Eduardo Infantes - Marine ecology 1

Question 1

Soft bottom

Answer 1

Sandy bottom. Infauna, animals living in the sand.

Question 2

Hard bottom

Answer 2

Stone. No infauna, animals living on top of the rock: epifauna.

Question 3

Food web

Answer 3

Who eats what?

Question 4

Trophic cascades

Answer 4

When predators in a food web suppress the abincance or alter the behavior of prey, by releasing the next lower trophic from predation. “Remove the wolves”.

Question 5

Regime shift

Answer 5

Large, abrupt persistent changes in the structure and function of a system. Physical or biological changes.

Question 6

Tipping point

Answer 6

The point in a regime shift, where it changes from one system to the other. Threshold.

Question 7

Factors effecting coastal habitats

Answer 7

Water temperature, currents, salinity, depth, type of bottom

Question 8

Temperature effecting coastal habitat

Answer 8

Affected by geographical latitude, water depth, the ocean currents, weather, river discharge, presence of hypothermal vents.

Question 9

Sunlight effecting coastial habitat

Answer 9

Photosynthetic processes depend in water depth and water turbidity.

Question 10

Nutrients affecting coastal habitats

Answer 10

Transported by ocean currents to different marine habitats from land runoff, or by upwelling from the deep sea, or they sink through the sea as marine snow.

Question 11

Salinity affecting coastal habitats

Answer 11

Important in eustuaries, river deltas, hydrothermal vents,

Question 12

Dissolved gas affecting coastal habitats

Answer 12

Oxygen levels can be increased by wave action and decreased during algal blooms (eutrophication).

Question 13

Acidity affecting coastal habitats

Answer 13

Controlled by dissolved gases, since the acidity is defined by how much carbondioxide is in the water.

Question 14

Cover affecting coastal habitats

Answer 14

Availability of cover by the presence of objects.

Question 15

Hydrodynamics afffecting coastal habitats

Answer 15

Waves and currents mix in the water and affect the nature of habitats modifying energy transfers.

Question 16

Organisms affecting coastal habitats

Answer 16

Since organisms modify their habitat by the act of occupying them, they create new habitats for other organisms.

Question 17

Sediment types

Answer 17

Gravel, sand, silt, clay. Bigger grains allow water to flow more freely and more oxygen, the opposite with small grains. Silt and clay is mud, where there is sulfide build up (organic carbon is broken down to sulfied).

Question 18

Sediment particle movement

Answer 18

Suspended load - sediment flows up into the water, silt and clay.
Bed load - Sand and gravel on the bottom.

Question 19

Primary production soft bottom

Answer 19

The conversion of carbon from an inorganic form, carbon dioxide, into organic matter by autotrophs (plant and phytoplankton).

Question 20

Suspension feeders soft bottom

Answer 20

Animals, including filter feeders, that feed on particles suspended in the water column. Filter feeders that are actively pumping water, like mussles. Passive suspension feeders without active pumping

Question 21

Deposit feeders soft bottom

Answer 21

Animals that feed on organic matter that settles in the sediment. Sea cucumber, gathropods.

Question 22

Detritus soft bottom

Answer 22

Particles of dead organic matter

Question 23

Bioturbators soft bottom

Answer 23

Animals that rework the sediment

Question 24

Biomass soft bottom

Answer 24

The total weight of living organisms

Question 25

Communities depend on sediment types soft bottom

Answer 25

Small particles - little movement, less oxygen, more detritus, more deposit feeders.
Bigger particles - more movement, more oxygen, less detrius, suspension feeders.

Question 26

Saltmarsh ecosystems

Answer 26

Coastal ecosystem in the upper coast, usually dominated by tides. Saltwater or brackish water. Zonation determined by water inundation time. Rich and productive environment. Birds, grass, muddy grass, fish, carnivores, some mammals. Usually very muddy, very little hydrodynamics. Usually in colder climates than mangroves.

