bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2023,
Volume and Issue:
unknown
Published: June 3, 2023
ABSTRACT
Heat
stress
threatens
the
survival
of
symbiotic
cnidarians
by
causing
their
photosymbiosis
to
break
down
in
a
process
known
as
bleaching.
The
direct
effects
temperature
on
cnidarian
host
physiology
remain
difficult
describe
because
heat
depresses
symbiont
performance,
leading
and
starvation.
sea
anemone
Exaiptasia
diaphana
provides
an
opportune
system
which
disentangle
vs.
indirect
host,
since
it
can
survive
indefinitely
without
symbionts.
Here,
we
tested
hypothesis
that
directly
influences
comparing
aposymbiotic
individuals
clonal
strain
E.
.
We
exposed
anemones
range
temperatures
(ambient,
+2°C,
+4°C,
+6°C)
for
15-18
days,
then
measured
population
densities,
autotrophic
carbon
assimilation
translocation,
photosynthesis,
respiration,
intracellular
pH
(pH
i
).
Anemones
with
initially
high
densities
experienced
dose-dependent
loss
increasing
temperature,
resulting
corresponding
decline
photosynthate
accumulation.
In
contrast,
low
initial
did
not
lose
symbionts
or
assimilate
less
increased,
similar
response
anemones.
Interestingly,
decreased
at
higher
regardless
presence,
cell
density,
indicating
disrupts
acid-base
homeostasis
independent
symbiosis
dysfunction,
regulation
may
be
critical
point
vulnerability
hosts
this
vital
mutualism.
Summary
Statement
Warming
oceans
threaten
marine
invertebrates.
found
model
presence
function,
highlighting
bleaching-independent
climate
change.
Ecology and Evolution,
Journal Year:
2023,
Volume and Issue:
13(5)
Published: May 1, 2023
Ocean
acidification
(OA)
is
a
severe
threat
to
coral
reefs
mainly
by
reducing
their
calcification
rate.
Identifying
the
resilience
factors
of
corals
decreasing
seawater
pH
paramount
importance
predict
survivability
in
future.
This
study
compared
adapted
variable
pHT
(i.e.,
7.23-8.06)
from
semi-enclosed
lagoon
Bouraké,
New
Caledonia,
more
stable
7.90-8.18).
In
100-day
aquarium
experiment,
we
examined
physiological
response
and
genetic
diversity
Symbiodiniaceae
three
species
(Acropora
tenuis,
Montipora
digitata,
Porites
sp.)
both
sites
under
pHNBS
conditions
(8.11,
7.76,
7.54)
one
fluctuating
regime
(between
7.56
8.07).
Bouraké
consistently
exhibited
higher
growth
rates
than
environment.
Interestingly,
A.
tenuis
showed
highest
rate
7.76
condition,
whereas
for
M.
sp.
was
8.11
conditions,
respectively.
While
OA
generally
decreased
ca.
16%,
environment
(21%
increase
93%
with
all
pooled).
superior
performance
coincided
divergent
symbiont
communities
that
were
homogenous
corals.
Corals
appear
have
better
capacity
calcify
reduced
native
condition.
not
gained
exposed
during
suggesting
long-term
exposure
fluctuations
and/or
differences
benefit
OA.
Proceedings of the Royal Society B Biological Sciences,
Journal Year:
2023,
Volume and Issue:
290(2003)
Published: July 19, 2023
The
flexibility
to
associate
with
more
than
one
symbiont
may
considerably
expand
a
host's
niche
breadth.
Coral
animals
and
dinoflagellate
micro-algae
represent
of
the
most
functionally
integrated
widespread
mutualisms
between
two
eukaryotic
partners.
Symbiont
identity
greatly
affects
coral's
ability
cope
extremes
in
temperature
light.
Over
its
broad
distribution
across
Eastern
Pacific,
ecologically
dominant
branching
coral,
Pocillopora
grandis
,
depends
on
dinoflagellates
Durusdinium
glynnii
Cladocopium
latusorum
.
Measurements
skeletal
growth,
calcification
rates,
total
mass
increase,
calyx
dimensions,
reproductive
output
response
thermal
stress
were
used
assess
functional
performance
these
partner
combinations.
results
show
both
host–symbiont
combinations
displayed
similar
phenotypes;
however,
significant
differences
emerged
when
exposed
increased
temperatures.
Negligible
physiological
colonies
hosting
thermally
tolerant
D.
refute
prevailing
view
that
have
considerable
growth
tradeoffs.
Well
beyond
pocilloporid
are
found
Pacific
warm,
environmentally
variable,
near
shore
lagoonal
habitats.
