Ocean Life: Understanding the Nature of Ocean Life!
The organisms of the sea are bore, live breathe feed, excrete, move, grow, mate, reproduce, and die within a single interconnected medium. These interactions among the marine organisms and interactions of the organisms with the chemical and physical processes of the sea range across the entire spectrum from simple, adamant constraints to complex effects of many subtle interactions.
A general discussion of a living system should consider the ways in which plants elaborate basic organic material from inorganic substances and the successive and often highly intricate stems by which organisms then return this material to the inorganic reservoir. The discussion should also slow the forms of life by which such processes are conducted.
Some organic material is carried to the sea by rivers and some is manufactured in shallow water by attached plants. More than 90% of the basic organic material that fuels and builds the life in the sea, however, is synthesized within the lighted surface layers of open water by the many varieties of phytoplankton.
These sunny pastures of plant cells are grazed by the herbivorous zooplankton and by some small fishes. These in turn are prey to various carnivorous creatures, large and small, which have their predators also.
The debris from the activities in the surface layers settles into the dimly lighted and unlighted mid-layers of the sea, the twilight mesopelasic zone and the midnight bathypelagic zone, to serve as one source of food for their strange inhabitants.
This process depletes the surface layers of some food and particularly of vital plant nutrients, or fertilizers that become trapped below the surface layers, where they are unavailable to the plants. Food and nutrients are also actively carried downward from the surface by vertically migrating animals.
The depleted remnants of this constant “rain” of detritus continue to the sea floor and support those animals that live just above the bottom, on the bottom and burrowed into the bottom. There filter feeding and burrowing animals and bacteria rework the remaining refractory particles.
The more active animals also find repast in mid water creatures and in the occasional falls on carcasses and other larger debris.
Except in unusual small areas there is an abundance of oxygen in the deep water. And the solid bottom presents advantages that allow the support of denser populations of larger creatures than can exist in deep mid water.
In shallower water such as banks, atolls, continental shelves and shallows seas conditions associated with a solid bottom and other regional modifications of general regime enable rich populations to develop. Such areas constitute about 7% of the total area of the ocean. In some of these regions added food results from the growth of larger fixed plants and from land drainage.
The cycle of life in the sea, like that on land, is fuelled by the sun’s visible light acting on green plants. Of every million photos of sunlight reaching the earth’s surface, some 90 enter into the net production of basic food.
Perhaps so of the 90 contribute to the growth of the land plants and about 40 to the growth of the single called green plants of the sea, the phytoplankton. It is this minute fraction of the sun’s radiant energy that suppresses the living organisms of this planet not energy that suppress the living organisms of this planet not only with their food but also with a breathable atmosphere.
The terrestrial and marine plants and animals arose from the same sources, through similar evolutionary sequence and by the action of the same natural laws.
In some importance respected this imaginary conditions is not unlike that of the dominant, food web of the sea, where almost all marine like is sustained by microscopic plants and near microscopic herbivore 45 and carnivorous, which pass on only a greatly diminished supply of food to sustain the larger, more active and more complex creatures.
In other respects the analogy is substantially inaccurate, because the primary marine food production is carried out by cells dispersed widely in a dense fluid medium this fact of an initial dispersal imposes a set of profound general conditions on all forms of life in the sea.
In moderately rich areas of the sea, food is 100th times more dilute in volume and hundreds of thousands of time more dilute in relative mass. To crop this meager either a blind herbivore or a simple pore in a filtering structure would need to process a weight of water hundreds of thousands of times the weight of the cell if eventually captures.
In even the densest concentrations the factor exceeds several thousands and with each further step in the food web dilution increases. Thus, from the beginnings of the marine food web we see many adaptations accommodating to this dilution: eyes in microscopic herbivorous animals. Filters of exquisite design, mechanisms and behaviours for discovering local concentrations, complex search gear and, on the bottom.
Attachments to elicit the aid of moving water in carrying out the task of filtration. All these adaptations stem from the conditions that limit plant life in the open sea to microscopic dimensions.
