MARINE BIOLOGY: WHAT IT STUDIES AND BRANCHES - BIOLOGY - 2025

The marine biology is a branch of biology that is responsible for the study of the living creatures in the sea. The marine biologist studies the different marine environments and the biotic factors that comprise it, as well as the relationships that exist between these factors and their environment.

The study of marine biology began with Aristotle; This Greek sage described numerous species of annelids, crustaceans, mollusks, echinoderms and fish. He was also the first to recognize that dolphins and whales were mammals, and made numerous contributions to oceanography.

View of the Pacific Ocean. Taken and edited from osdarin

A little less than three-quarters of the Earth's surface is covered by seawater. It is estimated that about a million species inhabit marine environments, and some of these species provide man with food, medicine and other elements.

What does marine biology study? (Field of study)

The marine biologist is in charge of identifying the species that inhabit the sea, as well as their distribution and the cause of this phenomenon. Likewise, it also studies the interaction that exists between species, and between them and their environment.

As for their life cycles, you can study their reproduction, embryonic development and population fluctuations, or their variations and inheritance. Through marine biology, the mechanisms of adaptation to the marine environment or the depths can be analyzed.

It can also determine the effects of pollution on individuals, this discipline offers the possibility of using them as indicators of pollution or environmental stress.

Bioactive

Some bioactives can be obtained from aquatic organisms. For example, the first approved anticancer drug was obtained from a species of sea squirt (a marine invertebrate).

Among the products obtained from seaweed there are substances that are used in cosmetology, pharmacy, medicine and in the food industry, among other areas.

In short, marine biology is very broad and can be studied from multiple approaches. The product of his studies ranges from pure knowledge to that which has multiple applications.

History

Aristotle

Aristotle is considered the father of marine biology, as well as the forerunner of the scientific method. He was the first to describe species from the sea and made observations about the reproduction of marine mammals. For many centuries Aristotle was thought to have studied everything about the oceans and their inhabitants.

James cook

Modern marine biology began in the 18th century. This new impetus is due to the voyages and discoveries of Captain James Cook.

During his travels he discovered and described numerous species of marine animals and plants. With Cook, the era of great exploration with oceanographic cruises began.

Charles Darwin

Charles Darwin made valuable contributions to marine biology. He made expeditions aboard the HMS Beagle (1831-1836) and was the forerunner of studies of coral reefs.

Likewise, Darwin was the first to point out that barnacles (including barnacles) were really crustaceans and not mollusks, as they were considered to date.

HMS Challenger

The voyages of HMS Challenger (under the command of Captain Sir Charles Wyville Thomson) and their results gave rise to oceanography.

They were also the basis for numerous marine biology studies over several years. More than 4,500 species new to science were collected during these expeditions.

Bathyspheres

The technological advance of the 20th century allowed researchers to descend to depths that were forbidden in previous centuries.

In 1934 it was possible to reach a depth of 923 meters in a bathysphere, and in 1960 the Trieste bathyscaphe -built by Auguste Piccard- managed to reach 10,916 m in the Las Marianas trench.

Bathysphere on display at the National Geographic Museum in Washington DC. Taken and edited from Mike Cole, via Wikimedia Commons.

Diving

Jacques Cousteau invented the scuba air tank and, together with Emilie Gagnan, designed the scuba air regulator.

These inventions gave marine biologists greater mobility and autonomy to study marine life in situ, which undoubtedly meant a great advance within the discipline.

Branches of marine biology

Marine biology is very broad, so there are several branches or subdivisions. These divisions may or may not be based on particular taxonomic groups or groups of organisms. The following are the main branches based on groups of organisms:

Marine bacteriology

Study single-celled organisms that lack a nucleus (prokaryotes).

Planctology

It is responsible for the study of all organisms that inhabit the water column and that are unable to oppose the weaker water current. Plankton includes organisms considered both animals (zooplankton) or plants (phytoplankton), in the traditional sense of these terms.

The term is traditionally associated with microscopic organisms; however, some jellyfish can grow to be over a meter in diameter.

Plankton organisms are very important, as they are the basis of almost all trophic chains in aquatic environments.

Marine botany

Study marine plants. The vast majority of aquatic plants are algae (their study is called phycology).

However, there are also so-called marine phanerogams, considered of a higher order since they contain roots, stems, and even flowers and leaves. They are very important since the grasslands of these plants form one of the most productive ecosystems in marine environments.

Malacology

Study the mollusks. This group includes clams (bivalves) and seashells (gastropods), elephant tusks (scaphopods), chitons (polylacophores), octopus, and squid (cephalopods).

Carcinology

Study the crustaceans. They are the most diverse group in terms of body shape and size, and form the most abundant group within zooplankton.

The best-known crustaceans include shrimp, crabs, and lobsters. Krill (Eufausiaceae) is the main food of the whales.

Marine shrimp Leander tenuicornis. Cubagua Island, Venezuela. Taken and edited by Jonathan Vera Caripe from Barcelona-Anzoátegui, Venezuela, via Wikimedia Commons

Ichthyology

Study fish and related groups, including jawless fish. The term "fish" currently lacks taxonomic validity, as it is a paraphyletic group; however, it is still used in the traditional way for practical purposes.

The specialists who study these organisms are still called ichthyologists.

Marine ornithology

Study seabirds. Birds adapted to live most of their lives in or near the sea are known as seabirds.

It is a name without taxonomic validity, since it groups birds from different families that share the same habitat.

Marine mammalogy

Study marine mammals. As in the case of birds, they are mammals that share the marine environment and have adapted to it.

They include mainly cetaceans (whales, dolphins), pinnipeds (seals, walruses) and sirens (manatees, dugongs).

Other branches

Some subdivisions of marine biology, not based on taxonomic groups, include marine paleontology, marine ecology, marine ethology, conservation and resource management, and the physiology of marine organisms, among others.

References

1. CR Nichols & RG Williams (2009). Encyclopedia of Marine Science. Facts On File, Inc.
2. P. Castro & ME Huber (2010). Marine Biology. McGraw-Hill.
3. History of the Study of Marine Biology. Recovered from MarineBio.org
4. A Brief History of Marine Biology and Oceanography. Recovered from Meer.org
5. Marine Biology. Recovered from en.wikipedia.org
6. What is a Marine Biologist? Recovered from environmentalscience.org