Final Exam

Question 1

Explain the characteristics of a sedimentary bottom in an area with low turbulence and in an area with high turbulence

Answer 1

Low turbulence:
The seafloor is composed of mud sediments which means it has less oxygen and more detritus. These areas have deposit feeders, which extract organic material (detritus) from the the mud.
- Tidal flats, estuaries

High turbulence:
The seafloor is composed of sand sediments which means it has more oxygen and less detritus. These areas have suspension feeders, which eat suspended particles of material in the water.

Question 2

How does mean grain size and sediment sorting affect the seafloor?

Answer 2

Size:
Mud (<63 um), Sand (2mm-63 um), and Gravel (> 2mm)

Sorting:
Well-sorted (coarse): water drains quickly
Well-sorted (fine): water drains slowly
Poorly sorted: water blocked

These two parameters effect detritus and oxygen availability. Grains that are the same size have space in between them which allows circulation of water (and oxygen). Poorly sorted grains that are tightly packed have no space, preventing any water circulation.

Question 3

What are the two functional groups that effect the seafloor?

Answer 3

The two functional groups are Bioturbators and Stabilizers, which consist of deposit and suspension feeder species.

Bioturbators: Mine and increase the vulnerability of erosion. These species create ‘feeding pits’ which are disturbances in the sediment caused by feeding or moving through it. This includes species such as rays and kill shrimp.

Stabilizers: Bind or stabilize substrate and enhance sedimentation. This includes species such as tube worms and diatoms.

Question 4

What is the critical erosion velocity and how does it change with grain size?

Answer 4

The minimum current velocity needed to move a sediment from the bottom of the seafloor. Gravel has the highest required velocity, and sand has the lowest. Minimum current velocity increases for mud grains because of the diatoms and microbes present in it.

Question 5

Infauna

Answer 5

Organisms that burrow and live in the sediment

Question 6

Trophic Amensalism

Answer 6

The interaction between two species where one is destroyed or inhibited while the other is unaffected.

Between suspension and deposit feeders: Deposit feeders resuspend sediments into the water column which clogs the filtering mechanism of filter feeders.

Question 7

How does sedimentation and it’s inhabitants differ in the deep sea (Abyssal plains)? How do carbon/oxygen levels differ?

Answer 7

Most of the deep sea floor is composed of muddy sediments that don’t hold a lot of oxygen but are high in detritus. The deep sea gets it’s detritus from a constant drizzle of small particles. Seafloor diversity increases until 2000m and then decreases (no clear explanation).

At 4,000m, sinking carbonates dissolve and change the composition of the sediments below it (Carbon Compensation Depth)

Most of the deep sea is unexplored so there is still a lot unknown but deposit feeders dominate.

Question 8

What is the Carbon Compensation Depth (CCD)?

Answer 8

The Carbon Compensation Depth is at approximately 4,000 m (deep sea), where sinking carbonates dissolve and change the composition of the sediments below it.

Question 9

What species are commonly found in the sediment of the seafloor?

Answer 9

Deposit feeders (Polychaete: tube worm/trumpet worm, clams) and suspension feeders (clams)

Question 10

How are sandy beaches formed? (E.g. how are sand grains formed?) How are sand dunes formed?

Answer 10

Sandy beaches form from the weathering or erosion of larger rocks and shells into finer sediments. The colour of the sediment reflect its main component
- PEI beaches are mostly dark red due to sandstone.

Sand dunes are formed by onshore winds moving sediments through the process of saltation:
- Sand forms a sediment trap and a transient dune, which won’t grow further without dune plants.

Question 11

How does grain size along with other physical factors differ between sandy beaches and dunes?

Answer 11

Grain size increases towards the ocean. Beaches are made up of mid to coarse sediment that is poorly sorted whereas dunes are made up of very fine and well sorted sediment.

Water content, grain size, and compactness all increase towards the ocean. Temperatures decrease towards the ocean.

Question 12

If weathering causes the formation of sandy beaches, how do they differ between winter and summer seasons?

Answer 12

In the summer, sand accumulates and the beach profile becomes flat (dunes also form).

In the winter, sand erodes and the beach profile becomes steeper. Dunes also lose their sand.

Beach habitat is modified by wave action.

