marine ecology

Prepared By: SULTIZ, LARRY J.

Biologists early became intrigued with the amazing variety of life to be found along the shores and among the coral reefs.

HMS Challenger (1872) – the first to be specifically equipped for the study of the sea.

What is marine ecology?

It is an interactive science that studies thebasic structural and functional relationships withinand among living populations and their physical-chemical environments in marine ecosystem.

Estuaries

Subtopics:

• Ecological features of the seaEcological features of the sea

Zonation

Mangroves and Coral Reefs

Marine Biota and Communities

Features of Marine Ecology


1. The sea is big – it covers 70% of the Earth’s surface.

2. The sea is deep and life extends to all its depths

- Although apparently there are no abiotic zones in the ocean, life is much denser around the margin of continents and island.

3. The sea is continuous, not separated as our land and fresh water habitats.

4. The sea is in continuous circulation- air temperature differences between poles and equator set up strong winds such as the trade winds (blowing steadily in the same direction the year around) which, together with rotation of the Earth, create different currents.


2 types of water movement that contributes to coastal fertility

Upwelling- occurs where the winds consistently move surface water away from precipitous coastal slopes, bringing to the surface cold water rich in nutrients which have been accumulating in the depths.

-The most productive marine area is located in this region.

Insert Figure

The major currents acts as giant pinwheel (gyres) which run clockwise in the northern hemisphere and counter clockwise in the southern hemisphere.

Example:

Peru Current- it creates one of the richest fisheries in the world.

It also support large population of seabirds that deposits countless tons of nitrate and phosphate-rich guano on coastal island.

Out-welling-occurs which nutrient-rich estuarine water move out the sea.

5. The sea is dominated by waves of many kind and by tides produced by the pull of moon and sun.

Tides are chiefly responsible for the mark periodicities. Tides have periodicity of about 121/2 hours.

High tides- occur in most localities twice daily, being about 50 minutes later on successive day.

6. The sea is salty- the average salinity or salt contents is 35 parts of salts by weight per 1000 parts of water, or 3.5%.

Sea water has the pH of 8.2

7. The concentration of dissolved nutrients is low and constitutes an important limiting factor in determining the size of marine population.

Every two weeks when sun and moon are “working together” the amplitude of tides increased.

Spring tides- when high tides are very high andlow tides are very low.

Neap tides- when the sun and moon cancel oneanother. The tidal range varies from less than 1foot in the open sea to 50 feet in the certainenclosed bays.

8. The ocean and some groups of organismsthat live in it are older than the ocean floor,which is constantly altered and renewed bytectonic and sedimentary processes.

- the sea floor is apparently slowly spreadingoutward from mid-ocean ridges, pushingcontinents apart as it progresses.

Example: continental drift

The Marine Biota

What is Marine Biota?

Biota

The combined flora and fauna of a region.

The animal or plant life of a particular region.

The great richness of the marine biota can beillustrated by comparing a sample of marineplankton with a comparable one taken from a largelake.

Zonation in the Sea

What is zonation ?

Figure 2.2 Main division of the marine environment

Zonation is a bit of biological terminologythat refers to the way an ecosystem can bedivided up into zones based on a particularfactor, such as altitude or latitude.

Zonation

Marine Environments

Life Zones in the Ocean

I. Horizontal zones

- Those extending from the sea.

A.Coastal Zone:

- region in which tides expose the sea bottom for

some part of each day. The habitats are

alternately submerge under salt water and

waterlogged for hours and then exposed to the

air and dried out for hours. Also known as littoral,

near shore, and intertidal zone.

B. Pelagic Zone:

- located seaward of the coastal zone’s low-tide mark, this contains the vast open waters of the ocean. Two subdivisions are recognized:

b. Oceanic Zone- the region of the sea extending to the edge ofthe continental shelf, over the continental slope,and over ocean floor. It is characterized bydarkness and tremendous pressure. Vertical linezones are significant here.

a. Neretic Zone- the water underlying the continental shelf. With the exemption of Antarctica, these waters usually extend to a depth of 600 ft. Sunlight penetrates the entire water column.


II. Vertical line zones of the oceanic zone

A.Neustic zone:

the thin film or “skin” formed by surface tension

at the surface of the water.

B. Euphotic zone:

the top of the water column as far down as light is

available for photosynthesis. Depending upon

water clarity, the bottom of the euphotic zone is

about 500 ft. below sea level. Also known as

epipelagic zone.

C. Aphotic zone:the remainder of the water column below the euphotic zone. Food chains usually begin with detritus or living algae and bacteria sinking from above. This zone is further subdivided by depth as follows:

Mesopelagic zone: 500 to 3,280 ft. below the sea surface.

Bathypelagic zone: 3,280 to 13,000 ft. below the sea surface.

Abyssopelagic zone: 13,000 to 20,000 ft. below the sea surface.

Hadal zone: 20,000 to 35,000 ft. below the sea surface.

III. Benthic Zone

This zone contains all the habitats of the seabottom, whether in coastal, continental shelf,or deep sea environments. Organisms may livewithin the bottom material or on its surface.


III. Benthic Zone

Mangrove and Coral Reefs

Emergent land plants that tolerate the

salinities of the open sea.

Mangrove and Coral Reefs

This ecosystem traps and cycles various

organic materials, chemical elements, and

important nutrients. Mangrove roots act not

only as physical traps but provide attachment

surfaces for various marine organisms.

Many of them attached to organisms filter

water through their bodies and, in turn, trap

and cycle nutrients.

It provides:

- Protection

- Food

- Shelter

- Extension coast

- Building islands

- Major energy input into fisheries

Florida’s mangroves are tropical species;

therefore, they are sensitive to extreme

temperature fluctuations as well as

subfreezing temperatures.

Research indicates that salinity, water

temperature, tidal fluctuations, and soil also

affect their growth and distribution.

Coral Reefs

- Widely distributed in swallow waters of

warm seas.

- Among the most biologically productive,

taxonomically diverse and aesthetically

celebrated of all communities.

Three types of Reef according to Darwin

a.Barrier reefs along continents

b.Fringing reefs around islands

c.Atolls, which are horseshoe-shaped ridges of

reefs and islands with lagoon in the center.

In certain conditions coral reefs develop far

from the continents, around small islands, or

towards the edge of the continental shelf.

Here the reefs do not join up to the mainland,

but grow upwards on all sides. Large, elongated

structures far offshores are called barrier

reefs. They are separated from the land by a

lagoon. When barrier reefs grow up in remote

ocean areas, they are termed bank reefs.

Mooréa Fringing Reef

A fringing reef is a type of coral reef that

extends outward from the shore of an island

or mainland, with no body of water separating

land reef. The fringing reef pictured here

surrounds much of the Polynesian island of

Mooréa.

By submarine volcanic activity

- Pacific reef developed into basaltic rock.

Biological deposition of calcium carbonate

is the means by which the reef builds up

to sea level.

I.DEFINITION AND TYPES

ESTUARY

ESTUARY

Semi-enclosed coastal body of water which has

a free connection with the open sea

Strongly affected by tidal action

Within it sea water mixed with fresh water

Estuarine or blackish water is classified as

oligomeso or polyhaline according to average

salinity

Physical condition in estuaries are stressful

with low species diversity

The food conditions are also favorable that

the region is packed with life

It belongs to the important class of

“fluctuating water-level ecosystems”

CLASSIFICATIONS WILL BE PRESENTED

BASED ON:

a) GEOMORPHOLOGY

b) WATER CIRCULATION AND

STRATIFICATION

c) SYSTEMS ENERGETICS

According to GEOMORPHOLOGY

1. DROWNED RIVER VALLEYS

are developed along coastlines with

relatively low and wide coastal plain

2. FJORD-TYPE ESTUARIES

are deep U-shaped coastal indentures

gouged out by glaciers and generally with a

shallow sill at their mouths formed by terminal

glacial deposits.

3. BAR-BUILT ESTUARIES

are shallow basins, often partly exposed at

low tide, enclosed by a chain of offshore bars

or barrier islands, broken at intervals by inlets.

4. ESTUARIES PRODUCED BY TECTONIC

PROCESSES

are coastal indentures formed by

geological faulting or by local subsidence often

with large inflow of fresh water.

RIVER DELTA ESTUARIES

Found at the mouths of large rivers such as

the Mississippi or the Nile.

Semi-enclosed bays, channels, and brackish

marshes are formed by shifting silt

deposits.

1. Highly stratified or “salt-edge” estuaries.

The river water is more dominant over tidal

actions. This will exhibit a salinity profile with a

“halocline” or zone of sharp change in salinity

from top to bottom.

CIRCULATION AND STRATIFICATION

2. The partially mixed or moderately

stratified estuary.

Fresh water and tidal inflow are more nearly

equal. Turbulence is the dominant mixing

agent. This create a complex pattern of layers

and water masses.


3. The completely mixed or vertically

homogenous estuary.

Tidal action is strongly dominant and

vigorous. The water tends to be well mixed

from top to bottom and the salinity relatively

high.


HYPERSALINE ESTUARY

Flow of fresh water is small, the tidal

amplitude low, and the evaporation is very

high. Salinity may rise above that of the

ocean.

ECOSYSTEM ENERGETICS

1. Physically stressed systems of wide

latitudinal range.

Subjected to high energy breaking waves,

strong tidal currents, severe temperature or

salinity rocks, low nighttime oxygen, or high rates

of sedimentation.

2. Natural arctic ecosystems with ice stress.

Exemplified by glacial fjords, winters ice

stressed intertidal zones and under—ice

communities on arctic coast.


3. Natural temperate coastal ecosystems with

seasonal programming.

The more subdued tides, waves and currents

in the semi-enclosed basins provide energy

subsidies rather than stresses.


4. Natural tropical coastal ecosystems of high

diversity.

Temperature, salinity, and other physical

factor stresses are low so that much energy of

special adaptation can go into diversity rather

than into “anti-thermal maintenance”


5. Emerging new systems associated with

man.

These are ecosystems developed for

adaptation for man-made wastes.


Biota of hypersaline estuaries is of marine

origin.

Seafood population are observable in

estuaries.

Estuaries are used as nursery grounds because

of protection and abundant of food.

II. BIOTA AND PRODUCTIVITY

Intertidal and adjacent shallow-water zones

--- most productive and most important part

of the estuaries.

Estuaries are more productive than either

the sea on one-side or the freshwater

drainage on the other.

marine ecology

Science