ACS ES&T Water,
Год журнала:
2024,
Номер
5(1), С. 20 - 32
Опубликована: Дек. 10, 2024
Metals
are
ubiquitous
in
Earth's
Critical
Zone
and
play
key
roles
ecosystem
function,
human
health,
water
security.
They
essential
nutrients
at
low
concentrations,
yet
some
metals
toxic
a
high
dose.
Permafrost
thaw
substantially
alters
all
the
physical
chemical
processes
governing
metal
mobility,
including
movement
solute
transport
(bio)geochemical
interactions
involving
water,
organic
matter,
minerals,
microbes.
The
outcomes
of
these
interconnected
changes
nonintuitive
hold
global
implications
for
resources
health.
This
Perspective
outlines
primary
factors
affecting
mobility
thawing
permafrost
underscores
urgent
need
priorities
interdisciplinary
research
to
better
understand
this
emerging
issue.
Progress In Oceanography,
Год журнала:
2024,
Номер
222, С. 103224 - 103224
Опубликована: Фев. 18, 2024
Despite
the
lack
of
local
anthropogenic
mercury
sources,
methylated
(MeHg)
concentrations
in
Arctic
biota
are
higher
than
from
lower
latitudes.
The
main
entry
route
occurs
during
bioconcentration
seawater
monomethylmercury
(MMHg)
into
phytoplankton.
known
seasonal
changes
biological
activity
region,
little
is
about
cycling
total
(THg)
and
MeHg
Ocean.
Here,
we
report
THg
sampled
northwestern
Barents
Sea
water
column
late
winter
spring.
In
upper
500
m,
significantly
spring
(0.64
±
0.09
pmol
L-1)
compared
to
(0.53
0.07
L-1),
driven
by
inputs
surface
waters
atmospheric
deposition
dynamics
changing
sea
ice
conditions.
Contrastingly,
were
(41
39
fmol
(85
42
L-1).
We
suggest
that
most
biotically
demethylated
both
phytoplankton
bacteria,
with
additional
losses
photodemethylation
evasion.
Our
observations
highlight
importance
demethylation
potential
uptake
methylmercury
coinciding
bloom.
Lastly,
use
our
new
data
together
previously
published
region
construct
a
simplified
cycle
an
marginal
zone.
The Science of The Total Environment,
Год журнала:
2025,
Номер
962, С. 178440 - 178440
Опубликована: Янв. 1, 2025
Substantial
amounts
of
mercury
(Hg)
are
projected
to
be
released
into
Arctic
watersheds
as
permafrost
thaws
amid
warmer
and
wetter
conditions.
This
may
have
far-reaching
consequences
because
the
highly
toxic
methylated
form
Hg
biomagnifies
rapidly
in
ecosystems.
However,
understanding
how
climate
change
affects
dynamics
regions
is
limited
due
lack
long-term
records.
Using
a
27-ka
sediment
record
from
Burial
Lake,
northwestern
Alaska,
we
examine
well-characterized
temperature,
precipitation,
vegetation
shifts
affected
mobilization
catchment
underlain
by
permafrost.
During
Last
Glacial
Maximum
(29.6-19.6
ka),
concentrations
(63
±
5
μg/kg)
flux
(8.6
2.2
μg
m-2
yr-1)
remain
relatively
stable.
Abrupt
warming
trends,
starting
at
17.6
ka,
do
not
coincide
with
levels.
After
15
ecosystem
transitions
shrub
tundra,
(101.2
peak
14.2
while
(5.3
1.3
declines
stabilizes.
At
~11
increased
precipitation
coincides
72
%
rise
32
increase
compared
average
levels
since
ka.
These
results
suggest
that
summer
rainfall
was
primary
driver
catchment,
shift
influenced
lake
concentrations.
1990
CE,
represent
an
88
(196.3
sixfold
(38.1
above
background
levels,
underscoring
need
for
further
research
understand
driven
anthropogenic
emissions
change.
Scientific Reports,
Год журнала:
2025,
Номер
15(1)
Опубликована: Фев. 28, 2025
Permafrost
soils
are
critical
reservoirs
for
mercury
(Hg),
with
the
thawing
process
leading
to
release
of
this
element
into
environment,
posing
significant
environmental
risks.
Of
particular
concern
is
methylated
form
mercury,
monomethylmercury
(MMHg),
known
its
adverse
effects
on
Human
health.