It is in the sunlight near surface of the open sea that the unique nature of the dominant system of marine life is irrevocably molded. The near surface, or mixed, layer of the sea varies in thickness from tens of feet to hundreds depending on the nature of the general circulation, mixing by winds and heating. Gear the basic food production of the sea is accomplished by single called plants.
One common group of small phytoplanktons is the coccolithophores, with calcareous plants. A swimming ability and often an oil droplet for food storage and buoyancy.
The larger microscopic phytoplanktons are composed of many species belonging to several groups: naked algal cells, diatoms with complex shells of silica and activity swimming and rotating flagellates.
Very small forms of many groups are also abundant and collectively are called nannoplankton. The species composition of the phytoplankton is everywhere complex and varies from place to place, season to season and year to year.
The various regions of the ocean are typified, however, by dominant major groups and particular species, seasonal effects are often strong, with dense blooms of phytoplankton occurring when high levels of plant nutrients suddenly become usable or available, such as in high latitudes in spring or along coasts at the onset of upwelling. The concentrations of phytoplankton vary on all dimensional scales, even down to small patches.
In addition the large-scale circulation of the ocean continuously sweeps the pelagic plants out of the region to which they are best adapted. It is essential that some individuals be returned to renew the populations.
More mechanisms for this essential return exist for single celled plants than exist for large plants or even for any conventional spores, seeds or juveniles. Any of these can be carried by oceanic gyres or diffused by large-scale motions of surface eddies and periodic counter currents while temporarily feeding on the food particles or perhaps dissolved organic material.
Other mechanisms of distribution undoubtedly are also occasionally important. For example, having marine plant cells are carried by storm- borne spray. In bird feathers and by wellfed fish and birds in their undigested food. No large plant has solved the many problems of development, dispersal, and reproduction.
There are no pelagic trees, and these several factors in concert therefore restrict the open sea in a profound way. They confine it to an initial food web composed of microscopic forms, whereas larger plants live attached only to shallow bottoms.
Attached plants, unlike free-floating plants, are not subject to the aforementioned limitations. For attached plants all degrees of water motion enhance the exchange of nutrients and wastes.
Although species of phytoplankton will populate only regions with conditions to which they are adapted, factors other than temperature, nutrients and light levels undoubtedly are important in determining the species composition of phytoplankton populations.
Little is understood of the mechanisms that give rise to an abundance of particular species under certain conditions. Grazing herbivores may consume only a part of the size range of cells. Allowing certain sizes and types to dominate temporarily.
Little is understood of the mechanisms that give rise to an abundance of particular species under certain conditions. Chemical by products of certain species probably exclude certain other species.
Often details of individual cell behaviour are probably also important in the introduction and success of a species in a particular area. In some cases we can glimpse what the mechanisms are for example, both the larger diatoms and the larger flagellates can more at appreciable velocities through the water.
The diatoms commonly sink downward, whereas the flagellates actively swim upward toward light. These are probably patterns of behaviour primarily for increasing exchange.
But the interaction of such unidirectional motions with random turbulence or systemic convective motions is not simple, as it is with an inactive particle. Rather, we would expect diatoms to be statistically abundant in upward moving water and to sink out of the near surface layers when turbulence or upward convection is low.
Conversely, flagellates should be statistically more abundant in down welling water and should concentrate near the surface in low turbulence and slow downward water motions. These effects seem to exist. Of some continental costs in summer flagellates may eventually collect in high concentrations.
As they begin to shade one to another from the light. Each individual struggles close to the lighted surface, producing such a high density that large areas of the water are turned red or brown by their pigments.
The concentration of flagellates in these “Red Tides” sometimes becomes too great for their own survival. Several species of flagellates also become highly foxic as they grow older. Thus, they sometimes both produce and participate in a mass death of fish and invertebrates that has been on own to give rise to such a highly yield of hydrogen sulfide as to blacken the white house’s of coastal cities.
Large diatom cells, on the other hand, spread a disproportionately greater time in upward moving regions of the water and an unlimited time in any region where the upward motion about equals their own downward motion.
Diatom cells are there statistically abundant in upwelling water, and the distribution of diatoms probably is often are flections of the turbulent convective region of the water.
