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Slowed down Ocean circulation, Climate Change - Coggle Diagram
Slowed down Ocean circulation
Disruption
of
marine food webs
Ocean circulation
allow for exchange of nutrient
s &
oxygen
between
surface & deep waters
However, sinking of water
reduced
at
poles
warm surface water mix
less
w cooler, deeper water
aquatic organism living near
surface of water,
especially
phytoplanktons
, would
not get supply of nutrients from deep oceans
phytoplanktons
-->
base
of food web --> species
higher up food chai
n (fish & whales)
decrease
due to
lack of food
Entire
ecosystem affected
Example: phytoplankton levels in
North Atlantic
dropped
by
10% since 1800s
Increase
in ocean
temperatures
Changes in
geographic distribution of aquatic species
aquatic species migrate
to areas where
temperatures are more favourable
(move
polewards
where there is
deeper cooler waters
)
Example:
Atlantic Cod
decrease
in
biodiversity
in
equatorial
regions/
increase
in
poleward
regions
diversity of species
in
tropical waters
(e.g fish)
dropped significantl
y in last
50 yrs
Geographic distribution
change
=
change
in mix and
population densitie
s of
prey, predators, competitors
new aquatic communities develop
Some species
flourish
, others
would not
/
decline
find
abundance of suitable sources of food
-->
increase population
BUT
species
that they
feed on decline
cannot
find
suitable
habitats
Mountain species prefer cold en
v -->
dont have anywhere if top of mountain too warm
face
competition
from
species from lower altitudes moving upwards
higher rate of extinctio
n in
mountainous areas
1 more item...
Example:
Wallabies
migrate to higher altitudes
--> feed on
herbfields
in mountains --> threaten to
reduce to grassy lawns
(r
eplace existing species)
1 more item...
plant species
decline
-->
unable to move/ adapt fast enough
dont warm uniformly
,
cool spots
of water found in
lower lattitudes
some species
migrate away from poles to this
Example:
Witch Flounder
in
US
shifted south
, toward lower lattitude
unable
to
migrate/ move fast enough
--> may be
unable
to
adapt to higher sea temp
.
local / global
extinction
--> environment
unsuitable
and habitats/ food sources
disappear
Threat to coral reef
Corals -->
highly fragile ecosystems
-->
bleach
due to variety of reasons (
pollution, lack of sunlight, warming oceans
)
Corals have
symbiotic
rlsp w algae that live in them --> algae
primary food source
&
give them colour
increase
Ocean temp. --> coral
expels
algae
coral
lose major source of food
-->
turn white
(
Coral bleaching
) and
vulnerable to diseases
/
starve
which may
lead to death
expected to
decline by up to 90%
if
ocean temp. increase by 1.5 degrees
algae make food through
photosynthesis
most passed to coral
millions
of aquatic species (e.g fish, seahorse, sea turtles)
depend
for
food and habitat
population decline
if corals die
affect other species
that depend on these organisms for food -->
affect entire ecosystem
Example:
Great Barrier Reef in Australia
severely affected in
2016 & 2017
2/3
corals died in
norther section
of reef -->
drastic decrease
in
species diversity
after
bleaching event
Ocean acidification
Ocean
important natural carbon sink
phytoplankton
absorb CO2
through photosynthesis
die
-->
sink
to deep ocean, carrying
stored carbon
along
absorb
excessive
amt of CO2 from
increase
in
atmospheric
CO2 emission
carbonic acid formed
in water
dissolve calcium carbonate
-->
key ingredient needed
for aquatic organism (coral, mussels, oysters) to
form skeletons/ shells
coral reefs
eroding faster
than
new corals
can
form
-->
coral skeleton shrink
avr coral cover
drop to 30%
since 1960s (Great Barrier Reef)
Since industrial revolution, acidity increase by 25%
Climate Change
Impact on
Terrestrial
ecosystems
Threat to flora & fauna
Increase
in atmospheric temp
Changes in
geographic distribution
of species
forced to adapt
due to warming atm
migrate
to places w
preferred temp.
shift toward
higher latitudes/ altitudes
where
temp. cooler
Example:
170 species
of bird tracked in
North America
expanded their range northwards by 50km
on avr during past
4 decades
Example:
Boreal forest
advancing
northwards into tundra
--> they themselves are being
replaced by temperate forests
other factors such as
water availability & sunlight conditions
usually
poleward movement
but some species in
California, USA
-->
migrate downslope
due to
greater shade and moisture downslope
Change in
population density & composition of ecosystems
same but terrestrial
Changes in
extreme weather
more
frequent & severe droughts
plants
vulnerable to water scarcity
-->
unable to move
elsewhere -->
wither and die
/
drier weakened plants more vulnerable to diseases & insect attack
Example:
drought
in
California, USA
(
2012 - 2016
)
death
of
102M forest trees
--> l
ack of water & spread of diseases
dried up wetlands
-->
kill
many
insects, fish,
plants
-->
migratory birds starved to death
spread of diseases such as botulism, cholera
(thrive in
warm conditions)
thousands
of ducks & geese crowd in remaining wetlands, allow
quick spread of cholera
deaths
of birds
species
unable to adapt
bc
habitat damaged & food supplies reduced
when trees die --> may be
driven to extinction
Example:
desert bighorn sheep
in
California
driven to extinction due to reduced food availability
Force animals to
move to new locations in search of food & habitat
Excessive Rainfall
unusually huge amts of water
overflow
their banks --> cause
floods
-->
submerge & destroy
surrounding habitat --> plants
uprooted
by fast moving flood waters/ terrestrial species may
drown
Example:
Assam, India
, unusually
intense rainfall in 2020
result in floods,
kill >200 wild animal
s (including
8 endangered rhinoceroses
)
saturate
rocks on steep slopes, making them
heavy
--> more likely to
slide down slope
--> cause
landslide
-->
destroy habitats as trees/plants uprooted
Example:
Nilgiri Hills, India
--> receive
intense rainfall in past few years
--> cause
many landslides
--> result in
death of thousands
of
trees/ flowers/ plants
Soil Erosion
-->
wash away soils
on slopes
removing important nutrients
for plants to grow well --> more
difficult for plants to survive