Temperature, light, Oxygen, salinity, pH are important marine factors which impact the major life and physical properties of the oceans. These factors make the marine environment a dynamic entity and otherwise impacting on the terrestrial ecosystems too.

1. Marine water parameters
Prof. S D Rathod
B N Bandodkar College of Science
Thane, Maharashtra, India

2. Temperature
• Global water surface temperature

3. • Picture courtesy NASDA/NASA
This is an image of global sea surface temperatures taken from Japan
National Space Development Agency's (NASDA) AMSR-E instrument
aboard NASA's Aqua spacecraft on August 27, 2003. The colors in this
false-color map represent temperatures of the ocean's surface waters,
ranging from a low of -2 °C (28 °F) in the darkest green areas to a high of
35 °C (95 °F) in the brightest yellow-white regions. Sea ice is shown as
white and land is dark gray.

4. Temperature
• Thermo-haline surface circulation: Thermohaline
circulation simply refers to global density-driven
circulation (convection) of the oceans.

5. Oceanic currents
• Trade winds cause circles near equator
• Westerly winds carry polar water towards equator
• Labrador current –very cold
• Equator currents slosh towards east after continetal heating
• Gulf currents –very warm

6. • The flow of cold, saline surface water (blue)
downward and toward the equator can only be
clearly recognized in the Atlantic. Warm surface
water (red) flows in the opposite direction,

7. Factors affecting: Oceanic currents
• Another key factor that influences ocean
currents is the density of seawater. Both
temperature and salinity contribute to
seawater density, thus local changes in
temperature and the magnitude of
freshwater inputs from rivers and streams
can alter near shore ocean currents.

8. Marine upwelling
• Winds near the peninsula push
warm water away from the
surface allowing deep, cool,
nutrient-rich water to rise,
bringing nourishment to
plankton, the basis of the
oceanic food web. This
process of upwelling is essential
to the ocean oasis.
• Remains of dead,
decomposing organisms sink to
the ocean bottom making
these deep, cold waters rich in
nutrients. However, it is in the
upper, sunlit layers of the
ocean that phytoplankton
(very small drifting plants) are
able to utilize these nutrients.

9. Temp. Impact on Fish

10. Temp. Tolerance
• Eurythermic species
• Stenothermic species
• There are many different ecosystems within the ocean depending on
conditions such as the water temperature, the amount of sunlight that
filters through the water, and the amount of nutrients.
• Sunlight breaks through the top layer of ocean water. It can make its way
as deep as 200 meters (656 feet).
• Almost all marine life (about 90%) lives within this top, sunlit layer of the
ocean.
• The temperature of ocean water varies depending on its location. Water
near the polar regions is colder than water near the equator. Water that
is deep in the ocean is colder than water that is near the ocean surface.
• Many animals and other organisms can only survive at certain
temperatures.
• Others are able to survive at wide range of temperatures and can live in
more places in the ocean.

11. Temperature tolerance and
Migration
• Because cold-blooded fish live within a small temperature range
(stenothermic).
• Many fish try to stay within what is called their thermal optimum —
not too warm, not too cold — just right. This thermal optimum varies
for different species.
• Water temperature is a key factor for fly fishermen who chase
striped bass and other game fish along the Atlantic seaboard. In
spring, as the ocean starts to warm, the first arrivals from the south
will be striped bass and bluefish, followed later by bonito and little
tunny (false albacore).
• This pattern reverses itself as the water starts to cool in the fall, when
the albies and bonito generally head south first. Looking in more
detail at the stripers, their spring migration may be more closely tied
to the northward migration of prey, such as herring, which in turn
are probably influenced by warming water and spawning urges.

12. Extreme temperature
• Tidal pools 40ºC
• Deep sea sulfur vents 380ºC

13. Antarctic creatures
• About 200 species have been
discovered. These include
midges, mites and tardigrades.
• Krill are found in huge swarms
which cover hundreds of
kilometers in the waters
around Antarctica.
• Many of the fish that live in
Antarctica (-2ºC) have
'antifreeze' in their bodies to
stop their body fluids from
freezing. Seaweeds, sponges,
corals, worms, sea anemones
and sea spiders are just some
of the creatures to be found
on the bottom of the Antarctic
oceans.

14. Antarctic amphipods and fish
Trematomus newnesi
(common name: dusky
rockcod)

16. Arctic creatures

18. Global
warming
affecting
(changes in)
oceanic
temperature
• Courtesy NOAA
Three-dimensional view of projected surface air
temperature and ocean warming due to
greenhouse gases as calculated by a low-resolution
GFDL coupled ocean-atmosphere climate model.

