What Do Marine Biologists Do and How Much Do They Earn?

What exactly is a marine biologist? What do they actually do?

It turns out they aren’t just a bunch of people who enjoy swimming and looking at underwater creatures with a snorkel and fins. I feel like this is one of those careers that sound so arbitrary and mystifying that we don’t take the time to find out about it or pay attention to it. It turns out their job is not as abstract and insignificant as space lawyers, extreme unicyclists or penguinologists.

Marine biologists actually study for a long time to acquire the necessary skills to study and observe underwater habitats and creatures. They are responsible for the discovery of many weird, wonderful and wacky sea creatures. They play a vital role in teaching us how to maintain and preserve this incredible source of food, medicine and raw materials that can help us build our future. By studying the natural habitats of sea plants and creatures, they are able to predict changes that we may experience in the future due to climate change and other factors. They have great ideas when it comes to preserving and sustaining this source and quite frankly, I feel they should be given a round of applause. Their job is pretty cool and very necessary for all of us!

ocean view

What is a Marine Biologist?

Marine biology can be defined simply as the scientific study of organisms in the ocean or other marine bodies of water. The ocean covers approximately 71% of the Earth’s surface thus providing for extensive study and research. Because such a large portion of life on Earth is found in the ocean, it is understandable that there is still an enormous amount of species yet to be discovered!

The study of the ocean ranges from tiny surface layers of water where organisms may be trapped to the depths of the oceanic trenches. Can you imagine how deep the ocean actually is? This is something that I cannot wrap my mind around. To put it into perspective, sunlight can only reach up to 1000m, 1,828m is the lowest point of the Grand Canyon, 4,267m is the average depth of the ocean, but it is deeper still! The height of Mount Everest is 8,850m, and the ocean is deeper than this. It has been discovered that the bottom of the Mariana Trench is 11,034m deep! Now this is something I just cannot comprehend.

This video from test Tube 101 may help you get your head around the depth of the ocean!

Specific habitats that are studied within marine biology are coral reefs, kelp forests, seagrass meadows, tidepools, muddy to rocky bottoms and the open ocean zone. Specific organisms that are studied range from phytoplankton to huge wales.

Marine life holds a multitude of resources for humans, from food, to medicine to raw materials. This is an important area of study because it is a resource that needs to well understood and well cared for.

For How Long Do They Study?

A Bachelor’s degree is required to qualify as a marine biologist. This takes about 4 years. An additional 2 to 3 years are taken to complete a Master’s degree and earning a PhD will take 6 years more!

How Much Do They Earn?

Entry level pay is around $39,700 per year. Experienced biologists in the USA earn $70,800 per year and the top 10% of Marine Biologists earn up to $124,680 per year.  

lion fish

What Are Some Interesting Discoveries?


In 2008, hundreds of new species were discovered off the coast of Australia. Among these, 130 new species of soft coral, some interesting shrimp-like species and dozens of tiny crustaceans. New to science was the discovery of what they called “Isopods” which were parasites.


In 2014, some unrecognised coral species was discovered. When looking at the coral, researchers found the two species to look almost identical; they could not tell the difference by eye. What piqued their interest was that some of the coral was not bleaching. This suggested that some of the coral was responding vastly different to climate change as compared to the other coral.

After some research they discovered that genetically, the coral that looked so similar was in fact quite different. Data showed two separate lineages of coral. The next step was to research whether the two coral lived in the same way.

Firstly, they found that the new species was less susceptible to bleaching. Bleaching occurs when the symbiotic relationship between the coral and algae breaks down due to water temperature increase. The fact that this new species was not bleaching revealed to researchers that it was able to adapt to climate change. With the prediction of future climate change on the rise, this means that a shift in coral species will be evident.

They also discovered that this new species produced asexually, that is, by breaking apart. The other species however, produces sexually through its own larvae. The new species was also found to house many more mussels than the other species. Some coral are the target of biting triggerfish. These fish would bite off parts of the coral to get to the mussels and would spit out the fragments that cannot eat. With the new coral species, these fragments could easily develop into new colonies. These fish were therefore found to help the process of producing new colonies significantly.

This asexual reproduction is beneficial because coral living in harsh conditions would find it difficult to discover a suitable partner. Only a few can survive under this harsh environment and asexual reproduction results in a higher chance of survival for this new species of coral.

You can read more about this research here.


