Ocean acidification is a term used to describe the changes in the chemistry of the Earth’s ocean i.e. ongoing decrease in the pH and increase in acidity caused by the uptake of anthropogenic carbon dioxide from the atmosphere causing major problems for the coral reefs and other organisms.
Call Girls Budhwar Peth Call Me 7737669865 Budget Friendly No Advance Booking
Ocean acidification
1.
2. A PROJECT OF ENVIRONMENTAL BIOLOGY
OUR TEAM
SUMANTA BOSE
Roll No. - 2043
ARNAB gHOSH
Roll No. - 2017
SUPRITI PIPLAI
Roll No. - 2029
KANKANA DUTTA
Roll No. - 2027
Subhajit KAR
Roll No. - 2053
Sayantan roy
Roll No. - 2052
5. INTRODUCTION
OCEAN ACIDIFICATION is a term used to describe the changes in the chemistry of
the Earth’s ocean i.e. ongoing decrease in the pH and increase in acidity caused by
the uptake of anthropogenic carbon dioxide from the atmosphere.
The absorption of massive amount of carbon dioxide into the sea altering
water chemistry of the ocean by triggering reactions that make sea water
more acidic.
Since the beginning of industrial era, burning of fossil fuel and deforestation
have increased the amount of carbon dioxide emitted to the atmosphere - &
the amount that dissolve into the ocean.
This acidification threatening disaster for marine organisms and food supplies
across the globe. Acidity have been increased by 30% from normal range & its
effect is irreversible.
If carbon dioxide emission continue unchecked - key parts of marine environment that
are essential for fish - such as coral reefs, algae and plankton will be severely affected,
leading to the extinction of some species by 2050.
7. PROOF OF EXCESS CO2
Roger Ravelle first proposed that oceans are absorbing
CO2 at much slower rate resulting higher accumulation
in the atmosphere.
David Keeling, who had developed the first instrument
for accurately measuring atmospheric CO2 levels, sets
up ‘Keeling Curve’ which provides evidence for natural
carbon cycling is not keeping pace with CO2 emissions.
Further studies have shown that the concentration of
CO2 in the ocean is increasing in parallel with the rise
in atmospheric CO2.
At the same time, the pH of the ocean is decreasing
(becoming more acidic) indicating that CO2 levels have
exceeded the ocean’s natural capacity to buffer pH.
Calculated partial pressure of CO2 in seawater
Calculated partial pressure of CO2 in air
Direct measurement of pH in surface seawater
Calculated pH
8. Figure showing majority of ocean pH throughout the world ABOVE 8.0 which is depicted by blue colour.
SEA WATER pH IN 1850
9. Figure showing majority of ocean pH throughout the world BELOW 7.6 which is depicted by yellowish colour.
SEA WATER pH IN 2100
10. CHEMISTRY OF ACIDIFICATION
CO2 is absorbed
by seawater from
the atmosphere
Reduced carbonate
ion & increased free
proton concentration
Present of insufficient
carbonate ion in sea
water & lowered
ocean pH
Seashells doesn’t get
the calcium carbonate
needed for their
development.
11. AFFECTED BIOLOGICAL PROCESSES
Building Shells - Many animals and some algae use carbonate ions to make calcium
carbonate shells and skeletons. Because ocean acidification decreases the availability
of carbonate ions, these organisms will have to work harder to produce shells.
Boosting Photosynthesis - CO2 can stimulate plant growth by boosting the rate of
photosynthesis. Many plants grow rapidly under elevated CO2 condition. These plants
overgrow less robust species and reduce the ecosystem’s biodiversity.
Obtaining Essential Minerals and Nutrients - Ocean acidification makes it harder for
marine organisms to absorb nitrogen, phosphorus, iron, and other elements essential
which are very important for their growth.
Maintaining Metabolism - Many physiological processes are fine-tuned to operate
within a narrow pH range; outside of that range, the biochemical reactions may be
too slow or inefficient to keep the organism healthy. Lower pH affects neurological
processes in adult fish.
12. Under more acidic conditions, their larvae had lighter, less dense shells, which
could make then more susceptible to predation and less able to survive.