While
rising
ocean
temperatures
threaten
persistence
contemporary
coral
reefs,
lessons
from
indicate
co-evolved
likely
spread
geographically
dominate
reef
ecosystems
future.
Proceedings of the National Academy of Sciences,
Journal Year:
2023,
Volume and Issue:
120(52)
Published: Dec. 19, 2023
Increasingly
frequent
marine
heatwaves
are
devastating
coral
reefs.
Corals
that
survive
these
extreme
events
must
rapidly
recover
if
they
to
withstand
subsequent
events,
and
long-term
survival
in
the
face
of
rising
ocean
temperatures
may
hinge
on
recovery
capacity
acclimatory
gains
heat
tolerance
over
an
individual’s
lifespan.
To
better
understand
trajectories
successive
heatwaves,
we
monitored
responses
bleaching-susceptible
bleaching-resistant
individuals
two
dominant
species
Hawai’i,
Montipora
capitata
Porites
compressa
,
a
decade
included
three
heatwaves.
Bleaching-susceptible
colonies
P.
exhibited
beneficial
acclimatization
stress
(i.e.,
less
bleaching)
following
repeat
becoming
indistinguishable
from
conspecifics
during
third
heatwave.
In
contrast,
M.
repeatedly
bleached
all
seasonal
bleaching
substantial
mortality
for
up
3
y
Encouragingly,
both
remained
pigmented
across
entire
time
series;
however,
pigmentation
did
not
necessarily
indicate
physiological
resilience.
Specifically,
displayed
incremental
yet
only
partial
symbiont
density
tissue
biomass
phenotypes
35
mo
heatwave
as
well
considerable
mortality.
Conversely,
appeared
most
metrics
within
2
experienced
little
no
Ultimately,
results
even
some
visually
robust,
corals
can
carry
cost
recurring
multiple
years,
leading
divergent
erode
reef
resilience
Anthropocene.
Global Change Biology,
Journal Year:
2023,
Volume and Issue:
29(24), P. 6945 - 6968
Published: Nov. 1, 2023
Ocean
warming
has
caused
coral
mass
bleaching
and
mortality
worldwide
the
persistence
of
symbiotic
reef-building
corals
requires
rapid
acclimation
or
adaptation.
Experimental
evolution
coral's
microalgal
symbionts
followed
by
their
introduction
into
is
one
potential
method
to
enhance
thermotolerance.
Heat-evolved
generalist
species,
Cladocopium
proliferum
(strain
SS8),
were
exposed
elevated
temperature
(31°C)
for
~10
years,
introduced
four
genotypes
chemically
bleached
adult
fragments
scleractinian
coral,
Galaxea
fascicularis.
Two
acquired
SS8.
The
new
persisted
5
months
experiment
enhanced
thermotolerance,
compared
with
that
inoculated
wild-type
C.
strain.
Thermotolerance
SS8-corals
was
similar
from
same
colony
hosting
homologous
symbiont,
Durusdinium
sp.,
which
naturally
heat
tolerant.
However,
SS8-coral
exhibited
faster
growth
recovered
cell
density
photochemical
efficiency
more
quickly
following
chemical
inoculation
under
ambient
relative
Durusdinium-corals.
Mass
spectrometry
imaging
suggests
algal
pigments
involved
in
photobiology
oxidative
stress
greatest
contributors
thermotolerance
differences
between
heat-evolved
versus
proliferum.
These
may
have
increased
photoprotection
symbionts.
This
first
laboratory
study
show
(G.
fascicularis)
can
be
via
uptake
exogenously
supplied,
symbionts,
without
a
trade-off
against
temperature.
Importantly,
remained
moderate
abundance
2
years
after
inoculation,
suggesting
long-term
stability
this
novel
symbiosis
benefits
PLoS Biology,
Journal Year:
2024,
Volume and Issue:
22(11), P. e3002875 - e3002875
Published: Nov. 12, 2024
Rising
sea
surface
temperatures
are
increasingly
causing
breakdown
in
the
nutritional
relationship
between
corals
and
algal
endosymbionts
(Symbiodiniaceae),
threatening
basis
of
coral
reef
ecosystems
highlighting
critical
role
reproduction
maintenance.
The
effects
thermal
stress
on
metabolic
exchange
(i.e.,
transfer
fixed
carbon
photosynthates
from
symbiont
to
host)
during
sensitive
early
life
stages,
however,
remains
understudied.
We
exposed
symbiotic
Montipora
capitata
larvae
Hawaiʻi
high
temperature
(+2.5°C
for
3
days),
assessed
rates
photosynthesis
respiration,
used
stable
isotope
tracing
(4
mM
13
C
sodium
bicarbonate;
4.5
h)
quantify
metabolite
exchange.
While
did
not
show
any
signs
bleaching
experience
declines
survival
settlement,
depression
was
significant
under
temperature,
indicated
by
a
19%
reduction
respiration
rates,
but
with
no
change
photosynthesis.
Larvae
showed
evidence
maintained
translocation
major
photosynthate,
glucose,
symbiont,
there
reduced
metabolism
glucose
through
central
glycolysis).
larval
host
invested
nitrogen
cycling
increasing
ammonium
assimilation,
urea
metabolism,
sequestration
into
dipeptides,
mechanism
that
may
support
maintenance
stress.
Host
assimilation
via
dipeptide
synthesis
appears
be
limitation
Symbiodiniaceae,
we
hypothesize
contributes
retention
favoring
photosynthate
host.
Collectively,
our
findings
indicate
although
these
susceptible
diverting
energy
maintain
population
density,
photosynthesis,
allow
avoid
highlights
potential
stage
specific
responses
Proceedings of the Royal Society B Biological Sciences,
Journal Year:
2025,
Volume and Issue:
292(2040)
Published: Feb. 1, 2025
Mutualisms
can
increase
the
ability
of
foundation
species
to
resist
individual
stressors,
but
it
remains
unclear
whether
mutualisms
also
ameliorate
co-occurring
stressors
for
habitat-forming
species.
To
examine
a
suspected
mutualist
could
improve
species’
resistance
multiple
we
tested
how
common
coral-dwelling
crab
affected
corals
exposed
macroalgal
contact
and
physical
wounding
during
widespread
heat
stress
event
using
flow-through
tanks
supplied
with
seawater
from
nearby
reef
flat.
High
temperatures
on
flat,
which
raised
temperature
in
our
tanks,
appeared
trigger
rapid
tissue
loss
experimental
corals,
amount
lost
by
was
strongly
determined
treatment.
Macroalgal
increased,
while
presence
decreased,
lost.
Although
effect
not
strong
isolation,
when
occurred
crab,
coral
unexpectedly
decreased
below
that
all
other
treatments.
We
propose
increased
attracting
crabs—a
result
supported
field
experiment.
These
results
highlight
interact
unexpected
ways,
buffering
effects
both
local
global
Nature Communications,
Journal Year:
2025,
Volume and Issue:
16(1)
Published: April 11, 2025
Abstract
Populations
facing
lethal
environmental
change
can
escape
extinction
through
rapid
genetic
adaptation,
a
process
known
as
evolutionary
rescue.
Despite
extensive
study,
rescue
is
largely
unexplored
in
mutualistic
communities,
where
it
likely
constrained
by
the
less
adaptable
partner.
Here,
we
explored
empirically
likelihood,
population
dynamics,
and
mechanisms
underpinning
an
obligate
mutualism
involving
cross-feeding
of
amino
acids
between
auxotrophic
Escherichia
coli
strains.
We
found
that
over
80%
populations
overcame
severe
decline
when
exposed
to
two
distinct
types
abrupt,
stress.
Of
note,
all
cases
only
one
strains
survived
metabolically
bypassing
auxotrophy.
Crucially,
consortium
exhibited
greater
sensitivity
both
stressors
than
prototrophic
control
strain,
such
reversion
autonomy
was
sufficient
alleviate
stress
below
levels.
This
common
across
other
stresses,
suggesting
may
be
general
feature
acid–dependent
mutualisms.
Our
results
reveal
depend
critically
on
specific
physiological
details
interacting
partners,
adding
rich
layers
complexity
endeavor
predicting
fate
microbial
communities
intense
deterioration.
Phycology,
Journal Year:
2025,
Volume and Issue:
5(2), P. 14 - 14
Published: April 26, 2025
Functional
genomics
is
a
powerful
approach
for
uncovering
molecular
mechanisms
underlying
complex
biological
processes
by
linking
genetic
changes
to
observable
phenotypes.
In
the
context
of
algal
symbiosis,
this
framework
offers
significant
potential
advancing
our
understanding
interactions
between
marine
dinoflagellates
and
their
cnidarian
hosts,
such
as
corals—organisms
that
are
foundational
ecosystems
biodiversity.
As
coral
bleaching
reef
degradation
intensify
due
environmental
stressors,
novel
strategies
urgently
needed
enhance
resilience
these
symbiotic
partnerships.
This
opinion
piece
explores
emerging
directions
in
functional
applied
coral–algal
with
focus
on
pathways
govern
photosynthesis
stress
tolerance.
We
discuss
challenges
opportunities
applying
support
health,
improve
ecosystem
resilience,
inform
biotechnological
applications
agriculture
medicine.
Together,
insights
posit
engineered
symbioses
mitigating
biodiversity
loss
supporting
sustainable
management
face
accelerating
change.