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Plankton Laut
Produktivitas Primer di Laut
Romanus Edy Prabowo
Marine Plankton
• 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.
Marine Plankton
• The name plankton is derived from the Greek word πλαγκτος
("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 is
primarily 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 nekton organisms that can swim against the ambient
flow of the water environment and control their position (e.g. squid, fish,
and marine mammals).
Life Cycle
• Within the plankton, holoplankton are those organisms that
spend their entire life cycle as part of the plankton
Exempli gratia : most algae, copepods, salps, and some jellyfish).
• By contrast, meroplankton are 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.
• 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.
Size
• Megaplankton
>20mm
• Macroplankton
2-20mm
• Mesoplankton
0.2mm-2mm
• Microplankton
20-200µm
• Nanoplankton
2-20µm
• Picoplankton
• Femtoplankton
0.2-2µm
< 0.2µm
metazoans; e.g. jellyfish; ctenophores; pelagic Tunicata;
Cephalopoda
metazoans; e.g. Pteropods; Chaetognaths;
Euphausiacea (krill); Medusae; ctenophores;
pelagic Tunicata; Cephalopoda
metazoans; e.g. copepods; Medusae; Cladocera;
Ostracoda; Chaetognaths; Pteropods; Tunicata;
Heteropoda
large eukaryotic protists; most phytoplankton;
Protozoa (Foraminifera); ciliates; Rotifera; juvenile
metazoans - Crustacea (copepod nauplii)
small eukaryotic protists; Small Diatoms; Small
Flagellates; Pyrrophyta; Chrysophyta; Chlorophyta;
Xanthophyta
small eukaryotic protists; bacteria; Chrysophyta
marine viruses
Ecological Function | trophic level
• Phytoplankton (from Greek phyton, or plant), autotrophic, prokaryotic or
eukaryotic algae that live near the water surface where there is sufficient light to
support 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, and
annelids, are included here.
• Bacterioplankton bacteria and archaea, which play an important role in
remineralising organic material down the water column (note that the prokaryotic
phytoplankton are also bacterioplankton).
This scheme divides the plankton community into broad producer, consumer and recycler groups.
In reality, the trophic level of some plankton is not straightforward. For example, although most
dinoflagellates are either photosynthetic producers or heterotrophic consumers, many species
are mixotrophic depending upon their circumstances.
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. In
other 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.
“ The rate of primary production is usually measured in light and
dark bottles. Changes in the oxygen or carbon dioxide level in the
light bottle indicate both photosynthesis and respiration, whereas
changes in the dark bottle reflect only respiration “
“ The standing stock of phytoplankton is the total amount of
phytoplankton in the water column. Standing stock is usually
determined by measuring the chlorophyll concentration “
Photosynthetic Bacteria
Autotrophic Bacteria : Autotrophic bacteria make their own
organic compounds and thus are primary producers. Some of
them are photosynthetic (or photoautotrophs). They contain
chlorophyll 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.
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 are
found among chemosynthetic bacteria.
Stromatolite
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.
Hamelin Pool, Denham, WA
Archaea
Riftia sp
Phytoplankton: Diatom
• Diatoms (phylum Bacillariophyta) are unicellular, though
many species aggregate into chains or star-like groups. Diatom
cells are enclosed by cell walls made largely of silica (SiO2), a
glass-like material.
This glassy shell, or frustule, consists of two tightly fitting halves often
resembling a flat, round, or elongate box. The frustule typically has
intricate perforations and ornaments such as spines or ribs, making
diatoms strikingly beautiful when seen under a microscope. The frustule
allows light to pass through, so that the conspicuous golden-brown
chloroplasts can capture light energy for photosynthesis. The minute
perforations allow dissolved gases and nutrients to enter and exit. The
sinking of open-ocean diatoms below the well-lit surface layer is often
slowed by oil droplets in their cells and spines on the frustules.
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 other
forms 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. Some
cells develop eggs, others develop flagellated sperm. Fertilization then
results in the development of resistant stages known as auxospores.
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.
“ Diatoms are unicellular organisms that live mostly as part of the
plankton. A silica shell is their most distinctive feature. They are
important open-water primary producers in cold waters “
Diatom : Morphology
Diatom : Morphology
Diatom : Morphology
Diatom : Morphology
Diatom : Morphology
Diatom : Morphology
Diatom : Morphology
Diatom : Morphology
Frustule
upper frustule (epitheca)
oil droplet
nucleus
lower frustule (hypotheca)
chloroplast
Diatom : Reproduction
asexual reproduction
auxospore
sexual reproduction
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.
“ Dinoflagellates are unicellular organisms that have two unequal
flagella. They are mostly marine and are particularly common in
the tropics. Some are noted for their emission of light; others are
closely associated with marine animals, especially reef corals “
Dinoflagellata: Morphology
• Unicellular forms with two flagella. One of these extends towards the
posterior, called the longitudinal flagellum, while the other forms a lateral
circle, called the transverse flagellum. In many forms these are set into
grooves, called the sulcus and 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 called
the theca. These come in various shapes and arrangements, depending on
the species and sometimes stage of the dinoflagellate.
Dinoflagellata: Morphology
Dinoflagellata: Reproduction
Dinoflagellata
Life Cycle.
1-Binary fission,
2-Sexual reproduction,
3-planozygote,
4-hypnozygote,
5-planomeiocyte.
Red Tides
Other Primary Producers
Three additional groups of primary producers may be abundant in some areas.
• Silicoflagellates (phylum Chryosphyta) are characterized by a starshaped internal skeleton made of silica and a single flagellum.
• Coccolithophorids (phylum Haptophyta) are flagellated, spherical cells
covered 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 a
skeleton. Members of these three groups are so small that hundreds could
fit into a large diatom or dinoflagellate cell.
Foraminiferan
• The foraminiferans, (phylum Foraminifera), better known as
forams, are marine protozoans that usually have a shell, or
test, made of calcium carbonate (CaCO3). The test is usually
•
•
microscopic and may have several chambers that increase in size as the foram
grows.
Pseudopodia—extensions of the jelly-like contents of the cell, or cytoplasm—are
thin, long, and retractable in forams. The pseudopodia protrude through pores in
the shell and form a network used to trap diatoms and other organisms suspended
in the water. Food is then moved into the interior of the cell as if on a conveyor
belt. Most forams live on the bottom, either free or attached. Only a few species
are planktonic, but these can be very abundant. Their shells are smaller and
thinner than those that live on the bottom and may have delicate spines that aid in
flotation.
The shells of planktonic forams eventually sink to the bottom in such high numbers
that large stretches of the ocean floor are covered by foraminiferan ooze.
Protozoan (animal-like protist)
“ Protozoans are the most animal-like of the protists. They are
eukaryotic and unicellular. They are heterotrophic and ingest food
like true animals “
• Radiolaria
• Ciliata
• etc