1. Multiple choice: animal response to low oxygen concentrations
a. Accumulation of lactate and octopine + heart beat increase
b. Accumulation of succinate, propionate and acetate + lowers metabolism
Accumulation of lactate and octopine is not wrong (teleost fish + cephalopods and bivalves, but heart
beat increase is a trap! That’s definitely wrong)
This is true for facultative hypoxia tolerant animals → less ATP demand and as well ATP production
due to downregulation of 1. Decrease of protein synthesis 2. Reduction of ion channels 3. Lethal:
dump of membrane potential
What abiotic factors make life in the ocean different from life on land?
- Availability of light
o It is attenuated with depth and reflected at the surface → limits primary production
- Viscosity
o Adapted feeding mechanisms
o R>1 dominance of inertia – turbulent flow for nektonic animals → need for streamline
bodytype
o R<1 dominance of viscosity – laminar flow and diffusion for planktonic animals →
development of nutrient concentration gradients
- Density
o Ability to stay suspended as the density of organisms is close to the density of water
- High thermal conductivity
o poikilothermic organisms dominate
What defines light limitation?
- Lambert-Beer-Law: I(z) = I(0)*e^(-k*z)
o Whereas: I(z)/I(0): irradiance at depth z or surface, z: water depth, k: attenuation
coefficient
- Light limitation is strongly determined by the attenuation coefficient k
o k is a factor of the water itself, the abundance of suspended or colloidal particles, the
abundance and community of phytoplankton absorbing light and the abundance of
chromophoric active DOM (humic acids, Gelbstoffe)
o but: being limited by light is strongly dependent on the species light compensation
point (different adaption mechanisms possible)
Why is seawater salty and not chalky?
calcification
the river discharge of Ca2+ and HCO3- into the ocean is much higher, than that of
Na+/Mg+/Cl-/SO42- but Ca2+ and HCO3- do not behave conservative, as they are bio-active
elements. Calcium and Bicarbonate are taken up during calcification in organisms. This
results in a lower residence time for these ions in the ocean. Tau = mean oceanic
concentration * (ocean volume / mean river discharge flux). The residence time for Na+ and
Cl- are waaay higher, making the ocean salty
Difference in element profiles (conservative, particle reactive, bio-active or limiting)
between Atlantic and pacific?
- Conservative elements (e.g. Na) rather show no decline or increase of concentration with
depth. The concentrations are set largely due to the amount of river discharge into the
respective oceanic basin. Thus, generally speaking, concentrations of conservative elements
are generally slightly higher in the Atlantic, then in the pacific. This is because of the smaller
ocean volume, but higher overall river discharge
- Bio-active or limiting elements (e.g. NO3) typically show low concentrations in the mixed
surface layer or rather say euphotic layer. They are taken up during primary production. They
might be totally depleted in the mixed surface layer due to strong strong stratification
processes and no resupply from the deep. With increasing depth, they reach a maximum
concentration due to remineralization processes. Concentrations of bio-active elements are
usually higher in the pacific. During the journey of the thermohaline circulation, they have
received more OM input, which has been remineralized. Further, they are much older, and
there has been more time for even recalcitrant OM to remineralize.
- Particle reactive elements show different profiles. In general, areas of high productivity show
lower concentrations of particle reactive elements, as the adsorb to POM. If this OM gets
remineralized, below the mixed layers, the concentration of particle reactive matter increases
again. This can be a very local phenomena and should not be ascribed generally to the
respective oceans.
Where does formation of deep water occur?
- Formation of deep water occurs in the North Atlantic (NADW, and also Labrador Sea) and in
the Southern Ocean, close to antarctica (AAIW, AABW)
Describe two main processes how the ocean regions are connected horizontally?
- The main reasons for the horizontal connectivity of the oceans are wind generated friction
forces, which create currents. The winds are mainly driven by Hadley cells, which are a result
of the differing global radiation budget. In combination with the Coriolis force, due to earths
rotation, the currents are laterally deflected, resulting in an Ekman transport of water
masses.
