Marine invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters, including breathing tubes as in
mollusc siphons. Fish have
gills instead of
lungs, although some species of fish, such as the
lungfish, have both.
Marine mammals (e.g. dolphins, whales,
otters, and seals) need to surface periodically to breathe air. (Full article...)
Bivalvia (/baɪˈvælviə/), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a
class of marine and freshwater
molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no
head and they lack some usual molluscan organs, like the
radula and the
odontophore. The class includes the
clams,
oysters,
cockles,
mussels,
scallops, and numerous other
families that live in saltwater, as well as a number of families that live in freshwater. The majority are
filter feeders. The
gills have evolved into
ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from
predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and
file shells, can
swim.
Shipworms bore into wood, clay, or stone and live inside these substances.
The
shell of a bivalve is composed of
calcium carbonate, and consists of two, usually similar, parts called
valves. These valves are for feeding and for disposal of waste. These are joined together along one edge (the
hinge line) by a flexible
ligament that, usually in conjunction with interlocking "teeth" on each of the valves, forms the
hinge. This arrangement allows the shell to be opened and closed without the two halves detaching. The shell is typically
bilaterally symmetrical, with the hinge lying in the
sagittal plane. Adult shell sizes of bivalves vary from fractions of a millimetre to over a metre in length, but the majority of species do not exceed 10 cm (4 in). (Full article...)
Image 3
Main entrance in 2016, featuring the remodeled façade and fiberglass smokestacks of the
Hovden Cannery
Early proposals to build a public aquarium in
Monterey County were not successful until a group of four marine biologists affiliated with
Stanford University revisited the concept in the late 1970s. Monterey Bay Aquarium was built at the site of a defunct
sardine cannery and has been recognized for its architectural achievements by the
American Institute of Architects. Along with its architecture, the aquarium has won numerous awards for its exhibition of marine life,
ocean conservation efforts, and educational programs. (Full article...)
Image 4
The blue whale (Balaenoptera musculus) is a
marine mammal and a
baleen whale. Reaching a maximum confirmed length of 29.9 meters (98 ft) and weighing up to 199 tonnes (196 long tons; 219 short tons), it is the
largest animal known ever to have existed. The blue whale's long and slender body can be of various shades of greyish-blue on its upper surface and somewhat lighter underneath. Four
subspecies are recognized: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda (the
pygmy blue whale) in the Indian Ocean and South Pacific Ocean, and B. m. indica in the Northern Indian Ocean. There is a population in the waters off Chile that may constitute a fifth subspecies.
In general, blue whale populations migrate between their summer feeding areas near the poles and their winter breeding grounds near the tropics. There is also evidence of year-round residencies, and partial or age/sex-based migration. Blue whales are
filter feeders; their diet consists almost exclusively of
krill. They are generally solitary or gather in small groups, and have no well-defined social structure other than mother–calf bonds. Blue whales vocalize, with a
fundamental frequency ranging from 8 to 25 Hz; their vocalizations may vary by region, season, behavior, and time of day.
Orcas are their only natural predators. (Full article...)
Image 5
The pigeye shark or Java shark (Carcharhinus amboinensis) is an uncommon
species of
requiem shark, in the
family Carcharhinidae, found in the warm coastal waters of the eastern Atlantic and western
Indo-Pacific. It prefers shallow, murky environments with soft bottoms, and tends to roam within a fairly localised area. With its bulky grey body, small eyes, and short, blunt snout, the pigeye shark looks almost identical to (and is often confused with) the better-known
bull shark (C. leucas). The two species differ in
vertebral count, the relative sizes of the
dorsal fins, and other subtle traits. This shark typically reaches lengths of 1.9–2.5 m (6.2–8.2 ft).
The pigeye shark is an
apex predator that mostly hunts low in the
water column. It has a varied diet, consisting mainly of
bony and
cartilaginous fishes and also including
crustaceans,
molluscs,
sea snakes, and
cetaceans. This species
gives birth to live young, with the developing
embryos sustained to term via a
placental connection to their mother. Litters of three to thirteen pups are born after a
gestation period of nine or twelve months. Young sharks spend their first few years of life in sheltered
inshore habitats such as
bays, where their movements follow tidal and seasonal patterns. The pigeye shark's size and
dentition make it potentially dangerous, though it has not been known to attack humans. The shark is infrequently caught in
shark nets protecting beaches and by
fisheries, which use it for
meat and
fins. The
IUCN presently assesses this species as vulnerable. (Full article...)
Hemiramphidae is a
family of
fishes that are commonly called halfbeaks, spipe fish or spipefish. They are a geographically widespread and numerically abundant family of
epipelagic fish inhabiting warm waters around the world. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The similar
viviparous halfbeaks (family Zenarchopteridae) have often been included in this family.
Teleostei (/ˌtɛliˈɒstiaɪ/;
Greekteleios "complete" + osteon "bone"), members of which are known as teleosts (/ˈtɛliɒsts,ˈtiːli-/), is, by far, the largest
infraclass in the class
Actinopterygii, the ray-finned fishes, and contains 96% of all
extant species of
fish. Teleosts are arranged into about 40
orders and 448
families. Over 26,000
species have been described. Teleosts range from
giant oarfish measuring 7.6 m (25 ft) or more, and
ocean sunfish weighing over 2 t (2.0 long tons; 2.2 short tons), to the minute male
anglerfishPhotocorynus spiniceps, just 6.2 mm (0.24 in) long. Including not only torpedo-shaped fish built for speed, teleosts can be flattened vertically or horizontally, be elongated cylinders or take specialised shapes as in anglerfish and
seahorses.
