Marine Science Final

emphasis on section three - key themes and topics from sections 1-2

What are Nekton?

Free swimmers in the animal kingdom

Large size means ______ abundance.

low

What are the major groups of Nekton?

• large invertebrates

• fishes

• ocean-living reptiles

• marine birds

• marine mammals

What are three issues all nekton have adapted to solve?

1. They are large and have to swim through the ocean without sinking

2. They must deal with stressors in the ocean such as cold temps, high salinity, high pressure, and an abundance of life at depth

3. they must be able to find food, avoid predators, and reproduce

How have nekton adapted to swimming without sinking?

• Streamlining to reduce drag

• Fins for locomotion, balance, and lift

• Buoyancy mechanisms

Describe four buoyancy mechanisms

1. swim bladders which hold gases

2. storing blubber → reduce density to increase flotation (whales and seals)

3. oil storage in livers and muscles (sharks and fish)

4. sea birds have light bones, air sacs, and oil on feathers to seal air against skin

What are five adaptations nekton may have to deal with stressors in the ocean?

1. countercurrent heat exchange to maintain temps

2. cold and warm blood vessels run next to each other minimizing heat loss

3. regulating salt content

4. dealing with high pressure at depth (wax or fat lined bladders and bio-compounds)

5. obtaining oxygen and removing CO2 with gills

What are four adaptations nekton may have to find food, avoid predators, and reproduce?

1. schooling provides protections, foraging success, saves energy, and increases reproductive success.

2. migrations (both diel vertical and horizontal)

3. dispersal of offspring through a planktonic stage

4. camouflage

What are Anadromous fish

born and lay eggs in freshwater but spend juvenile period in ocean

what are catadromous fish

born and lay eggs in ocean but spend most of life in freshwater

what is countershading?

a form of camo, looking dark when viewed from above and light when viewed from below

what is bioluminescence?

a form of camo or startling predators, making your own light

most fish are found in areas of high/low primary productivity

high

what are adaptations deep sea fish have

• large mouths

• hinged jaws

• needle like teeth

• extendable stomachs

• bioluminescence

• stay small and float to conserve energy/able to go long periods without a meal

Nekton are autotrophs/heterotrophs in __________trophic levels

heterotrophs, middle to upper

how are nekton supported

mainly by planktonic production consumed by zooplankton

nekton are often top ______

predators

which group of marine organisms are able to swim against the currents?

Nekton

Regions with greater fish abundance and catches are generally associated with lower/greater GPP?

Greater

Benthos

bottom dwellers

Why is there tremendous diversity among benthos?

numerous habitats and niches to fill

What are infauna?

animals that live in the sediments

what are Epifauna?

animals that live on or attached to the seafloor

What are sessile’s?

animals not able to move

What are suspension feeders?

animals that feed on particles in the water

what are filter feeders?

animals that actively filter particles from the water

What are deposit feeders?

Animals that ingest sediment and extract organic matter

what are detritivores?

animals that ingest detritus

What are scavengers?

Animals that search for carcasses and other organic matter

What do most benthos rely on for food?

rain of organic matter or food falls

Where is the highest biomass of benthos?

below areas of highest pelagic productivity and in productive coastal regions

Many benthic organisms have a ___________ stage allowing dispersal

planktonic

What are meroplankton?

spend only part of their lives in the plankton

what are some adaptations of seaweeds and marine plants?

• holdfast and stape to stay anchored

• pigments in green, brown, and red algae help maximize use of light over depth

what is the role of seaweeds and marine plants in the benthos habitat?

they provide food and shelter for animals, most food enters as detritus

What is the rocky intertidal habitat of benthos

highly energetic and rapidly changing conditions over tidal cycles

What do organisms have to face in the upper zone of the rocky intertidal?

Exposure to stressors such as drying/wetting, temp, salinity, moisture, pH, DO, and food supply, AND predation

What do organisms have to face in the lower zone of the rocky intertidal?

organisms must compete for space and deal with predation

An organisms ability to cope with stresses results in __________ zonation in the intertidal

vertical

Why are coral reefs so productive?