- Further: the thermohaline circulation, also driven by the differing global radiation budget,
plays a major role. Besides being responsible for major vertical mixing it also provokes
horizontal currents. The main aspect in the THC is the density differences of different water
def keystone species
A keystone species is a species which has a disproportionately large effect on its natural environment relative to its abundance
What is the euphotic zone ? (Engel)
- The euphotic zone is until the depth, where sufficient light for net primary production is
available. (roughly 100m depth, very variable in different regions)
What is the compensation depth?
- depth, at which gross primary production equals respiration in primary production
processes
- Rule of thumb: Depth at which 1% of light penetrates
Which wavelength of PAR reaches deepest?
- PAR = photosynthetic active radiation
- The quality of light changes in depth due to different attenuation processes
- Light of 500nm wavelength reaches the deepest
o Blue, blue violet, blue green
- This might be highly variable in different regions
What are typical absorption ranges of photosynthetic active molecules?
- Different chlorophyll types: between 420 + 480nm and again at +- 650nm7
- Carotenoids harvest light at +- 500nm
- Phycobillins harvest light at 550 and or 620 nm
What is the basis of the Redfield ratio?
- H1: Redfield ratio is the optimal balance of nutrient acquisition and utilisation
o Phytoplankton at balanced growth show C:N:P ratio close to the Redfield ratio
- H2: Redfield ratio is a time and space average of cells with different strategies
o At a certain time and space cell deviate from Redfield. Cells have different strategies
to cope with non-balanced growth (survivalist: high N:P due to resource acquisition
machinery; bloomer: low N:P due to high amount of growth machinery)
- Both arguments are valid
How will a cell respond to changes in light and nutrient availability?
- Different carbon allocations inside a cell;
- F: structures, always stays the same
- P: photosynthesis apparatus, allocation decreases with increasing light intensity
- S: storage increases with light intensity until a certain threshold
- B: biosynthesis components (mitochondria) increases at high light intensities
What elements comprise 95% of all biomass?
- CHONSP
Why is chl-a so low in the Southern Ocean?
- The Southern Ocean is a typical high nutrient low chlorophyll area. This generally occurs,
when macronutrients are present (not limiting), but cannot be taken up due to a lack of
cofactors. The micronutrient iron is only present in very low concentrations in the Southern
Ocean. This is in line with Liebig’s law of the minimum.
How do macroalgae optimize photosynthetic performance? (Weinberger)
- They can change the composition of light harvesting molecules to a small extent
- They have cellular differentiation: lots of chloroplasts in the epidermis, less in the inner lying
cells
- Some have carbonate-concentration mechanisms (Ulva spp)
- Some are able to move chloroplasts, to adapt to varying light intensities
- Some are able to reduce the size of light harvesting complexes to avoid light inhibition
- Some can increase the concentration of rubisco for high productivity at high irradiance
What is the difference between auto and heterotrophy? (Perner + Böhmke Brandt)
- Differences are in the carbon and energy source
- Heterotrophs: organic carbon is used as an energy and carbon source
- Autotrophs: derive energy (lithospheric or light) and carbon (CO2) from inorganic sources
What is one chemical redox-reaction, that can be catalysed by microbes to gain energy from
chemosynthesis?
- divided into chemolithotrophs and chemoorganotrophs
- typical reaction for organolithotrophs would be the reduction of sulphate to sulphide
compounds while oxidizing methane to carbonates
Name the three most important CO2 fixation pathways?
- Calvin Bensson Bassham cycle
- Reductive tricarbocylic acid cycle (rTCA)
- Reductive acetyl CoA pathway
o Depends on environmental conditions, which pathway is present
What do heterotrophic bacteria do?
- consume OM previously bound in primary production as an energy and carbon source.
How do marine heterotrophic bacteria satisfy their carbon requirements?
- consume OM previously bound in primary production as a carbon source
- either direct “predation” on phytoplankton or feeding on POM (marine snow)
What is the microbial loop?
- DOC is returned to higher trophic levels due to the incorporation in bacterial biomass. This
returns the carbon to the food chain (via zooplankton and nekton). Most organisms are not
able to directly use this DOC as it is high molecular weight.