The difference between teleosts and other bony fish lies mainly in their jaw bones; teleosts have a movable
premaxilla and corresponding modifications in the jaw musculature which make it possible for them to
protrude their jaws outwards from the mouth. This is of great advantage, enabling them to
grab prey and
draw it into the mouth. In more
derived teleosts, the enlarged premaxilla is the main tooth-bearing bone, and the maxilla, which is attached to the lower jaw, acts as a lever, pushing and pulling the premaxilla as the mouth is opened and closed. Other bones further back in the mouth serve to grind and swallow food. Another difference is that the upper and lower lobes of the
tail (caudal) fin are about equal in size. The
spine ends at the
caudal peduncle, distinguishing this group from other fish in which the spine extends into the upper lobe of the tail fin. (Full article...)
A coral "group" is a colony of very many
genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of
tentacles surround a central mouth opening. Each polyp excretes an
exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by
asexual reproduction of polyps. Corals also breed sexually by
spawning: polyps of the same species release
gametes simultaneously overnight, often around a
full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, when mature, settles to form a new colony. (Full article...)
Image 9
A dugong photographed underwater
The dugong (/ˈd(j)uːɡɒŋ/; Dugong dugon) is a
marine mammal. It is one of four living species of the order
Sirenia, which also includes three species of
manatees. It is the only living representative of the once-diverse family
Dugongidae; its closest modern relative,
Steller's sea cow (Hydrodamalis gigas), was hunted to
extinction in the 18th century.
The dugong is the only sirenian in its range, which spans the waters of some 40 countries and territories throughout the
Indo-West Pacific. The dugong is largely dependent on
seagrass communities for subsistence and is thus restricted to the coastal habitats that support
seagrass meadows, with the largest dugong concentrations typically occurring in wide, shallow, protected areas such as
bays,
mangrovechannels, the waters of large
inshore islands and inter-reefal waters. The northern waters of Australia between
Shark Bay and
Moreton Bay are believed to be the dugong's contemporary stronghold. (Full article...)
Phoronids (scientific name Phoronida, sometimes called horseshoe worms) are a small
phylum of marine animals that
filter-feed with a
lophophore (a "crown" of tentacles), and build upright tubes of
chitin to support and protect their soft bodies. They live in most of the oceans and seas, including the Arctic Ocean but excluding the
Antarctic Ocean, and between the
intertidal zone and about 400 meters down. Most adult phoronids are 2 cm long and about 1.5 mm wide, although the largest are 50 cm long.
Felix Anton DohrnFRSFRSE (29 December 1840 – 26 September 1909) was a prominent German
Darwinist and the founder and first director of the first zoological research station in the world, the
Stazione Zoologica in
Naples, Italy. He worked on embryology and examined vertebrate origins in terms of functional phylogeny and proposed a principle of succession of functions in 1875 on how one organ could become the basis for the evolution of another of an entirely different function. He was an elected International Member of the
American Philosophical Society. (Full article...)
Image 1Archaea were initially viewed as
extremophiles living in harsh environments, such as the yellow archaea pictured here in a
hot spring, but they have since been found in a much broader range of
habitats. (from Marine prokaryotes)
Image 3Common-enemy graph of Antarctic food web. Potter Cove 2018. Nodes represent basal species and links indirect interactions (shared predators). Node and link widths are proportional to number of shared predators. Node colors represent functional groups. (from Marine food web)
Image 4In the open ocean, sunlit surface
epipelagic waters get enough light for photosynthesis, but there are often not enough nutrients. As a result, large areas contain little life apart from migrating animals. (from Marine habitat)
Image 9Food web structure in the euphotic zone. The linear food chain large phytoplankton-herbivore-predator (on the left with red arrow connections) has fewer levels than one with small phytoplankton at the base. The microbial loop refers to the flow from the dissolved organic carbon (DOC) via heterotrophic bacteria (Het. Bac.) and microzooplankton to predatory zooplankton (on the right with black solid arrows). Viruses play a major role in the mortality of phytoplankton and heterotrophic bacteria, and recycle organic carbon back to the DOC pool. Other sources of dissolved organic carbon (also dashed black arrows) includes exudation, sloppy feeding, etc. Particulate detritus pools and fluxes are not shown for simplicity. (from Marine food web)
Image 12Scanning electron micrograph of a strain of Roseobacter, a widespread and important genus of marine bacteria. For scale, the membrane pore size is 0.2μm in diameter. (from Marine prokaryotes)
Image 13Microplastics found in sediments on the seafloor (from Marine habitat)
Image 14Phylogenetic and symbiogenetic tree of living organisms, showing a view of the origins of eukaryotes and prokaryotes (from Marine fungi)
Image 20The Ocean Cleanup is one of many organizations working toward marine conservation such at this interceptor vessel that prevents plastic from entering the ocean. (from Marine conservation)
Image 25On average there are more than one million microbial cells in every drop of seawater, and their collective metabolisms not only recycle nutrients that can then be used by larger organisms but also catalyze key chemical transformations that maintain Earth's habitability. (from Marine food web)