19. LIGHT
• The visible light spectrum is the section of the electromagnetic
radiation spectrum that is visible to the human eye. It ranges in
wavelength from approximately 400 nm to 700 nm and is also
known as the optical spectrum of light.
Electromagnetic spectrum

20. Fate of light in aquatic systems:
• Reflection - prevented from
entering water by air-water
surface interface
• Scattering - suspended
particles reflect light at a
massive array of angles
• Absorption - diminution of
light by transformation into
heat energy

21. Visible light penetration
• Visible light penetrates
into the ocean, but
once past the sea
surface, light is rapidly
weakened by
scattering and
absorption (coastal
water). The more
particles that are in the
water, the more the
light is scattered. This
means that light travels
farther in clear water
(open ocean).

22. Light: Oceanic Zonation
• 45% of red and 2% of
blue light is absorbed for
every meter of depth.
• Euphotic zone (00 to 200
m)
• Disphotic zone (200 to
1000 m)
• Aphotic zone (1000 to
4000 m)
• Abyssal zone more than
4000 m.

24. Photic zone animals
• The dark backs and light
undersides of
• these near-surface fish help
them match
• their environment in the
open ocean. To
• a predator looking from
above, their dark
• backs seem to blend into
the dark depths.
• From the side, their lighter
sides blend
• with the sunlit water

26. Middle water fish (Disphotic zone)
• As light deems up
below 200 meters,
the body color of
animals change
from silvery to blue
and then
combination of
blue-red and finally
deeper creatures
have red colored
body.

27. Deep sea animals
• Several organisms living in ocean
depths have red coloration. Their
red color effectively makes them
“disappear” in the inky darkness,
because no red wavelengths are
present.
• Many deep sea organisms are able
to produce their own light, called
bioluminescence. Some animals,
like the viperfish, lantern fish and
others possess bioluminescent
organs on their bellies. As they
migrate upwards to find food in
shallower depths, where some
visible light does penetrate, the
bioluminescent organs on their
bellies brighten.

29. Sluggish flabby fishes
Chimaera Frill shark Blobfish
Tripodfish Snailfish Goblin shark

30. Many bristlemouth species, such as the "spark angle -mouth"
above, are also bathypelagic ambush predators which can
swallow prey larger than themselves.
Angler fish Dragon fish Gulper fish

31. Light: Vertical migration
• Marine zooplankton perform daily excursions (i.e., vertical
migrations) up and down in the water column, with changing
levels of light triggering these daily migrations. For example,
the classic pattern consists of zooplankton residing deep in the
water column during the day when light levels are high. They
ascend at dusk to the surface waters where they graze on
phytoplankton at night. Known as diurnal migration.

32. Vertical migration
• Figure 1. Vertical distribution of the sardine (Sardina
pilchardus) in the Thracian Sea. The dots show the
observed average depths, and the solid line shows the
predicted average depth of the distribution according
to a cosine function model based on the time of day.

33. Plankton at the sea surface is consumed by
vertically migrating midwater fishes and
squids. The daily migrations of these
midwater species take them to the surface
at night to feed, and to depths below 500
meters during the day. This helps them avoid
predators by keeping them in constant
darkness. However, these vertical migrators
decend on the bottom during daytime
(downward migrations), are available to
bottom dweller wreckfish to consume them.
This vertical migration completes a transfer
of energy from sunlit surface layers to the
dark depths where wreckfish dwell.

34. • Red flabby whale fish make nightly
vertical migrations into the lower
mesopelagic zone to feed on
copepods.

35. Night light fishing

36. Oxygen
• Oxygen is a very important gas in the ocean because of its role in
biological processes. Marine plants such as phytoplankton ,
seaweed, and other types of algae produce organic matter from
carbon dioxide and nutrients through photosynthesis , the process
that produces oxygen. The oxygen molecules occupy the spaces
between the water molecules is called as dissolved oxygen.
• The upper 10 to 50 meters (33 to 164 feet) of the ocean can be
highly supersaturated with oxygen owing to photosynthesis.

37. Oxygen regime at depths
• Compensation depth
is the balance
between the
photosynthesis of
phytoplankters and
the oxygen
cosumed in
respiration of all
organisms and
decomposition.

38. Factors governing DO
• Atmospheric pressure, temperature and the rates of
photosynthesis and decomposition.
• Oxygen is produced during photosynthesis and consumed
during respiration and decomposition (compensation
depth). The latter processes occur throughout the day and
night, while the former occurs only during the day. For this
reason, dissolved oxygen levels are often lowest just before
dawn before photosynthesis resumes.
• Since the concentration of oxygen in our atmosphere is about
21%, and only a fraction of 1% in water, oxygen seeks
equilibrium by dissolving into water. This diffusion is increased
by any turbulent flow over riffles in the creek, or by wind-driven
waves both of which increase the surface area through which
the diffusion can occur.
• The other major control of DO concentration is water
temperature. Cold water can hold more dissolved gas than
warm water.