Question 13

Aside from intermediate beaches, what are the two main types and how do they differ from each other?

Answer 13

Dissipative beaches are composed of fine sediments that form gentle/flat slopes. Waves are large and far away and Swash conditions are benign. Rip currents are more common at this type.

Reflective beaches are composed of coarse sediments that form steep slopes. Waves are small and nearby. Swash conditions are harsh. These types of beaches are better for swimming.

Question 14

What type of currents are related to sandy beaches and which types do they effect?

Answer 14

Rip currents are currents that run into deeper waters. They are present in both types but are more common in dissipative beaches.

Longshore currents are currents that run parallel to the shore and are key for spread of plankton and seaweeds. Sand barriers can change their direction.

Question 15

What is the key component in soft-bottom trophic webs and how do sandy beaches get it?

Answer 15

Detritus; sandy beaches do not have any primary producers. This means they rely on currents from estuaries, rocky shores, etc to carry in that material.

Examples of detritus include wrack or stranded seaweed.

Question 16

Which species of seaweed are found on PEI sandy beaches?

Answer 16

Rockweed, Irish moss (which is commonly harvested here), and Eelgrass.

Question 17

What are the intertidal zones of sandy beaches and which species are found in each?

Answer 17

(The intertidal is the area between the high tide and low tide mark)

Upper Intertidal: Isopods + amphipods, ghost crabs

Middle Intertidal: Polychaetes, amphipods

Low Intertidal: Clams, worms, sand dollars

Question 18

What are the different dune classifications and how do they differ?

Answer 18

Ridge Dunes: Formed by light onshore winds and have heavy vegetation that binds the sand together.

Parabolic Dunes: Formed by medium onshore winds and have spare vegetation that leads to ridge failure.

Transgressive Dunes: Formed by heavy onshore winds with little vegetation. They are unstable.

Question 19

What are saltmarshes and their characteristics?

Answer 19

Saltmarshes are grassy areas bordering estuaries or sheltered coastlines and extend inland of mudflats; they typically flood during high tide. Saltmarshes are shore stabilizers and collector of pollutants/nutrients.

• Associated with freshwater marshes (wetlands)
• Present in temperate latitudes

Question 20

How do salt marshes differ with seasonality?

Answer 20

In the spring/summer, the growth and expansion of the salt marsh creates tidal flats.

In the fall, leaves/wrack accumulate during high tide. This increases the amount of bacteria which consume Nitrogen, causing the nutritive value of the marsh to decrease.

In the winter, salt marshes are covered in ice (recovery) and green plants start to grow.

Question 21

What are the 5 factors affecting saltmarsh zonation?

Answer 21

1. Tides and flooding
2. Salinity and draining
3. Stability (bioturbation and erosion)
4. Competition for space
5. Grazing (periwinkles)

Question 22

Seagrasses: Characteristics, species, & services

Answer 22

Seagrasses are found in the lower intertidal of estuaries & in association with mangroves. Their depth limit is compensation point (not enough light) and they relate to water clarity.

The first species is eelgrass and grows in temperate and cold areas. The second species is turtle grass which is found in tropical & subtropical areas.

Seagrasses are big nursery habitats and capture CO2. They are most affected by wasting disease and invasive tunicates.

Question 23

Which organisms are associated with seagrass?

Answer 23

• Polychaetes
• Sea squirts and bryozoans
• Green algae, herbivore snails
• Seagrass grazers: manatees, turtles

Question 24

What are mangroves and describe the three types.

Answer 24

Mangroves are tropical (Indo-West Pacific), flowering plants/trees adapted to living on the intertidal. The three types of mangroves are white, black, red.

White: Closest inland (high tidal level, up to 15m) with no aerial roots. Their seeds are diamond shaped.

Black: Found in the mid-high level (up to 20m) zone and have roots with pneumatophores. Pneumatophores are root extensions that project over anoxic mud and promote aeration. Perform salt interchange where selective absorption happens by root and salt is excreted by leaves. Seeds are lime-shaped.

Red: Found in the low-tide level (up to 25m high) and have prominent aerial roots with pores for O2 absorption. Their seeds are pencil-shaped.

Question 25

What are the services and challenges with mangroves?

