Divemaster exam A - chapters 1-8 Flashcards
what are two ocean resources vital to life?
1) oxygen
- from ocean phytoplankton and cyanobacteria
2) heat distribution
- ocean’s ability to absorb, carry and release heat
Primary producers
organisms that get their energy from sunlight = converting sunlight energy into energy-containing compounds
- the base of all food chains
photosynthesis
the process by which plants/primary producers convert CO2 and water into oxygen and carbs
Highly productive ocean areas
areas with coastal upwellings = nutrients
EG: Polar regions
Mangrove ecosystem services (2)
1) trap excess nutrients, pollutants and sediments
2) habitat for invertebrates and juvenile reef fish
Threats to mangroves (4)
1) real estate
2) dredging
3) aquaculture
4) chemicals
example of organic waste? (2)
- agriculture runoff
- red tides
cause of red tides?
nutrient pollution/algae overgrowth
solid wastes
heavy metals, toxic chemicals, oil accumulate in sediment
forces that cause currents (4)
1) surface winds
2) earth’s rotation
(deflect R. in Northern hemisphere, L. in Southern Hemisphere)
3) winds
4) weather
best time to dive based on tides
high tide or slack tide
three types of breaking waves
1) plunging breakers - moderately steep beaches
2) spilling breakers - gently sloping beaches
3) surging breakers - very steep beaches
what is a rip current?
A local current that occurs when waves push water over a long obstruction (sandbar or reef)
Primary productivity
a process by which energy enters the food chain by primary producers
% of water on Earth
71%
% of water that is Seawater?
97%
Why dive in an environmentally responsible manner? (4)
- You don’t want to harm aquatic life
- Role modeling environmentally responsible diving is in the PADI Member’s Code of Practice
- Kicking and bumping into aquatic life causes major damage.
- Directly encouraging other divers to reduce their effect on the environment
- Divers have a growing collective voice that can influence environmental initiatives and policies that affect the underwater world - to be credible as environmental ambassadors, we must show that we practice what we preach.
Diving in an environmentally responsible manner is important because:
You are a role model to others and should be a passionate ambassador
What ultimately connects all the water on Earth?
The hydrological cycle connects all water (inland and underground bodies).
What is the base of the marine food chain?
Primary producers - photosynthesis by phytoplankton, which need sunlight AND nutrients
why are some areas much more productive than others?
Areas (continental shelves, polar regions) that have costal upwellings (water flowing up from the deep) tend to be highly productive because upwellings bring nutrients to the surface.
Open ocean has little primary productivity due to lack of nutrients, ocean bottom has ample nutrients but sunlight doesn’t penetrate that far - except in areas with thermal vents where chemosynthesizers form small ecosystems by converting inorganic chemical energy into useable carbohydrates.
Why are coral reefs important?
Most productive, complex, and diverse ecosystems on Earth.
what benefits do coral reefs provide?
- Corals are primary producers
(symbiotic phytoplankton live in them)
- incredibly efficient at recycling available nutrients and the nutrient-free water protects coral from organisms from organisms that would compete/cloud water and block sunlight. - Nursery grounds for 25% of all known marine species, home to about 33% of all known fish species.
- Form extensive reef structures that protect island and coastal communities from storms, wave damage, and erosion by forming massive barrier reefs.
- Increasingly important to commerce and regional economies, tourism relies on the appeal of their coral reefs, pharmacologists find biomedical compounds such as antibiotics and anti-cancer agents.
What are the major threats to coral reefs?
Human activities
- Land clearing (choking polyps)
- Fishing practices (destroying coral structures)
Global warming (climate change)