Issue:
24, P. 101065 - 101065
Published: Dec. 15, 2023
The
study
integrates
hydrochemical
and
isotopic
(δ18O,
δ2H,
3H,
δ13C)
techniques
to
investigate
water
evolution
in
the
North
Kelantan
River
basin.
Groundwater
facies
were
mainly
classified
as
Ca–Mg–Cl,
Ca–Mg–Cl–HCO3,
Na–Cl
during
rainy
season
shift
toward
Ca–Mg–HCO3
Na–Ca–HCO3–Cl
dry
surface
shallow
aquifer,
while
intermediate
deep
aquifers
Na–HCO3
Na–Cl.
δ18O
δ2H
compositions
of
most
groundwater
samples
have
not
deviated
significantly
from
NKMWL
(δ2H
=
8.4
+
11.5)
with
slightly
depleted
values
due
humid
climate.
Isotopically,
evaporation
does
impact
recharged
significantly.
However,
are
enriched
than
area.
estimated
recharge
was
20.17%
22.52%
annual
rainfall
based
on
CMB
values,
respectively.
occurs
wet
is
influenced
mostly
by
amount
rain.
Aquifers
clustered
distinct
groups
their
signatures
results.
decomposition
organic
matter
primary
carbon
source
Building
this,
utilizing
isotope
hydrology
resources,
we
can
gain
a
deeper
insight
into
susceptibility
coastal
monsoonal
tropical
regions.