Symbiosis of photosynthetic dinoflagellates living inside the heterotrophic coral animal

Why are hydrothermal vents so productive?

Chemosynthetic communities - symbiosis between tube worms and bacteria

“Benthic” refers to which region of the ocean?

The seafloor

Benthic animals include:

• Herbivores

• Carnivores

• Omnivores

• Detritivores

• All of the above

all of the above

Organic matter that fuels benthic organisms originates from:

• sinking phytoplankton

• marine snow

• benthic plants and algae

• detritus

• food falls

• all of the above

all of the above

Organisms that feed on particles in the water column are called:

Suspension feeders

Organisms that ingest sediments and digest the associated organic matter are called:

Deposit feeders

What strategy do benthic organisms use to widely disperse their offspring?

Larval stages in the plankton

What are the most common water waves and what are they generated by?

short period waves generated by winds

What is wavelength?

The distance between adjacent crests and troughs

What is wave height?

elevation from trough to crest

energy moves in a ______ direction

linear

water moves in ______

orbits - circular paths

In waves there is _____ net water transport

zero

Wavelength (L) / 2 =

the wave base

Is there motion when depth = L/2?

no

deep water waves

depth > L/2

Shallow water waves

depth < L/20

Transitional waves

L/20 < depth < L/2

In shallow waves orbits become ______ with depth

flatter

at the bottom of shallow water waves water moves ______ & ______

back & forth

Longer waves move slower/faster than shorter waves

faster

Sorting/Dispersion

longer waves move ahead of the shorter waves with distance from the source

Swells

the pattern of crests and troughs formed by longer waves

what is wave height affected by?

• wind speed

• wind duration

• fetch

Fetch

the distance over water that the wind blows in the same direction

Wave energy increases/decreases rapidly with wave height

increases

why does the southern ocean have the largest waves?

less land and lots of storms

what is wave refraction

bending of the waves when they hit at an angle to depth contours

Waves are focused on __________ and refracted towards the edges of _________

headlands, embayments

What is wave reflection

the wave bounces off at the same angle it hit

what is wave diffraction

the spread of wave energy laterally around an obstacle

what is the surf zone

waves slow, steepen, and break at the coast as the shallow-water waves “feel bottom”

Rip currents

waves slowly pile water up along the beach which rushes back out at particular points

Tsunamis are produced by _________ action and can travel across entire _____ _________

seismic , ocean basins

Internal waves

develop along density interfaces within the ocean

Seiches/standing waves

do not progress but reflect back on themselves across an entire body of water

four types of long period waves

• tsunamis

• standing waves/sieches

• tides

• internal waves

what feature is marked with the arrow?

wavelength

what feature of the wave is marked with the arrow?

height

The time it takes for two successive wave crests to pass a point is called the ___________

period

as depth increases, size of wave orbits

decrease

which statement is true about deep water waves?

• wave base is shallower than water depth

• wave base is deeper than water depth

• wave base and water depth are equal

wave base is shallower than water depth

what happens to shallow water waves as they approach the coast?

orbitals flatten, the bottom of the wave drags along the bottom, friction with the bottom can change wave direction, the wave slows, steepens, and eventually breaks

what process is shown in the figure

wave refraction

waves that travel along the pycnocline are called

internal waves

Tides are generated by ________ forces and ______

gravitational, inertia

what is the tide range

the difference in water level from high to low tide

what is the flood tide

period when water level is rising, resulting in flood currents

what is the ebb tide

the period when water level is falling, resulting in ebb currents

what is slack tide

the period of slow or zero tidal currents at high and low tide

Diurnal tides

one high tide and one low tide per day

Semidiurnal tides

two high tides and two low tides per day (of equal height)

Semidiurnal mixed tides

two high and two low tides per day of unequal height

How long is a tidal day

24 hours and 50 min

how long is a tidal period

12 hours and 50 min

spring and neap tides are caused by what

gravitational attraction by the sun

how many spring and neap tides are there per month?

~2

what are spring tides

occur during new and full moons when the sun, earth, and moon are aligned

neap tides

tides with the smallest difference between high and low water levels

what leads to tidal patterns

declination of the moon and sun