Biologi Laut - Plankton Laut

8/10/2019 Biologi Laut - Plankton Laut

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Plankton Laut

Produktivitas Primer di Laut

Romanus Edy Prabowo


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MarinePlankton

Definisi : plankton consist of any drifting organisms (animals,

plants, archaea, or bacteria) that inhabit the pelagic zone of

oceans, seas, or bodies of marine water.

Plankton are defined by their ecological niche rather than their

phylogenetic or taxonomic classification.


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MarinePlankton

The name planktonis derived from the Greek word

("planktos"), meaning "wanderer" or "drifter".While some forms of plankton are capable of independent movement and

can swim up to several hundreds of meters vertically in a single day (a

behavior called diel vertical migration), their horizontal position isprimarily determined by currents in the body of water they inhabit.

By definition, organisms classified as plankton are unable to

resist ocean currents.This is in contrast to nektonorganisms that can swim against the ambient

flow of the water environment and control their position (e.g. squid, fish,and marine mammals).


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Life Cycle

Within the plankton, holoplanktonare those organisms that

spend their entire life cycle as part of the planktonExempli gratia : most algae, copepods, salps, and some jellyfish).

By contrast, meroplanktonare those organisms that are only

planktonic for part of their lives (usually the larval stage), and

then graduate to either the nekton or a benthic (sea floor)

existence.

Examples of meroplankton include the larvae of sea urchins, starfish,crustaceans, marine worms, and most fish.


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Plankton abundance and distribution are strongly dependent on factors

such as ambient nutrients concentrations, the physical state of the water

column, and the abundance of other plankton.


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Megaplankton >20mm metazoans; e.g.jellyfish; ctenophores; pelagic Tunicata;

Cephalopoda

Macroplankton 2-20mm metazoans; e.g.Pteropods; Chaetognaths;

Euphausiacea (krill); Medusae; ctenophores;

pelagic Tunicata; Cephalopoda

Mesoplankton 0.2mm-2mm metazoans; e.g.copepods; Medusae; Cladocera;

Ostracoda; Chaetognaths; Pteropods; Tunicata;

Heteropoda

Microplankton 20-200m large eukaryotic protists; most phytoplankton;

Protozoa (Foraminifera); ciliates; Rotifera; juvenile

metazoans - Crustacea (copepod nauplii)

Nanoplankton 2-20m small eukaryotic protists; Small Diatoms; Small

Flagellates; Pyrrophyta; Chrysophyta; Chlorophyta;

Xanthophyta

Picoplankton 0.2-2m small eukaryotic protists; bacteria; Chrysophyta

Femtoplankton < 0.2m marine viruses

Size


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Ecological Function| trophic level

Phytoplankton(from Greekphyton, or plant), autotrophic, prokaryotic oreukaryotic algae that live near the water surface where there is sufficient light tosupport photosynthesis. Among the more important groups are the diatoms,cyanobacteria, dinoflagellates and coccolithophores.

Zooplankton(from Greek zoon, or animal), small protozoans or metazoans(e.g. crustaceans and other animals) that feed on other plankton and telonemia.

Some of the eggs and larvae of larger animals, such as fish, crustaceans, andannelids, are included here.

Bacterioplanktonbacteria and archaea, which play an important role inremineralising organic material down the water column (note that the prokaryoticphytoplankton are also bacterioplankton).

This scheme divides the plankton community into broad producer, consumerand recyclergroups.In reality, the trophic level of some plankton is not straightforward. For example, although mostdinoflagellates are either photosynthetic producers or heterotrophic consumers, many speciesare mixotrophic depending upon their circumstances.


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Primary Producer

When autotrophs produce more organic matter than they use in

respiration, there is an overall gain of organic matter.

This net increase in organic matter is called primary

production.

The autotrophs use the extra organic material to grow and reproduce. Inother words, the extra organic matter forms more living material, and that

means more food for animals and other heterotrophs.

Organisms that perform this primary production of food are

called primary producers.


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The rate of primary production is usually measured in light anddark bottles. Changes in the oxygen or carbon dioxide level in thelight bottle indicate both photosynthesis and respiration, whereas

changes in the dark bottle reflect only respiration

The standing stock of phytoplankton is the total amount ofphytoplankton in the water column. Standing stock is usually

determined by measuring the chlorophyll concentration


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Photosynthetic Bacteria

Autotrophic Bacteria :Autotrophic bacteria make their own

organic compounds and thus are primary producers. Some of

them are photosynthetic (or photoautotrophs). They containchlorophyll or other photosynthetic pigments and, like seaweeds and plants,

tap light energy to manufacture organic compounds from CO2.Photosynthetic bacteria are now known to account for much of the primary

production in many open-ocean areas.


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Chemosynthetic Bacteria

Other bacterial autotrophs, called chemosynthetic or

chemoautotrophic, derive energy not from light but from

chemical compounds such as hydrogen (H2), ammonia (HN3),

hydrogen sulfide (H2S), and other sulfur or iron compounds.

Many other ways of obtaining energy to manufacture organic matter arefound among chemosynthetic bacteria.


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Cyanobacteria

Cyanobacteria, once known as bluegreen algae, are a group

of photosynthetic bacteria.In addition to having chlorophyll, most contain a bluish pigment called

phycocyanin. Most marine cyanobacteria also have a reddish pigment,

phycoerythrin. Cyanobacteria were perhaps among the first photosynthetic

organisms on earth.They are thought to have had an important role in the accumulation of

oxygen in our atmosphere. Stromatolites, massive calcareous mounds

formed by cyanobacteria, are known to date back some 3 billion years.Stromatolites are still being formed in tropical seas.