Sinking and the dependence of the larger diatoms on upward convection and turbulence for support aids item in reaching upwelling regions, where nutrients are high, it helps to explain their dominance in such regions and such other features of their distributions as their high proportion in rich ocean regions and their frequent inverse occurrence with flagellates.
Differences in adaptations to the physical and chemical products probably reinforce such relations. In some areas, such as parts of the equatorial current system and shallow seas.
Where lateral and vertical circulation is rapid, the species composition of phyto- plankton is perhaps more simply a result of the inherent ability of the species to grow, survive and reproduce under the local conditions of temperature, light, nutrients, competitors and herbivores.
Elsewhere second-order effects of the detailed cell behaviour often dominate. These details of behaviour that give rise to concentration on any dimensional scale are particularly important to all subsequent steps in the food chain. The grazing of the phytoplankton it principally conducted by the herbivorous members of that zooplankton.
A heterogeneous group of small animals that carry out several steps in the food web as herbivores, carnivores and detrital feeders. Among the important members of the zooplankton are the arthopods, animals and external skeletons that belong to the same broad groups as insects, crabs and shrimps.
The plank tonic arthropods induce the abundant copepods, which are in a sense the marine equivalent of insects. Copepods are represented in the sea by some 10,000 or more species that act not only as – herbivores.
Carnivores or detritus feeders but also as external or even internal parasites’ two or three thousand of these species live in the open sea. Other important arthropods are the shrimp like euphausidis, the strongest vertical migratory of the zooplankton.
They compose the vast shoals of krill that occur in high latitudes and that constitute one of the principal foods of the baleen whales.
The zooplankton also include the strange bristle jawed chateognaths or arrow worms, carnivores or mysterious origin and affinities know only in the marine environment.
Widely distributed and abundant. The chateognaths are represented by a surprisingly small number of species. Perhaps fewer than 50. Larvae of many types, worms, medusae, ctenophores, gastropods, pteropods and heteropods, salps, unpigmented flagellates and many others are also important components of this milieu.
Each with its own remarkably complex and often bizarre life history, behaviour and form. The larger zooplanktons are mainly carnivores, and those of herbivores habit are restricted to feeding on the larger plant cells.
Much of the blood supply, however, exists in the form of very small particles such as the nano-plankton, and these appear to be available almost solely to microscopic creatures.
Eyesight has developed in many minute animals to make possible selective capture. A variety of vebs, bristles, rakes, combs, cilia and other structures are found, and they are often sticky. Stickiness allows the capture of food that is finer than the interspaces in the filtering structures, and it greatly reduces the expenditure of energy.
A few groups have developed extremely fine and apparently quite effective nets. One group that has accomplished this is the “Larvacea”. A larvacian produces and inhabits a complex external “House,” much larger than its owner.
That contains a system of very finely constructed nets through which the creature maintains a gentle flow. The larvacea have apparently solved the problem of energy loss in filtering by having proportionately large nets; fine strong threads and a low rate of flow.
The composition of zooplankton differs from place to place day to night, season and year to year, yet most species are limited in distribution, and the members of plank tonic communities commonly show a rather stable representation of the modes of life.
The zooplanktons are of course, faces with the necessity of maintaining breeding assemblages and like the phytoplankton. With the necessity of establishing are inoculations of parent waters. In addition, their behaviour must lead to a correspondence with their food and to the pattern of large scale and small scale spottiness already imposed on the marine relearn by the phytoplankton.
The swimming powers of the larger zooplankton are quite adequate for finding local small scale patcho of food. That this task is accomplished on a large scale is indirectly demonstrated by the observed correspondence between the quantities of zooplankton and the plant nutrients in the surface waters.
There are many large and small puzzles in the distributions of zooplankton. As an ex-dense concentrations of phytoplankton are often associated with low populations of zooplankton.
These are probably rapidly growing blooms that zooplankton have not yet invaded and grazed on, but it is not completely clear that this is so. Chemical repulsion may be involved.
The concentration of larger zooplankton and small fishes in the surface layers is much greater at night than during the day, because of a group of strong swimming members that share their time between the surface and the mesopelagic region. Many small zooplankton organisms also make a daily migration of some vertical extent.
