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 Animals Terms 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

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 with appendages do not slip as easily through the water

Staying afloat – Swim!!! Pectoral fins reduce sinking.Adaptation to remain in epipelagic AND allows organisms to go deep and then return to surface

Finding food Build 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 groups Orcas can even hunt much larger whales

Finding food Stay with your food - Seabirds follow schools of fish Know where your food will be Hunt in areas with specific properties (e.g. upwelling regions or inside gyres) likely to retain or attract prey Cue in on timed migration of prey

Finding a mate Broadcast spawning Release of millions of eggs & sperm increases chance that sperm & egg will meet Ex. oysters, coral Stay together schooling fish, social marine mammals & deep sea angler fish

Finding a mate Meet at a predetermined location If separated or too costly to stay together (e.g. competition for food), meet at a specific time & place Ex. Colonial sea birds and Pacific salmon Be clonal Asexual reproduction - no mate needed!

Avoid being eaten Defend yourself Mechanical Spines Tough skin Chemical Taste bad Make predators sick

Avoid being eaten BE BIG! Big things have fewer predators, especially in the marine environment 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 ocean Epipelagic Mesopelagic Bathypelagic Abyssopelagic Hadalpelagic 200m 1000m 4000m 6000m The Trenches The Midnight Zone The Twilight Zone The Abyss

Unique Stresses of The Deep Pressure 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 O 2 O 2 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 deep Deep 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. – CH 4 Methane – H 2 S 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 (H 2 S). 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 (CH 4 ) 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: Opportunist Stage

Whale Fall: Sulfophilic Stage