Marine life

Marine life, life in the sea or ocean life, is made up of the plants, animals, and other organisms that live in the saltwater of the seas and oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life helps determine the very nature of our planet.

Marine organisms produce much of the oxygen we breathe.

Coasts are partly shaped and protected by marine life, and some marine organisms even help create new land.

Most life forms initially evolved in marine habitats. By volume, the oceans provide approximately 90% of the planet’s habitable surface area.1 The first vertebrates appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians who spend parts of their lives on water and land.

Marinen, Life

Other fish evolved into land mammals and later returned to the ocean as seals, dolphins, or whales.

Plants such as seaweeds and algae grow in the water and are the basis of some underwater ecosystems. Plankton, and particularly phytoplankton, are key primary producers that form the overall basis of the oceanic food chain.

Marine vertebrates need oxygen to survive, and they obtain it in a variety of ways.

Fish have gills instead of lungs, although some fish species, such as the lungfish, have both. Marine mammals such as dolphins, whales, otters, and seals need to surface periodically to breathe air.

Some amphibians can absorb oxygen through their skin. Invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters, including breathing tubes (see siphons of insects and mollusks) and gills (Carcinus). However, as invertebrate life evolved in an aquatic habitat, most have little or no specialization for respiration in water.

In total, there are 230 000 documented marine species, including more than 16 000 species of fish, and it has been estimated that nearly two million marine species have yet to be documented.2 Marine species range in size from microscopic, which include plankton and phytoplankton that can be as small as 0.02 micrometers, to large cetaceans (whales, dolphins, and porpoises) that in the case of the blue whale reach up to 33 m in length, being the largest animal.

Biodiversity, Water

What is marine biodiversity?

What is marine biodiversityMarine biodiversity is defined as an immense variety of microscopic and macroscopic living beings that inhabit the seas and oceans of the planet. Marine biodiversity is defined as the immense variety of microscopic and macroscopic living beings that inhabit the seas and oceans of the planet.

It also refers to the great genetic diversity of species, which makes possible multiple and marvelous forms of life.

The term biodiversity, as coined by the International Convention on Biological Diversity, encompasses all the diversity of species, of living beings that have been populating the Earth in its evolutionary evolution for millions of years, according to natural processes and the increasing intervention of man.

When we talk about marine biodiversity we refer then to all the flora and fauna that make up the ecosystems formed over some four billion years of evolution of the Earth, which began in the seas.

Where is the marine ecosystem found?

Where is the marine ecosystem found?The marine world is made up of ecosystems of a varied number of plant and animal species that interact harmoniously in environments very high in salt content in the water.

These ecosystems cover 70% of the planetary surface, mostly composed of water.

A marine ecosystem, therefore, is far from resembling terrestrial ecosystems. They have a different biological diversity, in structure and functioning.

What are marine organisms?

In the marine environment, the high density of saltwater ensures the so-called suspended life, which runs with low energy expenditure.

And the water has a much greater capacity to absorb energy, a characteristic that gives it greater stability than the terrestrial environment, because the temperature remains constant, to the point that the Earth’s seas and oceans are responsible for maintaining the global temperature because they control the climate of the Earth’s surface at the coastal level.

In addition, the water at sea is much denser than air, no less than 830 times, and gravity affects marine organisms differently.

This allows for an abundance of fascinating living organisms such as plankton and nekton and enables many life forms to thrive in that huge mass of water that occupies 70% of the planetary surface.

The plankton groups all aquatic organisms that, although not capable of swimming, are mobilized thanks to the whim of aquatic currents. The word plankton comes from the Greek word meaning “wanderer” or “wandering”.

marine organisms

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These organisms, imperceptible to the naked eye, share their pelagic life (they are always near the surface) with the nekton, which includes all those organisms capable of swimming and opposing the marine currents such as fish, turtles, cetaceans, cephalopods, among others.

The water also carries a large amount of food, in the form of organic particles and thousands of dissolved nutrients that have also allowed many marine animals to spending their lives attached to the substrate, which is known as sessile life.

However, the majority population of living things is maintained in the most superficial layers of seas and oceans, above 1,000 meters, where most of the marine biomass is concentrated.

Marine ecosystems also abound with sessile animals such as sponges, bryozoans, ascidians, phoronids, and endproducts. There are others called cnidarians, which have some free-living species, but for the most part, they are also sessile.

Similarly, there are groups of motile animals such as mollusks and annelids, with many species capable of living permanently, literally glued to the substrate because they are filter-feeding. 

In fact, many species are benthic, that is, they live associated with the seafloor and a large population, estimated at 70%, has one or more planktonic larval stages.

This allows them to have a remarkable dispersal capacity that depends largely on the period that these organisms or living beings spend in the plankton. 

What is the percentage of marine life on planet Earth?

What is the percentage of marine life on planet Earth?All marine organisms contribute to the production of much of the oxygen we breathe and some are even instrumental in the creation of new territories.

