Summary Marine Animal Ecology

Grade

 30% exam
 25% group assignment
 45% individual paper: 40% report, 5% pitch



Lecture 1: Introduction to the course
Marine vs terrestrial

 Aqueous vs gaseous
 Food availability
 Sedentary animals
 Filter feeding
 Larval dispersal
 Pressure
 Animals need less energy for stable structures
 Gas exchange & oxygen availability
 pH



The marine system




 important aspect: adaptation to change



Lecture 2: Marine biogeography & biodiversity
 Physical environment
- Population & community level
- Adaptation to change
 Marine biodiversity => shaped by genes, species, ecosystems

, - Highest biodiversity in coral triangle (Indonesia)



Basic concepts
Footprint of climate change

 Affects genes to biomes (almost everything)
 Response: marine species shift their distribution to track optimal conditions



Biogeography => study of distribution of biodiversity over space & time

 Aim: reveal where organisms live, at what abundance & why
 Smalls scale processes + coarser scale patterns
 Multidisciplinary
- Uses history to meteorology
 Famous biogeographers: Darwin & Wallace
- Geography & natural selection as agents of evolutionary change



Approaches
Species distributions

 Marine ecoregions of the world (MEOW) => biogeographic classification of world’s coast &
shelves
- Areas of relatively homogenous species composition, clearly distinct from adjacent
systems
- Tool for planning & assessing conservation




 High species richness in coral triangle (Australia & Indonesia)
- Coral distributions & mangroves
- High priority for marine biodiversity protection



Abiotic factors affecting species distributions

 Temperature (sea surface temperature = SST)
 Ocean currents
 Depth diversity (habitat heterogeneity)
- Benthic (bottom) & pelagic zone (open sea)

,Role of historical events
Geological history

 Geology & biological evolution are inseparable
- Currently: Holocene
 Glacial maxima & interglacials
- Coral triangle during last glacial max (LGM)  more land
- Sea level changes
 Coral triangle during LGM
- Extinction of species on continental shelves
- Ocean basins more isolated due to low sea level
- Increased turbid & hyposaline conditions  additional habitat
loss stenohaline species
 Continental drift
- Break up of Pangea 200 mya
- Drift to today’s position 65 mya – now
- Vicariance => distribution pattern common to several groups
Caused by geographical barriers  sequence of speciation events
- Earthquakes around major lithospheric plates
- Many plates in coral triangle



Hopping hotspots




 Shifting diversity distribution of larger benthic foraminiferal genera
- Centre of marine mega diversity moved over time (fossils & molecular evidence)
 Hotspots in time coincided with major collision between continental tectonic plates
- Shallow warm seas, many islands & bays  ideal for new species
- Tectonics modulate distribution of sea floors
- Hotspots explained by plate tectonics & climate change
 Mechanistic model:
- Habitat driven diversification & dispersal  current biodiversity pattern (coral & fish)



Lecture 3: Traits and interactions in the marine realm
Traits => features & capabilities that animals possess

 Mostly at individual & population level
 Morphological (structure)

, Physiological (feeding)
Reproductive (strategies)



Interactions

 Mostly at community level
 Types
1. Competition => animals have to share resources (chemical ecology)
2. Trophic => predator-prey (food web ecology)
3. Symbiosis => mutualism(++), commensalism(+=), parasitism(+-), competition (--)



Food web ecology
 Top down control => apex predators control food pyramid
- Predator effects on lower trophic levels
 Bottom up control => nutrients control food pyramid
- Effects of nutrient inputs
 Trophic cascade => effect of removing 1 type of animal (e.g. apex predators) that cascades
through food web
- Fisheries can effect whole food web ecology
 Benthic pelagic coupling => relationship between pelagic & benthic food production
- Sponge loop: dissolved organic matter (DOM) excreted by plankton & fish (pelagic) taken
up by sponges (benthic)  convert DOM into cellular material that is good food source
(pelagic)
- Filter feeders: benthic animals eating pelagic products




Symbiosis
 Mutualism => both animals benefit
- Trapezia crabs on coral
 Commensalism => one animal benefits, other is unaffected
- Barnacles on whales