Technically…a wetland

Hydrothermal vent

Life began in the ocean billions of years ago.

Even now, species are disappearing from and appearing in the seas without our knowledge.

Sea during the Ordovician Period

490 to 443 Million Years Ago

Water is key and essential for life on Earth.

First life:

single-celled organisms called Prokaryotes.

Eventually, over time, the seas began to come alive with multicellular organisms, as seen here.

Scientists hypothesize that this life may have begun along the mid-ocean ridge near the black smokers.

Marine regions cover about three-fourths of the Earth’s surface. This is the largest of Earth’s biomes. Marine regions include:

• Oceans

• Coral Reefs• Estuaries

Marine algae take in a huge amount of atmospheric carbon dioxide, and serve as a sink, or storage area.

The evaporation of the seawater provides rainwater for the land, in the hydrologic cycle.

Marine phytoplankton are responsible for a great deal of free oxygen in our atmosphere

Why is the ocean important?

• Saltwater Marsh• Hydrothermal Vents

When did life begin on Earth?

Where do scientists hypothesize that life began in the oceans?

How much of the Earth’s surface is covered by ocean?

What three reasons are oceans important?

Oceans are very large bodies of water that dominate the Earth’s surface. Oceanic regions are separated into different zones, based on depth, and distance from shore…similarly to freshwater:

• Intertidal• Pelagic

• Neritic• Oceanic

Which is subdivided into• epipelagic(euphotic zone)

• mesopelagic• bathypelagic • abyssalpelagic• hadalpelagic (trenches)

Aphotic

The intertidal zone is where the ocean meets the land—sometimes it is submerged and at other times exposedBecause of this, intertidal communities are constantly changing. Which communities change more rapidly? Rocky and Sandy

Where only the highest tides reach, there are only a few species of algae and mollusks.

In those areas usually submerged during high tide, there is a more diverse array of algae and small animals, such as herbivorous snails, crabs, sea stars, and small fishes.

At the bottom of the intertidal zone, which is only exposed during the lowest tides, many invertebrates, fishes, and seaweed can be found.

Rocky Intertidal Zones

Tidepool Sculpin

As tide pools can be exposed for a long time during periods of low tide, the salinity can vary greatly.

Which of these two tide pools would have the highest salinity concentration…and why?What other variable would influence life in this tide pool?

The intertidal zone on sandier shores is a much less forgiving area. Waves keep mud and sand constantly moving, thus very few algae and plants can establish themselves—and those that do are far from the action of the waves. The fauna include worms, clams, predatory crustaceans, crabs, and shorebirds.

What freshwater zone is comparable to the intertidal marine zone?

What variables make tide pool life difficult?

Which intertidal zone is least forgiving, and why?

The Neritic zone is that which extends from the edge of the intertidal region to the edge of the Continental Shelf.

The neritic zone has generally well-oxygenated water, low water pressure, and relatively stable temperature and salinity levels. These, combined with presence of light and the resulting photosynthetic life, such as phytoplankton, make the neritic zone the location of the majority of sea life.

For this reason we say the Neritic Zone forms the base of the food web which supports the fishing industry.

Oceanic zone

It is the region of open sea beyond the edge of the continental shelf and includes 65% of the ocean’s completely open water. Beneath the oceanic

zone there is a wide array of undersea terrain, including crevices that are extremely deep, as well as deep-sea volcanoes and ocean basins.

Oceanic zone

Since the Oceanic zone is a measurement of distance from shore, we will discuss life here in terms of the pelagic zone, which is the vertical zone that includes the surface waters, as well as the deep ocean.

The pelagic zone is a vertical zone and includes waters basically below the oceanic zone. The pelagic zone is subdivided into euphotic, and aphotic zones and is generally cold, but near the surface, in the epipelagic zone, a mixing of waters occurs, and it can be quite warm. The flora in the epipelagic zone (which is euphotic) include surface seaweeds.

The fauna include many species of fish and some mammals, such as whales and dolphins. Many feed on the abundant plankton.

Let’s explore the aphotic zones of the Pelagic, excluding the abyssal and hadal.

Mesopelagic zones include waters that are between 650 and 1,000 meters in depth. Not enough light penetrates this depth to accommodate photosynthesis.

Therefore the organisms here must either rely on a completely different energy source to power their food web, or they must migrate to eat.

Wolf Eel

CuttlefishChain catshark fluorescing

The bathypelagic zone includes waters that are between 1,000 and 4,000 meters deep. Bioluminescence is the only source of light here.Cnidarian Siphonophore

What about the Neritic Zone makes it the “support of the fishing industry”?

What freshwater zone is comparable to the Oceanic Zone?

What two major divisions exist within the Pelagic Zone?

How are seaweeds adapted to the euphotic zone?

What adaptation do the organisms within the mesopelagic, and bathypelagic zones begin to exhibit?