Who are the master recyclers in phytoplankton blooms?
- Rosebacter and Flaviobacter largely control phytoplankton blooms.
Where is the CO2 generated, that heterotrophs expire? (Melzner)
- During transport into the mitochondria, decarboxylation of pyruvate to acetyl-CoA
- within the citric acid cycle
- oxygen is hydrated to water within the oxidative phosphorylation
What is hypoxia, normoxia and anoxia?
- Normoxia: seawater fully saturated with oxygen
- Hypoxia: seawater not fully saturated with oxygen
- Anoxia: no or only traces of dissolved oxygen
What are mixotrophic organisms? (Hehenberger)
- they combine photosynthetic and heterotrophic nutrition traits
What are constitutive and non-constitutive mixotrophs?
- Constitutive: photosynthetic protists that possess a stable inherited plastid → phytoplankton
that also eat
- Non-const.: heterotrophic protists that acquire autotrophy through chloroplast retention
(kleptoplasty) or maintenance of algal endosymbionts
- Mixotrophic protists are going to be more successful in a warming climate and future ocean
conditions due to their nutritional flexibility. They will outcompete non mixotrophic organisms
due to their adaption to conditions where greater respiration rates are needed and a lower
nutrient availability will be there due to stratification
What are protists?
Protists are eukaryotes that are not fungi, animals or plants. They are mostly unicellular
What are differences between prokaryote and eukaryotes
Prokaryotes: no nucleus, circular DNA, no cell organelles, always unicellular
- Eukaryotes: nucleus, linear DNA inside nucleus, cell organelles, also multicellular
What is the great plate count anomaly?
- describes the observation, that microscopic cell counts are significantly higher, than the
corresponding counts of colony forming units on agar plates
- 99 percent of all known microorganisms cannot be cultivated in the laboratory
- Pelagibacter ubique is the most abundant bacteria in the ocean from the SAR11 clade, it is
culturable
What are candidate phyla?
- Term that stands for bacterial species that are uncultivated and only known from
metagenomics
- usually defined as candidate phyla if there is less than 75 percent similarity in the sequence of
the 16S rRNA gene, compared to the nearest phylum representative
What is nekton?
- organism that swims against currents
- minimal size is required to overcome the ocean currents
why do they have so few bones? (fish)
- Bones are a “recent” evolutionary trait of fish
- Are higher density, than surrounding water – additional energy expenditure for
staying buoyant: need for continuous swimming or swim-bladder
Why this mess in fish taxonomy?
- “fishes” are a paraphyletic group, they are a mix of monophyletic groups with
different ancestor
- Recent adaptive radiations
- Many unknown tropical species
- Heavily under sampled deep sea/ polar seas
Why are there different fin forms in fish?
- Adaptions to different lifestyles, pelagic, benthic, ambush predator, long migrations…
- different if it is a predatory fish (grouper, flat, large area fin) or a continual fast
pelagic swimmer (tuna, “splitted” fin, with small area)
bacteria vs archaea
2-Name three adaptations to life in the deep sea. (example exam)
drift
chainformation to increase drag
sense: echolocation
hide
colouration
def foundation species (example)
foundation species are species that have a strong role in structuring a community
-What abiotic factors change in deep water masses during their journey along the great conveyor belt? (example)
temp, salinity and thus density
Which biological processes impact oceanic nitrogen concentrations? (example)
marine nitrogen cycle:
nitrogen fixation, assimilation, nitrification, anammox and denitrification
7-Which factors define the lower distribution boundary of coastal macrophytes? example
light exposure
air exposure
not shure
10-What does the term Ekman transport mean? Why is it important? example
wind driven frictional layer where coriolis plays an important role (rotation)
net transport leads to curculation to right of the wind (NH)
important for biogeochemical properties (bc it induces upwelling and downwelling)
11-How does light intensity influence photosynthesis? example
s you rise from low light intensity to higher light intensity, the rate of photosynthesis will increase because there is more light available to drive the reactions of photosynthesis.
reaching light saturation point, photoinhibition starts
12-What genes are often used to construct phylogenetic trees and why? example
16S because is konservative RNA gene in mitochondria
16SrRNA
large database available
present in all living organisms
high kopy number in metabolic active cells
conserved and variable regions
What is the main purpose of the citric acid cycle and of the respiratory chain? Describe in general terms (non-quantitative, no drawings of biochemical reactions necessary).