In addition to its primary purpose daily vertical migration undoubtedly served the (migration) migrating organisms in a number of other ways. It enables the creatures to adjust their mean temperature.
So that by spending the days in cooler water the amount of food used during rest is reduced. Perhaps such processes as the rate of egg development are also controlled by these tactics.
Convincing arguments have also been presented to show that vertical migration serves to maintain species so that they will be more successful under many more conditions than if they lived solely in the surface layers.
This migration must also play an important part in the distribution of many species. Interaction of the daily migrants with the water motion produced by daily land sea breeze alteration can hold the migrants off store by a kind of “Rectification” of the oscillating water motion.
More generally descent into the (water) lower layers increases the influence of submerged counter currents. There by enhancing the opportunity to regions and hence to find high nutrient level and associated high phytoplankton productivity.
Even minor details of behaviour may strongly contribute to success. Migrants spend the day at a depth corresponding to relatively constant low light, where the moment of water commonly is different from that at the surface.
Most of the members rise somewhat even on the passage of cloud shadow. The principal food supplies of the pelagic populations are passed on in incremental steps and rapidly depleted quantity to the larger carnivores, zooplankton, then to small fishes and squids, and ultimately to the wide range of larger carnivores of the pelagic realm.
The Pelagic region contains some of the largest and most superbly designed creatures ever to inhabit this earth: the exquisitely constructed pelagic tunas. The multicolored dolphin fishes, captures of flying fishes; the conversational purposes; the shallow and deep feeding swordfishes and toothed whales, and the greatest carnivores of all, the baleen whales and some plankton eating sharks.
Whose preys are entire schools of krill or small fishes. Seals and sea lions feed far into the pelagic realm. In concert with these great predators, large carnivorous sharks a wait injured prey. Marine birds, some adapted to almost continuous pelagic life, consume surprising quantities of ocean food, diving, plunging, skimming and gulping in pursuit.
These larger creatures of the sea commonly move in schools, shoals, and herds. In addition to meeting the needs of mating such grouping is advantageous in both defensive and predatory strategy.
Small fishes of several species commonly school together. Diverse predators also form loosely cooperative groups, and many species of marine birds depend almost wholly on prey driven to the surface by submerged predators.
At night, schools of prey and predators are almost always spectacularly illuminated by bioluminescence produces by the microscopic and larger plankton. The reason for the ubiquitous production of light by the micro-organisms of the sea remains obscure, and suggested explanations are controversial.
It has been suggested that light is a kind of inadvertent by product of life in transparent organisms. It has also been hypothesized that the emission of light on disturbance is advantageous to the plankton is making the predators of the plankton conspicuous to their predators.
The fall out of organic material into the deep dimly lighted mid water supports a sparse population of fishes and invertebrates within the mesopelasic bathypelagic zones are found some of the most curious and bizarre creatures of this earth.
These range from the highly developed and powerfully predators intruders, toothed whales and sword fishes, at the climax of the food chain to the remarkable squids, octopuses, euphausidis, lantern fishes, gulpers and angler fishes that inhabit the bathypelagic region.
In the mesopelagic region, where some sunlight penetrates, fishes are often counter shaded, that is, they are darker above and lighter below. As are surface fishes. Many of the creatures of this dimly lighted region participate in the daily migration.
Swimming to the upper layers at evening like bath emerging from their caves. There are some much larger stronger and more active fishes and squids in this region, although they are not taken in trawls or seen from submersibles.
Knowledge of their evidence comes mainly from specimens found in the stomach of sperm whales and sword fish. There is evidence that the sperm whales posses highly developed long range hunting sonar. They may locate their prey over relatively great distances.
Perhaps miles, from just such an extremely sparse population of active bathypelagic animals. Although many near surface organisms are luminescent. It is the bathypelagic region that bioluminescence has reached a surprising level of development.
With at least two thirds of the species producing light. Clearly bioluminescence of the bathypelagic realm have developed light producing organs and structures to a high degree.
Strong fishes may confuse predators by “target alteration” effects or by producing residual images in the predator’s vision. Some squids and shrimps are more direct and discharge luminous organs are arranged on some fishes so that they can be used to counter shade their silhouettes against faint light coming from the surface.