Image 26An in situ perspective of a deep pelagic food web derived from ROV-based observations of feeding, as represented by 20 broad taxonomic groupings. The linkages between predator to prey are coloured according to predator group origin, and loops indicate within-group feeding. The thickness of the lines or edges connecting food web components is scaled to the log of the number of unique ROV feeding observations across the years 1991–2016 between the two groups of animals. The different groups have eight colour-coded types according to main animal types as indicated by the legend and defined here: red, cephalopods; orange, crustaceans; light green, fish; dark green, medusa; purple, siphonophores; blue, ctenophores and grey, all other animals. In this plot, the vertical axis does not correspond to trophic level, because this metric is not readily estimated for all members. (from Marine food web)
Image 27Sea ice food web and the microbial loop. AAnP = aerobic anaerobic phototroph, DOC = dissolved organic carbon, DOM = dissolved organic matter, POC = particulate organic carbon, PR = proteorhodopsins. (from Marine food web)
Image 29Waves and currents shape the intertidal shoreline, eroding the softer rocks and transporting and grading loose particles into shingles, sand or mud (from Marine habitat)
Image 32Sponges have no nervous, digestive or circulatory system (from Marine invertebrates)
Image 33The distribution of anthropogenic stressors faced by marine species threatened with extinction in various marine regions of the world. Numbers in the pie charts indicate the percentage contribution of an anthropogenic stressors' impact in a specific marine region. (from Marine food web)
Image 35Reconstruction of an
ammonite, a highly successful early cephalopod that first appeared in the
Devonian (about 400
mya). They became extinct during the same
extinction event that killed the land dinosaurs (about 66 mya). (from Marine invertebrates)
Image 36Lampreys are often parasitic and have a toothed, funnel-like sucking mouth (from Marine vertebrate)
Image 37640 μm microplastic found in the deep sea amphipod Eurythenes plasticus (from Marine habitat)
Image 41Some lobe-finned fishes, like the extinct Tiktaalik, developed limb-like fins that could take them onto land (from Marine vertebrate)
Image 42A protected sea turtle area that warns of fines and imprisonment on a beach in Miami, Florida. (from Marine conservation)
Image 43Oceanic pelagic food web showing energy flow from micronekton to top predators. Line thickness is scaled to the proportion in the diet. (from Marine food web)
Image 46Conceptual diagram of faunal community structure and food-web patterns along fluid-flux gradients within
Guaymas seep and vent ecosystems. (from Marine food web)
Image 47
Mycoloop links between phytoplankton and zooplankton
Chytrid‐mediated trophic links between phytoplankton and zooplankton (mycoloop). While small phytoplankton species can be grazed upon by zooplankton, large phytoplankton species constitute poorly edible or even inedible prey. Chytrid infections on large phytoplankton can induce changes in palatability, as a result of host aggregation (reduced edibility) or mechanistic fragmentation of cells or filaments (increased palatability). First, chytrid parasites extract and repack nutrients and energy from their hosts in form of readily edible zoospores. Second, infected and fragmented hosts including attached sporangia can also be ingested by grazers (i.e. concomitant predation). (from Marine fungi)
Image 63A microbial mat encrusted with iron oxide on the flank of a
seamount can harbour microbial communities dominated by the iron-oxidizing
Zetaproteobacteria (from Marine prokaryotes)
Image 68Antarctic marine food web. Potter Cove 2018. Vertical position indicates trophic level and node widths are proportional to total degree (in and out). Node colors represent functional groups. (from Marine food web)
Image 69Tidepools on rocky shores make turbulent habitats for many forms of marine life (from Marine habitat)
Image 71Estuaries occur when rivers flow into a coastal bay or inlet. They are nutrient rich and have a transition zone which moves from freshwater to saltwater. (from Marine habitat)
Image 72Ernst Haeckel's 96th plate, showing some marine invertebrates. Marine invertebrates have a large variety of
body plans, which are currently categorised into over 30
phyla. (from Marine invertebrates)
Image 73
Model of the energy generating mechanism in marine bacteria
(1) When sunlight strikes a rhodopsin molecule (2) it changes its configuration so a proton is expelled from the cell (3) the chemical potential causes the proton to flow back to the cell (4) thus generating energy (5) in the form of
adenosine triphosphate. (from Marine prokaryotes)
Image 78Ocean surface chlorophyll concentrations in October 2019. The concentration of chlorophyll can be used as a
proxy to indicate how many phytoplankton are present. Thus on this global map green indicates where a lot of phytoplankton are present, while blue indicates where few phytoplankton are present. – NASA Earth Observatory 2019. (from Marine food web)
Image 79
Different bacteria shapes (
cocci,
rods and
spirochetes) and their sizes compared with the width of a human hair. A few bacteria are comma-shaped (
vibrio). Archaea have similar shapes, though the archaeon
Haloquadratum is flat and square.
The unit μm is a measurement of length, the
micrometer, equal to 1/1,000 of a millimeter
Image 84Anthropogenic stressors to marine species threatened with extinction (from Marine food web)
Image 85Cnidarians are the simplest animals with cells organised into tissues. Yet the
starlet sea anemone contains the same genes as those that form the vertebrate head. (from Marine invertebrates)
Image 86Phylogenetic and symbiogenetic tree of living organisms, showing a view of the origins of eukaryotes and prokaryotes (from Marine prokaryotes)
Image 87
Bacterioplankton and the pelagic marine food web
Solar radiation can have positive (+) or negative (−) effects resulting in increases or decreases in the heterotrophic activity of bacterioplankton. (from Marine prokaryotes)
Image 88Some representative ocean animal life (not drawn to scale) within their approximate depth-defined ecological habitats.
