Open Ocean and Deep Sea

Ecosystems of the Open Ocean

• Epipelagic• Deep Ocean• Whale falls• Hydrothermal vents• Cold seeps

Epipelagic Zone

– The uppermost layer of the world's oceans is bathed in sunlight during the daytime.

– This bright ocean layer is called the photic zone, euphotic zone (euphotic means "well lit" in Greek) or the epipelagic zone (epipelagic means "upon the sea").

– The depth of this zone depends on the clarity or murkiness of the water.

Physical Characteristics of the Epipelagic Zone

– Photosynthetic organisms live in this zone and food is abundant.

– Photosynthesis in the oceans creates approximately 90% of the Earth's gaseous oxygen.

– Most of the oxygen is produced by phytoplankton. These primary producers (also called autotrophs) are the first link in the food chain in the oceans.

– The sea surface temperatures range from as 97°F (36°C) in the Persian Gulf to 28°F (-2°C) near the north pole.

Epipelagic Food Chain

–Primary producers – phytoplankton, green red and brown algae, and kelp–Primary consumers – zooplankton, small

fish– Secondary consumers – larger fish, baleen

whales, jellyfish, marine mammals–Top of the food chain – killer whales,

dolphins, sharks

Marine AnimalsTerms to Know• Plankton – lives floating in the water• Nekton - lives swimming in the water• Benthic - lives on the bottom of the ocean• Sessile – lives attached to a surface permanently

SessileBenthicNektonPlankton

Blue Planet: Open Ocean

• Write a paragraph describing how the open ocean is like a desert in terms of nutrient availability, shelter availability, mate availability, and density of organisms.

Answer the following questions using your notes or a tablet:

1) What are zones?2) On what basis are those divisions

made?3) Why is light so important to the

study of marine life?4) Describe the 2 subsections of the

pelagic zone.5) Describe the divisions of the

benthic zone.6) What is biomass?7) How much of the ocean’s

biomass is in the epipelagic zone? 8) How much of the ocean’s

biomass is in the deep ocean?

9) If there is no photosynthesis in the deep ocean, what do animals down there eat?

10) Describe the deep scattering layer (DSL)

11) What do animals in the DSL do during the day? Why?

12) What do animals in the DSL do at night? Why?

13) Describe a gulper eel.14) How often do gulper eels feed?

Why?15) What is bioluminescence?16) Why do animals bioluminate?

How do epipelagic organisms survive?What are their adaptations for survival?• 1) Stay within a physically tolerable zone• 2) Find enough food to eat and grow• 3) Find mate(s) and successfully reproduce• 4) Avoid being eaten

Staying afloat – most organisms are more dense than water. They have special adaptations to help them stay afloat.

Noctiluca (Sea Sparkle)•large buoyant vacuoles

Cranchiid (Glass squid)* large fluid-filled chamber filled with an ammonia solution

Janthina (violet snail)mucous bubbles

Fish - swim bladder

Flat surfaces or bodies withappendages do not slip aseasily through the water

Staying afloat – Swim!!!

Pectoral fins reduce sinking. Adaptation to remain in epipelagicANDallows organisms to go deep and then return to surface

Finding foodBuild a collection device or filter

BE BIG!• You can eat almost anything you encounter• Can swim across “ocean deserts” to find food• High storage capacity(longer between meals but need more food/unit time)

Hunt in groupsOrcas can even hunt much larger whales

Finding foodStay with your food - Seabirds follow schools of fish

Know where your food will beHunt in areas with specific properties (e.g. upwelling regions or inside gyres) likely to retain or attract preyCue in on timed migration of prey

Finding a mate

Broadcast spawningRelease of millions of eggs & sperm increases chance that sperm & egg will meetEx. oysters, coral

Stay togetherschooling fish, social marine mammals & deepsea angler fish

Finding a mateMeet at a predetermined locationIf separated or too costly to stay together (e.g. competition for food), meet at a specific time & placeEx. Colonial sea birds and Pacific salmon

Be clonalAsexual reproduction - no mate needed!