Coastlines also arise from, depend on, and are protected by marine life. But how many species live in the world’s seas and oceans?

To give an exact figure is almost impossible, but the scientific community estimates that there are almost one million species living in the world’s oceans, after billions of years of evolution.

Some well-documented research provides data that records about 972 thousand species of fully identified eukaryotic organisms. Some well-documented research provides data that records about 972 thousand species of fully identified eukaryotic organisms.

In 2010, the largest Marine Census ever recorded on the planet was released in London, where 2,600 scientists from 80 countries participated, covering from the coldest to the warmest waters of the globe.

It cost $650 million. It was initiated by scientists Fred Grassle of Rutgers University, New Jersey, along with Jesse Ausubel of the Alfred P. Sloan Foundation, New York.  It cost $650 million.

Over the 10-year duration of the study, the scientists were able to keep track of scores of marine creatures, following their migration habits, populations, and reproductive mechanisms. 

Large mollusks and bacteria hitherto unknown were discovered, but also a veritable sturgeon park in the Pacific Ocean alone, the largest marine reservoir on the planet.

In this study, it was estimated that there are about one million marine species, although only about 250,000 have been described by the scientific literature.

Marine biodiversityIn addition, the scientific community believes there are about one billion marine microbes and valuable information was collected about 16,764 species of fish that had not been discovered before, as well as another 5,000 species that had not even been seen before.

There are about 28 million marine observations of more than 120,000 species collected in the Census over the past centuries, which enabled the creation of the Ocean Biogeographic Information System (OBIS). Ocean Biogeographic Information System (OBIS).

But there is still a long way to go, because only about 10% of the marine diversity of European waters is known, although 75% of the species living in the Mediterranean Sea and 80% of the seas around the Australian continent have been studied.  But there is still a long way to go because only about 10% of the marine diversity of European waters is known.

Another scientific calculation was made with the participation of about 270 taxonomists, experts in the classification of species sponsored by the Consejo Superior de Investigaciones Científicas (CSIC) that were published in the journal Current Biology.

Thus, according to the study that has managed to bring together the largest number of taxonomists so far gathered, considers that marine species are around an estimated universe between 704,000 to 972,000. 

But of this estimated universe, only about 230,000 species have been classified with correct names and descriptions, including about 1,217 different names of the order of cetaceans, including whales and dolphins, among others, with only 87 species. 

Most of them correspond to species of animals.

Which is the most species-rich ocean?

The scientific community has also been able to establish that the waters richest in marine life are found around Australia and Japan, but the largest population is that of crustaceans, which make up one-fifth of all marine life.

This information has also been confirmed by the Marine Census released in 2010.

What are the benefits of the marine ecosystem?

What are the benefits of the marine ecosystemOne of the fundamental benefits for life on Earth comes precisely from the seas and oceans because from these waters emerges half of the oxygen necessary for breathing of every living being, but also provide us with many foods.

Another vital function of the seas is to regulate the climate of the entire world.

And it is a secure source of planetary biodiversity, the guarantor of well-being and balance in the biosphere, thus ensuring the survival of living beings, especially humans, who take advantage of the full potential of the variety of species that dominate the marine spaces, as well as the terrestrial ones.

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What are the causes and consequences of the loss of marine biodiversity in the world?What are the causes and consequences of global marine biodiversity loss?

One of the direst impacts of Climate change caused by human industrial and agricultural activities has a direct impact on the planet’s marine habitat, caused by the acidification of the oceans as a result of nitrogenous waste and sediment discharges.

Human beings, unfortunately, also figure as the main destructive agent of the marine environment.

This, evidently, has violated the great marine biodiversity. Let’s take a look at some of the most important causes associated with this phenomenon that endangers the very life of the planet.

  1. Overexploitation of the natural resources provided by the seas and oceans.
  2. Overexploitation of the natural resources provided by the seas and oceans.
  3. Pollution of saltwater bodies, derived from large-scale industrial activities.
  4. Habitat loss, fragmentation, or change.
  5. Introduction of invasive or exotic species into natural ecosystems.
  6. Climate change.


What are the causes and consequences of the loss of marine biodiversity in the world - ConsequencesAccording to the list of endangered species published year after year by the International Union for Conservation of Nature (IUCN), 17% of marine species such as rays, sharks, and chimeras, analyzed in a universe of 3,000 varieties, are under threat.

Also, overfishing of grouper reaches 13% and 6 types of sea turtle species are threatened because their eggs disappear, due to habitat alteration, accidental and specific catches, and predation.

Another major high-impact damage is being suffered by corals because more than a quarter of coral reefs are threatened, i.e. about 845 different species, due to acidification of waters and rising sea temperatures, as well as the enormous anthropogenic pressure exerted by urban developments in coastal regions, which produce coral extraction, severe pollution from illegal waste discharges and sedimentation. 