Marine microorganisms exist on the surfaces and within the tissues and organs of the diverse life inhabiting the ocean, across all ocean habitats. (from Marine habitat)
Image 89Jellyfish are easy to capture and digest and may be more important as food sources than was previously thought. (from Marine food web)
Estimates of microbial species counts in the three domains of life
Bacteria are the oldest and most biodiverse group, followed by Archaea and Fungi (the most recent groups). In 1998, before awareness of the extent of microbial life had gotten underway,
Robert M. May estimated there were 3 million species of living organisms on the planet. But in 2016, Locey and Lennon estimated the number of microorganism species could be as high as 1 trillion. (from Marine prokaryotes)
Image 92A 2016
metagenomic representation of the tree of life using
ribosomal protein sequences. The tree includes 92 named bacterial phyla, 26 archaeal phyla and five eukaryotic supergroups. Major lineages are assigned arbitrary colours and named in italics with well-characterized lineage names. Lineages lacking an isolated representative are highlighted with non-italicized names and red dots. (from Marine prokaryotes)
Image 98The pelagic
food web, showing the central involvement of
marine microorganisms in how the ocean imports nutrients from and then exports them back to the atmosphere and ocean floor (from Marine food web)
Image 100Topological positions versus mobility: (A) bottom-up groups (sessile and drifters), (B) groups at the top of the food web. Phyto, phytoplankton; MacroAlga, macroalgae; Proto, pelagic protozoa; Crus, Crustacea; PelBact, pelagic bacteria; Echino, Echinoderms; Amph, Amphipods; HerbFish, herbivorous fish; Zoopl, zooplankton; SuspFeed, suspension feeders; Polych, polychaetes; Mugil, Mugilidae; Gastropod, gastropods; Blenny, omnivorous blennies; Decapod, decapods; Dpunt, Diplodus puntazzo; Macropl, macroplankton; PlFish, planktivorous fish; Cephalopod, cephalopods; Mcarni, macrocarnivorous fish; Pisc, piscivorous fish; Bird, seabirds; InvFeed1 through InvFeed4, benthic invertebrate feeders. (from Marine food web)
Image 101Coral reefs provide marine habitats for tube sponges, which in turn become marine habitats for fishes (from Marine habitat)
Image 102Phylogenetic tree representing bacterial OTUs from
clone libraries and
next-generation sequencing. OTUs from next-generation sequencing are displayed if the OTU contained more than two sequences in the unrarefied OTU table (3626 OTUs). (from Marine prokaryotes)
Image 106Chytrid parasites of marine diatoms. (A) Chytrid sporangia on Pleurosigma sp. The white arrow indicates the operculate discharge pore. (B) Rhizoids (white arrow) extending into diatom host. (C) Chlorophyll aggregates localized to infection sites (white arrows). (D and E) Single hosts bearing multiple zoosporangia at different stages of development. The white arrow in panel E highlights branching rhizoids. (F) Endobiotic chytrid-like sporangia within diatom frustule. Bars = 10 μm. (from Marine fungi)
Image 110Cycling of marine phytoplankton. Phytoplankton live in the photic zone of the ocean, where photosynthesis is possible. During photosynthesis, they assimilate carbon dioxide and release oxygen. If solar radiation is too high, phytoplankton may fall victim to photodegradation. For growth, phytoplankton cells depend on nutrients, which enter the ocean by rivers, continental weathering, and glacial ice meltwater on the poles. Phytoplankton release dissolved organic carbon (DOC) into the ocean. Since phytoplankton are the basis of marine food webs, they serve as prey for zooplankton, fish larvae and other heterotrophic organisms. They can also be degraded by bacteria or by viral lysis. Although some phytoplankton cells, such as dinoflagellates, are able to migrate vertically, they are still incapable of actively moving against currents, so they slowly sink and ultimately fertilize the seafloor with dead cells and detritus. (from Marine food web)
Image 114The deep sea
amphipodEurythenes plasticus, named after microplastics found in its body, demonstrating plastic pollution affects marine habitats even 6000m below sea level. (from Marine habitat)
Image 117This
algae bloom occupies sunlit
epipelagic waters off the southern coast of England. The algae are maybe feeding on nutrients from
land runoff or
upwellings at the edge of the continental shelf. (from Marine habitat)
Image 118Halfbeak as larvae are one of the organisms adapted to the unique properties of the microlayer (from Marine habitat)
Image 120Schematic representation of the changes in abundance between trophic groups in a temperate rocky reef ecosystem. (a) Interactions at equilibrium. (b) Trophic cascade following disturbance. In this case, the otter is the dominant predator and the macroalgae are kelp. Arrows with positive (green, +) signs indicate positive effects on abundance while those with negative (red, -) indicate negative effects on abundance. The size of the bubbles represents the change in population abundance and associated altered interaction strength following disturbance. (from Marine food web)
Image 121Marine Species Changes in Latitude and Depth in three different ocean regions(1973–2019) (from Marine food web)
Image 122Conference events, such as the events hosted by the
United Nations, help to bring together many stakeholders for awareness and action. (from Marine conservation)
Image 123
Diagram of a mycoloop (fungus loop)
Parasitic
chytrids can transfer material from large inedible phytoplankton to zooplankton. Chytrids
zoospores are excellent food for zooplankton in terms of size (2–5 μm in diameter), shape, nutritional quality (rich in
polyunsaturated fatty acids and
cholesterols). Large colonies of host phytoplankton may also be fragmented by chytrid infections and become edible to zooplankton. (from Marine fungi)
Image 124Elevation-area graph showing the proportion of land area at given heights and the proportion of ocean area at given depths (from Marine habitat)
Image 125Only 29 percent of the world surface is land. The rest is ocean, home to the marine habitats. The oceans are nearly four kilometres deep on average and are fringed with coastlines that run for nearly 380,000 kilometres.
Image 7Lampreys are often parasitic and have a toothed, funnel-like sucking mouth (from Marine vertebrate)
Image 8Ecosystem services delivered by
epibenthicbivalve reefs. Reefs provide coastal protection through erosion control and shoreline stabilization, and modify the physical landscape by
ecosystem engineering, thereby providing habitat for species by facilitative interactions with other habitats such as
tidal flat benthic communities,
seagrasses and
marshes. (from Marine ecosystem)
Image 9Some lobe-finned fishes, like the extinct Tiktaalik, developed limb-like fins that could take them onto land (from Marine vertebrate)
... As a way to put off attackers (or to remove indigestible stomach content), sharks can turn their
stomachs inside out and vomit up their latest meal. Some
predators eat the vomit instead of the shark.
... Until the late 16th century sharks were usually referred to in the English language as sea-dogs. The name "Shark" first came into use around the late 1560s to refer to the large sharks of the Caribbean Sea.
... newborn cetacean calves ‘suckle’ three to four times each hour and will suckle from their mothers for six months or more.
The Double-crested Cormorant (Phalacrocorax auritus) is a
North American member of the
cormorant family of
seabirds. Its name is derived from the
Greek words phalakros (bald) and kora (raven), and the
Latinauritus (eared). Folk names of this bird include Crow-duck, Farallon Cormorant, Florida Cormorant, lawyer, shag, and Taunton turkey.
