What are the typical anthropogenic pressures on coastal marine habtats?
Land reclamation/coastal development
Aquaculture
Mechanic damage due to fishng and boats/gear
Logging
Climate change
What are keystone species? Give an example.
—> species with a disproportionate influence on an ecosystem (relative to mass)
e.g. Predatio of mussels (Mytilus) by sea starts (Pisaster) enables complex communities; sea star removal leads to mussel monoculture
What are foundation sepcies ? Give an example.
—> species which define much of the structure of a community
e.g. kelp forests, allowing the existance of a group of “obligate understory” species
Other examples are mangroves, salt marshes and seagrass meadows
What coastal habitats (seagrass, salt marsh, mangrove, coral, tropical forest) have the biggest annual area loss?
Corals: 4-9%/yr
Seagrass: 2-5%/yr
Mangrove: 1-3%/yr
Salt marsh: 1-2%/yr
Tropical forest: 0.5%/yr
Describe the balance of East Pacific kelp forests and how that balance is altered by anthropogenic influences
Warming ocean waters are a stressor for kelp forests slowing down their growth. Another species affected by higher temperatures are seastars, a natural predator of sea urchins. The latter feed on the stalks of kelp and due to a lack of predators they wiped out over 90% of kelp forests between 2008 and 2017. Sea otters, another predator of sea urchins, was hunted nearly to extincion by the early 20th century.
What are typical field methods to study coastal species assemblages?
Beam trawl
Van Veen grab
Box corer
Line intersect transects (LITs)
Counting frames
Hyperspectral imaging 400-900nm
eDNA/metabarcoding (extract DNA from water samples, or use biological homogenates of individually sampled organisms, or mixtures of species - use PCR)
What are the benthos size classes?
Microbenthos (<100µm)
Meiobenthos (100 - 500µm)
Macrobenthos (>500µm)
Megabenthos (>1cm/>5cm)
pragmatic classification - boundaries are fuzzy
Why does it make sense to sample the benthos?
Macrozoobenthos is long-living (several seasons/years) and integrates environmental information over time
MZB is locally stable and shows effects of adverse phases even if these cannot be observed directly
MZB is thus a good indicator of environmental health
What is eDNA?
DNA released from an organism into the environment
What is Metabarcoding?
Massive parallel sequences of a mix of DNA sequences
Simultaneous DNA-based identification of many taxa found in the same environmental sample
How is Metabarcoding done?
Collect an environmental sample
DNA extraction from environmental sample
Amplufy DNA markers
High-throughput sequencing
Bioinformatic processing
Species identification
Ecological analysis
What are protists/cyanobacteria?
Protists: All single celled eucaryotes
Cyanobacteria: Phototrophic bacteria
What are the functional groups of plankton?
Phytoplankton: plant-type (O2-producing), photosynthesis
Zooplankton: animal nutrition - particulate organic substance <— Microzooplankton/Protozoa
Bacterioplankton: usually heterotrophic - nutrition by DOC, at Redox-interfaces also chemoautotrophic bacteria (more often in sediements)
Mixotrophs
What is the Utermöhl-Method?
What characterizes bacteria?
Bacteria (prokaryotes)
usually with chlorophyll a or divinyl-chlorophyll a & b (Prochlorococcus)
phycobilins (hydrophilic pigments): phycocyanin, phycoerythrin
Some species:
gas vacuoles
nitrogen fixation
filamentous cyanobacteris: Trichodesmium
What charcterizes Chryophyta?
only flagellates
two flagella of slightly diifferent length, both hairy
found almost everywhere. but rarely dominant in the ocean
chlorophyll a and c2
olive, brown, red, blue - also phycobilins
no cell wall
What is the great plate count anomaly?
~99% of all microorganisms cannot be cultivated in the laboratory
What are the most important human pressures on the baltic sea?
Eutrophication
Climate Change
Introduction of Alien species
What characterizes the german Baltic Sea Coastline?
1150km
predominantly soft:
glacial sediments (clay, sand , gravel, boulders)
characterized by fjords, sand drifts, beaches, coastal lagoons (Bodden)
How does salinity change in the SW-Baltic anually?
