What is Marine Biology?
Marine Biology versus Biological Oceanography
Marine Biology
marine biology is the study of life in the oceans and other saltwater environments such as estuaries and wetlands. All plant and animal life forms are included from the microscopic picoplankton all the way to the majestic blue whale, the largest creature in the seaand for that matter in the world.

The study of marine biology includes a wide variety of disciplines such as astronomy, biological oceanography, cellular biology, chemistry, ecology, geology, meteorology, molecular biology, physical oceanography and zoology and the new science of marine conservation biology draws on many longstanding scientific disciplines such as marine ecology, biogeography, zoology, botany, genetics, fisheries biology, anthropology, economics and law.

These steps are all used in the study of marine biology, which includes numerous sub fields including:
Microbiology: The study of microorganisms, such as bacteria, viruses, protozoa and algae, is conducted for numerous reasons. One example is to understand what role microorganisms play in marine ecosystems. For example, bacteria are critical to the biological processes of the ocean, as they comprise 98% of the ocean''s biomass, which is the total weight of all organisms in a given volume. Microbiology is also important to our understanding of the food chain that connects plants to herbivorous and carnivorous animals. The first level in the food chain is primary production, which occurs at the microbial level. This is an important biological activity to understand as primary production drives the entire food chain.

Fisheries and Aquaculture: to protect biodiversity and to create sustainable seafood sources because of the world''s dependence on fish for protein. There are many areas of study in this field. The ecology of fisheries includes the study of their population dynamics, reproduction, behavior, food webs, and habitat.

Fisheries management includes studies on the impact of overfishing, habitat destruction, pollution and toxin levels, and ways to increase populations for sustainability as seafood.

Aquaculture includes research on the development of individual organisms and their environment. The objective is most often to develop the knowledge needed to cultivate certain species in a designated area in open water or in captivity in order to meet consumer demand. Technological advances have enabled seafood "farms" to produce high-demand products that traditional commercial fisheries cannot meet. This is a controversial area however, and an issue that will become of greater importance as our fish stocks continue to decline.

Environmental marine biology: includes the study of ocean health. It is important for scientists to determine the quality of the marine environment to ensure water quality is sufficient to sustain a healthy environment. Coastal environmental health is an important area of environmental marine biology so that scientists can determine the impact of coastal development on water quality for the safety of people visiting the beaches and to maintain a healthy marine environment. Pollutants, sediment, runoff are all potential threats to marine health in coastal areas. Offshore marine environmental health is also studied, for example an environmental biologist might be required to study the impact of an oil spill or other chemical hazard in the ocean. Environmental biologists also study Benthic environments on the ocean bottom in order to understand such issues as the chemical makeup of sediment, impact of erosion, and the impact of dredging ocean bottoms on the marine environment.

Deep-sea ecology: advances in technology of equipment needed to explore the deep sea have opened the door to the study of this largely unknown space in the sea. The biological characteristics and processes in the deep-sea environment are of great interest to scientists. Research includes the study of: deep ocean gases as an alternate energy source, how animals of the deep live in the dark, cold, high pressure environment, deep sea hydrothermal vents and the lush biological communities they support.

Ichthyology: is the study of fishes, both salt and freshwater species. There are some 25,000+ species of fishes including: bony fishes, cartilaginous fishes, sharks, skates, rays, and jawless fishes. Ichthyologists study all aspects of fish from their classification, to their morphology, evolution, behavior, diversity, and ecology. Many ichthyologists are also involved in the field of aquaculture and fisheries.
Marine mammology: This is the field of interest to most aspiring marine biologists. It is the study of cetaceansfamilies of whales and dolphins, and pinnipedsfamilies of seals, sea lions, and the walrus. Their behaviors, habitats, health, reproduction, and populations are all studied. These are some of the most fascinating creatures in the sea, therefore this is an extremely competitive field, and difficult to break into because the competition for research funding is also quite heavy.
One area of research currently being conducted on whales is the impact of military sonar on their health and well being. The scientific community believes that high frequency sound waves cause internal damage and bleeding in the brains of whales, yet the military denies this claim. Military sonar can also interfere with the animal''s own use of sonar for communication and echolocation. More research is needed, however in recent years science has proven the claims to be valid and the military has begun limiting its use of sonar in specific areas.
Marine ethology: The behavior of marine animals is studied so that we understand the animals that share the planet with us. This is also an important field for help in understanding how to protect endangered species, or how to help species whose habitats are threatened by man or natural phenomena. The study of marine animal behavior usually falls under the category of ethology because most often marine species must be observed in their natural environment, although there are many marine species observed in controlled environments as well. Sharks are most often studied in their natural habitat for obvious reasons.
Why Study Marine Biology?
Health of the oceans/planet
Climate change
Pollution (toxicology, dumping, runoff, impact of recreation, blooms)
Coral reefs
Invasive species....
Human health
Air quality
Dissolution of carbon dioxide....
Sustainability and biodiversity
Endangered species
Impacts on the food chain....
Research and product development
Biomedical applications
Alternate energy sources....