Question 27

Saltmarshes importance

Answer 27

Nursery for fish, and breeding, overwintering and feeding grounds for birds. Coastal defence, protects the lands from erosion. The muddy clay is good at trapping organic polution. Biodiversity.

Question 28

Saltmarshes species

Answer 28

A wide range of species. Plants, algae, fish, mammals like rats, filter feeders such as oysters, shrimp, clams, herons, insects and so on.

Question 29

Saltmarsh zones

Answer 29

Dike or dune - high marsh - low marsh - pioneer zone - unvegitated, intertidal mudflat. Each zone has a unique habitats and range of species.

Question 30

Mangrove ecosystems

Answer 30

Coastal. In tropical or warmer areas. Water that go in and out with tides, trees that can tolerate some time under water. With water it’s a three dimentional habitat, which creates more habitats for more species. Muddy. Can be close to sea grass. Predators, like sharks, smaller fish. A very dynamic area because of the water fuctuations. The roots are in the air, because the ground is so anaerobic.

Question 31

Mangrove zonation

Answer 31

Terrestrial forest, landward zone - higher part - , mid zone, seaward zone.

Question 32

Mangrove importance

Answer 32

Coastal protection, habitat for many species, climate regulation, resources, carbon dioxide absorption, traps sediment.

Question 33

Mangrove engineering

Answer 33

In many places they have been destroyed, there is interest to replace them.

Question 34

Seagrass ecosystems

Answer 34

Usually close to mangroves, intertidal or subtidal. Dugaons and manatees eat seagrass, also turtles, pipe fish, sea horses, crabs

Question 35

Difference between sea grass and algae

Answer 35

Algae: 15000 - 20000 species, nutrient uptake in leaves, reproduction in sporse, anchoring by holdfast.
Seagrass: 55 species, nutrient uptake in roots, reproduction with flowers and seeds, anchoring with roots.

Question 36

Sea grass importance

Answer 36

Produces wave action, realease oxygen, traps carbon, releases nutrients, habitat for many species, nursery.

Question 37

Seagrass distribution

Answer 37

All over, except antarctica. Both temperate and warm and tropical.

Question 38

Seagrass morphology

Answer 38

Long leaves, or branching tree. Rhizome can be thin or thick and woody.

Question 39

Seagrass distribution and depth

Answer 39

Determined in the lower part by sediment movement, needs certain stability. In deeper part, determined by light. Depth limit of eelgrass in Sweden has decreased from 20 meters in the late 1800s to 2-5 meters today because of the darkening of the water.

Question 40

Segrass reproduction

Answer 40

Vegetative: rhyzome elongation, asexual.
Sexual: seeds and seedlings. Seed floats away, then drops to the bottom.

Question 41

Eel grass

Answer 41

Zostera marina. A species of seagrass.

Question 42

Seagrass decline

Answer 42

Natural impacts: sorms, hurricanes, diseases.
Human impact: eutrophication, coastal development, overfishing, boat anchoring and propellers, introduced species, dredging shallow areas, bottom trawling, conversion to aquaculture.

Question 43

Tipping points in seagrass

Answer 43

The corrects way: light - seagrass growth - flow attenuation - sediment stabilazation - good water quality - light
Disturbed state: light - bare sediment - flow - sediment resuspension - poor water quality - bare sediment.
When the seagrass i disturbed, there will grow less seagrass, and more particles are dragged into the water by the water currents, which gives poorer light.

Question 44

The Swedish coast

Answer 44

Many areas are dominared by complex bathymetry, sandy and rocky shorse.

Question 45

Eelgrass community in Sweden

Answer 45

Top fish predators, intermediate fish predators, omnivores, mesohervivores, herbivores/detritivores.

Question 46

Important species in eelgrass

Answer 46

Tångloppa: eats algae, keeps the eelgrass clean and healthy.
Tångräka.
Fishing of big predators and adding nutrients to the water destroys the eelgrass.