Marine invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters, including breathing tubes as in
mollusc siphons. Fish have
gills instead of
lungs, although some species of fish, such as the
lungfish, have both.
Marine mammals (e.g. dolphins, whales,
otters, and seals) need to surface periodically to breathe air. (Full article...)
Bivalvia (/baɪˈvælviə/), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a
class of marine and freshwater
molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no
head and they lack some usual molluscan organs, like the
radula and the
odontophore. The class includes the
clams,
oysters,
cockles,
mussels,
scallops, and numerous other
families that live in saltwater, as well as a number of families that live in freshwater. The majority are
filter feeders. The
gills have evolved into
ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from
predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and
file shells, can
swim.
Shipworms bore into wood, clay, or stone and live inside these substances.
The
shell of a bivalve is composed of
calcium carbonate, and consists of two, usually similar, parts called
valves. These valves are for feeding and for disposal of waste. These are joined together along one edge (the
hinge line) by a flexible
ligament that, usually in conjunction with interlocking "teeth" on each of the valves, forms the
hinge. This arrangement allows the shell to be opened and closed without the two halves detaching. The shell is typically
bilaterally symmetrical, with the hinge lying in the
sagittal plane. Adult shell sizes of bivalves vary from fractions of a millimetre to over a metre in length, but the majority of species do not exceed 10 cm (4 in). (Full article...)
Image 3
Main entrance in 2016, featuring the remodeled façade and fiberglass smokestacks of the
Hovden Cannery
Early proposals to build a public aquarium in
Monterey County were not successful until a group of four marine biologists affiliated with
Stanford University revisited the concept in the late 1970s. Monterey Bay Aquarium was built at the site of a defunct
sardine cannery and has been recognized for its architectural achievements by the
American Institute of Architects. Along with its architecture, the aquarium has won numerous awards for its exhibition of marine life,
ocean conservation efforts, and educational programs. (Full article...)
Image 4
The blue whale (Balaenoptera musculus) is a
marine mammal and a
baleen whale. Reaching a maximum confirmed length of 29.9 meters (98 ft) and weighing up to 199 tonnes (196 long tons; 219 short tons), it is the
largest animal known ever to have existed. The blue whale's long and slender body can be of various shades of greyish-blue on its upper surface and somewhat lighter underneath. Four
subspecies are recognized: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda (the
pygmy blue whale) in the Indian Ocean and South Pacific Ocean, and B. m. indica in the Northern Indian Ocean. There is a population in the waters off Chile that may constitute a fifth subspecies.
In general, blue whale populations migrate between their summer feeding areas near the poles and their winter breeding grounds near the tropics. There is also evidence of year-round residencies, and partial or age/sex-based migration. Blue whales are
filter feeders; their diet consists almost exclusively of
krill. They are generally solitary or gather in small groups, and have no well-defined social structure other than mother–calf bonds. Blue whales vocalize, with a
fundamental frequency ranging from 8 to 25 Hz; their vocalizations may vary by region, season, behavior, and time of day.
Orcas are their only natural predators. (Full article...)
Image 5
The pigeye shark or Java shark (Carcharhinus amboinensis) is an uncommon
species of
requiem shark, in the
family Carcharhinidae, found in the warm coastal waters of the eastern Atlantic and western
Indo-Pacific. It prefers shallow, murky environments with soft bottoms, and tends to roam within a fairly localised area. With its bulky grey body, small eyes, and short, blunt snout, the pigeye shark looks almost identical to (and is often confused with) the better-known
bull shark (C. leucas). The two species differ in
vertebral count, the relative sizes of the
dorsal fins, and other subtle traits. This shark typically reaches lengths of 1.9–2.5 m (6.2–8.2 ft).
The pigeye shark is an
apex predator that mostly hunts low in the
water column. It has a varied diet, consisting mainly of
bony and
cartilaginous fishes and also including
crustaceans,
molluscs,
sea snakes, and
cetaceans. This species
gives birth to live young, with the developing
embryos sustained to term via a
placental connection to their mother. Litters of three to thirteen pups are born after a
gestation period of nine or twelve months. Young sharks spend their first few years of life in sheltered
inshore habitats such as
bays, where their movements follow tidal and seasonal patterns. The pigeye shark's size and
dentition make it potentially dangerous, though it has not been known to attack humans. The shark is infrequently caught in
shark nets protecting beaches and by
fisheries, which use it for
meat and
fins. The
IUCN presently assesses this species as vulnerable. (Full article...)
Hemiramphidae is a
family of
fishes that are commonly called halfbeaks, spipe fish or spipefish. They are a geographically widespread and numerically abundant family of
epipelagic fish inhabiting warm waters around the world. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The similar
viviparous halfbeaks (family Zenarchopteridae) have often been included in this family.
Teleostei (/ˌtɛliˈɒstiaɪ/;
Greekteleios "complete" + osteon "bone"), members of which are known as teleosts (/ˈtɛliɒsts,ˈtiːli-/), is, by far, the largest
infraclass in the class
Actinopterygii, the ray-finned fishes, and contains 96% of all
extant species of
fish. Teleosts are arranged into about 40
orders and 448
families. Over 26,000
species have been described. Teleosts range from
giant oarfish measuring 7.6 m (25 ft) or more, and
ocean sunfish weighing over 2 t (2.0 long tons; 2.2 short tons), to the minute male
anglerfishPhotocorynus spiniceps, just 6.2 mm (0.24 in) long. Including not only torpedo-shaped fish built for speed, teleosts can be flattened vertically or horizontally, be elongated cylinders or take specialised shapes as in anglerfish and
seahorses.
The difference between teleosts and other bony fish lies mainly in their jaw bones; teleosts have a movable
premaxilla and corresponding modifications in the jaw musculature which make it possible for them to
protrude their jaws outwards from the mouth. This is of great advantage, enabling them to
grab prey and
draw it into the mouth. In more
derived teleosts, the enlarged premaxilla is the main tooth-bearing bone, and the maxilla, which is attached to the lower jaw, acts as a lever, pushing and pulling the premaxilla as the mouth is opened and closed. Other bones further back in the mouth serve to grind and swallow food. Another difference is that the upper and lower lobes of the
tail (caudal) fin are about equal in size. The
spine ends at the
caudal peduncle, distinguishing this group from other fish in which the spine extends into the upper lobe of the tail fin. (Full article...)
A coral "group" is a colony of very many
genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of
tentacles surround a central mouth opening. Each polyp excretes an
exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by
asexual reproduction of polyps. Corals also breed sexually by
spawning: polyps of the same species release
gametes simultaneously overnight, often around a
full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, when mature, settles to form a new colony. (Full article...)
Image 9
A dugong photographed underwater
The dugong (/ˈd(j)uːɡɒŋ/; Dugong dugon) is a
marine mammal. It is one of four living species of the order
Sirenia, which also includes three species of
manatees. It is the only living representative of the once-diverse family
Dugongidae; its closest modern relative,
Steller's sea cow (Hydrodamalis gigas), was hunted to
extinction in the 18th century.
The dugong is the only sirenian in its range, which spans the waters of some 40 countries and territories throughout the
Indo-West Pacific. The dugong is largely dependent on
seagrass communities for subsistence and is thus restricted to the coastal habitats that support
seagrass meadows, with the largest dugong concentrations typically occurring in wide, shallow, protected areas such as
bays,
mangrovechannels, the waters of large
inshore islands and inter-reefal waters. The northern waters of Australia between
Shark Bay and
Moreton Bay are believed to be the dugong's contemporary stronghold. (Full article...)
Phoronids (scientific name Phoronida, sometimes called horseshoe worms) are a small
phylum of marine animals that
filter-feed with a
lophophore (a "crown" of tentacles), and build upright tubes of
chitin to support and protect their soft bodies. They live in most of the oceans and seas, including the Arctic Ocean but excluding the
Antarctic Ocean, and between the
intertidal zone and about 400 meters down. Most adult phoronids are 2 cm long and about 1.5 mm wide, although the largest are 50 cm long.
Felix Anton DohrnFRSFRSE (29 December 1840 – 26 September 1909) was a prominent German
Darwinist and the founder and first director of the first zoological research station in the world, the
Stazione Zoologica in
Naples, Italy. He worked on embryology and examined vertebrate origins in terms of functional phylogeny and proposed a principle of succession of functions in 1875 on how one organ could become the basis for the evolution of another of an entirely different function. He was an elected International Member of the
American Philosophical Society. (Full article...)
Image 1Archaea were initially viewed as
extremophiles living in harsh environments, such as the yellow archaea pictured here in a
hot spring, but they have since been found in a much broader range of
habitats. (from Marine prokaryotes)
Image 3Common-enemy graph of Antarctic food web. Potter Cove 2018. Nodes represent basal species and links indirect interactions (shared predators). Node and link widths are proportional to number of shared predators. Node colors represent functional groups. (from Marine food web)
Image 4In the open ocean, sunlit surface
epipelagic waters get enough light for photosynthesis, but there are often not enough nutrients. As a result, large areas contain little life apart from migrating animals. (from Marine habitat)
Image 9Food web structure in the euphotic zone. The linear food chain large phytoplankton-herbivore-predator (on the left with red arrow connections) has fewer levels than one with small phytoplankton at the base. The microbial loop refers to the flow from the dissolved organic carbon (DOC) via heterotrophic bacteria (Het. Bac.) and microzooplankton to predatory zooplankton (on the right with black solid arrows). Viruses play a major role in the mortality of phytoplankton and heterotrophic bacteria, and recycle organic carbon back to the DOC pool. Other sources of dissolved organic carbon (also dashed black arrows) includes exudation, sloppy feeding, etc. Particulate detritus pools and fluxes are not shown for simplicity. (from Marine food web)
Image 12Scanning electron micrograph of a strain of Roseobacter, a widespread and important genus of marine bacteria. For scale, the membrane pore size is 0.2μm in diameter. (from Marine prokaryotes)
Image 13Microplastics found in sediments on the seafloor (from Marine habitat)
Image 14Phylogenetic and symbiogenetic tree of living organisms, showing a view of the origins of eukaryotes and prokaryotes (from Marine fungi)
Image 20The Ocean Cleanup is one of many organizations working toward marine conservation such at this interceptor vessel that prevents plastic from entering the ocean. (from Marine conservation)
Image 25On average there are more than one million microbial cells in every drop of seawater, and their collective metabolisms not only recycle nutrients that can then be used by larger organisms but also catalyze key chemical transformations that maintain Earth's habitability. (from Marine food web)
Image 26An in situ perspective of a deep pelagic food web derived from ROV-based observations of feeding, as represented by 20 broad taxonomic groupings. The linkages between predator to prey are coloured according to predator group origin, and loops indicate within-group feeding. The thickness of the lines or edges connecting food web components is scaled to the log of the number of unique ROV feeding observations across the years 1991–2016 between the two groups of animals. The different groups have eight colour-coded types according to main animal types as indicated by the legend and defined here: red, cephalopods; orange, crustaceans; light green, fish; dark green, medusa; purple, siphonophores; blue, ctenophores and grey, all other animals. In this plot, the vertical axis does not correspond to trophic level, because this metric is not readily estimated for all members. (from Marine food web)
Image 27Sea ice food web and the microbial loop. AAnP = aerobic anaerobic phototroph, DOC = dissolved organic carbon, DOM = dissolved organic matter, POC = particulate organic carbon, PR = proteorhodopsins. (from Marine food web)
Image 29Waves and currents shape the intertidal shoreline, eroding the softer rocks and transporting and grading loose particles into shingles, sand or mud (from Marine habitat)
Image 32Sponges have no nervous, digestive or circulatory system (from Marine invertebrates)
Image 33The distribution of anthropogenic stressors faced by marine species threatened with extinction in various marine regions of the world. Numbers in the pie charts indicate the percentage contribution of an anthropogenic stressors' impact in a specific marine region. (from Marine food web)
Image 35Reconstruction of an
ammonite, a highly successful early cephalopod that first appeared in the
Devonian (about 400
mya). They became extinct during the same
extinction event that killed the land dinosaurs (about 66 mya). (from Marine invertebrates)
Image 36Lampreys are often parasitic and have a toothed, funnel-like sucking mouth (from Marine vertebrate)
Image 37640 μm microplastic found in the deep sea amphipod Eurythenes plasticus (from Marine habitat)
Image 41Some lobe-finned fishes, like the extinct Tiktaalik, developed limb-like fins that could take them onto land (from Marine vertebrate)
Image 42A protected sea turtle area that warns of fines and imprisonment on a beach in Miami, Florida. (from Marine conservation)
Image 43Oceanic pelagic food web showing energy flow from micronekton to top predators. Line thickness is scaled to the proportion in the diet. (from Marine food web)
Image 46Conceptual diagram of faunal community structure and food-web patterns along fluid-flux gradients within
Guaymas seep and vent ecosystems. (from Marine food web)
Image 47
Mycoloop links between phytoplankton and zooplankton
Chytrid‐mediated trophic links between phytoplankton and zooplankton (mycoloop). While small phytoplankton species can be grazed upon by zooplankton, large phytoplankton species constitute poorly edible or even inedible prey. Chytrid infections on large phytoplankton can induce changes in palatability, as a result of host aggregation (reduced edibility) or mechanistic fragmentation of cells or filaments (increased palatability). First, chytrid parasites extract and repack nutrients and energy from their hosts in form of readily edible zoospores. Second, infected and fragmented hosts including attached sporangia can also be ingested by grazers (i.e. concomitant predation). (from Marine fungi)
Image 63A microbial mat encrusted with iron oxide on the flank of a
seamount can harbour microbial communities dominated by the iron-oxidizing
Zetaproteobacteria (from Marine prokaryotes)
Image 68Antarctic marine food web. Potter Cove 2018. Vertical position indicates trophic level and node widths are proportional to total degree (in and out). Node colors represent functional groups. (from Marine food web)
Image 69Tidepools on rocky shores make turbulent habitats for many forms of marine life (from Marine habitat)
Image 71Estuaries occur when rivers flow into a coastal bay or inlet. They are nutrient rich and have a transition zone which moves from freshwater to saltwater. (from Marine habitat)
Image 72Ernst Haeckel's 96th plate, showing some marine invertebrates. Marine invertebrates have a large variety of
body plans, which are currently categorised into over 30
phyla. (from Marine invertebrates)
Image 73
Model of the energy generating mechanism in marine bacteria
(1) When sunlight strikes a rhodopsin molecule (2) it changes its configuration so a proton is expelled from the cell (3) the chemical potential causes the proton to flow back to the cell (4) thus generating energy (5) in the form of
adenosine triphosphate. (from Marine prokaryotes)
Image 78Ocean surface chlorophyll concentrations in October 2019. The concentration of chlorophyll can be used as a
proxy to indicate how many phytoplankton are present. Thus on this global map green indicates where a lot of phytoplankton are present, while blue indicates where few phytoplankton are present. – NASA Earth Observatory 2019. (from Marine food web)
Image 79
Different bacteria shapes (
cocci,
rods and
spirochetes) and their sizes compared with the width of a human hair. A few bacteria are comma-shaped (
vibrio). Archaea have similar shapes, though the archaeon
Haloquadratum is flat and square.
The unit μm is a measurement of length, the
micrometer, equal to 1/1,000 of a millimeter
Image 84Anthropogenic stressors to marine species threatened with extinction (from Marine food web)
Image 85Cnidarians are the simplest animals with cells organised into tissues. Yet the
starlet sea anemone contains the same genes as those that form the vertebrate head. (from Marine invertebrates)
Image 86Phylogenetic and symbiogenetic tree of living organisms, showing a view of the origins of eukaryotes and prokaryotes (from Marine prokaryotes)
Image 87
Bacterioplankton and the pelagic marine food web
Solar radiation can have positive (+) or negative (−) effects resulting in increases or decreases in the heterotrophic activity of bacterioplankton. (from Marine prokaryotes)
Image 88Some representative ocean animal life (not drawn to scale) within their approximate depth-defined ecological habitats.