They use the calcium carbonate to harden their shell in a very different process
which requires a lot of energy. Increasing ocean acidity may drive lobsters to
create larger shells. Thereby wasting more energy in shell forming rather than
activities that are vital to survival.
Acidified ocean also causes abnormal shell growth.
Sea urchins reproduce by releasing eggs and sperm directly into the surrounding sea
water. Under acidified conditions the sperm of some sea urchins swim more slowly,
which reduces their chances of finding and fertilizing an egg.
Acidic conditions could reduce the number of sperm certain species release, thereby
further decreasing the size of the next generation of sea urchins.
Sea urchins are likely to find it more difficult to build their calcium carbonate skeletons
in an acidified ocean.
EFFECTS ON MARINE ANIMALS
Lobster
Sea Urchin
EFFECTS ON SHELLFISH
13. The spindly arms of a brittle star break off when the animal senses danger and,
under normal conditions, can quickly regenerate. However, this process is likely
to be disrupted in the future as the oceans become more acidic.
They are sacrificing building muscle in order to create the calcium carbonate of
their arms. Weakened arms decrease their ability to survive in a acidic ocean.
Brittle stars appear to be very vulnerable to increasing ocean acidity both as ad
ults and larvae, which could result in severe population declines in the future.
Under acidification the purple sea star decreases calcification but increases its overall
growth. This increase in growth rate leads to increased feeding rates, putting more
pressure on preferred food sources and thus causing population declines among preys.
Increasing growth rates among sea stars could cause large changes through the
ecosystems that sea stars have traditionally kept in balance.
Another type of sea stars has also been found developing early, this could put juveniles
in adverse conditions that prevent them from growing properly or surviving.
Sea Star
Brittle Star
EFFECTS ON SHELLFISH
14. Squid Clownfish Damselfish
EFFECTS ON ANIMALS WITHOUT SHELL
Increased ocean acidity inhibit a squid’s
ability to transport large amounts of O2
which impede their fast bursts & inhibit
serious activities like hunting & avoiding
predators. This would inevitably affect a
squid’s ability to survive.
Significant drops in metabolic rates and
activity levels occurs in jumbo squid.
More acidic condition alters the normal
development of otoliths in the larvae of
damselfish which makes it difficult for
fish to locate appropriate reef habitats
and result in population declines.
Abnormal otolith growth has been
shown to create serious disruptions in
locomotion and balance of the fish.
Under acidic conditions larvae may not
be able to discern between the smells
of suitable home & hostile environment,
which could result in their death.
Under acidified condition smell-related
predator defense system is disrupted &
most clownfish larvae are no longer be
able to differentiate between predator a
nd non-predator cues.
15. IMPACTS ALREADY OCCURRING
PACIFIC OYSTER FARMS FAIL
Other molluscs, including mussels, scallops and clams, also appear to be
extremely vulnerable to increasing acidity. These animals all create CaCO3
shells to protect their soft bodies from predators, disease & harsh ocean
conditions. Severe decline in shell growth rate are happening.
Slower shell growth is likely to reduce the ability of molluscs to survive,
which would have significant impacts on commercial fisheries. One study
suggests that if this slowed growth predicted for 2100 had occurred in
2006, mollusc fisheries would have Lost between 75-187 million dollars.
Shellfish farmers may already be feeling the devastating impacts of ocean
acidification on their livelihood as they have been experiencing difficulties
raising oyster larvae since 2005.
Deceased oyster
16. CORALS SHOW DECREASED GROWTH
Coral reefs are very important to many coastal
communities and national economies, and they
too have started to show signs of decline that are
due to ocean acidification.
Some of the largest reef-building corals started
showing reductions. Declines in growth rate could
result in a mass die-off of tropical coral reefs by
the middle to end of this century.
Due to loss of coral reef coastal communities will bear the brunt
of these losses. Serious health consequences could ensue for
the estimated 30 million people who rely almost solely on coral
reef ecosystems for protein and protection
The potential losses from a decline in coral reefs will be
felt from the smallest coastal subsistence communities
all the way up through the global economy.
17. CORAL REEF HABITAT LOSS
Coral reefs are probably home to at least a quarter
of the entire biological diversity of the oceans, a
seemingly limitless number of species, & serve as
some of the most beautiful habitats in the world.
