Patterns in the Marine Environment

Question 1

How can the marine environment be classified?

Answer 1

• By depth and position
• By distribution of organisms
• By mechanism of energy capture: primary producers (algae), predators, grazer, filter-feeders/suspension feeders, deposit feeders, detritivores, parasites
• By trophic level e.g. position in food web
• By method of larval development: planktotrophic, lecithotrophic, direct development

Question 2

What are examples for the different mechanisms of energy capture?

Answer 2

Grazers = limpet
Filter-feeder = barnacle 
Deposit feeder = sea cucumber 
Predators = sharks
Parasites = isopod - replacing fish tongue 
Detritivores = harpacticoid copepods class maxillopoda

Question 3

Ecosystem function: what are the functional groups of species inhabiting ecosystems?

Answer 3

• Deposit or suspension feeders
• Herbivores (grazers), carnivores, omnivores, detritivores
• Pioneer encrusting filter-feeders
• Competitively dominant encrusting filter-feeders

Question 4

Ecosystem function: What is functional diversity?

Answer 4

A measure of the number of different functionally distinct species in a given area (e.g. how many grazers, predators, deposit feeders, primary producers etc.)

Question 5

Ecosystem function: What are keystone species?

Answer 5

Species that if removed cause major ecological consequences for other species e.g. loss if sea-otters leads to “Urchin barrens” (over-abundance of urchins which has detrimental effects on other species)

Question 6

Patterns & the marine environment - a variable 3D space: What is zonation?

Answer 6

The distribution of plants and animals into specific zones according to parameters such as altitude or depth, each characterised by its dominant species.

Question 7

What is zonation small scale distribution patterns?

Answer 7

• In shallow parts of the sea, the nature and type of organisms change over 10s of cm or m

Question 8

Where is zonation most apparent?

Answer 8

In the littoral zone - where the land meets the sea

Question 9

What is an example of zonation?

Answer 9

The rocky shores: Macroalgae zone -> Mussel zone -> Barnacle zone -> Littorinid & Lichen zone

Question 10

What are the causes of zonation in the littoral zone?

Answer 10

• Vertical gradient of tidal height
• Horizontal gradient of exposure to wave action
• Particle size gradient

Question 11

Oceanography - vertical structure: What ecological processes are effected by vertical stratification?

Answer 11

• Light - euphotic, twilight, midnight
• Temperature - thermocline
• Salinity - halocline
• Oxygen - oxycline
• Nutrients (NO3) - nitracline

Question 12

What ecological processes are effected by horizontal structure?

Answer 12

• Major ocean surface currents e.g. Humboldt Current - short interchange between cold water and warm water organisms
• Global sea surface temperature gradient

Question 13

Biogeography (large-scale distribution patterns): What is biogeography?

Answer 13

Explores the geographic distribution of plants and animals

Question 14

What does macro-ecology study?

Answer 14

The relationship between organisms and their environment at large spatial-scales

Question 15

What is biodiversity?

Answer 15

The diversity among living organisms and all those that have ever lived; including diversity within species, between species and of ecosystems

Question 16

What are the 3 components of biodiversity?

Answer 16

• Ecological (biomes/province, ecosystems, habitats)
• Organism (kingdoms, phyla, species)
• Genetic (populations, individual)

Question 17

What is the most common method of quantifying diversity?

Answer 17

Species richness

Question 18

What are the two categories of species and their meaning?

Answer 18

• Morpho-species - look different and are genetically different
• Cryptic-species - morphologically indistinguishable biological groups that are incapable of interbreeding

Question 19

What determines a species?

Answer 19

What ever scientists decide through identification

Question 20

What are the hypotheses as to why there is more species richness in tropical regions than in temperate?

Answer 20

• Speed of reproduction and how many mutations arise?
• Temperature - faster metabolism = faster reproduction / shorter gestation?
• Time - tropics are older - over time more species have developed there - glacial and interglacial cycles in the temperate and polar regions - animals squeezed into the tropics?
  Still open questions

Question 21

What is the hypothesis for there being more species richness in the ocean in the Indo-West Pacific?

Answer 21

• Lots of different islands - population separation and evolution - shallow - lots of coastal areas for species to diverge?
  Still open question

Question 22

What is morphological biological diversity?

Answer 22

• Diversity in shape, size and colour
• Normally measured as disparity - measure of how different species look
• Biodiversity is not just about numbers (richness)
• Also encompasses biological richness (i.e. diversity of morphology/shape/size