Chapter #9

Question 1

Ocean acidification

Answer 1

term used to describe the changes in the chemistry of the world’s seas, primarily as a result of burning fossil fuels.

Question 2

Acids and Bases

Answer 2

An acid is defined as a substance that donates protons (hydrogen ions, H+) during a
chemical reaction.

In contrast, a base (alkali) donates hydroxyl ions (OH–) in chemical reactions.

Question 3

How we measure pH?

Answer 3

pH is actually a measure of the free hydrogen ions that exist within a solution.

Acid solutions are deemed to have an excess of hydrogen ions, and alkaline
solutions have an excess of hydroxide ions

Question 4

Oceanic pH formula

Answer 4

pH = log[H+]

Question 5

Acid solution have excess ____ ions and a pH of ______

Answer 5

excess H+ ions, pH of less than 7

Question 6

Alkaline solution have excess ____ ions and a pH of ______

Answer 6

excess of OH- ions, pH of more than 7

Question 7

How what does the pH formula increase by in each num difference. I.e. the difference between 6 and 7 then 6 and 8

Answer 7

10x each time, so 6-7 is a 10x, and 6-8 is a 100x since 10*10 = 100

Question 8

The pH Scale
______ numbers indicate alkalis,
while ______numbers signify
acidic liquids

Answer 8

Higher, lower

Question 9

The Chemistry of OA

Answer 9

When carbon dioxide (CO2) is absorbed by seawater, chemical reactions occur that
reduce seawater pH, carbonate ion concentration, and saturation states of
biologically important calcium carbonate minerals. These chemical reactions are
termed “ocean acidification” or “OA” for short. Calcium carbonate minerals are the
building blocks for the skeletons and shells of many marine organisms. In areas
where most life now congregates in the ocean, the seawater is supersaturated with
respect to calcium carbonate minerals. This means there are abundant building
blocks for calcifying organisms to build their skeletons and shells. However,
continued ocean acidification is causing many parts of the ocean to become
undersaturated with these minerals, which is likely to affect the ability of some
organisms to produce and maintain their shells.

Question 10

The Earth’s carbon cycle

Answer 10

The exchange of CO2 between land, sea and air, is generally meant to be in
equilibrium.
Note:
However, human activities, such as burning fossil fuels and deforestation,
mean that an increasing amount of CO2 is being released into the
atmosphere.
But not all of the unlocked CO2 remains in the atmosphere. Up to 50% of
the emissions are absorbed by the ocean.

Question 11

The physical carbon pump (pumping of carbon between atmosphere and ocean)

Answer 11

Physically, CO2 dissolves into cold
ocean water near the poles, and it
is carried to the deep ocean by
sinking currents, where it stays for
hundreds of years.
Over time, thermal mixing brings the
water back to the surface and the
ocean emits carbon dioxide into the
atmosphere in tropical regions.
This natural system helps pump
carbon from the atmosphere into
the sea for storage.

Question 12

Biological Carbon pump

Answer 12

The biological absorption of
CO2 involves phytoplankton,
which use sunlight, water and
CO2 to produce carbohydrates
and oxygen.
When the plankton and the sea
animals that eat the plankton
die, they sink to the ocean
floor.
A small percentage of the
carbon in the creatures’
remains is eventually buried
and stored in the sediment.

Question 13

What are the two ways the ocean absorbs carbon?

Answer 13

The oceans absorb carbon in two main ways - physically and biologically.

Question 14

The Biological Carbon Pump removes and stores dissolved ocean CO2 through two different processes:

Answer 14

1. Photosynthesis and food chains
2. Shell-building organisms

Question 15

Feedback mechanisms, example (Green house)

Answer 15

For example, ocean acidification could reduce plankton blooms,
resulting in less CO2 being absorbed from the atmosphere.
In theory, the extra CO2 in the atmosphere could lead to an
acceleration in global warming, which will warm the oceans.
As a result, the warmer waters will not be able to absorb as much
carbon dioxide as cooler seas.
So even less CO2 is taken from the atmosphere, resulting in more of
the greenhouse gas being available to warm the planet.

Question 16

DIC consists of

Answer 16

1. aqueous CO2
2. Bicarbonate HCO3
3. Carbonate CO32

Question 17

What does DIC operate as?

Answer 17

a natural buffer to the addition of hydrogen ions known as the “carbon buffer”

Question 18

Why is the carbon dioxide going into the oceans?

Answer 18

Carbon dioxide is a gas, and like every gas it obeys Henry’s Law with respect to passing
into a solution. As the atmospheric concentration of carbon dioxide increases, the carbon dioxide will go into the seawater. Some of it is just taken up as aqueous carbon dioxide, whilst the rest of it turns into carbonic acid H2CO3.
Carbonic acid is a weak acid which easily breaks down into hydrogen ions and its
constituent anions.

So, what we have is a distribution of the carbon dioxide between the major carbonate
groups, bicarbonate HCO3 and carbonate CO3.
These carbonate, bicarbonate and CO2 elements are referred to as dissolved
inorganic carbon, and all of these elements are very important for ocean systems. We
can see from the distributions on the previous slide that bicarbonate is by far the most
abundant.

The oceans naturally maintain a high abundance of bicarbonate, and they do that by
using carbonate to buffer excess CO2 as it goes in. This is known as the ‘carbonate buffer’, and we perceived that this was the way in which the oceans maintained their pH. It is the way they maintained a very stable chemistry for many, many years. Our previous thoughts were that this buffer was very resilient and pH would not change.

However, we are becoming aware of the fact that the carbonate buffer cannot deal with
the amount of carbon dioxide that we are now putting into the oceans.

Question 19

What is the Oceans pH and type

Answer 19

alkaline 8.1 +- 0.3

Question 20

How do oceans become more acidic

Answer 20

they are taking in more CO2

Question 21

The net effect of dissolving carbon dioxide in seawater is

Answer 21

to increase the carbonic acid concentration, increase the hydrogen ions and increase the bicarbonate ions. You decrease the carbonate ions. So, you are shifting the whole equation back towards the left. And when we get onto talking about the environmental impacts of this, that is a very important thing to remember, because carbonate plays a very important role in aspects of the marine ecosystem

Question 22

2050 what will happen possibly to the pH of the ocean?

Answer 22

Most likely be in unknown territory

Question 23

What is CaCO3?

Answer 23

Calcium Carbonate

Question 24

What is CaCO3 important for?

Answer 24

Marine organisms rely on carbonate for their calcium carbonate structures

Question 25

What does CaCO32- stand for?

Answer 25

Carbonate

Question 26

What happens to CaCO3 when there is little CaCO32 ions?

Answer 26

The calcium carbonate begins to dissolve without a steady supply of the carbonate ions

Question 27

When does CaCO3 become more soluble?

Answer 27

With decreasing temperature and increasing pressure.

Question 28

The boundary of water between CaCO3 dissolving and not, is called…

Answer 28

Saturation horizon
Maybe, Carbonate compensation depth (As well)

Question 29

Carbonate comes in two forms, they are called…

Answer 29

Calcite and Aragonite

Question 30

calcite is used by what organisms?

Answer 30

Mostly marine organisims

Foraminifera, which are small microorganisms; coccolithophores, which are marine algae; echinoderms, the starfish and urchins; molluscs, the seashells; and macroalgae all use calcite, which is much less soluble than aragonite.

Question 31

The Biological Impacts caused by a pH change

Answer 31

Ocean acidification is expected to impact ocean species to varying degrees.
Photosynthetic algae and seagrasses may benefit from higher CO2 conditions in
the ocean, as they require CO2 to live just like plants on land. On the other hand,
studies have shown that a more acidic environment has a dramatic effect on
some calcifying species, including oysters, clams, sea urchins, shallow water
corals, deep sea corals, and calcareous plankton. When shelled organisms are at
risk, the entire food web may also be at risk. Today, more than a billion people
worldwide rely on food from the ocean as their primary source of protein. Many
jobs and economies around the world depend on the fish and shellfish in our
oceans.

Question 32

pH change on larger organisms causes..

Answer 32

Decreased motility, reduced growth, respiratory distress, shell dissolution, inhibition of feeding, reduced recruitment, decrease in population size, mortality, increased susceptibility to infections, destruction of chemosensory systems.

Question 33

Effects on microorganisms. from a pH change

Answer 33

Microorganisms are sensitive to carbon changes and pH changes

Why are plankton important, why are the small plants that float around our oceans
important?
Well, it is because they produce 50 per cent of the global primary productivity. All the
rainforests and all the temperate forests add up to only the same amount of carbon
production, of primary productivity, as all the small microorganisms in the ocean. So,
on a global scale these plants are very important.
Carbon dioxide and pH change could influence a whole host of different processes.
With regard to photosynthesis, you would think that if you increased carbon dioxide
for a plant, photosynthesis would increase. But marine plants evolved in a time when
carbon dioxide levels were much lower than they are today, and many species have
developed specific enzymes, called Rubisco enzymes, which act to concentrate
carbon dioxide.
So, what we have is marine plants which are not limited by carbon dioxide. We will
only see small increases in photosynthesis, because most of the organisms are
limited by other factors such as temperature, light or nutrients.
That impacts again on growth and composition: there is little effect. Most of the
effect will be due to changes in nutrients. These organisms, as well, are limited by
trace metals.

Question 34

Coral reefs occur in…

Answer 34

warm, alkaline, sunlit waters with high aragonite saturation.

Question 35

What are coral reefs?

Answer 35

Corals form a powerful mutualistic symbiosis with tiny dinoflagellate algae known as zooxanthellae. Sitting in the tissues, the algal symbionts photosynthesize and pass most of their production to coral. In return, the animal provides inorganic nutrients such as ammonia and phosphate - from their waste metabolism.

Question 36

What are coral reefs referred to as, as a comparison.

Answer 36

Coral reefs are often compared to rainforests for the vast biodiversity they
support. Despite covering only one five-hundredth of the ocean floor, more than
one fourth of all marine fish species call coral reefs home. Reefs also support
economies by attracting tourists, protect coastal communities from the potentially
damaging effects of storms, and may hold the secrets to curing fatal diseases.

Question 37

What are the two basic types of coral?

Answer 37

hard corals and soft corals

Question 38

Hard Corals

Answer 38

Hard corals have an outer skeleton made of limestone, also known as calcium carbonate (CaCO3)
In hard corals, polyps sit inside little cups built from calcium
carbonate.

Question 39

Soft Corals

Answer 39

soft corals have bits of calcium carbonate
embedded inside their bodies.
The CaCO3 in soft corals is in the form of
little spikes that help bind many individual polyps together in fan- or whiplike structures

Question 40

How are coral reefs made

Answer 40

Many cups connected together make up a coral colony, and when hundreds of hard coral colonies grow next to and on top of one another, coral reefs are formed

Question 41

What do zooxanthellae do?

Answer 41

The
zooxanthellae, like all plants, convert sunlight, carbon dioxide, and water
into oxygen and carbohydrates that feed the coral polyps and help them
produce reef-building calcium carbonate. In return, the corals provide the
zooxanthellae with protection and the compounds they need for
photosynthesis. Pigments in zooxanthellae also give corals their beautiful
orange, red, purple, and yellow colors

Question 42

Why are coral reefs dying?

Answer 42

Largely due to increasingly frequent and intense periods of warm sea temperatures

Question 43

What are cold water corals?

Answer 43

Often referred to as “Deep water” corals but exist at between depths of 10m to over 1000m.
Distribution caused by temperature.
Non-photosynthetic, rely on organic matter from above.
Found all over the world.
Support a diverse ecosystem

Question 44

Solutions to prevent the ocean from becoming more acidic

Answer 44

1. Drastically reduce the release of industrial CO2
2. Ocean Fertilization
3. Ocean Sequestration
4. Geological Sequestration

Question 45

Ocean fertilization:

Answer 45

The process of adding iron or other nutrients to the ocean to cause large algal
blooms, has been proposed as a possible solution to global warming because
the growing algae absorb carbon dioxide as they grow.
However, this process, which is analogous to adding fertilizer to a lawn to help
the grass grow, only reduces carbon dioxide in the atmosphere if the carbon
incorporated into the algae sinks to deeper waters. This process, which
scientists call the “Biological Pump”, has been thought to be dependent on the
abundance of algae in the top layers of the ocean. The more algae in a bloom,
the more carbon is transported, or “pumped”, from the atmosphere to the deep
ocean.

Question 46

Ocean Sequestration

Answer 46

The direct injection of unwanted carbon dioxide deep into the ocean
is one suggested strategy to help control rising atmospheric carbon
dioxide levels and mitigate the effects of global warming.
But, like the problems associated with the long-term storage of
nuclear waste, finding a safe place to sequester the carbon may be
more difficult than scientists first anticipated.
Because the atmosphere interacts with the oceans, the net uptake
of carbon dioxide and the oceans’ sequestration capacity would be
affected by a change in climate. Just how effective carbon
sequestration would be, in light of projected climate change, has not
been studied before. Indeed, estimating the impact of carbon
injection is complicated because of a limited understanding of
climate and oceanic carbon cycle feedback mechanisms.

Question 47

Geologic Sequestration (GS)

Answer 47

It is the process of injecting carbon dioxide (CO2), captured from an industrial (e.g., steel and cement production) or energy-related source (e.g., a power plant or natural gas processing facility), into deep subsurface rock formations for long-term storage. This is part of a process frequently referred to as “carbon capture and storage” or CCS.