The deep ocean is the abyssal zone. The water in this region is very cold (around 3° C), highly pressured, high in oxygen content, but low in nutritional content. The abyssal zone supports many species of invertebrates and fishes. Some of the strangest creatures you'd ever want to meet live in the Abyssal Zone.

Adaptations include large eyes, no eyes, and bioluminescence.

Rattail or grenadier fish

Sea Pig

Fangfish

Grammatostomias flagellibarba

Viper Fish

Giant Squid

Vampire SquidHimantolophus groenlandicus

Giant Sea Spider

Dragon Fish

Caulophryne polynema

stalked toad with many filaments

Gulper Fish anglerfish

Linophryne arborifera

toad that fishes with a net

Describe water conditions in the abyssal depths.

What types of adaptations might you find on consumers in the abyss?

What types of adaptations might you find on producers in the abyss?

This zone represents the absolute deepest places in the ocean. They exist where one tectonic plate “subducts” beneath another.

They accompany and are found near geologically active areas, including earthquakes and volcanoes. There is one trench in the north Atlantic, known as the Puerto Rican Trench. Its waters are nearly 9,000 meters deep (29,000 feet).

Of course the deepest place on the planet is the Challenger Deep within the Marianas Trench, in the southpacific.

The challenger deep was explored by manned vehicles only twice in history! Once by the Trieste. This vessel, piloted by Jacques Piccard and Don Walsh, reached the bottom of the trench on January 23, 1960. At a depth of 35,814 feet, which took the men nearly 5 hours to reach, the first thing they saw was a fish!

Apparently, this fish was of the “sole” family, as it was flattened, and swam about burying itself in the bottom sediment.

The other manned vessel was the Deep Sea Challenger, which carried filmmaker James Cameron to the Challenger Deep in March of 2012. The trip took only 2 1/2 hours!

He described the bottom as a “lunar landscape, desolate and untouched”.

The only “free-swimming” organisms he saw were these deep sea amphipods. They must be adapted to extreme hydrostatic pressures of more than 16,000 lbs/in2

Coral reefs are widely distributed in warm shallow waters. They can be found as barriers along continents (the Great Barrier Reef off Australia), fringing islands, and atolls.

Naturally, the dominant organisms in coral reefs are corals. Most corals consist of both algae and animal polyp. Corals obtain nutrients through the algae via photosynthesisThey can also extend tentacles to obtain plankton from the water. Besides corals, the fauna include several species of invertebrates, fishes, sea urchins, octopus, and sea stars.

Reefs have functions ranging from providing food and shelter to fish and invertebrates to protecting the shore from erosion Because many coral reef organisms can tolerate only a narrow range of environmental conditions, reefs are sensitive to damage from environmental changes. Corals are susceptible to diseases and bleaching. Also, dramatic natural events such as hurricanes can damage coral reefs. In addition, many problems to reefs are anthropogenic.

How do deep ocean trenches (hadalpelagic zones) form?

Where might you expect to find these trenches on Earth?

What is an atoll?

Describe a coral organism.

Why are corals and coral reefs considered fragile?

There are creatures which thrive around hydrothermal vents, located on the ocean floor near oceanic “hot spots”. These include the mid-ocean ridge that runs down the middle of the Atlantic, and the “Ring of Fire” circumnavigating the Pacific Basin.

Hydrothermal vents are volcanic mountains that expel super heated water that is rich in minerals.

Organisms that live there, feed off of chemosynthetic bacteria, which use the super heated water and chemicals from the hydrothermal vents to create energy in place of photosynthesis. This is an excellent adaptation to areas that are aphotic!

The existence of these bacteria allow creatures like squids, hatchet fish, octopuses, tube worms, giant clams, spider crabs and other organisms to survive, as they form the base of the food chain, just as photosynthetic producers do in the euphotic zone.

Estuaries are areas where freshwater streams or rivers merge with the ocean. Waters which are part salty, and part fresh are called “brackish”. This mixing of waters with such different salt concentrations creates a very interesting and unique ecosystem. It can also be very challenging for those that live there!Microflora like algae, and macroflora, such as seaweeds, marsh grasses, and mangrove trees (only in the tropics), can be found here. Estuaries support a diverse fauna, including a variety of worms, oysters, crabs, and waterfowl.

Saltwater Marshes: blue herons, clapper rails, ducks, raccoons, blue and fiddler crabs, clam worms, killifish, and snails.

Remember…marshes are wetlands, and they contain herbaceous plants.

Some of the animals that abound in salt water marshes include:

Both animals and plants of these areas must adjust to constant changes in water level, due to changing tides, and varying salinity levels.

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Diamondback Terrapin

How are autotrophs from the hydrothermal vents (aphotic zones) adapted?

What type of water is found in estuaries?

Describe one waterfowl adaptation to the estuary.

What types of plants are found in saltwater marshes?