Answer 25

Services:
Primary producers, habitat for organisms such as sponges and fish, shore stabilizers (buffer zone)

Challenges:
Being removed for the construction of marinas and other buildings

Question 26

What are the zonations of the Atlantic Coast rocky shore intertidal? Which species are associated with each zone?

Answer 26

Upper Intertidal: The zone lies above the high tide mark and is hardly submerged so organisms are threatened by desiccation. It is also called the Spray Zone because organisms mainly get wet from wave spray. Lichens and encrusting algae species are found here.

Middle Intertidal: Barnacles, Rockweeds (brown algae), and blue mussel are found here. Blue mussels are a competitive dominant species.

Lower Intertidal & Tide Pools: Lower intertidal is dominated by seaweeds (e.g. Irish Moss) which need to always be fully submerged. Tide pools also have many seaweeds but also sea anemones, sea stars and urchins, chitons, etc. This zone often deals with grazing and competition.

Question 27

How do rocky shore zonations differ between the Atlantic and the Pacific?

Answer 27

In the Atlantic Ocean: Lichens dominate during high tide and Irish Moss dominates during low tide.

In the Pacific Ocean: Periwinkles dominate during high tide and various seaweeds (NOT Irish moss) dominate during low tide.

Question 28

In the rocky shore intertidal, what are the species’ responses and adaptations to wave action?

What are the responses/adaptations to temperature and salinity changes?

Answer 28

Wave Action:

• The development of holdfasts by seaweed
• The development of glue, cement, or byssal threads to attach permanently to rocks (e.g. blue mussel, acorn barnacle)
• The development of a strong muscular foot by chiton & other snails
• The development of tube feet with ampulla for attachment (e.g. sea star)
• Shorter and thicker shape in rough conditions
• Thicker shells in rough conditions
• Flexibility of seaweeds
• Group in numbers to avoid dislodgement

Temperature & Salinity Change:
When low tides occur, species are exposed to high temperature & desiccation
- Snails seal off the shell with operculum
- Aggregate in large devices within crevices
- Shells adapt ridges for heat loss and colours to reflect light
- Reduce movement (e.g.limpets)

Question 29

How do competition and predation affect the rocky shore intertidal? How have species adapted to this?

Answer 29

The intertidal has dominant competitors and keystone predators that interact for space. Dominant competitors are species that monopolize the use of space. Keystone predators keep the dominate competitor under control.

Species Adaptations:

• Dispersal ability: arriving first
• Fast reproduction
• Undermine neighbours (take over)

Question 30

How would the rocky shore intertidal differ if all sea stars were removed?

Answer 30

In it’s normal state, sea stars maintain the mussel population which allows space for other species.

If sea stars were removed (or absent because of wave action), mussels would outcompete and overcrowd other sessile species. This means sea stars maintain the diversity of the middle intertidal (keystone predators).

Question 31

What is the Intermediate Disturbance Hypothesis?

Answer 31

Wave action (physical disturbance) interactions with competition in the rocky shore intertidal. This hypothesis states that species diversity is highest when disturbance is moderate.

Question 32

What type of relationship do hard corals have with a species of dinoflagellate?

Answer 32

Hard corals have polyps in their tentacles which have a symbiotic relationship with Zooxanthellae.

Coral polyps catch nutrients (nitrogen + phosphorus) from zooplankton which the Zooxanthellae uses during photosynthesis. Photosynthesis provides the coral with O2 and sugars. They help corals form their calcium carbonate skeleton.

Question 33

What are corals and what are the three different types of coral reefs?

Answer 33

Corals are Cnidarians that have a thick calcium carbonate exoskeleton which forms the reef (hard corals). Soft corals do not form reefs. There are organisms which feed directly over corals while others feed on their mucous secretions (parrotfish).

Fringe Reefs: The most common type of reef. They grow in bands along the shoreline, under the low tide level. Because they are so close to land, they are exposed to sediment, runoffs & pollutants. It’s main area is the reef flat which is exposed in very low tide.

Barrier Reefs: They lie along the coast but occur farther out from shore and are separated from the shore by a deep lagoon. These reefs consist of a reef flat, and fore/back-reef slopes.

Atolls: A ring of reef, and some islands, surrounding a central lagoon. Winds and encrusting coralline algae create windward and leeward sides.

