Chemical characteristics of Marine Environment

1. Presentation on
• Md. Eftekharul Alam (19103413)
Course code: ESE- 2103

2. AGENDA
▪ Definition
▪ Classification
Marine
Environment
▪ Biogeochemical
▪ Nutrients
▪ Organic Matter
Chemical
Characteristics
▪ Flora and Fauna
▪ Food chain
Biological
Productivity

3. Marine Environment
❑ A marine environment consists of an area with water bodies.
❑ Marine waters can be salty or fresh
❑ The marine environment is an essential component of the global life-
support system
❑ Marine environment can be divided into two major divisions:
I. Pelagic division
II. Benthic division

4. Types of Marine Ecosystems
Deep Sea
Over 60% of our planet is covered by
water more than a mile deep. The
deep sea is the largest habitat on
earth and is largely unexplored
01
Mangrove
Mangrove trees are salt-tolerant
plant species with roots that dangle
into the water and provide shelter
for a variety of marine life
03
Polar
Polar ecosystems are found in
the extremely cold waters at
the Earth's poles
02
Coral Reef
Coral reefs are large underwater
structures composed of the skeletons of
colonial marine invertebrates called coral.
04

5. Chemical Characteristics of Marine Ecosystem
Weather
Weather
• Winds
• Waves
• Tides
• Currents
Physical
Physical
• Temperature
• Salinity
• Pressure
• Density
• Viscosity
Biogeochemical
Biogeochemical
• Essential
nutrients
• Organic matter
• Pollutants
Sediment
• Grain size
• Organic
substrates
Environmental factors

6. Marine Water Chemistry
❑ The chemical properties of the Marine Ecosystem are important to
understand because the marine environment supports the greatest
abundance of life on earth
❑ This life is largely made up of the same chemicals that comprise the
ocean- water and salts
❑ Dissolved Oxygen, Carbon dioxide, pH, Alkalinity, Salinity, Nutrients
Levels

7. ❑ Dissolved Oxygen
❑ The concentration of dissolved gases in water is of prime importance in
considering the quality of water along with the other physicochemical
characteristics
❑ 6CO2 + 12H2O + Sunlight --------C6 H12 O6 + 6O2 + 6H2O
Plants utilize carbon dioxide, water and sunlight to form simple sugars
and oxygen – a process known as Photosynthesis
Chemical Feature (Dissolved Gases)

8. Oxygen levels within the bottom layer of the pond can drop to lethal levels
specially for bottom dwelling culture animals such as freshwater crayfish

9. ❑ Carbon dioxide content in air is only 0.03%, But it is highly soluble
in water like oxygen
❑ Carbon dioxide in free( dissolved) or bound form (bicarbonate and
carbonate) in water depending on the pH of the water
❑ Carbon dioxide is very soluble in water, though; the proportion of
dissolved carbon dioxide in water is about 15% of all dissolved gas
❑ The amount of a given gas that can dissolve decreases with an
increase in temperature
Carbon dioxide

10. ❑ Ph is defined as a negative decimal logarithm of the hydrogen ion
activity in a solution.
❑ Seawater is slightly alkaline between 8.0-8.6 on average
• Acid: amount of hydrogen ions H+
• Base: amount of hydroxide ions oh-
Chemical Feature (pH)

11. ❑ With higher algae concentration, more carbon dioxide is removed from
the system and hence Ph will rise
❑ The reverse will occur at night when more carbon dioxide is produced
therefore leading to a drop in pH levels
pH

12. ❑ Keeps marine water Ph about same (8.1)
❑ Ph too low, bicarbonate combines with H++
❑ Calcium carbonate neutralizes acid
❑ Ph too high, carbonic acid releases H+
❑ Carbonic acid neutralizes base
❑ If base is added, it is neutralized by carbonic acid so the pH
stabilized, If acid is added, it dissolves calcium carbonate and the pH
is stabilized
Chemical Feature (Carbonate buffering)

13. ❑ Sea water contains a variety of dissolved solids
▪ Solutes
❑ Salinity is measure by:
▪ Conductivity of Cl-
▪ Refractometer
❑ Water and carbon dioxide combine to form carbonic acid (H2CO3),
a weak acid that breaks into hydrogen ions (H+) and bicarbonate
ions (HCO3-).
❑ As the ocean continues to absorb more CO2, the pH decreases and
the ocean becomes more acidic.
Chemical Feature (Salinity)