Litoral Zone

Text Version
These storms usually occur in the afternoon and can cause wind shear, heavy rain, hail and high winds. They are a danger to airborne operations and can hurt communications and the ability to move around the land.
Winds blowing off the shore can travel at speeds of 4 to 6 knots and extend 5 to 10 nautical miles. These winds, which can carry smoke, fog and dust offshore, can reduce visibility and hurt coastal operations.
Winds can blow from the ocean onto the shore at speeds of 8 to 14 knots and extend as much as 5 to 10 nautical miles. They can make the waves taller and, if coastal hills are present, create clouds as the moist sea air is lifted over the hill. These winds make periscope and mine detection harder and can block inland targets as the waves become higher.
Features on land can disrupt the wind''s flow. For example, the wind patterns above a mountain can differ from the wind patterns around the mountain. This creates wind shear. Wind shear happens when wind flows in different directions or at different speeds over a short amount of space. How does this affect the Navy? Think about aircraft flying in low to drop parachutes or gliders or helicopters flying in to drop off or pick up soldiers. The wind shear could cause turbulence, which would make these missions dangerous.
Where a river meets the ocean, fresh water flows into salty water. The colder river waters are often less dense than the warmer ocean waters. The density differences can create distinct layers in the relatively shallow waters. A submarine or diver operating in this environment would have to alter its buoyancy to adjust to the density changes. Also, a river flowing into the ocean often brings a load of sediment into the ocean. This can alter in the shape of the ocean bottom, which would create problems for submarines and divers.
Reefs are usually found in shallow tropical waters, but bars and channels can form almost anywhere. Bars and channels are known to change slowly with the turn of the seasons or daily with tides and currents. Boats, submarines, swimmers and torpedoes must all take care when approaching any of these. These features may also get in the way of sonar systems.
Most shipwrecks occur near shore. They can be a problem to avoid, or they can help submarines, which can linger close to them and avoid being spotted.
Some organisms that float on the surface can produce their own light. This ability is called bioluminescence. Swimmers, periscopes, boats and submarines must all be careful when traveling along the water''s surface. Disturbances cause the bioluminescent organisms to glow. Because of these glowing organisms, a ship''s wake may be visible for 6 nautical miles!
Tides or currents may disturb water, which is separated into distinct layers because of density. These disturbances can change the depth of the thermocline. Submarines and other submerged vehicles may have to alter their buoyancy to maintain depth.
Dangerous marine life (e.g., jellyfish, scorpion fish, saltwater crocodiles) may be present, and typically there is more marine life present than in near-surface open ocean. These creatures may harm divers.
Sand profiles change seasonally and often after a storm. Beaches with sandbars often have rip currents. Equipment-laden troops can drown in the deep trough in between a sandbar and the shore. Waves can damage amphibious watercraft.
Coastal currents are caused by the wind, tides and sea surface slope and can travel at speeds greater than 4 knots. These currents can change rapidly, making charts of the currents useless. These currents affect all operations near the coast.
Sea ice attached to the coast can extend on top of waters with 2 to 25 meters (6.5 to 82 feet) depth, sometimes up to 100 to 200 kilometers (62.1 to 124.2 miles) depth around offshore islands. The ice, which can be 2 to 3 meters (6.6 to 9.8 feet) thick, can completely block or severely restrict channels and bays. The ice also changes the salinity of the water. Ice causes problems to ships and submarines, which have to steer around or dive beneath it. It can block swimmers and torpedoes.

