West Spring Secondary Research on Marine Microbe Beneficial or Detrimental Discussion

“Marine microbes are a source of natural products that can be detrimental or beneficial to the marine environment.” Share your findings and thoughts on this statement.

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A229 Marine Biology
Problem 1
The Unseen Majority
6th P
Activity Owner: Ms. Pong Yoke Fong
Approved by:
Dr. Laura Yap
Module Chair:
Ms. Pong Yoke Fong
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Diploma in
Environmental and
Marine Science
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What do you Recognize?
• There are different types of microorganisms in
the oceans.
• They may play different roles in the marine
environment.
• Some of these microorganisms are able to
glow.
• The bioluminescent glow is likely to be due to
some metabolic reactions in the
microorganism.
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The Problem
• You are shown that a drop of seawater can
contain thousands of microorganisms and that
tiny organisms living in the ocean can make it
glow.
• You are tasked to find out about these
microorganisms and the roles they play in the
marine environment.
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The Approach
What are all these tiny organisms that live in the oceans?
– How are marine organisms classified?
– What are the different groups of microorganisms?
– What are some examples of aquatic microorganisms?
What roles do they perform in the marine environment?
– What kind of metabolic reactions do microbes perform
that will affect the other organisms in the marine
environment?
– What types of roles can microorganisms perform in the
marine environment?
– What is the food web like starting from the microbial
level?
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How are marine organisms classified?
• Neuston inhabiting
the surface layer
or moving on the
surface film
• Plankton are the
drifters (which also
include the
neuston while at
the surface),
• Nekton live in the
water column
• Benthos live on or
in the sea floor.
Source: https://www.oceanclassrooms.com/ms101_u4_c1_sa_3
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What are the different groups of microorganisms?
Prokaryotes
Eukaryotes
Unicellular
algae
Bacteria
Protozoans
Fungi
Archaea
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Marine
Viruses
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Marine Viruses
• Non-cellular, parasites of all organisms
• Consist of only nucleic acids (DNA and
RNA) and protected by an outer protein
coat, or capsid.
• Can infect bacteria and other marine
microbes that form part of the
phytoplankton.
• Bursting of cells of bacteria and
phytoplankton due to infection releases
large amounts of organic molecules and
cell debris, which make up dissolved
organic matter (DOM)
• Example: Bacteriophages
Source: http://oceans.mit.edu/featured-stories/little-greens-age-marine-genomics-2
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Prokaryote – Bacteria
• Prokaryotic, unicellular organisms
• Abundant in all parts of the ocean
• Many shapes including spheres,
spirals, rods and rings.
• In large numbers, marine bacteria
are sometimes visible as whitish
hairs on rotting seaweed or pink
patches on the surface of stagnant
pools in mudflats and salt marshes.
• Example – Photosynthetic
autotrophic cyanobacteria.
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Stromatolites deposited
by cyanobacteria
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Archaea
•
•
•
•
•
•
•
•
Unicellular organisms
Among the simplest, most primitive forms of life.
Thought to have had an important role in the early
evolution of life.
Cells are small and may be spherical, spiral or rod-shaped.
More closely related to eukaryotes than to bacteria.
Some groups of archaea are extremophiles, living in
extreme environments such as hot sulfur springs, saline
lakes, hydrothermal vents and very deep waters where
survive at pressures 300 to 800 times higher than the
pressure we are experiencing.
Archaea are also found living in association with
eukaryotes. For example, methanogenic archaea are
present in the digestive systems of fish. Some archaea form
symbiotic relationships with corals and sponges.
Example – Methanococcus jannaschii
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Methanococcus jannaschii
is an autotropic
hyperthermophillic
organism that belongs to
the kingdom of Archaea.
They were found to live in
extreme environments such
as hypothermal vents at the
bottom of the oceans in
which water reaches boiling
temperature or pressure is
extremely high
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Eukaryote – Unicellular Algae
• Eukaryotic
• Very diverse group of simple, mostly
aquatic
• Some algae are not photosynthetic
• Photosynthesis takes place in
chloroplasts – green, brown, or red
organelles with layers of internal
membranes that contain
photosynthetic pigments
• Colour of algae is due to the pigments.
• Example: Diatoms, Dinoflagellates
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Biologists used to refer to
algae as plants. Many of
the unicellular algae,
however, show animal-like
characteristics. Some swim
by moving their flagella.
Some species carry out
photosynthesis as plants
do, and very similar
species move and eat food
particles as animals do.
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Eukaryote – Unicellular Algae
•
•
•
•
•
•
Blue waves caused by Noctiluca scintillans
One of the largest phytoplanktons in the
world, ranging from 400 to 1500 μm in length
One of the most common bioluminescent
organisms in coastal areas of the world
N. scintillans is less prone to predation when in
this ‘phase’ of bioluminescence, so this
theoretically may be one of the functions of the
bioluminescence
The proliferation of N. scintillans can lead to a
harmful algae bloom, and has been linked to
massive mortality of fish and marine
invertebrates even though the species doesn’t
produce toxins.
Though classified among the dinoflagellates, a
phytoplankton group, N. scintillans is known to
have no photosynthetic pigments and to feed on
other phytoplankton, small zooplankton and
their eggs
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Eukaryote – Protozoans
•
•
•
Structurally simple and very
diverse eukaryotic organisms
Mainly heterotrophs though there
are some that contain chlorophyll
and can photosynthesize
Major groups consist of
•
•
•
•
•
•
Sarcodina
Ciliophora
Apicocomplexa
Mastigophora
Feed on other microbes such as
diatoms, small zooplanktons
Example: radiolarians (marine
heliozoans)
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Radiolarians are single-celled Protista
marine organisms that distinguish
themselves with their unique and
intricately detailed glass-like
exoskeletons. During their life cycle,
radiolarians absorb silicon compounds
from their aquatic environment and
secrete well-defined geometric networks
that comprise a skeleton commonly
known as a test. The radiolarian tests are
produced in a wide variety of patterns, but
most consist of an organized array of
spines and holes (pores) that regulate a
network of pseudopods useful in
gathering food.
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Eukaryote – Fungi
•
•
•
•
•
Eukaryotic and mostly multicellular,
though some such as yeasts is
unicellular
Heterotrophs that lack chloroplasts and
chlorophyll and cannot perform
photosynthesis
Decompose detritus but some are
deadly parasites
Can form symbiotic associations with
green algae or cyanobacteria to form
lichens
Example: Turgidosculum complicatum
lives in association with a green algae
and offers protection from dreaded
dehydration during low tides
Some marine fungi are being investigated
as a source of antibiotics for use in
medicine
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Metabolic reactions
Can you recall who are the major groups who carry out each type of
reactions?
Name of reaction
Energy source
Photosynthesis
Light
Other Raw materials By Products
Carbon
dioxide,
Oxygen
Autotrophs such
as algae,
cyanobacteria
water
Chemosynthesis
e.g. Sulfur oxidation
Chemical
Chemical compound Chemical compound
Chemotrophs such as bacteria or archaea that live
compound eg.
e.g. Oxygen
e.g. Sulfate
in extreme conditions
Hydrogen sulfide
Aerobic respiration
Organic matter
OxygenEukaryotes
Carbon
dioxide,
Bacteria
water
Anaerobic respiration
e.g. Methanogenesis
Organic matter
Hydrogen, carbon
dioxide Bacteria
Chemical or organic
compound
e.g. Methane
Nitrogen fixation
ATP Planktonic
Nitrogen gas
Ammonium
Light mediated ATP
synthesis
Light
Cyanobacteria
Archaea
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ATP
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Metabolic reactions
Classification of prokaryotes can be based on their energy and nutrient
sources.
e.g. Purple non-sulfur
bacteria uses organic
compounds as electron
donors in anaerobic
photosynthesis
e.g. cyanobacteria
performing
photosynthesis
e.g. Hydrothermal
vent bacteria
oxidise hydrogen
sulfide for energy chemosynthesis
e.g. aerobic respiration
by amoeba
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Roles of microorganisms
Trophic
levels
Tertiary
consumers
Secondary
consumers
Primary Consumers
Primary Producers
heterotrophs – Seal
heterotrophs – Fish
heterotrophs – zooplankton
Autotrophs – phytoplankton
Chemoautotrophs – bacteria/archaea
Energy Pyramid
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Microbial loop and classic food chain
The microbial loop is simply a model of the pathways
of carbon and nutrient cycling through microbial
components of pelagic aquatic communities.
Protistan and zooplankton are the most important
microbial consumers and have major functions in
organic carbon utilization and nutrient recycling.
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Microbial loop and classic food chain
Nekton
Protozoan
(e.g. ciliates)
Microbial
loop
zooplankton
Classic
food
chain
Bacteria
viruses
phytoplankton
Dissolved Organic
matter (DOM)
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What have you learnt?
• State that microorganisms are the most important
primary producers in many marine environments
• Recall the difference between eukaryotes and
prokaryotes
• Describe the different groups of microbes such as viruses,
bacteria, archaea, unicellular algae, protozoans, fungi etc.
• Give examples from the different groups of aquatic
microbes
• Give examples of metabolic reactions in marine
prokaryotes such as photosynthesis nitrogen fixation,
aerobic respiration etc.
• Explain how cyanobacteria are a group of photosynthetic
bacteria.
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What have you learnt?
• Discuss the roles of autotrophic bacteria and
archaea as primary producers
• Discuss the differences between autotrophs,
chemoautotrophs and heterotrophs.
• Describe microbial loop as a trophic pathway in
the marine microbial food web where dissolved
organic carbon is returned to higher trophic
levels via its incorporation into bacterial
biomass, and then coupled with the classic food
chain formed by phytoplankton-zooplanktonnekton
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A229 Marine Biology
Worksheet 02: Symmetry and Lifestyles
Sagittal planes and body symmetry
1. In many metazoans, their bodies can be divided into equal parts through an
imaginary plane known as the sagittal plane (see Figure 1).
Figure 1: Numerous imaginary planes can be used to divide the body of an
organism. Picture credit: Wolfram Tetzlaff.
Reference:
https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Boo
k%3A_General_Biology_(Boundless)/27%3A_Introduction_to_Animal_Diversi
ty/27.2%3A_Features_Used_to_Classify_Animals/27.2A%3A_Animal_Charac
terization_Based_on_Body_Symmetry
a. Define sagittal plane.
A longitudinal plane that divides the body into left and right parts.
b. At the very basic level of classification, true animals can be largely
divided into three groups based on the type of symmetry of their body
plan: radially symmetrical, bilaterally symmetrical and asymmetrical. In
Table 1 below, determine the number of sagittal planes and the type of
body symmetry that the following animals have. Table 1.
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Animal picture
Number of
Sagittal planes
Type of body
symmetry
Phylum
INFINITE
Radial
cnidaria
1
Bilateral
Arthropoda
One
bilateral
Mollusca
1
radial
Porifera
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Radial and bilateral symmetry
2. Fill in the sentences below with the correct helping words:
Radial
crab
sagittal
radially symmetrical
bilateral
transverse
“head” and “tail”
bilaterally symmetrical
upper and underside
sponge
Bilateral symmetry involves the division of the animal through a __transverse____
plane, resulting in two mirror-images, right and left halves, such as those of a butterfly,
__crab__, or human body. Animals with _sagital_ symmetry have a _”head” and “tail”_
(anterior vs. posterior), _upper and underside_ (dorsal vs. ventral), and right and left
sides. Majority of animals are _bilaterally symmetrical_.
3. Carry out your own research and fill in the blanks in Table 2 below:
Table 2.
Body
Symmetry
Bilateral
Radial
Example
Anemone
Blue fin Tuna
Lifestyle
category
based on
Nekton
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Benthos
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where
they live
Do they
move?
Fast or
slow?
Fast
Sessile – stays on the substrate of
sea floor
How do
Tuna is a pursuit predator that
they
actively chases after its prey at
capture
high speed.
their prey?
Sea anemone tentacles’ have
specialised stinging cells
(nematocysts)
How do
they
sense and
escape
their
predators
?
Stinging cells deter many
predators, but some animals can
still make a meal of an anemone.
Many anemones can detach
themselves, catch a current and
reattaching. Stomphia are sea
anemones that are known for
their swimming behaviour.
https://www.youtube.com/watch?v
=qfKq34FAdrs
Anemones has no vertebral
column or central nervous
system, and instead have a
“nerve net” that spans throughout
their entire bodies. These nerve
nets are dense and the neurons
have fairly thick axons, allowing
for fast conduction velocities up to
10 cm/s. This could be the reason
that the anemones can react to
stimuli remarkably fast. Little is
known on the entire nervous
they sense their predators using
their eyes ( which are located
on weather side of the fish’s
body ) and escape from
predators using their swimming
speed.
Tuna have specialized blood
vessel structure (countercurrent
exchanger). This allows them to
maintain body temperature that
is higher compared to the
surrounding water. This
adaptation provides them with
an advantage when hunting in
cold water
They also have crescent moonshaped tails and two dorsal fins
on their backs which is used to
reduce the resistance in the
water.
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The stinging cells are used to
immobilise their prey to allow their
tentacles to move the food into
the mouth.
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system of Stomphia, and how
they determine how to react to
certain stimuli.
In
summary
The evolution of bilateral
symmetry and, therefore, the
formation of anterior and
posterior (head and tail) ends
promoted a phenomenon called
cephalization, which refers to
the collection of an organized
nervous system at the animal’s
anterior end. Bilateral symmetry
allows for streamlined and
directional motion. This simple
form of symmetry promoted
active mobility and increased
sophistication of resourceseeking and predator-prey
relationships.
Radial symmetry enables these
sea creatures, which may be
sedentary or only capable of slow
movement or floating, to
experience the environment
equally from all directions. This
form of symmetry is best suited
for stationary or limited-motion
lifestyles.
Reference: https://www.lakeforest.edu/news/stomphia-the-swimminganemone
https://dtmag.com/thelibrary/defense-mechanisms-how-marine-creaturesavoid-predation/
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4. Answer the following questions based on Figure 2 below.
Figure 2
a. What is the number of sagittal planes you can observe in a sea star?
5
b. What type of body plan is sea star (Echinodermata) classified as? Why
do you think that is so?
pentaradial. There are 5 planes that the sea star can be divided in.
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Breaking symmetry
5. Symmetry is a frequent pattern in nature, often perceived as a source of beauty,
and is also a striking property of animal body plans. Can you give examples of
marine animals classified under Bilateria but appear to have asymmetry in their
external features?
–
–
narwhals. they have a horn on their forehead but the horn might slant
Male fiddler crabs and hermit crab possess one big claw and one small claw.
The big claw is used for offensive, defensive as well as mating.
strawberry squid. its eyes are not the same. one eye is normal whale the oter
eye has been ‘bloated’
Flounder fish. When born it is bilaterally symmetrical, after a few days, one of
the eye begin to lean to one side, and the eye on that side slowly migrate to the
top side of the fish.
perissodus microlepis, a cichlid in lake tanganyika. its mouth bends towards
one side to match its feeding habits.
6. Read the ‘Presentation of the hypothesis’ in the paper below and explain why
it is advantageous for animals to be bilateral.
The maneuverability hypothesis to explain the maintenance of bilateral
symmetry in animal evolution:
https://biologydirect.biomedcentral.com/articles/10.1186/1745-6150-7-22
To move in a fluid, a body must overcome drag, which is resistance to movement
imposed by the medium in which it moves.
Magnitude of drag force: F = – ½ ρ c A v 2
F: drag force
ρ: density of the medium
c: dimensionless drag coefficient dependent on the body shape
A: area of the maximal section of the body dimension
v: body’s velocity
Considering that a swimming body must minimize overall drag, its skin friction, and
thus its wetted area, has to be adequately minimized. Radial bodies with a star-shaped
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section are suboptimal since they have very large surfaces that are not ideal for
swimming forward.
Bilateral body will have a greater advantage in turning because it can produce a
pushing force much greater than the cylindrical body because laterally it is less
streamlined. Both coefficients A and c can be altered by a bilateral body. Due to its
one plane of symmetry (in the main direction of motion), vertically it is capable of
supporting structures with a large surface area. These structures will further expand
the lateral surface area (A) of the body (think about the vertically positioned fins of a
shark). Further, with these components as well as the flattened sides of its body, the
animal’s drag coefficient can be greatly increased. Due to its only frontal streamlined
appearance, the lateral friction coefficient (or vertical friction coefficient if the animal is
dorsoventrally flattened) is very high.
Reading Resources:

Body Plans

https://courses.lumenlearning.com/boundless-biology/chapter/features-used-toclassify-animals/
Demystification of animal symmetry: symmetry is a response to mechanical forces:
https://biologydirect.biomedcentral.com/articles/10.1186/s13062-017-0182-5
The manoeuvrability hypothesis to explain the maintenance of bilateral symmetry in
animal evolution:
https://biologydirect.biomedcentral.com/articles/10.1186/1745-6150-7-22
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A229 Marine Biology
Worksheet 01: The Unseen Majority
Microbes in the sea
1. Microorganisms live everywhere in the ocean, from the deepest trenches to
the highest tide pools.
a. List down the microorganisms that you have learnt/heard about. (Recall
from your Microbiology module)
viruses, bacteria, archaea, plankton
–
b. Recall that microbes can also be categorised into eukaryotes or
prokaryotes. What are the major differences between these two groups?
Can you give an example of each?
eukaryotes are microorganisms with a nuclear envelope
prokaryotes are microorganisms without a nuclear envelope, just nuclear
pasta floating within the cell
2. Marine life is incredibly diverse. Scientists can classify marine life into three
lifestyle categories. Refer to this link
https://www.differencebetween.com/difference-between-nekton-and-vsplankton-and-vs-benthos/ and fill in the definitions and give some examples in
the table below.
Term
Definition
Examples
Nekton
animals actively moving
in water, can propel
through water. Nekton
lives throughout the water
column and can move
faster than water
currents.(middle water
column)
fish ,whale, turtle, sharks.
Phytoplankton
cannot propel through
water, they are buoyant
algae, dinoflagellates
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and float in the upper part
of the ocean. They
contain chlorophyll and
require sunlight in order
to live and grow.
Zooplankton
Type of heterotrophic
plankton. They are small
animals that cannot
propel through water.
larvae of fish, crabs
Benthos
animals ecologically
echinoderms,
linked to the bottom of the crustaceans, mollusks,
seafloor, cannot swim.
poriferans, annelids
They can be free moving
forms near the ocean bed
or attached to the
seafloor.
Neuston
Inhibiting the surface
layer
Marine Viruses
3. A litre of seawater collected from marine surface waters typically contains at
least 10 billion microbes and 100 billion viruses—the vast majority of which
remain unidentified and uncharacterised.
a. What are viruses?
A virus is an infectious agent that can only replicate within a host
organism. Viruses can infect a variety of living organisms, including
bacteria, plants, and animals. Viruses are so small that a microscope is
necessary to visualize them, and they have a very simple structure.
b. Viruses can only reproduce and develop by infecting a living cell. What do
you think viruses infect in the ocean?
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Virus can infect bacteria and other marine microbes that form part of the
phytoplankton, including bacteria, aquatic plants, fish and marine
mammals.
4. The bursting of the cells of bacteria and phytoplankton infected by viruses
releases large amounts of dissolved organic matter (DOM). Refer to the link
https://editors.eol.org/eoearth/wiki/Marine_dissolved_organic_matter and
answer the following questions.
a. What is DOM?
Marine DOM is a complex mixture of molecules of diverse origins found in
seawater from throughout the world ocean.
b. Besides the release of DOM due to viral infection, what are other ways in
which DOM is released into the ocean?
DOM is released by phytoplankton by direct extracellular release during
growth, release during predation by grazing organisms, release during
viral lysis of cells.
c. How is DOM removed from the ocean?
DOM is removed through the consumption by heterotrophic bacteria.
Prokaryotes
5. There are two prokaryotic domains, Bacteria and Archaea. Like bacteria,
archaea have small cells and may be spherical, spiral or rod-shaped. In fact,
until recently, archaea (singular, archaeum) were thought to be bacteria.
( marine bacteria Visible as whitish hairs on rotting seaweed or pink patches
on the surface of stagnant pool in mudflats and salt marshes)
5a. Based on figure 1 below, do you think archaea is more closely related to
bacteria or eukarya? Why do you think so?
Archaea is more closely related to eukaryotes because they share more
characteristics compared to bacteria.
–
Both are unicellular
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–
Lack organelles/internal membrane – bound structures
No nucleus present to separate genetic material
Single circular chromosomes (double – stranded)
Reproduce via fission
Absent of peptidoglycan in cell wall
Figure 1. A comparison of the three domains of Life
5b. Where do we find archaea in the marine and coastal environment and
what are their roles? (links to help:
https://ucmp.berkeley.edu/archaea/archaea.html,
https://pubmed.ncbi.nlm.nih.gov/23808334/#:~:text=Archaea%20thus%20play
%20crucial%20roles,nitrite%20is%20performed%20by%20Thaumarchaeota)
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Archaea inhabit in extreme environment: saline waters, thermal vents,
hypersaline water, deep sea anaerobic sediments
Roles
–
Fix carbon from inorganic sources
Global geochemical cycle
Influence greenhouse gas emission
Conducts methanogenesis & anaerobic methane oxidation in carbon
cycle (by anaerobic archaea)
6. Classification of prokaryotes can be based on their energy and nutrient
sources.
a. Based on your prior knowledge from microbiology module, fill in the flow
chart below using the helping words: photoautotroph, photoheterotroph,
chemoheterotroph, chemoautotroph
photoautotroph
Photoheterotroph
Chemoautotroph
Chemoheterotroph
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b. Cyanobacteria are one of the examples of autotrophs. That means they
make their own organic compounds and are thus primary producers. How
do they make their own organic compounds?
Cyanobacteria are photoautotroph meaning they are able to make their
own organic compound by using energy from the light. This allows them to
photosynthesize to obtain their own food.
They do not have chloroplast but they use a bluish pigment phycocyanin
to capture light for photosynthesis. They use water to donate electrons
and produce oxygen as a by-product
c. Many planktonic cyanobacteria are able to carry out nitrogen fixation,
converting gaseous nitrogen (N2) in the air into ammonium (NH4+).
Nitrogen fixation requires energy.
i.
What is the energy currency used? What metabolic reactions could
have generated this energy currency
ATP (common current energy) – drives biomolecules production
Convert carbon(from CO2) into CHO, CHO broken down to
generate ATP,
ii.
Most ammonium is converted into nitrates and other nitrogen
compounds. They served as a nitrogen source for primary
producers. Why is nitrogen needed for primary producers? (
Nitrogen is needed for plant growth, plant food processing, and
creation of chlorophyll.
nitrogen is needed for the formation of proteins
Eukaryotes
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7. The word algae represent a large group of different organisms from different
phylogenetic groups, representing many taxonomic divisions.
Read more: http://www.lenntech.com/eutrophication-waterbodies/algae.htm#ixzz4ZO9xy4j2
a. What are algae?
The plant-like organisms that are usually photosynthetic and aquatic, but
do not have true roots, stems, leaves, vascular tissue and have simple
reproductive structures. There many photosynthetic pigments continued
in the organelles with layers of internal membrane in the chloroplasts
b. Cyanobacteria are the first organisms known to have produced oxygen as
a byproduct of photosynthesis. And virtually all algae have photosynthetic
machinery ultimately derived from cyanobacteria. However, scientists later
exclude Cyanobacteria from the taxonomy of algae (Eukaryotes). Explain.
–
This is because they have a prokaryotic cell structure (algae are
eukaryotes) and conduct photosynthesis directly within the cytoplasm,
they also lack a nucleus or membrane bound organelles, like
chloroplasts. Cyanobacteria are the relatives of bacteria and not
eukaryotes since only the chloroplast found in eukaryotic algae are
considered related to cyanobacteria.
8. Protozoans are structurally simple and very diverse eukaryotic organisms that
are traditionally considered to be animal-like. Refer to this link to help you
answer the following questions: https://eol.org/docs/discover/protists-orprotozoa
Mainly hetertroph
Diatoms, small zooplankton (radiolarians – marine heliozoans)
a. What and how do protozoans consume?
Flagellates use their flagella to create a water current to draw in food
particles such as bacteria which are trapped on mucous coated microvilli.
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Large amoebas eat algae, other protists and smaller multi-celled animals.
Smaller amoebas feed on bacteria. THey ingest food through a process
called phagocytosis. They can wrap themselves around the food which is
then embedded in a food vacuole for digestion.
Cilliates have toxicysts which they eject at prey to subdue. Sessile forms
use haptocysts on feeding tentacles to catch smaller ciliate prey and suck
out the cytoplasm.
b. Based on your own research, describe how protozoa is able to survive under
(i) Low oxygen level in the water
–
Some ciliates have specially adapted green algae living inside them
In higher light conditions, these algae convert the carbon dioxide
produced by the ciliate into oxygen.
few groups are anaerobic and intolerant of oxygenated water. These
organisms are often endosymbionts living in the digestive system of
multi-celled animals.
(ii) Maintain osmotic balance in the cells
–
Osmoregulation (maintenance of water balance) carried out by
contractile vacuole that helps to prevent excessive water influx (by
pumping excess water out) that could rupture (lysis) to the cell.
–
The contractile vacuole functions periodically via expansion (collect
water) and contraction (release water)
9. Marine fungi are distinct from terrestrial and freshwater fungi in their taxonomy
and morphology, as well as in their adaptations to an aquatic habitat. They are
an ecological, not a taxonomic group and cannot be defined by nutritional or
physiological requirements.
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Refer to the link: https://www.mdpi.com/2673-8392/2/1/37/pdf and answer the
following questions:
a. What is the definition of ‘marine fungi’?
Species of fungi that live in marine environments
b. Microorganisms play a key role in nutrient recycling and in the regulation of
energy flow in marine ecosystems. Define marine fungi roles as saprobes,
mutualists, endobionts and parasites.
Saprobes – They have the ability to colonize and transform organic
matter from (plants,algae etc) into nutrients
Mutualists – associated with sponges or protozoans
Endobionts – Ability to provide energy to the host and benefit to be
under their protection
Parasites (to phytoplankton, macrophytes, algae, animals) – Leach
dissolved organic matter and cause destruction to host’s population
Form symbiotic relationship with green algae or cyanobacteria to form
lichens (turgidosculum complicatum)
The Microbial Loop
10. Look at this animation here: https://vimeo.com/395568298 and using the
information you have learnt earlier, draw out your own microbial loop and link
it to the classic food chain formed by phytoplankton-zooplankton-nekton.
phytoplankton -> zooplankton→ grazers
Additional References:
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Kingdoms of Marine Life | Marine Biology | The Good and the Beautiful
https://www.youtube.com/watch?v=nvSM9A-qW8w -> note: click on the playlist on
the right to select the topic of interest.
https://ocean.si.edu/ocean-life/microbes/marine-microbes
What we know
–
Microbes cannot be seen with a naked eye, microscope needed
Categorised into prokaryotes and eukaryotes(is archaea classified under
prokaryotes?)
Single celled organisms
3 different lifestyle: plankton, bethos, nekton
Can be harmful (eg: salmonella, paralytic shellfish poisoning
What do you need to find out
–
Why are microbes growing??
How do they help the marine organisms
Is bioluminescence produced by more than one type of microbes?
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