Higher salinity input from the North Sea during Autumn and Winter due to storms
What are the parameters describing a community in the SW-Baltic?
diversity of species/functional groups
substrate coverage
annual productivity
changes is parameters along gradient e.g. salinity
differences between sites
What are functional groups?
express similarity/dissimilarity of ecologically relevant functions due to different traits
e.g. Mythilus: Large in size, massive growth form, suspension feeder, sessile
generally more species present mean more functional groups
more functional groups and more species per functional group make a communty more resilient to disturbance
What are the different diversity levels?
alpha: species richnes on panel
beta: differences among panels assessed by alpha and gamma
gamma: cumulated species richness on one site
What is an important information thats not taken into account by diversity?
relative amount of autotrophs to heterotrophs to total productivity
—> tells a lot about community/food web structure
What is a community?
A group of organisms occurring in a particular environment, presumably interacting with each other and the environment and seperable by of ecological survey.
fundamental concept of ecology
controversy on: Scope, Boundaries, Regulation
wide variety of definitions
What is the hirarchy of statistics in community analysis?
Descriptive statistics
graphical presentation of communty patterns
Explorative statistics
explorative description
reduction of data complexity
Analytical statistics
test of hypothesis
parametric vs. non-parametric approaches
regresson analysis
“search for cause of patterns”
What is the significance of sampling?
True natural patterns go through a sampling filter that is defined by multiple diifferent factors (gear, selectivity, number of samples, replicates, randomness)
—> observed patterns are different from true patterns
What are the dominant currents in the Kiel Bight?
Surface currents: Baltic outflow
Deep currents: North Sea inflow
What is the seasonal change in the thermocline in the Baltic?
Summer: warming surface water —> shallow thermal stratification
Winter: cooling —> deep mixing: new nutrients in surface
What has the strongest effect on startification in the baltic?
The pycnocline
What is the compensation depth/critical depth of light intensity?
Compensation depth: depth at which 1% of the light intensity is left
Critical depth: depth at which net photosynthesis is positive
What are the most characteristc properties of seasonal nutrient (and others) distribution in the baltic?
oxygen depletion of at depth during summer startification
salinity drop due to outflow of Baltic Sea (influenced by rivers (in summer)
Spring bloom after mixing, rise intemperatures and increased light availability and small autumn bloom after stratification decreases
How can we determine the flow of energy and mass through marine ecosystems?
What is the Redfield ratio?
C : N : P — 106 : 16 : 1
106CO2 + 122H2O + 16HNO3 + H3PO3
consumption/remineralization of nutriients in fixed stoichiometry
production/consumption of oxygen
production/connsumption of CO2
What are the three most importat factors in biogeochemistry and why?
water column physics
stratification (temperature salinity)
Light
compensation light intensity (below or above pycnocline)
comparing k-values (light meter vs. Secchi Disk)
potential for light limitation
Nutrients
which macronutriient would limit growth if uptake is according to Redfield
are changes in oxygen related to T or S
do we see hypoxia (sat. <30%)
How are abundance and carbon fixation rate related to cell size?
Abundance decreases with increasing cell size
Carbon fixation increases with increasing cell size
what is k when talking about light attenuation?
extinction coefficient, empirical equation: k = 1.7/Secchi depth
Why do we have light attenuation in the water?
Because of objects in the water e.g.
particles
phytoplanktondissolved OM
phytoplankton
even water has a certain attenuation coefficient
What is the Sverdrup Model?
When the mixed layer depth is < compensation depth —> bloom
What is the disturbance-recovery-hypothesis?
Decrease in cell division in autumn
overgrazing and dilution due to deepening of mixed layer depth
depletion of grazer populations
by early winter depletion grazers exceeds light-limitation of cell division
bloom is initiated
concentrations remain low due to convective mixing
mixed layer stops deepening by the end of winter
phytoplankton and grazer concentrations rise in parallel
ecosystem feedbacks and light driven increase in division rate trigger bloom during spring stratification period
What is the biggest difference between the Sverdrup Model and the disturbance-recovery hypthesis?
The latter is taking grazers into account
What is the unit of light measuremnts using a quantum sensor?
1E = 1mol of photons
usually in µE//s*m2)
What are particles?
anything that is not deissolved
produced in situ: phytoplankton, fecal pallets
added: dust, wood particles, microplastic
generally: more small particles than bigger ones
What does the vertical particle distribution in the ocean look like?
highest in the surface —> due to phytoplankton
sinking particles decrease with depth -> do not increase in the deep
increase at seafloor due to suspension
What drives the temporal particle distribution?
produced in different concentrations at different times of the year
higher production during blooms (spring and summer)
less production during absence of phytoplankton (winter)
How can seafood be traced using genetic barcoding?
—> single nucleotide polymorphism (SNP) as genetic marker
different stocks/populations of different species have multiple SNPs that allow to distinguish between them
only 8 SNPs (point mutations) aliow to discrminate cod stocks
What are Homologies and Alignments?
Homology:
homology of characteristics evolving from one ancestor (e.g. mammal extremities)
genomes evolve through mutations
Alignments
same thing on a genetic scale —> sequences that show similarities
What is a BLAST
Basic Local Alignment Search Tool
can search for matching sequences in large databases
What is Sanger Sequencing?
Method for DNA sequencing
What is the difference between Meroplankton and Holoplankton?
Meroplankton:
planktonic larvae of benthic organisms
Holoplankton:
live their whole life in the water column
Give examples for the different Zooplankton size groups. How can you sample those?
Microzooplankton:
<0.2mm
Foraminifera, Copepod nauplii, Ciliates
water bottles, nets
Mesozooplankton:
0.2-20mm
Copepods, Pteropods, Decapod larvae
multinet, bongos net
Makrozooplankton:
>20mm
Polychaetes, fishlarvae, chaetognaths
RMT, MOCNESS
What does the general light structure of the ocean look like?
Light zone (photic): 0-100m
Twighlight zone (dysphotic): 100-470m
Dark zone (aphotic): >470
What does the seasonality in plankton succession look like in different climate zones?
Arctic: strong summer bloom in phyto- and zooplankton when sea ice melted
North Atlantic: Strong spring bloom and weak late summer bloom
Tropics: shifted oscillation between phyto- and zooplankton
What does the taxonomic distribution look like in different climate regions? What are specific characteristics?
Polar:
low diversity -> low species in high abundances
most species with large oil sac or droplets
mainly calanoid copepod species
Arctic: Calanus species
Antarctic: calanoids euphausiids
(Sub)tropics:
many species in low abundances -> high diversity
most species: small, no oil sac or oil droplets
mainly cyclopoid copepod species
What is teh difference between shelf and open ocean in terms of taxonomic distribution?
Shelf:
few species, low diversity
mainly smaller speciies -> few large taxa
e.g. cladocera, meroplanktonic larvae
Oceanic:
more species, higher diversity
no to very few meroplanktonic larvae
e.g. siphonophora, pteropoda, ostracoda
What is the ecological role of Diatoms?
over 100.000 species
35-50% of oceanic primary production
20-50% of global oxygen production per year
assimilate over 6.7 billion tons of silicon per year
distribution: ubiquitous: plankton (centric) & benthos (pennate) -> oceanic, coastal and fresh water
Why are diatoms so succesful?
silica cell wall -> more stability (grazing, abiotic factors)
advanced photo system
large central vacuole
efficient nutrient uptake and recycling system
resting stages
efficient CO2 uptake system
biochemcal defense system
What is special about Phaeocystis?
forms foam at the shore
adaptive response to predation pressure due to size
may experince lower nutrient uptake
skin like structure: virus protection
mucus: Mn & Fe storage
single cells:
over-wintering strategy
mixotrophy (ingesting bacteria or other small particles)
inefficient food source for mesozooplankton
Name one organism that produces DMS
Phaeocystis
Why does everybody love Coccolithophora?
have coccoliths (calcified plates that form coccosphere/exoskeleton) -> not all species calcify at all stages
5-100µm
mostly sperical
ecological success due to increased defense, buoyancy control, protection from UV damage
involved in the BCP and CCP
How do Coccolithophores reproduce?
asexual through meiosis and mitosis
2 distinct phases:
haploid/holococcolith stage (thin)
diploid/heterococcolith stage (thick)
What taxonomical groups make up microzooplankton?
Protists: unicellular, eucaryotic organisms
Metazoa: all multicellular organisms
—> heterotrophic and mixotrophic organisms between 20-200µm
What is the ecological role of microzooplankton?
links samller phytoplankton and larger Mezozooplankton
key composer of microbial loop
consumption: 75% of particulate primary production -> 50% of plankton biomass/day
control pico- and nano sized flagellate abundances
What is anatomy good for?
species identification
individual examinations (stomach content, diseases, parasites)
gain better understanding of interrelationships of structure and function, evolutionary pathways
What are the most important external morphological features in fish
Mouth
Eyes
Nares (Nostrils)
Operculum
Spiny dorsal fin
Soft dorsal fin
Caudal (tail) fin
Pectoral fins
Pelvic fins
Scales
Vent
Anal fin
Lateral line
Peduncle
What are the different muscle tissues in fish and what are they for?
Red muscle:
steady constant-effort swimminng
well supplied with oxygen
londitudinal arrangement
White muscle:
anaerobe
quick bursts of movement (escape/hunt)
helically arranged
pink muscle:
intermediate form
How are the tail and trunk muscles of fish build?
series of muscle blocks -> myotomes
myotomes -> seperated by connective tissue -> myosepta
horizontal septum seperates myotomes -> dorsal and ventral
What does the digestive system of fish generally look like?
Esophagus:
short and expandable -> walls are layered with muscle
Stomach:
in most bony fishes (not all) -> usually bent musculat tube (U or V shape)
gastric galnds -> release substances: break down food, preparation for digestion
pyloric caecae -> blind sacs at posterior part
Intestine:
nutrient absorption -> length varies greatly
herbivorous -> long, coiled intestines -> food is harder to break down
carnivorous -> short intestine
pancreas -> secretes anzymes into intestine for digestion
What is the swim bladder and how is it filled?
gas filled bladder
in most bony fishes
originally developed as respiratory organ (from lung of lung fishes)
neutral buoyancy
some fish: can function as sound amplifier
developes in later live stages and is filles with oxygen by gas gland
O2 diffusion from venous to arterial capillaries
pO2 (blood) > pO2 (bladder)
production and release of lactate and CO2 inside gland cells
root effect: lower O2 binding capacity of fish hemoglobin/O2 transport agains gradient
How is the heart of a fish build?
two chambers -> atrium (bulbus arteriosus) and ventricle (sinus venosus)
What is a function of the swim bladder besides buoyancy?
Hearing
connected to ear via slim air ducts -> 360 species of clupeiformes
What are alternatives for the swim bladder?
bone reduction
squalene enriched liver oil
fine tuning lipid content
active swimming
fin positioning
extracellular enrichment of lipids
What fish tend to have more red/white muscle fibre?
Red: pelagic
white: benthic
WHat does the gill system look like in Teleosts?
4 gills on each side
protected by operculum
held by bony arches (have gill rakers wiith hooks)
act like sieve (dense when plankton feeders)
high amounnt of lamella
large surface area for respiratory exchange (diffusion)
Whats the thing with Tuna and body temperature?
endothermic: maintain temperature higher than surroundng water
net of arteries and veins -> counter current exchange system
heat of venous blood -> allows more efficient muscle use
heat conservation from normal metabolism
How does osmoregulation work in fish?
Osmolytes:
maintain integrity of cells
amino acids and derivates, urea, etc.
TMAO -> trimethylaminooxid
Osmocomformer and Osmoregulators
Euryhaline:
tolerate wide range of salinity
need osmosensors
What is the difference between salt water and fresh water fishes in terms of osmosis?
Salt water:
Gills are primary site of net sodium and chloride transport
Fresh water:
Gills, kidneys and digestive tract = maintenance of body fluid balance
What are the specialized senses of fishes?
current detection
somatotopic maps
ampullae of lorenzini
detect (or create) electric fields
modified hair cells
Do fish feel pain?
Pro
Contra
changes in brain activity of fishes during stimulation and aversive behavior, physiological reactions, suspension of normal behavior
reflex response to noxious stimuli with limited behavioural repertoire
Convergent evolution in brain. structure and function -> alternative ways for pain receptiion
Lack of Neocortex and therefore conscious information processing -> only concious animals can feel pain
animals have to associate painful stimuli with context (learning process) -> realiise long-term fitness
No direct measurement of subject experience possible -> no proof for pain reception
How do bony/cartilagenous fish reproduce?
Bony fish:
External fertilization -> Ovipary
large number of eggs
larval stage
dispersion
some exceptions known: seahorses, eelpout
Cartilagenous fish:
internat fertilization -> Ovovivipary
embryo develops within a layed egg
large yolk
fewer eggs needed
Internal fertilization ->
embryo develops within uterus
more protection
direct nutrient supply from parent
—> mor parental care -> higher aurvival rate -> less offspring needed
Last changed7 months ago