Other species severely impacted by irresponsible human actions, including cetacean hunting, are wiping out marine mammals such as whales, dolphins, porpoises, sea lions, seals, otters, dugongs, manatees, and the iconic polar bear.”.

In this group, it has been quantified that 25% of the species are under threat of death, of total extinction, thanks to factors such as:

Climate change and its effects on marine waters

Climate change and its effects on marine watersThe intensive hunting is undertaken by man and entanglement of gear during fishing activities. Water pollution and acoustic pollution, as well as loss of the littoral zone.

Reduction of food available for the different marine species. Loss of natural habitat, of these wonderful marine animals, as is happening with polar bears, due to the melting of the poles caused by global warming resulting from climate change.

There is still time to face our responsibility in the marine and terrestrial ecological disaster generated thanks to highly polluting activities developed by man around the world, especially the industrialized one. 

The sea is one of the main sources of oxygen production for the planet, food, medicines, raw materials, renewable energy and even fuels and biochemical systems. Unfortunately, only 0.1% of the world’s seas are under protected areas. Only 0.1% of the sea is in a protected area.

There is increasing evidence of the accelerated loss of biodiversity of species living on Earth, especially during the 20th century, with a rate of approximately 200 extinctions per day, a criminal outrage that far exceeds any other time in the history of humanity. 

What should we do to take care of the sea and marine life?

There are several decisive actions we can take to reduce our individual carbon footprint, truly simple measures that would greatly help combat the effects of climate change on the planet’s marine and terrestrial ecosystems if practiced on a regular basis.

The following tips are effective, even more so if adopted with religious devotion. Let’s see.

    1. Reduce your own carbon footprint with energy savings. 
    2. Try to reduce car use. Whenever you can, accomplish your personal errands by pedaling on your bicycle. This will help reduce the perverse effects of climate change on the oceans. Better yet, if you can, buy an electric car, but also rationalize its use for long journeys.
    3. Use energy-saving light bulbs with LED technology at home, use the stairs and not the elevators, and don’t leave electronic equipment on standby because they still consume energy.
    4. Limit consumption of food from the sea.
    5. Seafood definitely needs to be reduced. Many global fish stocks have declined because of unsustainable fishing practices and because humans have also caused them to lose their natural habitat
    6. Seafood definitely needs to be reduced. Do not buy endangered or overfished species. It is preferable to decide on another type of healthy, green food. Due to demand, habitat loss, and unsustainable fishing practices, global fish populations have declinedAlthough it would be far better to pressure governments to adopt measures to ban the mass consumption of endangered species, you have to start somewhere. So you take this initiative and invite all your family and friends to do the same. Say no to plastic consumption. Plastic is one of the worst enemies of the oceans. Many plastic containers and pots of multiple mass consumption products, end up in the world’s seas, with a tremendous impact on the marine habitat, because many species end up trapped, poisoned, and extinct because of such a blunder.
    7. Say no to plastic consumption.
    8. Eliminate your individual impact just by stopping consuming products packaged in plastic containers. Use commercial brands with glass jars, store food in reusable or non-disposable containers, use eco-friendly or cloth bags and recycle as much as you can at home. It’s the best way to reduce your own carbon footprint.
    9. Protect the beaches and be an activist in defense of the seas.
    10. Participate in group or community initiatives that generate responses to the problem of pollution on beaches due to the accumulation of garbage generated by swimmers. Do not become one of those, when you enjoy a sunny day at the beach, collect all your waste, and do not intervene in the habitat by appropriating rocks or corals in their natural state. Leave them in the same place where they are. Nothing will be better than respecting the marine environment.
    11. Products made from marine resources. Nothing worse than acquiring garments or ornaments produced from materials from the marine habitat, such as coral-based jewelry, or worse, items made from turtles and products made from shark species.
      Say no to aquariums. Try by all means not to breed saltwater fish in aquariums. It is also not wise to release them into the ocean because they may be non-native species that can be detrimental to the local ecosystem.
    12. Environmental activism. Another way to actively cooperate with the protection of the marine environment is with the promotion and participation in environmental organizations that protect the beaches, the entire ocean habitat. Sign up for one of these NGOs and get your friends and family excited about doing the same for the marine environment.
    13. And if you don’t have time for activism, then give a little financial support to globally recognized organizations.
    14. Sail responsibly in the ocean. If you enjoy outdoor marine activities, such as surfing, windsurfing, sailing, and other sports like scuba diving, among others, please never throw waste into the waters and respect the marine species you have the privilege of contemplating.
    15. Sail responsibly.
    16. Similarly, if you sail in sports or tourist boats, try to avoid environmental impact by spilling fuel or garbage. Be prudent and very conscious.
    17. Marine education. Take advantage of beach visits and vacations to sow in your children and other family members a higher environmental responsibility around the supreme importance of the world’s seas and oceans for planetary life.
    18. Investigate with your children as much as you can about the benefits of the world’s oceans to the planetary balance. You’ll be fascinated by what you’ll discover about the marine world.


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