Marine biology is the scientific study of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather than on taxonomy.
A large proportion of all life on Earth lives in the ocean. The exact size of this large proportion is unknown, since many ocean species are still to be discovered. The ocean is a complex three-dimensional world covering approximately 71% of the Earth's surface. The habitats studied in marine biology include everything from the tiny layers of surface water in which organisms and abiotic items may be trapped in surface tension between the ocean and atmosphere, to the depths of the oceanic trenches, sometimes 10,000 meters or more beneath the surface of the ocean. Specific habitats include coral reefs, kelp forests, seagrass meadows, the surrounds of seamounts and thermal vents, tidepools, muddy, sandy and rocky bottoms, and the open ocean (pelagic) zone, where solid objects are rare and the surface of the water is the only visible boundary. The organisms studied range from microscopic phytoplankton and zooplankton to huge cetaceans (whales) 25–32 meters (82–105 feet) in length. Marine ecology is the study of how marine organisms interact with each other and the environment.
Marine life is a vast resource, providing food, medicine, and raw materials, in addition to helping to support recreation and tourism all over the world. At a fundamental level, marine life helps determine the very nature of our planet. Marine organisms contribute significantly to the oxygen cycle, and are involved in the regulation of the Earth's climate. Shorelines are in part shaped and protected by marine life, and some marine organisms even help create new land.
Many species are economically important to humans, including both finfish and shellfish. It is also becoming understood that the well-being of marine organisms and other organisms are linked in fundamental ways. The human body of knowledge regarding the relationship between life in the sea and important cycles is rapidly growing, with new discoveries being made nearly every day. These cycles include those of matter (such as the carbon cycle) and of air (such as Earth's respiration, and movement of energy through ecosystems including the ocean). Large areas beneath the ocean surface still remain effectively unexplored.
The study of marine biology dates back to Aristotle (384–322 BC), who made many observations of life in the sea around Lesbos, laying the foundation for many future discoveries. In 1768, Samuel Gottlieb Gmelin (1744–1774) published the Historia Fucorum, the first work dedicated to marine algae and the first book on marine biology to use the then new binomial nomenclature of Linnaeus. It included elaborate illustrations of seaweed and marine algae on folded leaves. The British naturalist Edward Forbes (1815–1854) is generally regarded as the founder of the science of marine biology. The pace of oceanographic and marine biology studies quickly accelerated during the course of the 19th century.
The observations made in the first studies of marine biology fueled the age of discovery and exploration that followed. During this time, a vast amount of knowledge was gained about the life that exists in the oceans of the world. Many voyages contributed significantly to this pool of knowledge. Among the most significant were the voyages of HMS Beagle where Charles Darwin came up with his theories of evolution and on the formation of coral reefs. Another important expedition was undertaken by HMS Challenger, where findings were made of unexpectedly high species diversity among fauna stimulating much theorizing by population ecologists on how such varieties of life could be maintained in what was thought to be such a hostile environment. This era was important for the history of marine biology but naturalists were still limited in their studies because they lacked technology that would allow them to adequately examine species that lived in deep parts of the oceans.
The creation of marine laboratories was important because it allowed marine biologists to conduct research and process their specimens from expeditions. The oldest marine laboratory in the world, Station biologique de Roscoff, was established in France in 1872. In the United States, the Scripps Institution of Oceanography dates back to 1903, while the prominent Woods Hole Oceanographic Institute was founded in 1930. The development of technology such as sound navigation ranging, scuba diving gear, submersibles and remotely operated vehicles allowed marine biologists to discover and explore life in deep oceans that was once thought to not exist.
As inhabitants of the largest environment on Earth, microbial marine systems drive changes in every global system. Microbes are responsible for virtually all the photosynthesis that occurs in the ocean, as well as the cycling of carbon, nitrogen, phosphorus and other nutrients and trace elements.
Microscopic life undersea is incredibly diverse and still poorly understood. For example, the role of viruses in marine ecosystems is barely being explored even in the beginning of the 21st century.
The role of phytoplankton is better understood due to their critical position as the most numerous primary producers on Earth. Phytoplankton are categorized into cyanobacteria (also called blue-green algae/bacteria), various types of algae (red, green, brown, and yellow-green), diatoms, dinoflagellates, euglenoids, coccolithophorids, cryptomonads, chrysophytes, chlorophytes, prasinophytes, and silicoflagellates.