These millions of species feed, reproduce, shelter
larvae & take refuge from predators in the vast 3
dimensional framework offered by coral reefs.
if CO2 emissions remain unabated coral reefs could
be eroding through natural processes faster than
they can grow their skeletons due to the combined
pressures of increasing acidity and global warming.
Reefs may become nothing more than eroded rock
platforms, greatly changed from the structures tha
t so many species rely upon for habitat. Corals face
severe declines & even extinction, which will in tur
n threaten the survival of reef dependent species.
Dying off of Coral reefs due to Ocean Acidification
18. ANIMALS HABITAT LOSS
Thousands of fish species depend on coral reefs for habitat.
Some of these fish, like butterfly fish, feed exclusively on the
coral itself. Other species of fish also depend on coral reefs
as sources of food, shelter and nurseries. Loss of coral reef
dependent fish can be expected as reef habitat become less
available.
Extensive die-offs of coral due to bleaching events can serve
as an example of how interrelated coral reef fish are with the
ir coral habitats. After one event in Papua New Guinea, 75%
of the coral reef fish species declined in abundance & several
species even went extinct.
Sea turtles are often found resting and feeding on coral reef.
They like to feed on reef species such as sponges, molluscs,
algae and soft corals. Declines in coral reefs could impact sea
turtle feeding behaviors & could cause them to turn to less
nutritious food sources or even go hungry.
As acidification worsens the abundance of reef species will
diminish, which could result in change to the type & amount
of sand reaching nearby beaches. Changes in the make up of
the sands on nesting beaches could negatively impact sea
turtles’ ability to successfully produce new hatchlings & red-
uce the population size of these already endangered species.
FISH
TURTLE
SEA
19. THREAT TO LARGEST CORAL REEF
Great Barrier Reef of Australia
- the largest reef of the Earth
Ocean acidification also threatens Earth’s largest reef
by reducing the viability & strength of coral reefs. That
reef is currently experiencing degradation.
Calcifying organisms are under risk, due to the lack of
aragonite in water & the decreasing pH. This decreased
health of coral reef result in reduced biodiversity.
Organisms become stressed due to ocean acidification
& the disappearance of healthy coral reefs, such as the
Great Barrier Reef, is a loss of habitat for several taxa.
Ocean acidification, together with other stressors such
as rising ocean temperature and pollution, is likely to
make it harder for corals to grow or repair damage.
The growth of the Great Barrier Reef’s coral colonies ha
s decreased by 14% since 1990. If growth rates continue
to decline that damage and erosion will outpace repair.
20. FOOD WEB DISRUPTION
Pteropods - Pteropods, abundant, tiny swimming sea snails are some
times referred to as the “potato chips of the sea” because of their
importance as a food source for so many species.
Pteropods build calcium carbonate shells, a process that is particularly
vulnerable to increasing ocean acidity. As early as the year 2050, they
may be unable to form these shell, threatening their ability to survive.
If they cannot adapt to living in more acidic waters, their populations
will plummet, which could result in ripple effects throughout the food
webs that depend on them.
Salmons - North Pacific salmons depend heavily upon pteropods for food. In fact, pteropods can make up 45 % of the diet of
juvenile salmon. The North Pacific salmon fisheries provided 3 billion $ worth of personal income to fishermen and others in
2007, and supported 35000 jobs in just the harvesting and processing of the fish. Other commercially important fish species
that eat pteropods include mackerel, herring and whale —all of which could risk collapse if pteropod populations decline.
Killer Whales - killer whales in the North Pacific ocean prefer to eat salmon, in fact 96% of some killer whales diet is made up
of salmon. When the base of the food web disappears, the effects can travel all the way to the top. If predators are unable to
supplement their diets with other food sources, food webs may even collapse entirely. Top predators like the emblematic killer
whale could suffer, which in turn could have further implications like lost of this iconic species and low tourist attraction.
21. IMPACT ON ECOSYSTEMS
This ecosystem is based on
plankton- a mixture of tiny
free floating plant, animals
that live and grow in sunlit
surface water and serve as
the foundation of marine
food chain. A huge number
of planktonic species and
Open ocean ecosystems
pteropods, need carbonate ions to build their
shells.
If ocean acidification increases, these carbonat
e based plankton species may decline – and th
at means that a range of species, including fish,
seals, and whales, could lose their preferred
foods, or have less food altogether.
The polar waters of Arctic &
Southern oceans harbour
protected and endangered
marine mammals & support
some of the most producti-
ve fisheries in the world.
CO2 dissolve more readily in
cold water, acidifying polar waters faster than in
lower latitudes. Scientists have determined that
the surface waters of the Southern Ocean will
begin to become corrosive to some types of
carbonate structures by the year 2050 if carbon
dioxide emissions continue to increase at the
current rate.
Polar ecosystems
22. IMPACT ON ECOSYSTEMS
Deep water coral ecosystems Tropical coral ecosystems
Acidification is expected to
take longer time to reach
the deeper waters, but over
time it reduces calcification,
decreasing growth rate of
deep-water corals.
Furthermore, deep water
species may be less able to tolerate changing
conditions than shallow water counterparts.
Many deep-dwelling organisms are adapted to
the unvarying conditions that characterize the
deep sea and may be less able to cope with
change, such as increasing ocean acidity.
In the natural world, corals
must grow rapidly to outpace
predation by fish and other
organisms, and to compete
for space with algae and sea
grasses.
Ocean acidification prevents
reef building corals from growing fast enough
to escape predation and competition, or to
repair physical damage sufficiently. Slowed
growth is not the only impact that acidification
could have on coral reefs - some scientists think
that more acidic condition could also contribute
to coral bleaching.
23. IMPACT ON PEOPLE
Tourism - Millions of scuba divers visit coral reefs to enjoy their beauty & abundant sea life.
Local businesses generate income by offering diving tours and recreational fishing trips, and
hotels, restaurants, and other businesses based near the reef ecosystems also benefit from
the influx of visitors. One estimate global value of coral-reef based recreation and tourism is
$9.6 B. Ocean acidification threatens the survival of these beautiful & valuable ecosystems.
Impacts on wild fisheries - In 2007, the wild fish and shellfish harvested by the U.S. fishing industry
were valued at $3.7 billion. Ocean acidification could jeopardize this industry by altering the growth
and development of economically important species of fish, either directly or through effects on the
ecosystems of which these species are a part.
Impact on health - Ocean acidification can modify the abundance and chemical composition
of harmful algal blooms in such a way that shellfish toxicity increases and, therefore, human
health is negatively affected. In both cases, ocean acidification has been found to lead to an
increased algal growth rate, a change which could accelerate the production of toxic algae.
24. ECOLOGICAL WINNERS
Jellyfish is one of the “winners” in a more acidic ocean. It is likely that even if acidification
is not directly responsible for their recent increased prevalence, it may be creating ocean
conditions that are ripe for jellyfish to flourish.
Jellyfish blooms could have disastrous impacts, especially if past disruptions from these
creatures are replicated.
In addition, they also represent a threat to beach-goers and can harm economies that
depend on coastal tourism.
Algae and sea grasses are likely do well in an acidified ocean. These species take up CO2 &
sometimes directly compete with calcifiers. So as acidity increases, conditions will shift in
their favour & they will be able to go into areas where they have not previously flourished.
One study of naturally occurring carbon dioxide vents off the coast of Italy found 30% lower
species diversity, but higher levels of invasive algal species. These vents may serve as an
example of how future oceans may look after acidification sets in — our oceans may be
dominated by algae and invasives.
25. PROTECTING THE OCEAN
As individuals, we can reduce
our carbon footprint and buy
products that support sustain
able fisheries and aquaculture
As societies, we can harness
knowledge about marine bio-
logy through research & focus
on monitoring and forecasting
changes
Support initiatives and policies
that reduce carbon emissions.
Could make strict laws which
people have to follow for
controlling carbon emissions
Protect vulnerable societies such
as island communities that
depend on reefs for protection
and seafood for proteins
We can’t stop ocean acidification entirely,
but we can do our best to mitigate the
impacts and protect those affected
A clear marine ecosystem
is what we all want
