Research Square (Research Square),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Jan. 17, 2023
Abstract
The
study
goal
was
to
determine
spatio-temporal
variations
in
chlorophyll-a
(Chl-a)
concentration
using
models
that
combine
hydroclimatic
and
nutrient
variables
150
tropical
reservoirs
Brazil.
investigation
of
seasonal
variability
indicated
Chl-a
varied
response
changes
total
nitrogen
(TN),
phosphorus
(TP),
volume
(V),
daily
precipitation
(P).
Simple
linear
regression
showed
nutrients
yielded
better
predictability
than
variables.
Fitted
relationships
between
the
above-mentioned
parameters
resulted
equations
capable
representing
algal
temporal
dynamics
blooms,
with
an
average
coefficient
determination
R²
=
0.70.
blooms
presented
interannual
variability,
being
more
frequent
periods
high
low
volume.
demonstrate
different
responses
parameters.
In
general,
positively
related
TN
and/or
TP.
However,
some
cases
(22%),
concentrations
reduced
Chl-a,
which
attributed
limited
phytoplankton
growth
driven
by
light
deficiency
due
increased
turbidity.
49%
models,
intensified
levels,
increases
from
external
sources
rural
watersheds.
Contrastingly,
51%
faced
a
decrease
precipitation,
can
be
explained
opposite
effect
dilution
at
reservoir
inlet
urban
terms
volume,
67%
reservoirs,
water
level
reduction
promoted
increase
as
higher
concentration.
other
cases,
decreased
lower
levels
wind-induced
destratification
column,
potentially
internal
release
bottom
sediment.
Finally,
application
model
two
largest
studied
greater
sensitivity
use
classes
regarding
TN,
followed
TP,
V,
P.
Ecological Indicators,
Journal Year:
2023,
Volume and Issue:
154, P. 110924 - 110924
Published: Sept. 8, 2023
This
study
assessed
a
high
Andean
lake's
trophic
state
and
water
quality
using
methodologies
with
eutrophication
indexes.
Water
samples
were
collected
at
six
points
in
the
lake,
monthly
frequency,
for
three
winter
summer
months.
Dissolved
oxygen,
pH,
phosphates,
nitrates,
transparency,
chlorophyll-a,
fecal
coliforms,
biological
oxygen
demand
(BOD),
temperature,
turbidity
determined
each
point.
The
of
lake
was
categorized
by
applying
Organization
Economic
Cooperation
Development
(OECD)
index,
Carlson's
index
(CTSI)
(TRIX).
In
addition,
National
Sanitation
Foundation
(NSF-WQI),
Canadian
Quality
Index
(CCME-WQI)
Oregon
(OWQI)
used
to
evaluate
quality.
Results
indicated
that
had
level
eutrophication,
suggesting
an
excessive
accumulation
nutrients
water.
CTSI
TRIX
showed
hyper-eutrophic
state,
while
according
OECD
methodology,
related
phosphorus
transparency
hypereutrophic,
chlorophyll,
it
varied
from
mesotrophic
eutrophic.
NSF
classified
average
quality,
CCME
fair
OWQI
as
very
poor.
Therefore,
andean
indexes
presented
significant
differences
based
on
physicochemical
characteristics.
human
influence
identified
main
cause
including
tourism
agriculture.
These
results
suggest
measures
should
be
taken
reduce
activity
area
control
pollution
lake.
Frontiers in Microbiology,
Journal Year:
2023,
Volume and Issue:
14
Published: Aug. 30, 2023
Lake
Okeechobee
is
a
large
eutrophic,
shallow,
subtropical
lake
in
south
Florida,
United
States.
Due
to
decades
of
nutrient
loading
and
phosphorus
rich
sediments,
the
eutrophic
frequently
experiences
cyanobacterial
harmful
algal
blooms
(cyanoHABs).
In
past,
surveys
phytoplankton
community
structure
have
been
conducted
by
morphological
studies,
whereas
molecular
based
studies
seldom
employed.
With
increased
frequency
cyanoHABs
(e.g.,
2016
2018
Microcystis-dominated
blooms),
it
imperative
determine
diversity
taxa
that
exist
within
limnological
parameters
drive
bloom-forming
genera.
A
spatiotemporal
study
was
over
course
1
year
characterize
(cyano)bacterial
structure,
using
16S
rRNA
metabarcoding,
with
coincident
collection
nutrients,
water
temperature,
major
ions),
cyanotoxins.
The
objectives
this
were
elucidate
trends
identify
drivers
examine
cyanobacteria-bacterial
relationships
lake.
Results
indicated
communities
significantly
different
between
wet
dry
season,
but
not
periods
nitrogen
limitation
co-nutrient
limitation.
Throughout
year,
primarily
dominated
picocyanobacterium
Cyanobium.
genera
Cuspidothrix,
Dolichospermum,
Microcystis,
Raphidiopsis
highly
abundant
throughout
had
disparate
requirements
niches
Anatoxin-a,
microcystins,
nodularins
detected
across
both
seasons.
There
no
correlated
(cyano)bacteria
shared
common
cyanobacteria
Raphidiopsis.
This
first
its
kind
use
methods
assess
These
data
greatly
improve
our
understanding
physiochemical
which
may
Okeechobee.