marine biology
Ocean In Motion
Coastal Currents
Quick Quiz
Quick Quiz
Beaufort Wind Scale
The Navy & Waves

Animal & Plant Life
Humans & the Environment
Quick Quiz
Coral Reefs
Location/ Reef Life
Humans & the Environment
Quick Quiz
Estuary Life
Salt Marshes
Humans & the Environment
Quick Quiz
Hydrothermal Vents
Hydrothermal Vent Life
Humans & the Environment
Quick Quiz
Kelp Forests
Animal Life
Humans & the Environment
Quick Quiz
Sea Grass Beds
Sea Life
Humans & the Environment

Marine Mammals
Migration & Distribution
Quick Quiz
California Sea Lion
Status & Threats
Current Research
Green Sea Turtle
Current Research

Ocean Water

Ocean Regions
Blue Water
Deep Ocean
Humans & the Environment
Quick Quiz
Littoral Zone
The Navy & the Littoral Zone
Ocean Floor
Continental Margin & Rise
Deep Ocean Basin
Mid-Ocean Ridge

Research Vessels
Surfaces Vessels
Other Vessels

Experiments with the CyberScientist
Why Don''t Big Ships Sink?
Saltwater vs. Freshwater, which is Heavier?
Saltwater vs. Freshwater, which is Denser?

Marine Biology
Life in the Ocean
1. Classification
! Of environments, Of organisms
2. Distribution of species
! Pros & cons of the salty life
! Limiting factors, Adaptations
3. Energy & Food (or, Energy = Food)
! Photosynthesis, Chemosynthesis
! Primary productivity, Biomass
! Biogeochemical cycles
! Trophic pyramid, Food webs
4. Classifification & Change
! Ecosystems, Communities, Populations
! Taxonomy, Kingdoms, Phylogeny, Diversity
! Mass extinctions

Classification & Systems of Liiviing Thiings
Hierarchy: Biosphere to Atom
Taxonomy (classification & naming)
Artificial, Linnaean, Natural; The 6 Kingdoms
Phylogeny (evolutionary relationships)
Species Diversity
Abundances; Some mechanisms for speciation
Ecosystems (= community + habitat)
Communities (of different species)
Change; Interactions (+, , o)
Populations (of one species)
Distribution patterns; Growth & change; Limiting factors

Biosphere = The sum total of living things on Earth and the
areas they inhabit
Ecosystem = A functional system consisting of a community,
its non-living environment, and the interactions between them
= Community + Habitat
Community = Set of populations of different species living
together in a particular area
Habitat = an organisms address in the community (location)
Niche = its job there (relationships to food, enemies, etc)
Population = A group of individuals of one species that live in
a particular area
Distribution patterns; Growth and change; Limiting factors
Competition - For resources (food, light, space, etc) - Between and/or
within populations
Organism = An individual living thing
Organ ! Tissue ! Cell ! Molecule ! Atom

An example from the oceans
Marine foraminifera of genus Globorotalia --
recovered from complete, uninterrupted,
well-dated sections of deep-sea cores --
indicate an evolutionary line of descent that
produced at least 4 species of this genus
over a span of ~8 million years.

Diversity of Life
1. All populations have the potential to increase in size
2. Many populations retain a constant size
Many individuals die young (limited carrying capacity)
3. Individuals in a population differ in their abilities
Some of these abilities affect survival
4. Best-adapted individuals are most likely to survive and
produce offspring (natural selection)
Some abilities (heritable traits) are passed on to offspring
5. Net result: Over time, the abilities of the population shift to
include advantageous traits -- Populations change with time
to become better adapted to their environment (evolution)
Natural selection affects individuals
Evolution affects populations (individuals do not evolve