39. Relationship between temperature
and DO
• Oxygen has
limited solubility in
water, usually
ranging from 6 to
14 mg L -1
• Oxygen solubility
varies inversely
with salinity,
water
temperature and
atmospheric and
hydrostatic
pressure.

40. Monthly DO variation

41. DO at different depths
• Surface is richest due
to surface diffusion
and photosynthesis
• Minimal zone where
respiration exceeds
the photosynthesis
• The deeper zone
retains oxygen due
to less respiration
and decomposition
rate

42. Diurnal pattern of DO
• Diurnal pattern of
DO in sea shallows
control the vertical
migration of
zooplankters and
fish

43. Salinity
• Definition: Total amount of solid materials in
grams dissolved in one kilogram of sea water
when all the carbonate has been converted to
oxide, the bromine and iodine replaced by
chlorine and all organic matter completely
oxidized.
• It is calculated by Knudsen’s formula
• It is referred by ppt (part per thousand or %°)
• Salinity is an ecological factor of considerable
importance, influencing the types of organisms
that live in a body of water.

44. • Marine waters are those of the ocean,
another term for which is euhaline seas. The
salinity of euhaline seas is 30 to 35. Brackish
seas or waters have salinity in the range of 0.5
to 29 and metahaline seas from 36 to 40
• On average, seawater in the world's oceans
has a salinity of about 35 ppt.
• Although the vast majority of seawater has a
salinity of between 31 ppt and 38 ppt,
seawater is not uniformly saline throughout
the world.
• Climate, weather, currents and seasons can
all have an affect on salinity.

45. Extremes of salinity
• Where mixing occurs with fresh water runoff
from river mouths or near melting glaciers,
seawater can be substantially less saline.
• The most saline open sea is the Red Sea (41
ppt), where high rates of evaporation, low
precipitation and river inflow, and confined
circulation result in unusually salty water.
• The salinity in isolated bodies of water like, the
Dead Sea ranges between 300 and 400 ppt.

46. Conveyor belt
• The degree of salinity in oceans is a driver of the world's
ocean circulation, where density changes due to both
salinity changes and temperature

47. Salinity tolerance
• Euryhaline organisms are able to adapt to a wide range
of salinities. An example of a euryhaline fish is the molly
(Poecilia sp.) which can live in fresh, brackish, or salt
water. The European shore crab (Carcinus maenas) is an
example of a euryhaline invertebrate that can live in salt
and brackish water. Euryhaline organisms are commonly
found in habitats such as estuaries and tide pools where
the salinity changes regularly. However, some organisms
are euryhaline because their life cycle involves migration
between freshwater and marine environments, as is the
case with salmon and eels.
• The opposite of euryhaline organisms are stenohaline
ones, which can only survive within a narrow range of
salinities.

48. • Salinity tolerance leads to zonation in estuarine
plants and animals. Estuarine organisms have
different tolerances and responses to salinity
changes.
• Many bottom-dwelling animals, like oysters and
crabs, can tolerate some change in salinity, but
salinities outside an acceptable range will
negatively affect their growth and
reproduction, and ultimately, their survival.
• Some groups of animals, such as the
echinoderms, which include animals such as
sea stars, brittle stars and sea cucumbers, have
very few species living in estuaries because of
their low tolerance of reduced salinity.

49. Euryhaline fish
Molly
Sturgeon
Carcinus maenas
Eel
Salmon

50. Stenohaline fish
HaddockGoldfish
Br Star
Sea cucumber

51. Osmoregulation
Marine bony fish
Marine cartilaginous fish

52. pH
• pH is generally understood to be an expression of
acidity or the hydrogen ion (H+) concentration in
water. The value is a negative (reciprocal)
• logarithm, which means that acidity increases as
the value decreases and that each unit change
reflects a 10-fold change(logarithmic).
• Normal pH values in sea water are about 8.1 at the
surface and decrease to about 7.7 in deep water.
• Many shellfish and algae are more sensitive than
fish to large changes in pH, so they need the sea’s
relatively stable pH environment to survive.

53. • pH balance is one of the biggest factors in
affecting marine life. The ocean absorbs vast
amounts of carbon dioxide from the
atmosphere, which reacts with the water and
produces carbonic acid. This causes the
water's natural pH balance to lower to an
increased acidic level. This damages marine
life because it destroys the essential calcium in
the water that is needed to build their internal
and external skeletons.
• Shallow waters in subtropical regions that hold
considerable organic matter often vary from
pH 9.5 in the daytime to pH 7.3 at night.
Organisms living in these waters are able to
tolerate these extremes

54. • As the carbon dioxide is absorbed, it reacts
with the ocean water to form carbonic
acid. This process is called ocean
acidification. Over time, this acid causes
the pH of the oceans to decrease, making
ocean water more acidic.

55. Thank You