The citric acid cycle provides the electrons that fuel the process of oxidative phosphorylation--our major source of ATP and energy
14-What is the difference between mero- and holozooplankton? Name 2 examples each. example
Holozooplankton: planktic their whole lifecycle: krill, copepod, diatoms
Merozooplankton: not only planktic in lifecycle: corals, fish
15-What are factors that determine vertical zonation of marine organisms along coasts? example
light
wave exposure
wet/dryness
salinity
16-Why does the magnitude of tides vary over monthly cycles? example
earth/moon system rotation: monthly
Why are there more endemic species in the Southern Ocean when compared with the Arctic Ocean? example
bc older: long term stability and more time to adapt bzw. longer apart from other waters
21-What are mesophotic reefs? example
located in photic zone, 30-50m
characterized by light dependent communities
22-Describe typical communities that thrive in upwelling ocean regions. example
large primary producers
food webs with view main participants
23-Name three important upwelling areas and describe how large-scale water mass flow is driven in these systems. example
westcoast southamerica
westcoast northamerica
westcoast northafrica
bc of winds/turbulences (ekman transport)
easterliers am äquator
2. Advantages and disadvantages of net sampling and in situ observations
The timing and methods strongly determine the results.
1. net sampling: able to catch large amounts and do quantitative studies. Able to recover
organisms and fix them, do taxonomy or if living even physiological studies (Copepods,
Amphipods, Chaetognaths, Annelids)
2. in situ camera observations: keeps gelatinous animals intact (Rhizaria, Cnidaria,
Ctenophores), see animal behavior, know exact position of animal and associated
environmental factors
3. N:P anomalies are common. What process causes a decrease in the ratio? What
process causes an increase in the ratio?
Decrease: N-loss processes, mainly due to hypoxia: if c(O2) < 20 μmol/L → NO3
- becomes
oxidant → Denitrification: NO3
2- → NO2 → (N2O) → N2 or Anammox: NH4
+ + NO2
- → N2 + H2O
in both cases: N2 not bioavailable anymore
Increase: N2 fixation via diazotrophic cyanobacteria (e.g.: Trichodesmium), but the enzyme
nitrogenase needs a lot of energy and iron
4. Multiple choice: what does the Reynold’s number indicates?
The reynold number indicates if the water around an object is flowing turbulent or laminar. This is
mostly determined by the size/length of the object and the relative velocity of water compared to the
object. In plankton the relative velocity of water to the object is close to zero, because it flows with
the water. Thus, for plankton, R < 1 and the viscose forces of water dominate (concentration
gradients develop). For nektonic, or large sessile animals, besides being larger, the relative velocity of
their bodies to the water is high(er). Thus, for nekton, R > 1 and inertia is dominating, causing a
turbulent flow.
R = (L*U*ρ)/μ
whereas: L = length of object, U = relative velocity, ρ = density of fluid, μ = fluid dynamic viscosity
Multiple choice: what are the consequences of a low Reynold’s number for
organisms?
laminar flow
diffusive boiundary layer
water sticks to cell
viscouse forces dominate
sinkin follows stokes law (<1)
6. Light penetration formula and what factor affect light penetration.
Lamber-Beer-Law: I(z) = I(0) * e-k*z
whereas I(z/0) = irradiance at depth z or surface, k = attenuation coefficient, z = water depth
attenuation dependend on:
phytopl density und community
abundance of particle
abundance of DOM of which parts can be chromophobic active
7. What’s Net Primary Productivity and how can we measure it?
Net primary production is the total amount of gross primary production within an algal cell subtracted by all its respiration processes.
light exclusion measurement
O2 measurement (14/13C: no clear seperation between net and gross)
8. Why is it difficult to assess the importance of heterotrophic protists in the food web?
In general: heterotroph protists = single celled eukaryotic bacteria → able to feed on phototrophic or
chemoautotrophic (in the deep) producers (feed on autotrophs); but: heterotroph protist are
mediating the “microbial loop” so they feed on POM and DOM (leaching phytoplankton, dying cells,
feces, sloppy eating). First of all, the amount of feeding is hard to quantify and secondly, they are
prone to lysing via viruses. This results in a shunt for DOM/POM and subsequently altered export of
previously bound OM due to primary production.
