Marine Science YR 1 exam

What is phytoplankton?

They are producers (perform photosynthesis)

What are zooplankton?

Consumers (eat other organisms)

How can you sample plankton?

1) Using a jar/bucket

2) Using a net

3) Using a bottle

4) Using a pump

5) Using light traps

What do phytoplankton need?

1) Nutrients (such as nitrate, phosphate, iron)

2) Need to live near the surface for light

3) All have chlorophyll

What are the five categories of plankton?

1) Diatoms

2) Dinoflagellates

3) Coccolithophores

4) Green algea

5) Photosynthetic bacteria/ cyanobacteria

What is the structure of a diatom?

• No flagella = can’t move

• skeleton is made of glass

• golden brown in coulour

• may form chains

• may have spines

What is the structure of dinoflagellates?

• Unicellular

• two flagella

What is the structure of coccolithophores?

• unicellular

• two flagella at one end of the cell

• covered in calcium carbonate disks

What are the two types of zooplankton?

1) Holoplankton

2) Meroplankton

What is Holoplankton?

They spend their whole life as plankton

What is meroplankton?

Only part of their life is spent as plankton before they metamorphose and live benthically or as nekton (i.e. sea urchin larvae, barnacle larvae and crab larvae)

What are phytoplankton adaptations for survival?

• Oil droplets for buoyancy

• may form chains

• may have spines

• flagella for movement

• bioluminescence

What are the physical adaptations of zooplankton?

1) Transparent/red

2) Big eyes

3) Gelatenious (i.e. jelly fish)

4) Increase surface area (spines, + flattening their body i.e. amphipods)

What are behavioural adaptations of zooplankton?

1) Vertical migration

2) Bioluminescence

Why are plankton important?

• Provide food for many animals

• Remove carbon from the atmosphere

• Produce 50-70% oxygen

• Contributes to biodiversity

What are the factors that affect primary productions of phytoplankton?

1) Light

2) Temperature

3) Nutrients

Why are some algal blooms harmful?

• Cause oxygen depletion (dead zones)

• Block light to macroalgae

• clog fish gills

How do we measure seawater temperature?

1) Using a thermometer

2) Using a reversing thermometer (for depth)

3) Using a bathythermograph

4) Using a CTD

5) Using ARGO floats

How do we measure seawater salinity?

1) Evaporation

2) Measuring conductivity ( using a CTD)

How do we measure the pH of seawater?

1) Using pH strips

2) Using a pH probe

How do we measure the seawater oxygen?

1) Using an oxygen probe

What are the properties of water?

1) Transparency

2) Cohesion and adhesion

3) Solvent

4) High specific heat capacity

5) Neutral pH

6) Low viscosity

What is the advantage of water being transparent?

1) Allows light to pass through (important for photosynthetic organisms)

2) Allows for organisms to see through it

What is the advantage of water being cogesive and adhesive

1) Creates surface tension

2) Allows certain organisms to walk on water

What is the advantage of water being a solvent?

1) Nutrients and gases can dissolve

2) Salinity of oceans

What is the advantage of water having a high specific heat capacity?

1) Ocean is involved in moderation of climate

2) Relatively little variations in ocean temperature

3) Ocean can store more heat than land surfaces

What is the advantage of water having a low viscosity?

1) Water flows easily

2) organisms can swim through water

What are water reservoirs on Earth?

1) Glaciers

2) Rivers and Streams

3) Lakes

4) Groundwater

5) Atmosphere

6) Oceans

7) Biosphere

8) Soil moisture

How where the oceans formed?

• Through the off-gassing of igneous rocks via volcanoes, followed by condensation, precipitation and accumulation of liquid water

• Comets & asteroids brought water to earth

What are the six most abundant ions in seawater?

1) Chloride

2) Sodium

3) Sulphate

4) Magnesium

5) Calcium

6) Potassium

What are the inputs of salt in the ocean?

• Freshwater run-off from the erosion of rocks/soils

• Volcanos/hydrothermal vents

• Input from the atmosphere

What are the outputs of salt from the ocean?

• Into the atmosphere

• Into ocean sediment

What affects the density of seawater?

1) Temperature

2) Salinitiy

What is the effect of temperature on density?

Cold water is more dense than warm water

What is the effect of salinity on density?

Salt water is more dense than fresh water

What is the relationship between temperature and depth?

As depth increases, temperature decreases

What is the relationship between salinity and depth?

As depth increases, so does salinity.

What is the mixed layer?

The layer of water that exists between the water’s surface and the clines. Water temperature & salinity remain constant in this mixed layer.

What causes the mixed layer?

Wind and wave action. It is deepend with increasing wind strength + duration

What is the thermocline?

Steep change in temperature leads to the arrangement of water columns into layers

What is the halocline?

Steep change in salinity leads to the arrangement of the water columns into layers.

What is the pycnocline?

Steep change in density leads to the arrangement of the water columns into layers.

What are the 3 most abundant gases in seawater?

1) Nitrogen

2) Oxygen

3) Carbon dioxide

4) Argon

What is the relationship between solubility and temperature?

Solubility of gases decreases with increasing temperature (inverse relationship)

What is the spread of oxygen in the ocean?

1) Mixed layer has lots of oxygen due to diffusions from the atmosphere and photosynthesis

2) Oxygen minimum layer is due to the high rate of oxygen consumption by bacteria decomposers

3) Deep ocean has a reasonable amount of oxygen due to minimal consumptions and thermohaline circulation.

How does carbon dioxide affect ocean pH levels?

