Chapter 8- oceans and fisheries Flashcards Preview

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Flashcards in Chapter 8- oceans and fisheries Deck (54):
1

coral reefs

really struggling will be the canary in the coal mine for climate change

2

Ocean ecosystems

-72% of Earth's surface
-up to 9000m (no O2 when really deep)
-costal zones & continental shelves= most productive (in top 100m) (find estuaries)
-Nutrient availability, temperatures, and light=major ecological factors
-large bodies of water have a higher specific heat capacity
-can regulate temperatures around land masses

3

Land

limiting factor=water
-productivity increases from poles to tropics
-biotic pyramids- reduced at each trophic level

4

Ocean

limiting factor= nutrients
some most productive areas in Canada
-rapid turnover at 1st trophic level
-some areas in arctic are most productive due to interplay between ocean & land

5

Nutrients in the Ocean

-concentrations increase with depth
-most productive area=costal zones and areas of upwellings
-can be held for long periods of time due to low oxygen and bacterial influence
-Hope to Vancouver estuary= VERY diverse

6

Carbon sequestration

All carbon stored in dead animals in the ocean sink to the bottom of ocean and deompose there
1/4 to 1/3 of human CO2 emissions are absorbed creating carbonic acid= change in pH
-potential way to combat climate change

7

Carbon in the ocean

-oceans key in absorbing CO2
-carbon moved out of surface water to deeper ocean
-stored in dead organisms, ocean sediments, coral reefs
-takes up 2 billion tonnes of carbon/year

8

Coral Reefs

-regulation of environmental disturbances (due to biodiversity)
-treatment of organic waste too much= death of coral reef
-food production
-recreational opportunities
-high biodiversity= higher resilience

9

Coral Bleaching

happens when exposed to higher acidity

10

Coral and Global Warming

CaCO3 + COOH= erosion/dissolve
zooxanthellae produce CHO that feed corals, helps with photosynthesis
increased temperatures=expelling zooanthellae so coral leaching occurs

11

Coral

individual polyps and calcium carbonate skeletons

12

Dead coral

white due to absence of algae

13

Marine food webs

HUGE biodiversity
complex=resilient
global warming=negative implications

14

Marine Food Webs cold water

-simple in colder waters
-cannot afford to lose a lot of species

15

Thermocline

line where temperature in ocean gets colder
- sharp transition in temperature between warm surface waters and cool deeper waters
-colder water below thermocline due to carbon being absorbed and sinking

16

Thermocline Circulation

1. Cooled water sinks into deeper basin with water close to 0C (not frozen due to salt)
2. High salt content critical (increases water density)
3. Dense water sinks and carries carbon with it

17

Implications of Global warming on thermocline circulation

1. Ocean temperature increases therfore changing water density
2. Freshwater glaciers melting males seas water less salty which changes the salt:fresh water ratio

18

Management Challenges

The real problem is that we do not undersatnd our ocean ecosystems and we have yet to learn they cannot be managed
-need to learn about them before we can manage them well
-deep sea vents 50 to 100 years behind general natural history because they are really hard to explore

19

Costal Development

half of world's costal wetlands destoryed to support development
-lose estuary ecosystem and interface between terrestrial and ocean world just so we can have an inner harbour
-Canada= bad
US=worse

20

How much of the world's population lives in costal zones?

60%

21

Implications of Costal Development

lots of flooding
no way to absorb storms *hurricane Katrina
loss of biodiversity with loss of land/water interface (waves hit a wall and head back out to sea)

22

Fisheries

-1950s saw onset of industrial fisheries *almost to death
-resource base now less than 10% for entire communities of large fish species
-eating ourselves our of an ocean ecosystem

23

Global Fisheries

Major source of protein (too many people reliant on fish
-total catch grew, now stabalizing (but declining per capita amount of fish being caught)
-major employer (many towns dependant)
-high revenues (but many subsidies) help buy fishing boat

24

Global Fisheries Harvest

aquaculture=13% of worlds fish harvest
(fish farming or salmon & oyster)

25

Top marine and Inland Fisheries

=China
many countries highly dependent on fish
then Peru, USA, indonesia, Japan, Chilie, India, Russia, Thailand, Norway