Question 34

How is Darwin associated with coral reefs?

Answer 34

Darwin formed a hypothesis that atolls were formed by reef growth on a sinking island. A deep sea volcano erupts, builds an island, which corals soon colonize the shores of. A fringing reef develops. As the island slowly sinks, the fringing reef becomes a barrier reef, and then once it fully sinks it becomes an atoll.

Question 35

What type of interactions occur in coral reefs and what are the limited resources in these systems?

Answer 35

The limited resources for competitors are space and light availability. There are three common interactions in coral ecosystems: corals against corals, corals against sponges, and corals against seaweeds.

The interaction of corals against seaweeds is the most critical and is mediated by species/disturbances. Seaweed grazers like sea urchins are in favour of coral growth and coral eaters (crown of thorns starfish) + pollution are in favour of seaweed growth.

Question 36

Explain the complex trophic cascade between predator fish and coral reef systems. (E.g. pollution and overfishing)

Answer 36

Overfishing of bigger fish increases the amount of smaller coral-eating fish (and coral-mucus feeders), which decreases the amount of coral.

Pollution decreases the amount of fish species, which increases the amount of seaweed, which decreases the amount of coral.

An increase in sea urchins decrease the amount of seaweed which increases the amount if coral.

Question 37

List the stressors of coral reefs and describe them.

List the natural threats to coral reefs and describe them.

Answer 37

Stressors:
Pollution, sediments, and nutrients are all coral stressors. Processes such as deforestation, dredging, and run-offs increase these. Dredging causes re-suspension of sedimentation causing less water clarity/photosynthesis and corals die.

Threats:

• Bleaching: When water temperatures increase, corals expel their zooxanthellae (algae) and turn transparent (white color=skeleton).
• ENSO: Causes warming conditions which speeds up bleaching.
• Disease: Not a lot is known due to a lack of research but there are several diseases (black-band, white-band, white-plague, yellow blotch). Black-band disease is caused by bacteria that promotes anoxia.

Question 38

What are the five groups of seabirds and briefly list some species in each group.

Answer 38

1. Penguins
   - Galapagos, Emperor
2. Gulls & Relatives
   - Seagulls, auks, jaegers, skuas, terns, puffins, common murre
3. Tubenoses
   - Albatross, petrel, shearwaters
4. Pelicans & Friends
   - Cormorants, gannets, boobies, frigate birds
5. Shorebirds
   - Sandpipers, plovers

Question 39

Seabird diversity: What are the characteristics of the penguin group? What are some relevant species and their characteristics?

Answer 39

Penguins are flightless birds that use their wings as fins. They have high bone density to reduce their buoyancy and underwater vision. They have watertight feathers with a preen or oil gland, blubber for insulation, and paddle like feet.

They are pursuit divers that feed on krill, fish, and squid. An issue they face is the decline of krill, as well as warming of the ocean.

Emperor Penguin: egg care done by both parents, largest penguin

Question 40

Seabird Diversity: What are the characteristics of the ‘Gulls and Relatives’ group? What are some relevant species and their characteristics?

Answer 40

They are a diverse group of predators and scavengers with diverse feeding strategies:

• Seagulls dip
• Jaegars and skuas aerial pursuit others and take their food
• Puffins plunge dive shallow waters

The common murre (flying penguin) forms large colonies in high cliffs.
The Atlantic puffin (Iceland, NF) breeds in burrows in the ground, are surface divers for small fish.

Question 41

Seabird Diversity: What are the characteristics of the Tubenose group? What are some relevant species and their characteristics?

Answer 41

Species have tube-like nostrils and curved beaks. They are surface-predators of krill, squid, small fish, and plankton.

Albatrosses: The largest seabirds (North Pacific) that have a tendon in their shoulders which allows them to lock their wings while fully extended. Characterized by high partner fidelity.

Question 42

Seabird Diversity: What are the characteristics of the Pelicans and Friends group? What are some relevant species and their characteristics?

Answer 42

Species have a prominent web between their toes and their feathers are not waterproof. They also have diverse feeding strategies:

• Pelicans: surface plunge
• Cormorants: pursuit dive with feet
• Frigates: aerial pursuit

Double-Crested Cormorant: Atlantic Canada, crest is only visible in breeding season, nests on the ground in high cliffs

Northern Gannet: Breeding colonies in Gulf and NF, have high power vision for plunge diving

Frigatebird: Also called “man-o-war bird” or the pirate of the sea. Males and females look different; males grow a red balloon to scare other males.

