Sesarmid
crabs
modulate
nutrient
dynamics
of
tropical
mangroves
through
their
leaf-eating
habit.
How
N
enrichment
may
alter
this
regulatory
role,
and
the
implications
for
mangrove
dynamics,
remain
unclear.
Using
a
mesocosm
experiment,
we
tested
how
could
change
microphytobenthos
(MPB)
communities,
thus
modifying
crab’s
diet
role
in
dynamics.
The
factorial
experiment
combined
with
field
investigation
revealed
significant
increase
relative
abundance
cyanobacteria.
Stable
isotope
analysis
suggested
that
main
carbon
source
shifted
from
leaf
litter
to
cyanobacteria
mesocosms
under
both
high
(20x)
low
(2x)
treatments.
significantly
lower
total
cellulase
activity
might
explain
decreased
assimilation
litter.
changes
MPB
microbiome
presence
drive
higher
processing
rate
mangroves.
Environmental Research Letters,
Год журнала:
2021,
Номер
16(12), С. 124058 - 124058
Опубликована: Ноя. 23, 2021
Abstract
Marine
microplastics
(MPs)
accumulate
in
sediments
but
impacts
on
ecosystem
functions
are
poorly
understood.
MPs
interactions
with
stabilizing
benthic
flora/fauna
or
biostabilization
processes,
have
not
been
fully
investigated,
yet
this
is
critical
for
unraveling
effects
ecosystem-scale
processes
and
functions.
This
also
vital
understanding
feedback
that
may
moderate
the
stock
flow
of
as
they
transported
through
estuaries.
The
relationships
between
sedimentary
MPs,
biota,
environmental
properties
sediment
stability
from
field
sediments,
were
examined
using
variance
partitioning
(VP)
correlation
analyses.
VP
was
used
to
identify
common
unique
contributions
different
groups
variables
(environmental,
fauna
microplastic
variables)
stability.
influence
presence
(fragment/fiber
abundances
diversity)
(defined
erosion
thresholds
rates)
demonstrated.
Furthermore,
appeared
mediate
biostabilizing
(including
microorganisms)
fauna.
Environmental
could
explain
variation
across
sites
suggesting
abundance,
type
diversity
bed.
potential
biota
resuspension
dynamics
within
estuaries
discussed.
New Zealand Journal of Marine and Freshwater Research,
Год журнала:
2022,
Номер
56(3), С. 491 - 508
Опубликована: Июль 3, 2022
Estuaries
are
threatened
with
increasing
sedimentation
and
nutrients,
however
research
is
limited
on
the
interaction
of
these
stressors
ecosystem
functions.
A
field
experiment
adding
nitrogen
(N)
fertiliser
at
high
(600
g
N
m−2)
medium
(150
concentrations
control
plots
was
established
in
two
sandy
muddy
sites
(mud
content
0–15%)
to
investigate
context
dependency
enrichment
nutrient
cycling
primary
production.
There
a
significant
mud
x
treatment
ammonium
(NH4+)
fluxes.
High
N-addition
had
133x
greater
dark
NH4+
efflux
than
controls
sediments,
compared
17x
sediments.
Net
production
increased
content,
while
photosynthetic
efficiency
microphytobenthos
(GPPchl-a)
decreased
above
4%
mud.
Mud
also
affected
bivalve,
Austrovenus
stutchburyi
(>30
mm),
macrofaunal
abundance
functional
groups,
their
influence
cycling.
Thus
minor
increases
can
alter
response
directly
through
changes
sediment
properties
indirectly
by
affecting
bivalves
macrofauna
that
processes.
This
study
highlights
how
multiple
interact
predispose
estuaries
tipping
points.
Limnology and Oceanography,
Год журнала:
2022,
Номер
68(S1)
Опубликована: Ноя. 23, 2022
Abstract
Environmental
stressors
have
profound
implications
for
species,
communities,
and
ecosystems
by
altering
fundamental
processes.
With
increasing
human
impacts
on
aquatic
ecosystems,
two
main
scenarios
been
reported:
(1)
the
spatiotemporal
superposition
of
multiple
stressors,
leading
to
interactions
among
them
(2)
intensifying
environmental
gradients,
threshold
responses.
However,
studies
designed
assess
effects
(e.g.,
pulse
stressors)
along
gradients
press
are
uncommon,
between
may
cause
abrupt
changes
in
biological
We
conducted
a
laboratory
experiment
investigate
osmotic
stress
nutrient
enrichment
gradient
freshwater
community
composed
periphyton,
microorganisms,
zebra
mussels
(
Dreissena
polymorpha
).
Our
objectives
were
quantify
individual
combined
delineate
thresholds
(press)
absence
presence
(pulse),
(3)
test
stressors.
evaluated
metabolic
rates
D.
microbial
activity,
as
well
phototrophic
periphyton
biomass
physiological
status.
observed
periphytic
phaeopigments.
In
contrast,
we
found
an
effect
activity
chlorophyll
content.
Thresholds
only
identified
.
work
highlights
importance
combining
with
need
consider
compartments
when
evaluating
ecosystems.