26

Depleting Fisheries

-1/3 of fisheries are over-exploited
-70% of species used at or above sustainable levels
-now fishing down the food chain (good for good stuff until it runs out then we catch the next most desirable thing)
-equivalent to prey switching

27

By-catch

non targeted fish

28

Aquaculture

=farming of aquatic organisms (fish, shellfish, plants, in controlled environments
-BC and NB dominant
-Atlantic salmon is leading export
Effects:
-fish disease
-genetically modified fish
-impacts on wild species
(too many nutrients with dead zone due to overabundance of salmon feces

29

What is the limiting factor in terrestrial ecosystems?

water

30

What is the most common limiting factor in marine ecosystems?

nutrients

31

Fisheries and Marine mammals

-manages by fisheries and oceans
-many whales now hunted to extinction
-Northern Right Whale (one of most rare)
- get 160,000L of oil from 1 whale
-whale populations declining
-accumulates biotoxins

32

Fishing Methods

1. Seine Fishing
2. Bottom-Trawling
3. Trawling
4. Longline Fishing
5. Trolling
6. Dredging

33

Seine Fishing

using a large fishing net with weights along the net's bottom and floats along the top
-encircle school of fish
-dolphins may get caught

34

Bottom Trawling

heavy nets dragged along ocean floor- ground fish and cod, squid, halibut, rockfish
-lots of by-catch
-incidental damage to ocean floor

35

Drift netting

=illegal (hang line out for kms and leave it)

36

Trawling

pulling a large fishing net behind more than 1 boat
-midwater trawling=anchovies, shrimp, mackerel, tuna

37

Longline FIshing

uses 100s or 1000s of baited hooks hanging from a single line (swordfish, tuna, halibut, sablefish)

38

Trolling

one or more fishing lines baited with lure or bait fish are drawn through the water behind a moving boat (makerel, kingfish, tuna, marlin)
-go slowly through the water

39

Pollution

oceans are a sink for many pollutants *agriculture, industry, urbanization, waste disposal
-Chemical pollutants
-toxic materials
-nutriends
-endocrine disrupter (DDT) fish and polar bears
rain goes into ocean and takes all the stuff from the street with it

40

Bioaccumulation

accumulation of toxins in higher trophic level species

41

Dredging

towing a dredge along the ocean bottom (scallops, oysters, sea cucumbers)
-pull along productive zone of ecosystem

42

Worst method of fishing

drift nets, illegal
catch whales, sea turtles, dolphins as by-catch)

43

Oil and Gas development

60% of world's global oil production is from sedimentary basins under the ocean

44

Canada's oceans

-longest coastline in the world
-Management
fisheries and marine species (department of fisheries and Oceans)
sea birds=Environment Canada
shoreline=provinces and municipalities
-silo effect when they don't meet and talk
-lots of overlap but can also cause administrative difficulties

45

200 mile limit

set limit that is ours to manage

46

Pacific Ocean

-sea temperatures higher than Arctic
-important for waterfowl, seasbirds, and shoreline
-seas lions seals, whales

47

Threats to Pacific Ocean

-pollution
-habitat loss
-overfishing
-aquaculture

48

Arctic Ocean

-often covered by permanent pack ice
-biological and productivity generally low (poynas=high)
-bowhead, beluga, narwhal aka northern right whale floats when killed)

49

Threats to Arctic Ocean

-increase oil and gas activities
-habitat loss (melting)
-climate change
-political disputes

50

Atlantic Ocean

20C warmer than arctic
-highly productive
-abundant marine life
-22 species of whales and 6 species of seals
-cod fishery collapse (federal gov allowed this to happen)

51

Threats to Atlantic Ocean

-oil and gas activities
-over harvesting
-political disputes

52

Aboriginal Uses of Resources

treaty rights to subsistence fishing
-conflicts court cases cooperation

53

Ocean's Act

1. Sustainable development
2. Integrated Management
3. Precautionary Principle

54

Marine Protected Areas

Sagunenay St. Lawrence NMP
Fathom 5 NMP
Lake Superior NMP
Endeavour Hydropthermal Vents MPA
(managed by Parks Canada)