Question 43

Seabird Diversity: What are the characteristics of the Shorebird group? What are some relevant species and their characteristics?

Answer 43

A very diverse group of migratory birds that exploit many habitats. Each species’ bill, feeding method, and diet vary slightly to allow multiple groups in one site. They feed during low tides with two different feeding strategies:

1. The Sandpiper Way: Sandpipers have small eyes high up in the head, long bills, and long legs. This makes them feed by slow movements, and probing below the surface to touch prey. Some have pressure-sensitive pits on their bills.
2. The Plover Way: Plovers have large eyes, short/blunt bills, and short legs. This means they feed by running and stoping for visual detection. They then pick food off the surface by ambush.

Piping Plover: Arrive April/May, feed over intertidal, eggs are camouflaged

Question 44

What are the 4 types of estuaries classified by topography? Describe them.

Answer 44

1. Drowned River Valley/Coastal Plain Estuary: Created when a rise in sea level floods a river valley, mixing fresh and salt water. These estuaries are shallow, have average sedimentation and are the most common.
2. Tectonic Estuary: Flooding of a river valley resulting from tectonic activity. These estuaries are shallow, found in subsidence zones, and have average sedimentation.
3. Fjords & Rias: Flooding of a river valley resulting from a glacier retreating behind a ‘scratch’. These estuaries are very deep and have a sill, if there is no sill they are a RIAS. They are common in high latitudes and have low sedimentation.
4. Sand Barrier Estuaries & Lagoons: Result when sand accumulation forms sand bars which act as a wall between fresh and salt water. They are the most shallow with the highest sedimentation and are common in low latitudes.

Question 45

What are the types of estuary classifications by circulation?

Answer 45

Positive Estuaries: The most common; the input of freshwater is enough to undergo mixing with salt water.

Negative Estuaries: These are uncommon and have low to no freshwater input. Has high evaporation levels.

Question 46

What are the types of estuaries by stratification classification?

Answer 46

Highly stratified: Low degree of mixing between salt and fresh water.

Partially stratified: The most common type, partial mix between fresh water and salt water.

Not stratified: The water is vertically mixed.

Question 47

What are the classifications of estuaries by tidal range?

Answer 47

1. Microtidal (< 2m)
2. Mesotidal (2-4m)
3. Macrotidal (> 4m)

Question 48

What is the importance of estuaries?

Answer 48

Estuaries are highly productive (benthic secondary productivity). They are a key nursing area for nekton species and a key feeding ground for migratory species. They provide efficient treatment for coastal runoff and they filter/trap sediments and pollutants.

Vulnerable to invasive species and anthropogenic pollution.

Question 49

What are the five main human threats to marine communities?

Answer 49

1. Overfishing: Causes the depletion of stocks (fishing down the trophic web) and also results in bycatch. Bycatch involves quantity problems and quality problems (catch of threatened species)
2. Pollution: Overpopulation increases the load of waste, biological and chemical pollution. This also includes acoustic pollution which disrupts echolocation, and light pollution which effects migration.
3. Habitat Loss: Ghost fishing smothers corals. Trawling causes damage to the sea floor. Habitat loss also refers to habitat fragmentation of systems which disrupts the trophic links between habitat forming species (Ecosystem Engineers) and seafloor diversity.
4. Invasions: Arrive by primary (planktonic eggs and larvae) or secondary (hitchhiking) dispersal.
   Invasive species are a threat because they lack natural competitors, lack natural predators or parasites, and they bring in new diseases or parasites
5. Climate Change: Has three pressing scenarios:
   - Ice melting/sea level rise: coral/plant growth can’t keep up
   - Regional climate disruption: homogenizes diversity
   - Ocean acidification: loss of calcifying species

Question 50

What marine conservation priorities are there for each of the human threats?

Answer 50

To overcome overfishing: Enforce regulations and reduce bycatch + ghost fishing. Also to create networks of Marine Protected Areas.

To overcome pollution & habitat loss: Prevent and reduce emissions.