Avoid being eaten

Defend yourselfMechanical• Spines• Tough skinChemical• Taste bad• Makepredatorssick

Avoid being eaten

BEBIG!Big things havefewerpredators,especially in themarineenvironment

Be Cryptic • Be transparent• Be reflective• Be camouflaged• Be countershaded

Countershading in the Epipelagic Zone• Countershading is when an animal is light on its

underside and dark on its upper parts. • When a predator looks down at a countershaded

animal, it blends into the darker waters; when a predator looks at a countershaded animal from below, the light underbelly disappears into the light.

Deep Oceans

– Regions of the deep oceanEpipelagic

Mesopelagic

Bathypelagic

Abyssopelagic

Hadalpelagic

200m

1000m

4000m

6000mThe Trenches

The Midnight Zone

The Twilight Zone

The Abyss

Unique Stresses of The DeepPressure• For every 10m (33ft) pressure increases by 1atm (14.7

pounds per square foot)Lack of Food• 5% of food made at surface makes its way to deep

regions• Deep sea fish do not migrate Oxygen Minimum Layer: about 500m• Oxygen enters ocean by: gas exchange with atmosphere,

by-product of photosynthesis• Respiration uses up O2

• O2 can drop to practically nothing

Adaptations to low light• The only light is produced by bioluminescence, a

chemical reaction in the creature's body that creates a low level light. – Some produce red light to lure curious prey. – Sometimes used to signal potential mates with a specific light

pattern. • Fish here are often transparent, black, silvery and even

red in color. – The absence of red light at these depths being red makes

them invisible.• Large eyes to capture what little light exists. • Often equipped with a powerful sense of smell – to find

food and mates.

Mating in the deepDeep sea anglerfish –reproductive adaptation. • Males are tiny in comparison to females and attach themselves to

their mate using hooked teeth establishing a parasitic relationship for life.

• The blood vessels of the male merges with the female's so that he receives nourishment from her.

• In exchange, the female is provided with a very reliable sperm source.

Adaptations to high pressure• Deep sea creatures have adapted to pressure by

developing bodies with no excess cavities, such as swim bladders, that would collapse under intense pressure.

• The flesh and bones of deep sea marine creatures are soft and flabby.

Finding food in the deep

• Corpses of large animals that sink to the bottom provide infrequent feasts for deep sea animals.

• Large and expandable stomachs to hold large quantities of food.

• Don't expend energy swimming in search of food, rather they remain in one place and ambush their prey

• Large jaws ensure that any prey captured has little chance of escape.

Chemosynthesis

• Most life on Earth is dependent upon photosynthesis, the process by which plants make energy from sunlight.

• Cold Seep and Hydrothermal Vent communities do not rely on the Sun for energy. Organisms there derive their energy from the Earth through chemosynthesis.

• Chemosynthesis is the process by which certain microbes create energy from naturally occurring inorganic chemicals.– CH4 Methane

– H2S Hydrogen Sulfide

Hydrothermal Vents

• Form in places where there is volcanic activity, such as along the Mid-Ocean Ridge.

• Sunlight does not reach the hydrothermal vent communities at the bottom of the ocean.

• Microbes here get their energy from different chemicals in the hydrothermal fluid like hydrogen sulfide (H2S).

• Those microbes are the basis of the food chain.

Cold Seep Communities

• Deepwater communities associated with brine and hydrocarbon seepage from the Earth’s crust.

• This brine forms brine pools on the seafloor.• Microbes here use chemosynthesis and the

chemical methane (CH4) to obtain energy.• Those microbes are the basis of the food

chain.

Whale Fall Communities

• Communities of organisms that form around the carcasses of dead whales.

Whale Fall: Scavenger Stage

Whale Fall: O

pportunist Stage

Whale Fall: Sulfophilic Stage

• Students will design their own well-adapted species. Some of the things you need to think about are how the organism: collects food, finds a mate, avoids being eaten, and stays afloat .

• Sketch, color, and write a paragraph descriptionof the organism you designed.

• EXTRA CREDIT FOR ADDITIONAL DEEP WATER ADAPTATIONS

Design your own species

Create-a-Creature: Megasaurus

Finds a Mate Stays Afloat1) 1)2) 2)

Collects Food Avoids being Eaten1) 1)2) 2)