Towards the end of 2015, huge numbers of sea lions were found washing up on the shores of the Californian coast line. Marine biologists took to the case and began researching. What they discovered that due to a toxin produced by algae, the animals’ spatial memory was being impaired.  Because of their research and understanding of the animals and the environment they were in, they were able to treat and rehabilitate the animals back to health.


In 2016, marine biologists made quite an interesting discovery proving that contrary to popular belief, plastic on its own is not necessarily what is so dangerous to many of the seabirds ingesting it.

Seabirds spend most of their time in the open sea, feeding on fish, crustaceans and other food that they find on the surface of the water. Unfortunately, due to littering, plastic has been discovered in most of these birds’ digestive systems. This plastic remains in their stomachs for weeks and even months. The interesting discovery however, was that what was causing the high levels of contaminants in the birds’ system’s was not due to plastic, but due to the toxins the plastic absorbs from the food these birds feed on. However, I still don’t think we can use this as an excuse to litter carelessly!

More interesting discoveries and research can be read here.


What Have Marine Biologists Taught Us?

Acid rain

Acid rain is caused by pollution found in the atmosphere. The main causes of acid rain are the industrial burning of coal and other fossil fuels whose gases combine with atmospheric water, producing acid. Streams, lakes and marshes are mostly affected by this phenomenon. These water bodies hold a pH level of between 6 and 8.

Acid rain affects fish and other aquatic organisms, in that it reduces fish populations and in some cases, totally eliminates certain species from a waterbody. The young of a species are most sensitive to acid levels and thus many of them are not given the chance to grow to maturity. Fish eggs are not able to hatch under harsh conditions such as these either. Marine biologists are able to understand the causes of these organisms’ habitat and are therefore able to come up with solutions to protect the environment for further sustainability.

Bioluminescence – glow in the dark dinoflagellates

Bioluminescence is light produced by a chemical reaction within a living organism. Most bioluminescent  organisms are found in the ocean. They include organisms such as fish, bacteria and jelly.

Bioluminescent dinoflagellates are a type of plankton that can sometimes cause the surface of the ocean to sparkle at night. Can you imagine anything that would look more breath-taking than a glow-in-the-dark ocean? Bioluminescent dinoflagellate ecosystems are rare and mostly occur in warm-water lagoons with openings to the sea. Bioluminescent light is expressed in the blue-green light spectrum. These colours are most visible in the deep ocean and this light is used to hunt prey, defend against predators and find a mate.

It can be used as a defence mechanism in that some species uses this luminescence to confuse their predators. For example, a deep-sea squid ejects a bioluminescent mucus which startles and delays its predator while it quickly escapes. Starfish are able to detach parts of their bodies to distract their predators. While the predator follows the glowing arm, the starfish is able to crawl away quickly and unnoticed to safety.

Some species use their bioluminescent abilities to catch prey. Finding Nemo may have been our first introduction to bioluminescent species. We all remember the anglerfish with a long, thin growth and ball on the top of its head. The fish can turn this light on and off. When its prey sees the light, it curiously swims up for a closer look but by then, it’s already too late and the prey is behind the sharp teeth of the anglerfish. Except for Dori and Nemo of course. They were lucky cases.

Marine biologists also discovered that some species rely on organisms with bioluminescence to capture their own food. For example, sperm whales may seek out bioluminescent plankton even though they are not part of the whale’s diet. The whales will rely on the plankton to let him know when fish are around. Plankton “switch on their lights” when their predators are identified and this glowing in turn alerts the whales that their meal has arrived.


The cause of the rising and falling of ocean levels with respect to land is due to gravity. As the Earth spins on its axis, the ocean water is kept at an equal level around the globe due to gravitational forces. The Moon’s gravitational forces however, are stronger. Gravitational forces from the Moon are able to disrupt this balance. The water “bulges”, and follows the direction of the Moon as it continues its orbit. The areas of the Earth where the water “bulges” are areas that experience high tide.

Marine biologists hold many avenues for research and development, such as researching marine organisms, the discovery of medications from marine bacteria, providing the seafood industry with sustainable food choices and tagging and tracking whales, sharks and dolphins to learn better their behaviour.

We would never have known half the information we know about the ocean, had it not been for marine biologists! Do you harbour a dream to become one? Or maybe you know of another important contribution they have made to our understanding of the ocean. Please comment below, we would love to hear from you.


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