Chapter 9 - Oceans and Fisheries Flashcards
When was the first time an agreement has been reached. Agreement explicitly acknowledges the need for a clearer understanding of the impacts of fishing prior to allowing fishing?
Agreement to Prevent Unregulated High Seas Fisheries in the Central Artictic Ocean, 2018
____________- are the key components in global cycles and energy flows.
Oceanic ecosystems
What is one of the major difficulties in working against sustainable human use of the oceans?
Lack of understanding
On land, _________ is the most limiting factor for life.
water
In oceans, the limiting factor are ____________
nutrients
What are the most productive areas of oceanic ecosystems?
- Coastal zones
- Upwellings from deep ocean return nutrients to the surface layers
Surface waters in the ________________ are warmer and have higher light levels, resulting in higher productivity
euphotic zone
Define Thermocline:
A sharp transition in temperature between the warmer surface waters and the cooler waters underneath
The deepest part of the ocean is more than __________ metres deep, but more than three- quarters of the ocean is between _______________ metres deep
9,000, 4,000 and
6,000
Where is the most productive areas in oceanic ecosystems?
Continental shelves at a depth of less than 200 meters, and within the top 100m.
When does Acidification occur?
When water and CO2 mix to form carbonic acid (H2CO3). Carbonic acid releases hydrogen ions (H+), which increases the acidity of the water
Oceans are about _____ % more
acidic compared to pre-industrial times.
30
Define Thermohaline Circulation:
The carbon-saturated water moves around the globe
What is movement on subsrurface water of oceans densities contrasting from?
Temperature and Salinity
How will global warming affect the polar icecaps?
Melting, will reduce density in sea water and make thermohaline circulation weaker –shutdown of this circulation could trigger a new ice age
Coral reefs are known as the _________________ of the sea.
rain forests
___________ are among the most diverse and productive ecosystems on Earth
Coral reefs
What are coral reefs mainly made of?
Countless number of individual coral polyps held together by calcium carbonate (CaCO3)
What kind of algae lives inside corals skeletons and produce their food?
Photosynthetic / zooxanthellae algae
What is the technical explanation of coral bleaching?
When water temperatures get too warm, the zooxantheliae are often expelled
What are the main management challenges facing ocean ecosystems a result of?
- Fisheries pollution
- Coastal development
- Climate change
Where are the most important fishing grounds of the world found?
On and along continental shelves within less than 370 kms of the shore
Fisheries supply some ____% of the world’s annual animal protein supply
20
True or false: Fish populations are declining, and the fish being caught are smaller than those caught in the past.
True