Light may also for locating a mate. A problem of this vast, sparsely populated domain that has been solved by some angler fishes by the development of tiny males that live parasitically attached to their relatively huge mates.
Light level in the bathypelagic regain can be much lower. This is most probably the primary difference that accounts for the absence of bioluminescence in higher land animals and the richness of IPs development in the ocean forms.
There are some 2000 species of the larger invertebrates known to inhabit the bathypelagic zone. But only 4 few of these species appear to be widespread. The barriers to distribution in this widely interconnected mid water region are not obvious.
The floor of the deep sea constitutes an environment quite unlike the mid-water and surface environments. There are sites for the attachment of the larger invertebrates that filter detritus from the water.
Among these animals are representative of some of the earliest multicelled creature to exist on the earth glass sponges, sea little’s—once thought to have been long extinct- and lamp shells.
Larger numbers of active fishes and other creatures are attracted to the bait almost immediately. It is probably I feel that several rather independent branches of the food web coexist in support of the deep bottom creatures: one the familiar rain of fine detritus, and the other the widely separate falls of large food particles that are in excess of the local feeding capacity of broadly diffuse bathypelagic population.
Such falls would include dead whales, large sharks or other large fishes and fragments of these, the multitude of remnants that are left when predators attack a school of surface fish and undoubtedly, garbage from ships and kills from underwater explosions.
These sources result in an influx of high grade food to the sea floor, and we would expect to find a population of active creature adapted to its prompt discovery and utilization. Other sources of food materials are braided into these two extremes of the abyssal food web. There is the rather subtle downward diffusion of living and dead food that results initially from the daily vertical migration of small fishes and zooplankton near the surface.
This migration appears to impress a sympathetic daily migration on the mid water population down to great depths, far below the levels that light penetrates. Not only may such vertical migration bring feeble bathypelagic creatures near the bottom but also it accelerates in itself the flux of dead food material to the bottom of the deep sea.
Benthic animals are much more abundant in the shallower mater off continents, particularly offshore from large rivers. Here there is often not only a richer near surface production and less hazardous journey of food to the sea floor but also a considerable input of food conveyed by rivers to the bottom.
The deep slopes of river sediments wedges are typified by a comparatively rich population of burrowing and filtering animal that utilize this fine organic material. The shallow regions of such wedges are highly productive of active and often valuable marine organism.
The bottom is much more variable than the mid water zone is. There are as a result more environmental riches for an organism to occupy, and hence we see organisms that are of a wider range of from and habit.
Aside from the wide range of form and fraction the benthic environment elicits from its inhabitants, there are more fundamental conditions that influence the nature and form of life there. For example—the dispersed food material setting from the upper layers becomes much concentrated against the sea floor.
In the mid-water environment most creatures must move by their own energies to seek food, using their own food stores for this motion. On the bottom, however, substantial water currents are present at all depths, and creatures can await the passage of their food.
Here large organisms can grow by consuming microscopic or even submicroscopic food particles. Clams, scallops, mussels, tube worms, barnacles and a host of other creatures that inhabit this zone have developed a wide range of extremely effective filtering mechanisms.
Although the benthic environment enables the creatures of the sea to develop and major branch of the food web that is emancipated from successive microscopic steps. This makes little difference to the food economy of the sea.
The sea is quite content with a large population of tiny organisms. From man’s standpoint, however, the shallow benthic environment is an unusually effective producer of larger creatures for his food, and he widely utilizes these resources.
In short, there is, of course, much to learn about all marine life. The basic processes of the food web productivity, populations, distributions and the mechanisms of reinoculation, and the effects of intervention into these process, such as pollution, artificial upwelling, transplantation, cultivation and fisheries.
To learn of these processes and effects we must understand the (structure) nature not only of strong simple actions. But also of weak complex interactions, since the forms of life or the success of a species may be determined by extremely small second and their order effects.
In a synopsis warp we can also say that the possible benefits of broad marine-biological understanding are endless. Man’s aesthetic, adventurous, recreational and practical proclivities can be richly served.