Marine microorganisms exist on the surfaces and within the tissues and organs of the diverse life inhabiting the ocean, across all ocean habitats. (from Marine habitat)
Image 89Jellyfish are easy to capture and digest and may be more important as food sources than was previously thought. (from Marine food web)
Estimates of microbial species counts in the three domains of life
Bacteria are the oldest and most biodiverse group, followed by Archaea and Fungi (the most recent groups). In 1998, before awareness of the extent of microbial life had gotten underway,
Robert M. May estimated there were 3 million species of living organisms on the planet. But in 2016, Locey and Lennon estimated the number of microorganism species could be as high as 1 trillion. (from Marine prokaryotes)
Image 92A 2016
metagenomic representation of the tree of life using
ribosomal protein sequences. The tree includes 92 named bacterial phyla, 26 archaeal phyla and five eukaryotic supergroups. Major lineages are assigned arbitrary colours and named in italics with well-characterized lineage names. Lineages lacking an isolated representative are highlighted with non-italicized names and red dots. (from Marine prokaryotes)
Image 98The pelagic
food web, showing the central involvement of
marine microorganisms in how the ocean imports nutrients from and then exports them back to the atmosphere and ocean floor (from Marine food web)
Image 100Topological positions versus mobility: (A) bottom-up groups (sessile and drifters), (B) groups at the top of the food web. Phyto, phytoplankton; MacroAlga, macroalgae; Proto, pelagic protozoa; Crus, Crustacea; PelBact, pelagic bacteria; Echino, Echinoderms; Amph, Amphipods; HerbFish, herbivorous fish; Zoopl, zooplankton; SuspFeed, suspension feeders; Polych, polychaetes; Mugil, Mugilidae; Gastropod, gastropods; Blenny, omnivorous blennies; Decapod, decapods; Dpunt, Diplodus puntazzo; Macropl, macroplankton; PlFish, planktivorous fish; Cephalopod, cephalopods; Mcarni, macrocarnivorous fish; Pisc, piscivorous fish; Bird, seabirds; InvFeed1 through InvFeed4, benthic invertebrate feeders. (from Marine food web)
Image 101Coral reefs provide marine habitats for tube sponges, which in turn become marine habitats for fishes (from Marine habitat)
Image 102Phylogenetic tree representing bacterial OTUs from
clone libraries and
next-generation sequencing. OTUs from next-generation sequencing are displayed if the OTU contained more than two sequences in the unrarefied OTU table (3626 OTUs). (from Marine prokaryotes)
Image 106Chytrid parasites of marine diatoms. (A) Chytrid sporangia on Pleurosigma sp. The white arrow indicates the operculate discharge pore. (B) Rhizoids (white arrow) extending into diatom host. (C) Chlorophyll aggregates localized to infection sites (white arrows). (D and E) Single hosts bearing multiple zoosporangia at different stages of development. The white arrow in panel E highlights branching rhizoids. (F) Endobiotic chytrid-like sporangia within diatom frustule. Bars = 10 μm. (from Marine fungi)
Image 110Cycling of marine phytoplankton. Phytoplankton live in the photic zone of the ocean, where photosynthesis is possible. During photosynthesis, they assimilate carbon dioxide and release oxygen. If solar radiation is too high, phytoplankton may fall victim to photodegradation. For growth, phytoplankton cells depend on nutrients, which enter the ocean by rivers, continental weathering, and glacial ice meltwater on the poles. Phytoplankton release dissolved organic carbon (DOC) into the ocean. Since phytoplankton are the basis of marine food webs, they serve as prey for zooplankton, fish larvae and other heterotrophic organisms. They can also be degraded by bacteria or by viral lysis. Although some phytoplankton cells, such as dinoflagellates, are able to migrate vertically, they are still incapable of actively moving against currents, so they slowly sink and ultimately fertilize the seafloor with dead cells and detritus. (from Marine food web)
Image 114The deep sea
amphipodEurythenes plasticus, named after microplastics found in its body, demonstrating plastic pollution affects marine habitats even 6000m below sea level. (from Marine habitat)
Image 117This
algae bloom occupies sunlit
epipelagic waters off the southern coast of England. The algae are maybe feeding on nutrients from
land runoff or
upwellings at the edge of the continental shelf. (from Marine habitat)
Image 118Halfbeak as larvae are one of the organisms adapted to the unique properties of the microlayer (from Marine habitat)
Image 120Schematic representation of the changes in abundance between trophic groups in a temperate rocky reef ecosystem. (a) Interactions at equilibrium. (b) Trophic cascade following disturbance. In this case, the otter is the dominant predator and the macroalgae are kelp. Arrows with positive (green, +) signs indicate positive effects on abundance while those with negative (red, -) indicate negative effects on abundance. The size of the bubbles represents the change in population abundance and associated altered interaction strength following disturbance. (from Marine food web)
Image 121Marine Species Changes in Latitude and Depth in three different ocean regions(1973–2019) (from Marine food web)
Image 122Conference events, such as the events hosted by the
United Nations, help to bring together many stakeholders for awareness and action. (from Marine conservation)
Image 123
Diagram of a mycoloop (fungus loop)
Parasitic
chytrids can transfer material from large inedible phytoplankton to zooplankton. Chytrids
zoospores are excellent food for zooplankton in terms of size (2–5 μm in diameter), shape, nutritional quality (rich in
polyunsaturated fatty acids and
cholesterols). Large colonies of host phytoplankton may also be fragmented by chytrid infections and become edible to zooplankton. (from Marine fungi)
Image 124Elevation-area graph showing the proportion of land area at given heights and the proportion of ocean area at given depths (from Marine habitat)
Image 125Only 29 percent of the world surface is land. The rest is ocean, home to the marine habitats. The oceans are nearly four kilometres deep on average and are fringed with coastlines that run for nearly 380,000 kilometres.
Image 7Lampreys are often parasitic and have a toothed, funnel-like sucking mouth (from Marine vertebrate)
Image 8Ecosystem services delivered by
epibenthicbivalve reefs. Reefs provide coastal protection through erosion control and shoreline stabilization, and modify the physical landscape by
ecosystem engineering, thereby providing habitat for species by facilitative interactions with other habitats such as
tidal flat benthic communities,
seagrasses and
marshes. (from Marine ecosystem)
Image 9Some lobe-finned fishes, like the extinct Tiktaalik, developed limb-like fins that could take them onto land (from Marine vertebrate)
... As a way to put off attackers (or to remove indigestible stomach content), sharks can turn their
stomachs inside out and vomit up their latest meal. Some
predators eat the vomit instead of the shark.
... Until the late 16th century sharks were usually referred to in the English language as sea-dogs. The name "Shark" first came into use around the late 1560s to refer to the large sharks of the Caribbean Sea.
... newborn cetacean calves ‘suckle’ three to four times each hour and will suckle from their mothers for six months or more.
The Double-crested Cormorant (Phalacrocorax auritus) is a
North American member of the
cormorant family of
seabirds. Its name is derived from the
Greek words phalakros (bald) and kora (raven), and the
Latinauritus (eared). Folk names of this bird include Crow-duck, Farallon Cormorant, Florida Cormorant, lawyer, shag, and Taunton turkey.