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Hamelin Pool, Denham, WA


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ArchaeaRiftia sp


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Phytoplankton: Diatom

The characteristic color of diatoms is due to yellow and brown

carotenoid pigments present in addition to two types of

chlorophyll, a and c.Diatoms are efficient photosynthetic factories, producing much-needed

food (the food being the diatoms themselves), as well as oxygen for otherforms of life.

Diatoms reproduce mostly by cell division, a type of asexual

reproduction.The overlapping halves of the frustule separate, and each secretes a new,

smaller half. Diatoms may also reproduce by sexual reproduction. Somecells develop eggs, others develop flagellated sperm. Fertilization then

results in the development of resistant stages known as auxospores.


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Phytoplankton: Diatom

The glassy frustules of dead diatoms eventually settle to the bottom of the

sea floor. Here they may form thick deposits of siliceous material that

cover large portions of the ocean floor. Such sediments are known as

diatomaceous ooze.

Huge fossil deposits of these sediments can now be found inland in

various parts of the world. The siliceous material, or diatomaceous earth,

is mined and used in products such as filters for swimming pools, for

clarifying beer, as temperature and sound insulators, and as mild abrasives

that may find their way into toothpaste.


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Diatoms are unicellular organisms that live mostly as part of theplankton. A silica shell is their most distinctive feature. They are

important open-water primary producers in cold waters


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Diatom : Morphology


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Diatom : Morphology


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Diatom : Morphology


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Diatom : Morphology


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Diatom : Morphology


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Diatom : Morphology


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Diatom : Morphology

Frustule

upper frustule (epitheca)

nucleuslower frustule (hypotheca)

chloroplast

oil droplet


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Diatom : Reproduction

sexual reproduction

asexual reproduction

auxospore


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Phytoplankton: Dinoflagellata

The dinoflagellates (phylum Dinoflagellata or Pyrrhophyta)

make up another large group of planktonic, unicellular

organisms. Their most outstanding characteristic is the

possession of two flagella, one wrapped around a groove

along the middle of the cell and one trailing free.These flagella direct movement in practically any direction. Most

dinoflagellates have a cell wall that is armored with plates made of

cellulose, the characteristic component of the cell walls of seaweeds and

land plants. The plates may have spines, pores, or other ornaments.


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Dinoflagellates are unicellular organisms that have two unequalflagella. They are mostly marine and are particularly common inthe tropics. Some are noted for their emission of light; others areclosely associated with marine animals, especially reef corals


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Dinoflagellata: Morphology

Unicellular forms with twoflagella. One of these extends towards the

posterior, called the longitudinalflagellum, while the other forms a lateral

circle, called the transverseflagellum. In many forms these are set into

grooves, called the sulcusand cingulum. The transverse flagellum provides

most of the force propelling the cell, and often imparts to it a distinctive

whirling motion, which is what gives the name dinoflagellate refers to(Greek dinos, whirling). The longitudinal acts mainly as the steering wheel,

but providing little propulsive force as well.

Dinoflagellates have a complex cell covering called an amphiesma,

composed of flattened vesicles, called alveoli. In some forms, these

support overlapping cellulose plates that make up a sort of armor calledthe theca. These come in various shapes and arrangements, depending on

the species and sometimes stage of the dinoflagellate.


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Dinoflagellata: Morphology


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Dinoflagellata: Reproduction

Dinoflagellata

Life Cycle.1-Binary fission,

2-Sexual reproduction,3-planozygote,

4-hypnozygote,

5-planomeiocyte.


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Red Tides


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Other Primary Producers

Three additional groups of primary producers may be abundant in some areas.

Silicoflagellates (phylum Chryosphyta) are characterized by a star-shaped internal skeleton made of silica and a single flagellum.

Coccolithophorids(phylum Haptophyta) are flagellated, spherical cellscovered with button-like structures called coccoliths that are made of

calcium carbonate. Coccolith may be found in sediments as fossils.

Cryptomonads (phylum Cryptophyta) have two flagella and lack askeleton. Members of these three groups are so small that hundreds could

fit into a large diatom or dinoflagellate cell.


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Foraminiferan

The foraminiferans, (phylum Foraminifera), better known asforams, are marine protozoans that usually have a shell, ortest, made of calcium carbonate (CaCO3). The test is usuallymicroscopic and may have several chambers that increase in size as the foramgrows.

Pseudopodiaextensions of the jelly-like contents of the cell, or cytoplasmare

thin, long, and retractable in forams. The pseudopodia protrude through pores inthe shell and form a network used to trap diatoms and other organisms suspendedin the water. Food is then moved into the interior of the cell as if on a conveyorbelt. Most forams live on the bottom, either free or attached. Only a few speciesare planktonic, but these can be very abundant. Their shells are smaller andthinner than those that live on the bottom and may have delicate spines that aid inflotation.

The shells of planktonic forams eventually sink to the bottom in such high numbersthat large stretches of the ocean floor are covered by foraminiferan ooze.


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Protozoan (animal-like protist)

Protozoans are the most animal-like of the protists. They areeukaryotic and unicellular. They are heterotrophic and ingest food

like true animals


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Radiolaria

Ciliata

etc

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Biologi Laut - Plankton Laut