What’s the name of the ability organisms have to produce light? Name three
functions and one group that performs at least two of the mentioned functions.
Bioluminescense
General: Luciferase is catalyzing the oxidation of luciferin → light + inactive ‘oxyluciferin’; get new
luciferin via diet or internal synthesis
Functions:
counter illumination - disguise shadow, less visibility frim below
crustaceans, squid, fish
mate attraction, recognition
distractive body parts
squid
startle the predator (confusing flashlight)
a. What is the difference between symbiosis and mutualism?
Symbiosis (sensu deBary): close association of organisms of different species, regardless the benefits
or cost for each partner
Mutualism: both interacting organisms are experiencing a mutual benefit from the association to
each other – e.g. dinoflagellates synthesize carbon and transfer it to corals; Hawaiian bobtail squid
lives in association with bioluminescent Virbrio fisheri for counter illumination
Commensalism: only one of the organisms in close association is benefiting, whereas the other one is
neither harmed, nor profiting – e.g. some gut-microbiota
Parasitism: clearly, one organism of the association is benefiting, whereas the other organism
experiences a negative outcome
c. Name three possible mechanisms for symbiont transmission
1. From the environment to the host – horizontal transmission (e.g.: bobtail squid and Vibrio
fisherii)
2. From parents to progeny – vertical transmission (e.g.: insects)
3. Leaky vertical transmission – a mix of vertical + horizontal (transmission by parents and some
via environment – most common transmission type)
d. What is the role of the host on the holobiont?
habitat, mediating community to certain extend (discriminates certain microbes)
controls, maintain and reestablish homeostasis upon stress, injury and pathogens
feeding rates
11. Main sources and sinks of elements in the ocean.
source:
river discharge
atm deposition (dust)
hydrothermal vents
sink:
sedimentation
outgasing
1- How do wind and solar irradiation drive ocean currents? (3 p, Handmann)
= pressure gradient force: deltap = gh x deltakomisches p
wind: ekman transport
solar: thermohaline driven circulation
Name and briefly explain three important environmental similarities of the Arctic and Antarctic.
seasonal light and production regime -> pp driven by seasons
three marine habitats: sympagic, pelagic, benthic
cryo-pelagic-benthic coupling
temp permanently low -> low solar irradiance
What is the name of the vast extensive seafloor between 3000-6000 m? What is the main pathway
for food supply in this habitat?
abyssal plain
-> rely on organic matter sinking down (marine snow, whale falls etc.)
Name two chemical redox-reactions that can be catalyzed by microbes to gain energy via chemosynthesis.
H2 oxidation H2 + S -> H2S
sulfur cycling
methane oxidation
microbial fe(II) oxidation Fe2+ -> Fe3+
What generally happens in all CO2 fixation pathways?
A carboxylating enzyme links either CO 2 or HCO 3 with an organic acceptor molecule, which must be regenerated in the following steps of the pathway
always ATP needed
Name one CO 2 fixation pathway
calvin-benson-bassham cycle
reverse krebs cycle
What is the difference between autotrophy and heterotrophy
autotrophy: org compounds synthesized using c from co2
heterotrophy: c compounds as electron sources
How can marine invertebrates survive seasonally anoxic periods in their benthic habitats?
massive glycogen reserves
alternative anaerobic endproducts
massive metabolic reductions >99 %
Which group of phytoplankton can fix atmospheric nitrogen?