Carbon dioxide dissolving in the seawater increases the H+ ion concentration, decreasing pH

Why is it warmer at the equator than at the poles?

• Near the equator the sun’s rays strike the ocean almost perpendicular to its surface while at the poles they strike at an angle, rather than directly

What is the relationship between light and depth?

Light decreases with depth because it is absorbed by the water, sediment particles and plankton

What is the effect of light on seaweed distribution?

Blue light penetrates the deepest so seaweeds that can absorb blue light (red) live in deeper water than seaweeds that absorb red light (greens)

What are the three types of currents

1) Tidal currents (race rocks)

2) Wind-driven currents

3) Density-driven currents

What is the coriolis effect?

Object that are moving relative to the ground are deflected to the right in the northern hemisphere.

What causes surface currents?

The drag of the wind on the water and the Coriolis effect (water is set in motion by winds and affected by Coriolis effect.

What are the impacts of plastic pollution on marine organisms?

1) Ingestion of plastic garbage (fills stomach)

2) Ingestion of poisonous substances

3) Entanglement

What are the impacts of plastic pollution on marine ecosystems?

1) Destruction or smothering of the seabed

2) Transport of invasive species’

3) Contamination of beaches

4) Reduction of CO2 absorption by the ocean

What is upwelling?

When ekman transport moves water away from the coast and surface waters are replaced by deep (cold + nutrient-rich) water from belowe

What is downwelling?

When ekman transport moves water toward the coast.

What are apogee?

When the moon is further away from the Earth, the tidal range is smaller

What is perigee?

When the moon is closer to the Earth, the tidal range is larger.

What is a spring tide?

A tide just after a new or full moon, when there is the greatest difference between high and low water. (horizontal ellipse)

What is a neap tide?

A tide just after the first or third quarters of the moon when there is least difference between high and low water. (vertical ellipse)

What is perihelion?

The tidal range is bigger when the Earth is closer to the sun

What is aphelion?

The tidal range is smaller when the Earth is further from the sun.

What other factors can affect the tides?

1) Wind

2) Land masses

3) Barometric pressure (increase in pressure can result in decrease in tide height)

4) Large outputs from rivers during heavy rainfall can increase tide height

5) Coriolis effect

What are the upper limits of marine organisms usually set by?

Abiotic factors

What are the lower limits of marine organisms usually set by?

Biotic factors

How do you measure salinity?

Salinity meter or a refractometer

How do you measure wind speed?

With an anemometer

How do you measure density?

With a hydrometer

How do you measure distribution?

Transect study

How to measure photosynthesis?

1) Oxygen production

2) Glucose production

3) Carbon dioxide assimiliation

How do you measure feeding interactions?

1) Direct observations

2) Gut contents

3) Fecal analysis

What are exceptions to this rule?

• Predations by terrestrial organisms (Nori for herbavors)

• Light sets the lower limit for seaweeds

What are abiotic factors?

1) Desiccation

2) Temperature

3) Salinity

4) Food & Oxygen availability

5) UV light

6) Wave exposure

What is desiccation?

Water loss; drying out

What increases desiccation?

Wind and temperature

Species such as periwinkles and limpits are more tolerant to air and can therefore live higher in the intertidal zone.

What are adaptations to desiccation?

1) Lose water then rehydrate

2) Mucus (fucus and anemones)

3) Close up or clamp down (mussels, barnacles and limpits)

4) Conserve water

5) Live in a tide pool

Why is temperature so harmful?

Air temperature varies a lot more than water temperature (organisms out of water are subject to much larger temperature variations)

What are adaptations to temperature variations?

1) evaporative cooling in mussels and gooseneck barnacles

2) Mucus in anemones

3)Eurythermal enzymes in barnacles

Why is salinity so harmful?

Can increase with evaporation or decrease with fresh water input (variation)

What are adaptations to salinity?

1) Close up (barncles, mussels, anemones)

2) Ion pumps in gills (crabs)

What does euryhaline mean?

Tolerant to wide variations in salinity (mussles, barnacles)

What does Stenohaline mean?

Can only tolerate a narrow range of salinities (sea stars)

What are adaptations to food and oxygen availability?

1) Low activity levels

2) Feed/take in oxygen the whole time they are underwater (barnacles, mussels)

2) Modified oxygen absoption (tube feet of sea stars)

Why is UV light damaging?

Marine organisms can also get sunburnt

What are adaptations to UV light?

1) Sun screen

2) Protective shells

3) Under rocks & overhangs

How do organisms adapt to wave exposure?

Adapted to hang on (byssal thread of musses and some seaweeds are very flexible)

What are some biotic stresses?

1) Competition

2) Predation

3) Herbivory

What is competition?

The use or defense of a resource that reduces its availability to other individuals (barnacles compete for space, hermit crabs compete for shells, anemones compete for space)

What is interference?

direct interaction

What is exploitative?

Differential use of resource

What is interspecific

between species

What is intraspecific?

between individuals of the same species

What are generalist predators?

Eat a wide range of food types

What are specialist predators?

Eat a single prey type

What are predation adaptations?

1) Protective shells (hermit crabs)

2) Camouflage

3) Chemical defense in nudibranchs

4) Escape responses

5) Mutualistic associations

6) Height in the intertiday (from sea stars)

7) Size (some mussels are too big to be eaten by sea stars

8) Space (limpits live on vertical surfaces to avoid predation by Black Oystercatchers)

What are refuges from herbivory?

1) Chemical defenses (sulphuric acid in desmarestia)

2) Physical defenses (calcium carbonate in coralline algae)

3) Height in the intertidal