marine environment Flashcards
Challenges of marine conservation as people
- We are a Terrestrial species
- Ignorance + indifference
- Frontier mentality
- “tradgedy of the commons”
- Open to all of humanity – if I don’t take it someone else will
- “Burden of proof” - on scientists to prove the activity is actually harmful – precautionary approach/principle
- Clash of interests – field of fisheries biol has more focus on maintaining production and food supply rather than maintaining habitats
4 reasons humanity has the power to change the biosphere
- Sea’s dominant predator – fishing down marine food webs + removed 90% of ocean predators
- Leading source of sea bed disturbance
- Primary agent of biogeographic change - ships ballest waters
- Primary agent of geochemical change
what is the number 1 challenge to marine conservation
change peoples attitude
5 abiotic physical characteristics of the marine environment
depth
light
temperature
substrate type
fluid flow
4 depth zones of the ocean
0-200m = continental shelf
200-4000m = bathyal zone
4000-6000m = abyssal zone
>6000m = Hadal zone
mean depth of the ocean
3,800m
why is light important in marine environment
source of food + vision
3 light zones of the ocean
Adequate light for photosynthesis = euphotic zone - 0-200m
Some light, no photo = disphotic zone
No light = aphotic zone
3 factors that influence light in the ocean
cloud cover
turbidity
depth
how much sunlight remains At a depth of 100 meters
1%
2 substrate types
hard and soft
**most diversity in soft
what is epifaunal
live on surface of sediment
what is infaunal
live within sediment
3 major fluid flows
waves
tides
major ocean currents
what aspects of biology + ecology do fluid flows affect
Food
Adaptations to hold on / hold position to reduce drag
Dispersive larvae
Waste removal
Gas exchange
Sediment type
4 factors in the abiotic chemical environment
salinity
oxygen
carbonate chemistry
nutrients
what decreases and increases salinity in the sea
decrease - Freshwater input
increase - evaporation by high temp
4 factors that influence oxygen levels in the sea
Production by photosynthetic organisms (>o2)
Temperature – warm water holds less o2
Respiration uses up o2
Diffusion
what is the o2 minimum zone
700-1000m
Leads metazoans to struggle to breath
Natural causes
why is calcium carbonate important for the ocean
Incorporate into shells / exoskeletons
3 things that effect the calcium carbonate levels in the sea
- PH – internal pH needs to be maintained in some species
- Pco2 – partial pressure of co2
- Allcalinity – ability of a solution to neutralize an acid
essential nutrients for photosynthesis
N + P
what part of the ocean has the most nutrients and why
deep water - sinking of nutrients + no mixing
what is upwelling
offshore winds move water away from coast – draws up nutrient-rich deep water