Cyanobacteria
List four mechanisms that are used by marine macrophytes to prevent damage from excessive
solar irradiation.
chloroplast movement
thick epidermal cells
high pigmentations
(shut down photorespiration)
Which environmental factors typically determine the lower distribution limit of macrophytes in the
vertical zonation on a shore?
light limitations
Mention two important determinants of lower (vertical) distributional limits of invertebrate
species on many rocky shores.
competition
predation
Virophages are ___ viruses that replicate in giant virus-infected eukaryotic cells and can integrate
into the genome of host (eukaryotic) genomes and act as an immunity system against giant virus
infection.
ds DNA
One current prevailing hypothesis is that the rise of the eukaryotes (eukaryogenesis) has a/an
_____ origin; whereby eukaryogenesis involved a chain of events that lead to this primitive cell
establishing a symbiosis with a bacterium which became the mitochondrium.
archaeal
Name at least two properties of a submerged body which determine its sinking speed according to
Stokes’ law.
size
density
form (shape)
Which properties of solar light change with water depth? Name two or more.
color of light
intensity
What can ocean models be used for?
test hypotheses, concept, ideas
put isolated observations into coherent context
provide scenario simulations (predictions)
Give at least three principal differences in terms of reproductive biology between teleost (bony) fishes in contrast to sharks and rays.
sex reproduction with internal fertilization (shark)
mostly external fertilization
oviparous, ovoviviparous, viviparous
mostly oviparous
modified pelvic fin for reproduction (male modified to claspers)
not modified
What are main reasons for marine turtle declines in the past (historically) and in recent times?
past: eating turtles
now: bycatch and ingesting plastic
What is convergent evolution? Please give a marine example.
bodyformed streamline
gills
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time (species with no relation).
What is the Deep Reef Refugia hypothesis (DRRH)? What are its limitations?
= mesophotic populations can provide viable reproduction material for shallow reef areas following disturbances
but! there are limitations:
tested on a limited taxonomic, geographic, bathymetric and climatic bases
Mangroves have developed unique adaptations to two challenging abiotic conditions in their
environment. Name these two main conditions, along with specific adaptations to cope with them.
salt sediments
salt tolerance through
salt excretion through special glands
salt is delt with after entering the plant
salt exclusion
anoxic sediments
unique structures:
pneumatophores
prop roots
need roots
plank roots
alternative access to air
Please consider the following statements and indicate whether they are correct or false. What is
the difference between an autotrophic and a heterotrophic organism
a-Autotrophs are also called primary producers
b-Autotrophs and heterotrophs are two sides of the same coin
c-A heterotroph is an organism that consumes other organisms as food
d-An autotroph is able to synthesize its own food from raw materials and energy
a- RIGHT Autotrophs are also called primary producers
b-FALSE Autotrophs and heterotrophs are two sides of the same coin
c-RIGHT A heterotroph is an organism that consumes other organisms as food
d-RIGHT An autotroph is able to synthesize its own food from raw materials and energy
What is the physiological reaction of an autotrophic cell to nutrient limitation? Give 3 examples.
extracellular release of OM
lower carbon content will lead to:
lower exudation (ausschwitzen)
aggregation
sinking
SAR11 is among the most abundant bacteria in the ocean. Provide some characteristics of this
important bacterial clade
small carbon oxidising bacteria
aerobic free living chemoheterotroph
small genome
How are the regions A, B and C called in a typical P vs. I curve? How are the points D and E called?
A: light limited
B: light saturation
C: Photoinhibition
D: Light compensation point
E: light saturation point
Why is the ocean salty and not chalky (although the flux of Ca2+ and HCO3
- into the ocean is much
larger than that of Na+ and Cl-)?
bc of calcification (CaCO3) leading to dissapearance of Ca2+ and HCO3-
Marine primary production is conceptually distinguished into “new” and “regenerated production”.
Which form of inorganic nitrogen supports one and the other type of production?
new: NO3-
regenerated: NH4+
The N:P ratio of inorganic nutrients in the deep ocean (i.e. below the winter mixed surface layer)
shows distinct deviations from the Redfield ratio of 16:1, the so-called N:P anomalies
• (a) Which process is primarily responsible for higher than Redfield proportions (N:P>16:1)?
• (b) Which two processes are primarily responsible for lower than Redfield proportions
(N:P<16)?
a: nitrification
b: denitrification, annammox
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