Zooplankton tend to be somewhat larger, and not all are microscopic. Many Protozoa are zooplankton, including dinoflagellates, zooflagellates, foraminiferans, and radiolarians. Some of these (such as dinoflagellates) are also phytoplankton; the distinction between plants and animals often breaks down in very small organisms. Other zooplankton include cnidarians, ctenophores, chaetognaths, molluscs, arthropods, urochordates, and annelids such as polychaetes. Many larger animals begin their life as zooplankton before they become large enough to take their familiar forms. Two examples are fish larvae and sea stars (also called starfish).
Microscopic algae and plants provide important habitats for life, sometimes acting as hiding places for larval forms of larger fish and foraging places for invertebrates.
Algal life is widespread and very diverse under the ocean. Microscopic photosynthetic algae contribute a larger proportion of the world's photosynthetic output than all the terrestrial forests combined. Most of the niche occupied by sub plants on land is actually occupied by macroscopic algae in the ocean, such as Sargassum and kelp, which are commonly known as seaweeds that create kelp forests.
Plants that survive in the sea are often found in shallow waters, such as the seagrasses (examples of which are eelgrass, Zostera, and turtle grass, Thalassia). These plants have adapted to the high salinity of the ocean environment. The intertidal zone is also a good place to find plant life in the sea, where mangroves or cordgrass or beach grass might grow.
As on land, invertebrates make up a huge portion of all life in the sea. Invertebrate sea life includes Cnidaria such as jellyfish and sea anemones; Ctenophora; sea worms including the phyla Platyhelminthes, Nemertea, Annelida, Sipuncula, Echiura, Chaetognatha, and Phoronida; Mollusca including shellfish, squid, octopus; Arthropoda including Chelicerata and Crustacea; Porifera; Bryozoa; Echinodermata including starfish; and Urochordata including sea squirts or tunicates. Invertebrates have no backbone. There are over a million species.
Over 1500 species of fungi are known from marine environments. These are parasitic on marine algae or animals, or are saprobes on algae, corals, protozoan cysts, sea grasses, wood and other substrata, and can also be found in sea foam. Spores of many species have special appendages which facilitate attachment to the substratum. A very diverse range of unusual secondary metabolites is produced by marine fungi.
Reptiles which inhabit or frequent the sea include sea turtles, sea snakes, terrapins, the marine iguana, and the saltwater crocodile. Most extant marine reptiles, except for some sea snakes, are oviparous and need to return to land to lay their eggs. Thus most species, excepting sea turtles, spend most of their lives on or near land rather than in the ocean. Despite their marine adaptations, most sea snakes prefer shallow waters nearby land, around islands, especially waters that are somewhat sheltered, as well as near estuaries. Some extinct marine reptiles, such as ichthyosaurs, evolved to be viviparous and had no requirement to return to land.
Birds adapted to living in the marine environment are often called seabirds. Examples include albatross, penguins, gannets, and auks. Although they spend most of their lives in the ocean, species such as gulls can often be found thousands of miles inland.
There are five main types of marine mammals, namely cetaceans (toothed whales and baleen whales); sirenians such as manatees; pinnipeds including seals and the walrus; sea otters; and the polar bear. All are air-breathing, and while some such as the sperm whale can dive for prolonged periods, all must return to the surface to breathe.
Marine habitats can be divided into coastal and open ocean habitats. Coastal habitats are found in the area that extends from the shoreline to the edge of the continental shelf. Most marine life is found in coastal habitats, even though the shelf area occupies only seven percent of the total ocean area. Open ocean habitats are found in the deep ocean beyond the edge of the continental shelf. Alternatively, marine habitats can be divided into pelagic and demersal habitats. Pelagic habitats are found near the surface or in the open water column, away from the bottom of the ocean and affected by ocean currents, while demersal habitats are near or on the bottom. Marine habitats can be modified by their inhabitants. Some marine organisms, like corals, kelp and sea grasses, are ecosystem engineers which reshape the marine environment to the point where they create further habitat for other organisms.
Intertidal zones, the areas that are close to the shore, are constantly being exposed and covered by the ocean's tides. A huge array of life can be found within this zone. Shore habitats span from the upper intertidal zones to the area where land vegetation takes prominence. It can be underwater anywhere from daily to very infrequently. Many species here are scavengers, living off of sea life that is washed up on the shore. Many land animals also make much use of the shore and intertidal habitats. A subgroup of organisms in this habitat bores and grinds exposed rock through the process of bioerosion.
Estuaries are also near shore and influenced by the tides. An estuary is a partially enclosed coastal body of water with one or more rivers or streams flowing into it and with a free connection to the open sea. Estuaries form a transition zone between freshwater river environments and saltwater maritime environments. They are subject both to marine influences—such as tides, waves, and the influx of saline water—and to riverine influences—such as flows of fresh water and sediment. The shifting flows of both sea water and fresh water provide high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world.
Reefs comprise some of the densest and most diverse habitats in the world. The best-known types of reefs are tropical coral reefs which exist in most tropical waters; however, reefs can also exist in cold water. Reefs are built up by corals and other calcium-depositing animals, usually on top of a rocky outcrop on the ocean floor. Reefs can also grow on other surfaces, which has made it possible to create artificial reefs. Coral reefs also support a huge community of life, including the corals themselves, their symbiotic zooxanthellae, tropical fish and many other organisms.
Much attention in marine biology is focused on coral reefs and the El Niño weather phenomenon. In 1998, coral reefs experienced the most severe mass bleaching events on record, when vast expanses of reefs across the world died because sea surface temperatures rose well above normal. Some reefs are recovering, but scientists say that between 50% and 70% of the world's coral reefs are now endangered and predict that global warming could exacerbate this trend.
The open ocean is relatively unproductive because of a lack of nutrients, yet because it is so vast, in total it produces the most primary productivity. The open ocean is separated into different zones, and the different zones each have different ecologies. Zones which vary according to their depth include the epipelagic, mesopelagic, bathypelagic, abyssopelagic, and hadopelagic zones. Zones which vary by the amount of light they receive include the photic and aphotic zones. Much of the aphotic zone's energy is supplied by the open ocean in the form of detritus.
The deepest recorded oceanic trench measured to date is the Mariana Trench, near the Philippines, in the Pacific Ocean at 10,924 m (35,840 ft). At such depths, water pressure is extreme and there is no sunlight, but some life still exists. A white flatfish, a shrimp and a jellyfish were seen by the American crew of the bathyscaphe Trieste when it dove to the bottom in 1960. In general, the deep sea is considered to start at the aphotic zone, the point where sunlight loses its power of transference through the water. Many life forms that live at these depths have the ability to create their own light known as bio-luminescence. Marine life also flourishes around seamounts that rise from the depths, where fish and other sea life congregate to spawn and feed. Hydrothermal vents along the mid-ocean ridge spreading centers act as oases, as do their opposites, cold seeps. Such places support unique biomes and many new microbes and other lifeforms have been discovered at these locations .
The marine ecosystem is large, and thus there are many sub-fields of marine biology. Most involve studying specializations of particular animal groups, such as phycology, invertebrate zoology and ichthyology. Other subfields study the physical effects of continual immersion in sea water and the ocean in general, adaptation to a salty environment, and the effects of changing various oceanic properties on marine life. A subfield of marine biology studies the relationships between oceans and ocean life, and global warming and environmental issues (such as carbon dioxide displacement). Recent marine biotechnology has focused largely on marine biomolecules, especially proteins, that may have uses in medicine or engineering. Marine environments are the home to many exotic biological materials that may inspire biomimetic materials.
Marine biology is a branch of biology. It is closely linked to oceanography and may be regarded as a sub-field of marine science. It also encompasses many ideas from ecology. Fisheries science and marine conservation can be considered partial offshoots of marine biology (as well as environmental studies). Marine Chemistry, Physical oceanography and Atmospheric sciences are closely related to this field.
An active research topic in marine biology is to discover and map the life cycles of various species and where they spend their time. Technologies that aid in this discovery include pop-up satellite archival tags, acoustic tags, and a variety of other data loggers. Marine biologists study how the ocean currents, tides and many other oceanic factors affect ocean life forms, including their growth, distribution and well-being. This has only recently become technically feasible with advances in GPS and newer underwater visual devices.
Most ocean life breeds in specific places, nests or not in others, spends time as juveniles in still others, and in maturity in yet others. Scientists know little about where many species spend different parts of their life cycles especially in the infant and juvenile years. For example, it is still largely unknown where juvenile sea turtles and some year-1 sharks travel. Recent advances in underwater tracking devices are illuminating what we know about marine organisms that live at great Ocean depths. The information that pop-up satellite archival tags give aids in certain time of the year fishing closures and development of a marine protected area. This data is important to both scientists and fishermen because they are discovering that by restricting commercial fishing in one small area they can have a large impact in maintaining a healthy fish population in a much larger area.
In the United States, Advanced Placement Computer Science is a suite of Advanced Placement courses and examinations covering areas of computer science. They are offered by the College Board to high school students as an opportunity to earn college credit for college-level courses. The suite consists of two current classes and one discontinued class.
AP Computer Science was taught in Pascal for the 1984–1998 exams, in C++ for 1999–2003, and in Java since 2004.AP Computer Science Principles is an introductory course to computer science, "with a focus on how computing powers the world". It is designed as a parallel to AP Computer Science A, to emphasize computational thinking and fluency. It is meant to be the equivalent of a first-semester course in computer science.Aquatic respiration
Aquatic respiration is the process whereby an aquatic animal obtains oxygen from water.Aquatic science
Aquatic Science is the multidisciplinary study of aquatic ecosystems, both freshwater and marine. Scientific investigations range in scale from the molecular level of contaminants to the stresses on entire ecosystems.
Some of the major fields of study within aquatic sciences include: limnology (study of lakes, rivers, wetlands and groundwater); biogeochemistry; aquatic ecology; oceanography; marine biology; and hydrology.Artificial seawater
Artificial seawater (abbreviated ASW) is a mixture of dissolved mineral salts (and sometimes vitamins) that simulates seawater. Artificial seawater is primarily used in marine biology and in marine and reef aquaria, and allows the easy preparation of media appropriate for marine organisms (including algae, bacteria, plants and animals). From a scientific perspective, artificial seawater has the advantage of reproducibility over natural seawater since it is a standardized formula. Synthetic seawater is also known as artificial seawater and substitute ocean water.Ballantine scale
The Ballantine scale is a biologically defined scale for measuring the degree of exposure level of wave action on a rocky shore. Devised in 1961 by W. J. Ballantine, then at the zoology department of Queen Mary College, London, the scale is based on the observation that where shoreline species are concerned "Different species growing on rocky shores require different degrees of protection from certain aspects of the physical environment, of which wave action is often the most important." The species present in the littoral zone therefore indicate the degree of the shore's exposure.Brackish marsh
Brackish marshes develop by salt marshes where a significant freshwater influx dilutes the seawater to brackish levels of salinity. This commonly happens upstream from salt marshes by estuaries of coastal rivers or near the mouths of coastal rivers with heavy freshwater discharges in the conditions of low tidal ranges.Economics of Marine Biology
"Economics of Marine Biology" is the seventh episode of the fourth season of the NBC sitcom Community, which originally aired on March 21, 2013.
Dean Pelton enlists the help of the study group in order to enroll a wealthy new student whose laziness is expected to bring much needed funds to Greendale.Lentisphaerae
Lentisphaerae is a phylum of bacteria closely related to Chlamydiae and Verrucomicrobia.It includes two monotypic orders Lentisphaerales and Victivallales. Phylum members can be aerobic or anaerobic and fall under two distinct phenotypes. One consists of terrestrial gut microbiota from mammals and birds. The other phenotype includes marine micro-organisms: sequences from fish and coral microbiomes and marine sediment.Littoral zone
The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal environments, the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. The littoral zone always includes this intertidal zone, and the terms are often used interchangeably. However, the meaning of littoral zone can extend well beyond the intertidal zone.
The term has no single definition. What is regarded as the full extent of the littoral zone, and the way the littoral zone is divided into subregions, varies in different contexts. (Lakes and rivers have their own definitions.) The use of the term also varies from one part of the world to another, and between different disciplines. For example, military commanders speak of the littoral in ways that are quite different from marine biologists.
The adjacency of water gives a number of distinctive characteristics to littoral regions. The erosive power of water results in particular types of landforms, such as sand dunes, and estuaries. The natural movement of the littoral along the coast is called the littoral drift. Biologically, the ready availability of water enables a greater variety of plant and animal life, and particularly the formation of extensive wetlands. In addition, the additional local humidity due to evaporation usually creates a microclimate supporting unique types of organisms.
The word littoral may be used both as a noun and as an adjective. It derives from the Latin noun litus, litoris, meaning "shore". (The doubled tt is a late-medieval innovation, and the word is sometimes seen in the more classical-looking spelling litoral.)Meristics
Meristics is an area of ichthyology which relates to counting quantitative features of fish, such as the number of fins or scales. A meristic (countable trait) can be used to describe a particular species of fish, or used to identify an unknown species. Meristic traits are often described in a shorthand notation called a meristic formula.
Meristic characters are the countable structures occurring in series (e.g. myomeres, vertebrae, fin rays) in fish. These characters are among the characters most commonly used for differentiation of species and populations. In the salmonids, scale counts have been most widely used for the differentiation of populations within species. In rainbow and steelhead trout the most notable differences among populations occur in counts of scales.
Meristic characters are used in many other fields, such as in botany or in zoology. Meristic comparison is used in phenetic and cladistic analysis.Neritic zone
The neritic zone is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately 200 meters (660 ft) in depth.
From the point of view of marine biology it forms a relatively stable and well-illuminated environment for marine life, from plankton up to large fish and corals, while physical oceanography sees it as where the oceanic system interacts with the coast.Oregon Institute of Marine Biology
The Oregon Institute of Marine Biology (or OIMB) is the marine station of the University of Oregon. This 100-acre (0.40 km2) marine station is located in Charleston, Oregon at the mouth of Coos Bay. Currently, OIMB is home to several permanent faculty members and a number of graduate students. OIMB is a member of the National Association of Marine Laboratories (NAML). In addition to graduate research, undergraduate classes are offered year round, including marine birds and mammals, estuarine biology, marine ecology, invertebrate zoology, molecular biology, biology of fishes, biological oceanography, and embryology.The Loyd and Dorothy Rippey Library, one of eight branches of the UO Libraries, was added to the campus in 1999. The Rippey Library is open to the public by appointment, and the Oregon Card Program allows Oregon residents 16 years old and over to borrow from the collection.The Charleston Marine Life Center (or CMLC), currently under construction, will be a public museum and aquarium on the edge of the harbor in Charleston, OR, across the street from the OIMB campus. Displays aimed at visitors of all ages will emphasize the diversity of animal and plant life in local marine ecosystems. Visitors will learn where to interact with marine organisms in their natural environments and how local scientists study the life histories, evolution and ecology of underwater plants and animals.Scale (anatomy)
In most biological nomenclature, a scale (Greek λεπίς lepis, Latin squama) is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran (butterfly and moth) species, scales are plates on the surface of the insect wing, and provide coloration. Scales are quite common and have evolved multiple times through convergent evolution, with varying structure and function.
Scales are generally classified as part of an organism's integumentary system. There are various types of scales according to shape and to class of animal.Substrate (marine biology)
Stream substrate (sediment) is the material that rests at the bottom of a stream. There are several classification guides. One is:
Mud – silt and clay.
Sand – Particles between 0.06 and 2 mm in diameter.
Granule – Between 2 and 4 mm in diameter.
Pebble – Between 4 – 64 mm in diameter.
Cobble – between 6.4 and 25.6 cm in diameter
Boulder – more than 25.6 cm in diameter.Stream substrate can affect the life found within the stream habitat. Muddy streams generally have more sediment in the water, reducing clarity. Clarity is one guide to stream health.
Marine substrate can be classified geologically as well. See Green et al., 1999 for a reference.
Mollusks and clams that live in areas with substrate, and need them to survive, use their silky byssal threads to cling to it. See Cteniodes Ales for reference.Test (biology)
In biology, a test is the hard shell of some spherical marine animals, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae. The term is also applied to the covering of scale insects. The related Latin term testa is used for the hard seed coat of plant seeds.Teuthology
Teuthology (from Greek τεῦθος, "cuttlefish, squid", and -λογία, -logia) is the study of cephalopods.It is a branch of malacology, the study of molluscs, in marine zoology.
Those that study teuthology are known as teuthologists.Tide pool
Tide pools or rock pools are shallow pools of seawater that form on the rocky intertidal shore. Many of these pools exist as separate bodies of water only at low tide.
Many tide pools are habitats of especially adaptable animals that have engaged the attention of naturalists and marine biologists, as well as philosophical essayists: John Steinbeck wrote in The Log from the Sea of Cortez, "It is advisable to look from the tide pool to the stars and then back to the tide pool."Underwater camouflage
Underwater camouflage is the set of methods of achieving crypsis—avoidance of observation—that allows otherwise visible aquatic organisms to remain unnoticed by other organisms such as predators or prey.
Camouflage in large bodies of water differs markedly from camouflage on land. The environment is essentially the same on all sides. Light always falls from above, and there is generally no variable background to compare with trees and bushes. Three main camouflage methods predominate in water: transparency, reflection, and counter-illumination. Transparency and reflectivity are most important in the top 100 metres of the ocean; counter-illumination is the main method from 100 metres down to 1000 metres; while camouflage becomes less important in the dark waters below 1000 metres.
Camouflage in relatively shallow waters is more like terrestrial camouflage, where additional methods are used by many animals. For example, self-decoration is employed by decorator crabs; mimesis by animals such as the leafy sea dragon; countershading by many fish including sharks; distraction with eyespots by many fish; active camouflage through ability to change colour rapidly in fish such as the flounder, and cephalopods including octopus, cuttlefish, and squid.World Register of Marine Species
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms.