Bio Oc - General Topics

What are three local variation physical controls of primary production?

Langmuir frontal zones, equatorial upwelling, geographic fronts

What is equatorial upwelling?

Physical nutrient mixing control, cold nutrient rich water brought to the surface

What are geographic fronts?

Physical control, eastern boundary currents (upwelling and continental shelfs)

What is a river plume front?

Nutrient addition at the mouth of a river

What are langmuir frontal zones?

Steady wind over a calm sea, water converges in bands, convection cells create upwelling and downwelling

What is a P vs. I curve?

Photosynthesis versus irradiance curve (plots rate of photosynthesis against the intensity of light)

What is the photoadaptation trend in dinoflagellates and cyanobacteria?

Grow best at low light intensity

What is the photoadaptation trend in diatoms?

More tolerant of high light (can still use low light)

What is photoacclimation?

short-term phenotypic adjustments to light intensity

- Low intensity: more chl A

- Low light can develop more photopigments

What is the critical depth theory and its significance?

When respiratory loss = photosynthetic gain

- Can predict blooms

How is the amount of Carbon fixed per time, a measure of phytoplankton growth?

Amount fixed per unit of time and area (how effective producers convert C to organic matter)

What is the assimilation index (phytoplankton productivity)?

Can be used to compare different areas

- Amount of C fixed per mg of CHL A per hour

What is the population growth formula?

Xo+delta T = Xoe^ut

What is doubling time, and what is its equation?

The time it takes for the population to double/increase by 100%

- D = 0.69/u

What are the growth curve patterns in dinoflagellates and diatoms?

Dinoflagellates: Achieve max around 1.2

Diatoms: Achieve max around 2.5-3 (higher irradiance)

What is the renfield ratio?

Ratio of Carbon to inorganic nutrients in biotissue

- C:N:P --> 106:16:1

What is the limiting nutrient according to the renfield ratio?

Phosphorus is major limiting factor (N & P)

What is the source of nitrogen in the ocean?

Cyanobacteria (through nitrogen fixation), nitrate is the dominant form

What is the difference between new production and recycled Nitrogen production?

New: Newly fixed molecules arriving from the atmosphere

Recycled: Previously eaten, respired and excreted

What ratio describes production in the biological pump?

F ratio: new production / total production

- Helps to understand the biological pump and overall health of the marine ecosystem ( how Carbon is exported to the deep sea)

What does a small or large Ks mean in regards to nutrient response?

Large: High cell concentration needed to hit max growth rate

Small: Rapid response to nutrients

Where does Phosphate originate in the ocean?

Rocks, and enters ocean via erosion. Exists in the lowest amounts.

Describe trace elements in the ocean.

Can limit production in low amounts and are unevenly distributed. Minor nutrients and are depleted in surface waters (Fe, Zn, Cu, Co).

How can we calculate zooplankton from a plankton tow?

Use volume sampled, the radius of the net and the distance towed. Count number of plankton in a subsample and quantify.

What are holoplankton and what are some of its major groups?

Organisms that are planktonic during their entire life cycle.

- Everything arthropods, echinoderms, crabs/shrimp, molluscs

Describe Phylum Ctenophora (give an example, size, eat, predators, mechanisms, adaptations)

- Comb jellies

- Size: cm

- Eat zooplankton

- Are carbon sinks

- Feeding mech: Colloblasts, sticky cells, ambush predators

- Predators: ctenophores or fish

- Lobate and tentaculate form

- Use their eight combs of cilia to swim (refracts light)

Describe class Hydrozoa (phylum Cnidaria) (give an example, size, eat, predators, mechanisms, adaptations)

- Size: cm

- Portugese Man O' War, Vellela

- Eat: Zooplankton

- Feeding mech: stinging nematocysts

- Predators: Jellies, sea turtles, fish (if large)

- Adaptations: transparent, some bioluminescent

- Contract bodies to expel water and propel forward

- Benthic stage produces medusa stage

- Polyp --> medusa --> egg gets fertilized --> planula

Describe class Scyphozoa (give an example, size, eat, predators, mechanisms, adaptations)

Size: 1m (bigger than hydrozoa)

Example: True Jellies

Eat: Zooplankton

Feeding mech: stinging nematocysts

Predators: Other jellies, sea turtles, humans

Adaptations: Transparent, low nutritional value

Contract and relax circular muscles around bell to propel forward

Describe class Cubozoa (give an example, size, eat, predators, mechanisms, adaptations)

Size: 10's of cm

Example: Box Jellies, Chironex Fleckeri (MOST LETHAL)

Eat: Zooplakton, fish

Feeding mech: stinging nematocysts

Predators: Little known, maybe turtles

Adaptations: Have eyes, 8 lensed and 16 simple

Movement: Contract and relax bell to propel through water

Describe class Copepoda (subphylum arthropoda, subphylum crustacea) (give an example, size, eat, predators, mechanisms, adaptations)

Has 3 main orders: calcnoida, cyclopoida, harpactacoida

Life cycle: have dramatically different life stages

Eat: Plankton

Predators: EVERYTHING

6 naupliar and 6 copepodid stages

Describe Cladocerans

Size: mm

Ex: water flea

Feeding: Suspension feeders, scavengers

Predators: Fish, macrozooplankton

Describe class Ostracoda

Size: mm

Ex: String of Pearls

Eat: Scavengers

Predators: Fish. other zoo plankton

Create mating swarms (have species specific mating signals)

Are bioluminescent

Describe class Malacostraca

Size: mm-cm

Ex: Mysic shrimp and euphausids (krill)

Eat: Phytoplankton, protozoans, zooplankton

Predators: Whales, fish

Form swarms

Use swimming legs for propulsion (will also flap tail and propel backwards)

Have photophores on abdomen

Which class of organism is the most important link in the arctic and antarctic food webs?