14. ❑ Salinity is measure of the amount of
dissolved salts in seawater that
expressed as grams of salt per kilogram
of water, or parts per thousand (ppt)
❑ Salinity can affect the density of ocean
water
❑ Seawater becomes denser as it gets
saltier, colder or both
❑ Halocline and Pycnocline are
areas of the water column where
salinity and density change
rapidly
Salinity
Minor
Salts
5% SO4
9%
Na
31%
Cl
55%
SALTS

15. ❑ A nutrient is essential to an organism if it cannot be synthesized by
the organism in sufficient quantities and must be obtained from an
external source
❑ Plants in the ocean utilize mainly three basic nutrients namely
❑ Nitrate- NO3, PO4 and SIO4-
❑ Nutrients are generally present as dissolved ionic salts in marine
environment
Chemical Feature (Nutrient)

16. ❑ Most nutrients in oceans are present in sufficiently high concentration
so they never become limiting to primary production.
❑ Nutrients like N, P, Fe, Si are often in short supply, and become rare to
limit primary productivity
❑ Such nutrients are called as Bio-limiting nutrients
❑ Other example- Na+, K+, Cl- etc.
❑ The nutrient most commonly limiting in marine environment is Nitrate,
and Phosphorus is limiting in freshwater environment
Nutrient (as limiting factor)

17. Chemical Feature (Organic Matter)
❑ Sedimentary organic matter is the major reservoir of organic carbon in
the global carbon cycle
❑ In the marine environment it is composed of material derived from the
various plankton species that comprise the ecology of primary producers
and consumers in overlying surface waters
❑ Colored dissolved organic matter (CDOM) is estimated to range 20-70%
of carbon content of the oceans, being higher near river outlets and lower
in the open ocean
❑ As a consequence of adaption to salinity, marine organisms are the most
prolific source of Halogenated organic compounds

18. ❑ Net marine primary productivity is the amount of organic material
available to support the consumers (herbivores and carnivores) of
the sea.
❑ Marine life species are buoyed up by moving water and need not
have to store a large amount of energy in their skeletal material
❑ Majority of the marine plants are floating species. Size-wise, they
are microscopic
❑ Many of the marine animals are invertebrates
Biological Productivity

19. Marine Flora
❑ Phytoplankton are the major primary
producers in the pelagic zone
❑ Prasinomonad, Cryptomonads,
Chloromonads and Chrysomonads
are the other marine phytoplankton
see in the seas and oceans
❑ Most of the Phytoplanktons are
unicellular algae
Marine Flora and Fauna

20. Marine Fauna
❑ Marine animals are divided into three
groups as Zooplankton, Nekton and
Benthos
❑ Zooplanktons are drifting animals and are
usually small but grow to fairly large size
❑ The zooplankton includes some members
like fish eggs or larva of organisms which
may grow up and leave the
phytoplankton community to join the
Nekton or Benthos
Marine Flora and Fauna

21. Marine Food Chain
Level 4 Top Predators
The ocean’s top predators
(Larger and faster than most of their competition)
Level 4:
• Sharks
• Tuna
• Seals
Level 3 Carnivores
The ocean’s smaller carnivores, such as sardines,
feast on herbivores like zooplankton
Level 3:
• Squid
• Sardines
• Snapper
Level 2 Herbivores
Tiny grazing animals devour the sea’s
phytoplankton in staggering numbers
Level 2:
• Zooplankton
• Sea urchins
• Parrotfish
Level 1 Photo-Autotrophs
Every species in the sea’s food chain need organic
carbon to survive. Phytoplankton tap energy from
the sun to fuel the entire ocean ecosystem
Level 1:
• Phytoplankton
• Seaweed
• Seagrasses

22. Point 1
About 2% of the total food
consumption comes from marine
species
Conclusions
Point 2
Biological Oceanography is an
inter-disciplinary science and is a
rapidly developing field of
marine and earth sciences
Point 3
The economic utilization of natural
Marine resources is very high
Point 4
If marine life gets affected by
pollution, the human population may
get the impact while consuming such
resources

23. THE END THANK
YOU
“Think Blue and Go Green. Stop Marine Pollution”