Primary Productivity
Primary productivity = The synthesis of organic materials
from inorganic substances by photosynthesis or
Units = ( g C ) / ( m2 x yr )
= Grams (mass) of carbon bound into carbohydrates, per squaremeter
of ocean surface-area, per year
Phytoplankton (e.g., diatoms) make 90-96% of oceanic
carbohydrates (food)
Seaweeds = ~2-5%, Chemosynthesis = ~2-5%
Biomass = Mass of living tissue (Units = grams)


National Geographic: Marine Biology
How is Marine Biology Studied?
Trawling - has been used in the past to collect marine specimens for study, however trawling can be very damaging to delicate marine environments and it is difficult to collect samples discriminately. However, when used in the midwater environment, trawls can be every effective at collecting samples of elusive species with a wide migratory range.
Plankton nets - plankton nets have a very fine weave to catch microscopic organisms in seawater for study.
Remotely operated vehicles (ROVs) - have been used underwater since the 1950s. ROVs are basically unmanned submarine robots with umbilical cables used to transmit data between the vehicle and researcher for remote operation in areas where diving is constrained by health or other hazards. ROVs are often fitted with video and still cameras as well as with mechanical tools for specimen retrieval and measurements.
Underwater habitats - the National Oceanic and Atmospheric Administration (NOAA) operates Aquarius, a habitat 20 meters beneath the surface where researchers can live and work underwater for extended periods.
Fiber optics - Fiber optic observational equipment uses LED light (red light illumination) and low light cameras that do not disturb deep-sea life to capture the behaviors and characteristics of these creatures in their natural habitat.
Satellites - are used to measure vast geographic ocean data such as the temperature and color of the ocean. Temperature data can provide information on a variety of ocean characteristics such as currents, cold upwelling, climate, and warm water currents such as the Gulf Stream.

Satellites are also used for mapping marine areas such as coral reefs and for tracking marine life tagged with sensors to determine migratory patterns.
Sounding - hydrophones, the microphone''s counterpart, detect and record acoustic signals in the ocean. Sound data can be used to monitor waves, marine mammals, ships, and other ocean activities.
Sonar - similar to sounding, sonar is used to find large objects in the water and to measure the ocean''s depth (bathymetry). Sound waves last longer in water than in air, and are therefore useful to detect underwater echoes.
Computers - sophisticated computer technology is used to collect, process, analyze, and display data from sensors placed in the marine environment to measure temperature, depth, navigation, salinity, and meteorological data. NOAA implemented computer technology aboard its research vessels to standardize the way this data is managed

Brief History of Marine Biology
A History of the Study of Marine Biology
Captain James Cook (1728-1779)
Charles Darwin (1809-1882)
Sir Charles Wyville Thomson (1830-1882)
William Beebe (1877-1962) and Otis Barton
Rachel Carson (1907-1964)
Dr. Sylvia Earle (1935-)
Dr. Robert Ballard (1942-),
Jacques Cousteau''s (1910-1997)
Dr. Hans Hass (1919-),

Linnaean Taxonomic System
To demonstrate how an organism is classified, let us use the classification of the commonly named the blue whale. The information provided by this common name is not enough to put the whale into any evolutionary relationship with other organisms. Scientists however, call the blue whale by its scientific nameBalaenoptera musculus. An example of how scientists would classify and name a blue whale is as follows:

All whales are animals because they have more than one cell, eat food and originate from a fertilized eggso they first are categorized into the most general categoryKingdom Animalia.

Whales are placed into the Phylum Chordata (the category below Kingdom) because they have a spinal cord and gill pouches. In fact, humans are also in Phylum Chordata.

Because they are warm-blooded, produce milk for their young and have a heart with four chambers, whales are in the Class Mammalia.

At the Order category, whales begin to be distinguished from humans and other land mammals. Whales are classified as cetaceans because they live in the water all year round. The suborder is Mysticeti due to the baleen plates in the mouths of whales, helping them to filter in food.

Blue whales have folds around their throat that expand to take in large volumes of water when feeding. Because not all whales have this characteristic, blue whales are placed into the Family Balaenidae.

Within the Family is another group of species more immediately related to each other. The Genus for blue whales is Balaenoptera.

The definition of a species includes many factors, especially the requirement that individuals must be able to successfully breed with each other. The species name for blue whales is musculus, meaning that in addition to other common traits, whales of the species musculus are able to breed with each other and provide viable (living) offspring. The final scientific name is Balaenoptera musculus with the genus capitalized and the species name in lower case letters and both italicized.

Phylogenetic Trees

A phylogenetic tree is similar to a family tree except that it shows evolutionary relationships between species rather than relationships between individuals. Phylogenetic trees contain a lot of information and can reveal how far back in time a species began, along with the most recent common ancestors between species. DNA analysis is used to provide information to support the construction of phylogenetic trees. Every node on a phylogenetic tree is referred to as a taxonomic unit and represents a common ancestor. Scientists can zoom in on a particular part of a phylogenetic tree, omitting the root of the tree in order to focus on a particular segment. A rooted tree is simply the bigger, zoomed-out picture.

The Science of Classification

World Register of Marine Species (WoRMS)

European Register of Marine Species (ERMS),

Flanders Marine Institute (VLIZ).

Algae Base

Fish Base



Phytoplankton and Marine plants
The plant kingdom is made up of multicellular, photosynthetic eukaryotes.These multicellular organisms contain specialized cells that perform different tasks. Algae are some of the simplest aquatic plants, often referred to as seaweed in the marine environment. Marine algae are abundant throughout the ocean and can either float freely or cling to substrate such as rocks and reefs. The majority of seaweeds are classified as red algae (~6,000 species). There are also brown algae (~1,750 species) and green algae (~1,200 species). None of the algae species are known to be poisonous, and many species are harvested for human consumption. Find out more at The Seaweed Site.

Phytoplankton are microalgae that form an essential component of the marine food chain. These single-celled plants provide nourishment to many marine species and they also play an important role in regulating the amount of carbon in the atmosphere. There are two main types of the larger phytoplankton species: Diatoms and Dinoflagellates. Smaller phytoplankton categorized as nanoplankton and picoplankton.

The cell walls of diatoms are made of silica formed into their characteristic "pillbox" shape. Diatoms are composed of two valves or frustules, one on top of the other, within which the living matter of the diatom is found. Diatoms are either found singly where each individual lives in a single box, or found in chains. Diatoms reproduce by dividing in half. One half is attached to the top valve, the other is attached to the bottom valve. Once the division takes place, each half creates a new valve to form another whole. The new valve is secreted in the old valve, therefore the average size of each diatom is reduced with every new generation. It is thought that as many as 50,000 species of diatoms have inhabited the earth. They occur in both fresh and salt water. See also "What are diatoms?"

Dinoflagellates are the other primary form of large phytoplankton with about 2,000 species. Unlike diatoms, dinoflagellates are mobile through the use of a flagella. Also unlike diatoms, they do not have an external skeleton made of silica, however they are protected by cellulose.

Algae - Visit AlgaeBase (123,313 species)

Division Rhodophyta (Red Algae)
Red algae grow as single-celled plants or plants that grow as filaments, branched plants, broad flat plates, and ruffled plants. They come in a variety of sizes, but most red algae are small. All species attach to substrate such as rock or coral and sometimes to an animal shell or even another algae species.

Division Phaeophyta (Brown Algae)
Brown algae contain the largest and most complex algae plants. Pacific kelp are a brown algae species. There are no unicellular or colonial forms of brown algae. Brown algae stores food reserves as a substance called laminarin, similar to a lesser known species of gold algae in the division Chrysotphyta. Brown and gold algae also have in common the presence of flagellated cells of both sperm and motile spores. Brown algae are commonly found attached to substrate in cool, shallow waters near the shore in temperate and subpolar regions. Some forms of brown algae have developed adaptations to survive life on the coast where they may be pounded by surf or submerged then exposed with the tide. Large brown algae are used as shelter for some bottom-dwelling animals. They also provide serve as substrate for other algae that grow as epiphytes, or plants that grow on other plants.

Alaria esculenta (Dabberlocks, Wing Kelp, Murlins)
Ascophyllum nodosum (Asco, Sea Whistle, Bladderwrack)
Fucus serratus (Serrated Wrack)
Fucus spiralis (Spiralled Wrack)
Fucus vesiculosus (Bladderwrack)
Laminaria saccharina (Sugar Kelp)
Laminaria hyperborea (Kelp, May Weed)
Laminaria digitata (Kelp)
Laminaria ochroleuca (Kelp)
Macrocystis pyrifera (Giant Pacific Kelp)

Division Chlorophyta (Green Algae)
Chlorophyta (green algae) is the most biodiverse of the algaes with species that grow in a variety of forms and in a variety of habitats. They are typically small and simple, with many single-celled species, some that form branched filaments, hollow balls of cells, or broad, flat sheets. Some species attach to sandy shores by secreting a calcareous cement rather than holdfasts that might shift with the sand and become unstable.

Ulva compressa
Ulva rigida (Sea Lettuce)

Seagrasses, unlike seaweed, are flowering plants that live submerged in the marine environment. There are an estimated 50 species of seagrasses worldwide, most of which are found in the tropics. Seagrass beds grow in shallow waters forming thick beds that provide an important habitat for marine life in temperate and tropical seas. These habitats vary in size and abundance from isolated patches to a continuous area that grows for miles. In waters with a lot of wave activity, beds tend to be patchy. In calmer waters, seagrass beds tend to carpet the seafloor.

Seagrasses typically grow as long, thin leaves with air channels that grow up from a creeping rhizome. Seagrasses are found from the mid-intertidal region to depths of 50 m. Most species grow in soft substrates, such as sand, and form a dense mat of entwined rhizomes and roots that not only secure the plant, but also stabilize sediment. They also absorb wave motion and slow currents.

Kelp Beds: Forests of the Sea
As mentioned previously, Pacific kelp is a large species of brown algae.

Macrocystis and Nereocystis are the two genera that make up most kelp forests on the Pacific coast of North America.

Coral Reefs
The Variety of Coral Reefs - excellent photos!!!!!!

Deep-sea Corals May Be Oldest Living Marine Organism

Zooplankton (zoh-plankton) are tiny animals found in all ocean zones, particularly the pelagic and littoral zones in the ocean, but also in ponds, lakes, and rivers. They are a key component of marine ecosystems.


Zooplankton are classified by size and/or by developmental stage. Size categories include: picoplankton that measure less than 2 micrometers, nanoplankton measure between 2-20 micrometers, microplankton measure between 20-200 micrometers, mesoplankton measure between 0.2-20 millimeters, macroplankton measure between 20-200 millimeters, and the megaplankton, which measure over 200 millimeters (almost 8 inches). There are two categories used to classify zooplankton by their stage of development: meroplankton and holoplankton. Meroplankton are actually larvae that eventually change into worms, mollusks, crustaceans, coral, echinoderms, fishes, or insects. Holoplankton remain plankton for their entire life cycle and include pteropods, chaetognaths, larvaceans, siphonophores, and copepods.

Meroplankton and holoplankton are a component of almost every taxonomic group. However, the most common plankton are protists, nanoplanktonic flagellates, cnidarians, ctenophores, rotifers, chaetognatha, veliger larvae, copepods, cladocera, euphausids, krill and tunicates. Protists produce energy by photosynthesis and form the base of marine food webs as primary producers. Protozoa are also protists and are similar to animals. Protozoa make up a huge part of micro and nanozooplankton, such as amoebas, ciliates, and flagellates. These animals do not photosynthesize energy. Some amoebas such as those classified as Foraminifera and Actinopoda have hard skeletons, usually larger than 2 millimeters in diameter, that help form deep-sea sediment.

Marine Invertebrates
Animals that lack backbones are known as invertebrates. Over 98% of species on Earth are invertebrates that rely on other strategies than a backbone for support such as hydrostatic pressure, exoskeletons, shells, and in some, even glass spicules. Some invertebrate phylums have only one species, while others like Arthropoda include more than 83% of all described animal species with over a million species. The most common marine invertebrates are sponges, cnidarians, marine worms, lophophorates, mollusks, arthropods, echinoderms and the hemichordates.


Marine Worms





Class Cephalopoda

Marine Vertebrates

The Structures & Adaptations to Marine Living
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