Class Malacostraca (Mysid shrimp and euphausids)

Describe Phylum Chaetognatha (give an example, size, eat, predators, mechanisms, adaptations)

Size: mm

Eat: Zooplankton/copepods, are canibals

Feeding mech: Ambush predators, are transparent

2nd most abundant species to copepods

Use spines on head to capture food

Hermaphroditic

Describe Class Appendicularia (phylum Chordata) (give an example, size, eat, predators, mechanisms, adaptations)

Size: mm

Look like sperm

Eat: bacteria and picoplankton (suspension feeders)

Entirely planktonic

Predators: Fish and zooplankton

Spherical house of mucus

CONTRIBUTE TO MARINE SNOW & MVMNT OF C TO DEEP SEA

Which organism has a spherical house of mucus used to feed?

Appendicularians

Describe the feeding structure of Appendicularians.

Spherical house of mucus. Filters water through and catches small things on "screen", beat tail and notochord to bring water in and attract bacteria/food

What is an example of class Thaliacea?

Salps (jelly sacs/chains)

Describe class polycheata (phylum annelida)

Size: mm

Eat: Zooplankton

Predators: Fish, other predatory zooplankton

Look like balls with spikes or hairy worms

What are meroplankton and some examples?

Spend a portion of lives and plankton and remainder in benthis region

- Barnacles, echinoderms, bivalves, shrimp, crabs, fish)

What is the difference between plankotrophic and lecithotrophic?

Planktotrophic: feed on plankton

Lecithotrophic: supplied with energy from egg yolk

What organism lives at the lowest reynolds number?

Copepods

What does a low versus high reynolds number indicate?

Low: Viscous environment, laminar flow dominant (smooth and sticky)

High: Fluid environment, turbulent flow dominant (chaotic and less sticky)

What is the Phycosphere?

Boundary layer containing amino acids and chemical signatures of phytoplankton (deformed by compepod flow fields). Each sinks and leaves a trail that can be detected.

Which zooplankton are suspension feeders primarily?

Primarily salps and larvaceans, also done by euphausiids and copepods

What is retention efficiency, and what are two general trends associated with it?

Number of captures / Number of contacts

- Increase in size = increase in RE

- Increase in prey = increase in RE

Describe larvacean feeding mechanics and prey

- Tail pumps water through a mucous filter

- have 2 incurrent passageways covered by a filter

- Filter concentrates food and directs to the mouth

- Ex. Oikopleura longicaudata

Describe Euphausid feeding mechanics and prey

- Hairy legs with hairy hair: setae with setules

- Setae and setules form a filter basket

- Spread legs and hair apart to increase surface area and allow water to draw in

- Squeeze legs and hair together and release water to trap particles

Describe the early versus current copepod feeding hypothesis

Early: Sieving hypothesis, spread appendages to fan the water towards themselves. "Fling and clap" hypothesis

Current: Suspension feeding

Describe mechanical versus chemical sensory perception in copepods.

Mechanical: Can sense disturbances in the water through the bending of setae, causes a nerve impulse

Chemical: Passive or selective ingestion (also rejection), chemical signal produced by phytoplankton

Describe selection in copepods.

- Depends on INDIVIDUAL positive or negative signal recieved if ingested, rejected or avoided (detected from a distance)

- Phycosphere

- Feeding current: uses the strickler model, signals detected in core area of sensory cone

- Larger particles are individually detected and actively siezed

Describe copepod cleaning behaviour.

Will clean their antennae with setae to receive better signals.

What is the difference between clearance and ingestion?

Both are methods for calculating feeding rates

- Clearance: volume of water filtered / time

- Ingestion: prey consumer per hour or day (RATE)

What is the food removal method (include pros and cons)

- Control and treatment bottle, measures food remaining at beginning and end, calculates ingestion and clearance rate

Pros: Best counting method, easiest and longest used, large amount of data for comparison

Cons: Time consuming

What is the gut pigment method (include pros and cons)

- Measure photopigments in the gut of grazers, calculates gut passage time using a plankton tow

Pros: Gives direct info about gut content

Cons: Diel feeding variations, collection speed, can stress out animals and cause gut evacuation, can destruct pigments

Describe the radiotracer method (include pros and cons)

- Labels food with racioactive 12C isotope, measure uptake of tracer by organism. Same as the bottle method.

Pros: gives very accurate grazing rates

Cons: Very expensive, ends with radioactive waste