the ocean depths

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THE OCEAN DEPTHS

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THE OCEAN DEPTHS. THE OCEAN DEPTHS. From 100-200 m (600 ft) to the deepest part Mesopelagic (to depth of 3300 ft -1000 m) Twilight THE DEEP - Bathypelagic, Abyssopelagic & Hadopelagic No sunlight at all. THE MESOPELAGIC. From 100-200 m to depth of 3300 ft (1000 m) - PowerPoint PPT Presentation

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Page 1: THE OCEAN DEPTHS

THE OCEAN DEPTHS

Page 2: THE OCEAN DEPTHS

THE OCEAN DEPTHS From 100-200 m (600 ft) to the

deepest part Mesopelagic (to depth of 3300 ft -

1000 m)Twilight

THE DEEP - Bathypelagic, Abyssopelagic & HadopelagicNo sunlight at all

Page 3: THE OCEAN DEPTHS

THE MESOPELAGIC From 100-200 m to depth of 3300 ft

(1000 m) Not enough light for photosynthesis, no

primary productivity Enough light to see by – like twilight Chronically short of food High pressure

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THE MESOPELAGIC - ADAPTATIONS

Small size Large mouths Hinged, extendable jaws Needle-like teeth Unspecialized diets Flabby watery flesh – no swim

bladder Large sensitive eyes Countershading & bioluminescence

Page 5: THE OCEAN DEPTHS

THE MESOPELAGIC - ADAPTATIONS

Page 6: THE OCEAN DEPTHS

THE DEEP From 1000 m – deepest trenches

No light Cold High pressure (up to 1000 atm) Lack of food Lack of mates

Page 7: THE OCEAN DEPTHS

THE DEEP - ADAPTATIONS Small size (but larger than

mesopelagic) Black Small eyes Sluggish & sedentary Large mouths (consume prey larger

than themselves) Expandable stomachs Flabby watery flesh – no swim

bladder Hermaphroditism / Male parasitism /

Bioluminescence

Page 8: THE OCEAN DEPTHS

THE DEEP- ADAPTATIONS

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Characteristics of the benthic zone:

- 90% of the organisms are found on the continental shelf, others are in the abyss

- deep sea benthhic fishes dark brown or black- meso- and deep pelagic zone 99% of the organisms are bioluminescent (produce light by chemical reaction)

- very stable environment - increases with depth

- lack of light is a major limiting factor - reducing food, predation and mating

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- oxygen is supplied from cold, saline waters of the poles

- biomass decreases with depth - this low population density is directly related to food scarcity

- communities entirely composed of consumers and scavengers

- producers are found only in photic zones; decomposers like bacteria are more common in mid-water mesopelagic zone

NOAA

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Hydro-Thermal Vent Communities

The exception in benthic communities’ producers are the chemosynthetic bacteria around hydrothermal vent.

NOAA

In 1977, scientists working in the DSV Alvin with project FAMOUS (Robert Ballard), discovered unique hydrothermal vent communities of previously unknown organisms.

Since then, vent communities have been found in all oceans at depths varying from 1 to 2 miles down.

Bacteria living near the vent use hydrogen sulfide dissolved in seawater to build organic molecules in a process called chemosynthesis.

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Animals clustered near the vents grow to huge sizes; can withstand temperature differences from 36o to 662o.

The community also has many suspension-feeders attached to the hard rock bottom which is unusual in the deep sea.

Geologist estimate that the vents probably last for 100 years;when supply of H2S is exhausted, the ecosystem dies.

In other areas, called Cold Seeps, also have chemosynthesis. Here methane and sulfide-rich fluids seep into the ocean floor where symbiotic bacteria use sulfur-oxidation for survival.

Cold Seeps are home to millions of benthic worms, crabs and mollusks.

NOAA

Page 13: THE OCEAN DEPTHS

OCEAN FLOOR - SEDIMENTS

Continental shelf - terrigenous sediment derived from eroded continent

Ocean floor – biogenous sediment Derived from once living organisms

(plankton)

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20Radiolarians – equatorial regions

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21Diatoms – polar regions