Molecules,
Journal Year:
2024,
Volume and Issue:
29(14), P. 3370 - 3370
Published: July 18, 2024
Low-molecular-weight
(LMW,
<1000
Da)
dissolved
organic
matter
(DOM)
plays
a
significant
role
in
metal/organic
pollutant
complexation,
as
well
photochemical/microbiological
processes
freshwater
ecosystems.
The
micro
size
and
high
reactivity
of
LMW-DOM
hinder
its
precise
characterization.
In
this
study,
Suwannee
River
fulvic
acid
(SRFA),
commonly
used
reference
material
for
aquatic
DOM,
was
applied
to
examine
the
optical
features
molecular
composition
by
combining
membrane
separation,
ultraviolet–visible
absorption
Orbitrap
mass
spectrometry
(MS)
100–500
Da
weight
cut-off
(MWCO)
had
better
performance
regard
separating
tested
relative
500–1000
MWCO
membrane.
absorbance
decreased
dramatically
retentates,
whereas
it
increased
dialysates.
Specifically,
carbohydrates,
lipids
peptides
exhibited
selectivity
early
dialysis.
Lignins,
tannins
condensed
aromatic
molecules
displayed
permeability
late
Overall,
retentates
were
dominated
rings
phenolic
hydroxyls
with
O/Cwa
(weighted
average
O/C)
low
H/Cwa.
Conversely,
such
dialysates
numerous
aliphatic
chains
H/Cwa
compared
SRFA.
particular,
below
200
identified
MS.
This
work
provides
an
operational
program
identifying
based
on
SRFA
standard
MS
analysis.
Environmental Science & Technology,
Journal Year:
2023,
Volume and Issue:
57(48), P. 19723 - 19731
Published: Nov. 14, 2023
Substantial
amounts
of
particulate
organic
carbon
(POC)
are
released
during
macroalgal
growth;
however,
the
fate
these
POCs
and
their
sequestration
effects
remain
unclear.
Here,
field
investigations
found
that
Ulva
prolifera
caused
a
significant
increase
POC
in
seawater
below
surface
bloom.
However,
laboratory
simulations
revealed
77.6%
was
easily
degraded
by
microorganisms
short
period
time,
concurrently
resulting
production
dissolved
(DOC)
from
transformation.
Over
3
months,
bioavailable
components
macroalgae-released
POC-transformed
DOC
were
degraded,
leaving
39.6%
antibiodegradable
substances
composed
biorecalcitrant
DOC.
although
rich
humic-like
resisting
biodegradation,
exhibited
greater
sensitivity
to
photodegradation
than
The
removal
rate
(14.1%)
more
10
times
(1.2%).
Ultimately,
substantial
portion
(36.3%)
growing
macroalgae
could
potentially
perform
long-term
after
conversion
recalcitrant
DOC,
inert
carbons
derived
have
been
previously
ignored
should
also
be
included
accounting.