Microbial
communities
play
a
pivotal
role
in
formation
MMHg
by
facilitating
Hg
methylation
and
demethylation
MMHg,
slowing
crossing
toxic
threshold
concentration
environment.
However,
specific
microbes
involved
still
need
be
understood.
This
study
aimed
identify
microbial
drivers
behind
changes
speciation
(MMHg
Hg)
permafrost
thaw
lakes
assess
significance
biotic
component
biogeochemistry.
Sediment
samples
from
two
thermokarst
Canadian
sub-Arctic
were
collected
during
winter
summer
2022.
Gene-centric
metagenomics
using
whole-genome
sequencing
(WGS)
was
employed
key
genes
(hgcA
hgcB)
(merA
merB),
supported
qPCR
analyses.
A
seasonal
decline
diversity,
methylation,
hgcA
gene
coverage
observed
summer,
mirroring
patterns
rates.
Notably,
sequences
significantly
more
abundant
than
merAB
sequences,
contrasting
trends.
These
results
indicate
shift
community,
transitioning
dominance
predominance
summer.
Environmental
these
dynamics
integrated
conceptual
model.
provide
new
insights
processes
influencing
cycle
Arctic
undergoing
degradation.
Mercury
(Hg)
is
a
global
pollutant
with
substantial
human
health
impacts.
While
most
studies
focus
on
atmospheric
total
Hg
(THg)
deposition,
contributions
of
methylated
(MeHg),
including
monomethylmercury
(MMHg)
and
dimethylmercury
(DMHg),
remain
poorly
understood.
To
examine
this,
we
use
rain
aerosol
speciation
data
high-resolution
surface
DMHg
measurements,
collected
transect
from
Alaskan
coastal
waters
to
the
Bering
Chukchi
Seas.
We
observed
significant
fivefold
increase
in
MeHg:THg
fraction
10-fold
for
aerosols,
closely
linked
elevated
highest
evasion
(~9.4
picomoles
per
square
meter
hour)
found
upwelling
near
Aleutian
Islands.
These
highlight
previously
underexplored
aspect
MeHg
air-sea
exchange
its
importance
cycling
concerns.
Our
findings
emphasize
by
demonstrating
that
can
be
transported
long
distances
(~1700
kilometers)
Arctic,
posing
risks
ecosystems.
The Science of The Total Environment,
Год журнала:
2025,
Номер
976, С. 179276 - 179276
Опубликована: Апрель 9, 2025
Organic
matter
sequestered
in
permafrost
environments
contains
mercury
(Hg)
which
can
be
exposed
via
thaw
to
conditions
that
favour
its
microbial
conversion
into
organic
and
neurotoxic
form,
methylmercury
(MeHg).
Permafrost
affects
landscapes
unevenly,
creating
a
patchwork
of
controlled
by
ground
ice
distribution
time
since
degradation.
However,
little
is
known
about
the
relationship
between
evolution
features
net
MeHg
production
thawing
landscapes.
Near
Kangiqsualujjuaq,
Nunavik
(Québec),
degradation
mounds,
such
as
lithalsas,
creates
evolving
mosaics
hydrological
ecological
with
well-drained
elevated
surfaces,
rim
ridges,
ponds
where
succession
leads
terrestrialisation.
This
research
investigated
whether
geomorphic
degrading
lithalsa
field,
including
revegetation
ponds,
environmental
conducive
methylation
inorganic
(IHg).
Hydrological
conditions,
well
total
(THg),
MeHg,
percent
carbon
(C),
nitrogen
(N),
sulfur
(S),
were
assessed
for
175
soil
samples
collected
along
chronosequence
pond
revegetation.
The
lithalsas
increased
Hg
potential,
%MeHg
increasing
from
0.57
%
on
intact
mounds
4.6
thermokarst
depressions.
Among
latter,
highest
values
associated
earliest
phase
evolution,
newly
submerged
high
activity
reduced
environment.
decreased
colonisation
Cyperaceae
(4.8
%)
further
terrestrialisation
Sphagnum
spp.
(2.6
%),
contain
recalcitrant
compounds
may
inhibit
raising
surface
above
water
table.
Air
photo
analysis
reveals
rapid
progression
towards
complete
disappearance
field
full
ponds.
In
state,
potential
expected
stabilise
at
levels
comparable
non-permafrost
bogs.