To overcome climate change: Education

Question 51

What is a Gyre and how are they created?

Answer 51

A Gyre is a large circular circulation system composed of 3-4 smaller water current systems. They are formed by trade winds, westerlies, and by the shape of the continents.

Gyres drive several processes such as regional weather, scattering of nutrients, and the scattering of organisms.

Question 52

What are trade winds?

Answer 52

Trade winds are created when air is heated by the equator and rises. As the air rises, it displaces cooler air into the tropics. Trade winds are bent 45 degrees as they move towards the equator because of the Coriolis effect.

Trade winds create the westerlies and polar easterlies winds away from the equator.

Question 53

What is the Ekmann Spiral and how does it affect water circulation?

Answer 53

A process where wind blows over the surface if water, it drags the water moving it at a 45 degree angle. This layer then drags the layer beneath it in the same direction but slightly more bent (less powerfully), and so on.

The spiral affects the net transport of nutrients and organisms.

Question 54

What are the three types of tide cycles?

What are Spring and Neap tides? How do they differ?

Answer 54

The first and most common tide cycle is semidiurnal which has two HT and two LT of similar heights. The second is mixed semidurnal which has two HT and two LT of unequal heights. The third is diurnal which has one HT and one LT (very uncommon).

Spring tides occur during full and new moons when the gravitational pull from sun and moon is additive. They have the highest high tide and lowest low tide.
Neap tides occur when the moon is in the first and third quarters when the gravitational pull from sun and moon counteract each other. The tidal range is small.

Question 55

What are permanent clines? List the different types and how thermoclines differ with seasonality and latitude.

Answer 55

Permanent clines are sharp transitions of physical properties in the water column. Thermoclines refer to temperature, haloclines refer to salinity, and picnocline refers to density. The transition is referred to as the ‘Zone of rapid change’.

In relation to latitude, tropic thermoclines are the widest and strongest.
In relation to seasonality, thermoclines are strongest in the summer with no vertical mixing. They are weak in the winter with full vertical mixing, which causes problems for upwelling.

Question 56

What is upwelling and what effects it?

Answer 56

Upwelling occurs when winds move surface waters, which prompts cold nutrient-rich water from the bottom to rise to the surface. This brings nutrients and light to the surface waters, promoting photosynthesis.

Upwelling is affected by the ocean conveyor belt, which is a deep circulation pattern that replenishes the deep sea with oxygen. It is also affected by the El Niño Southern Oscillation.

Question 57

What are the continental margins of the seafloor?

Answer 57

The continental margin is composed of the continental shelf, continental slope, and continental rise. This is where you find benthos organisms.

Question 58

What are the zones of the water column?

Answer 58

The first layer (0-200m) is the Epipelagic zone and it is where photosynthesis happens. The second layer (200-1000m) is the mesopelagic zone where there is some light but no photosynthesis. The third layer (1000-4000m) is the bathypelagic and the fourth layer (>4,000m) is the abyssopelagic. There is no light in these layers.

The neritic zone is everything that is on top of the continental shelf and the oceanic zone is everything beyond the shelf.

Question 59

What are phytoplankton blooms and how do they differ with latitude?

Answer 59

Phytoplankton blooms are sudden, big growths of phytoplankton populations that are limited by sunlight and nutrients.

Temperate latitudes: There are two blooms, one in spring and one in fall. Light and nutrients are limiting factors but never both.

Polar latitudes: There is one bloom during spring/early summer. The limiting factor is sunlight because nutrients are brought in by upwelling.

Tropical latitudes: No blooms due to a permanent thermocline that doesn’t allow vertical mixing. The limiting factor is nutrients.

Question 60

What is the difference between Gross Primary Productivity, Net Primary Productivity, and Compensation Depth when talking about primary productivity?

Answer 60

Gross primary productivity is the total organic carbon produced by phytoplankton photosynthesis. The net primary productivity is the total organic carbon minus the carbon used for respiration. The compensation depth is where photosynthesis is equal to respiration and the net productivity is zero.

Question 61

What are the three groups of phytoplankton and their characteristics?

Answer 61

Phytoplankton consists of microplankton (20-200um) and nanoplankton (2-20um). The three groups are:

1. Diatoms: