Diatoms are predominantly autotrophic plants; in them, like other autotrophic organisms, the process of formation of organic matter occurs in chloroplasts with the help of pigments during photosynthesis. It was initially found that pigments in diatoms consist of a mixture of chlorophylls with xanthophylls and fucoxanthin. Later, to clarify the composition of pigments in diatoms, the chromatographic method was used, with the help of which the presence of eight pigments in the chloroplasts of diatoms was determined (Dutton, Manning, 1941; Strain, Manning, 1942, 1943; Strain a. oth., 1943, 1944; Wassink, Kersten, 1944, 1946; Cook, 1945; Hendey, 1964). These pigments are as follows: chlorophyll α, chlorophyll c, β-carotene, fucoxanthin, diatoxanthin, diadinoxanthin, neofucoxanthin A and neofucoxanthin B. The last four pigments are part of diatomine, which was discovered earlier. Some authors also point to the minimal presence of xanthophyll and pheophytin (Strain and. oth., 1944).

The total amount of pigments in diatoms is on average about 16% of the lipid fraction, but their content varies among various types. There is very little data in the literature on the quantitative content of pigments in marine planktonic diatoms, and for benthic species, which are especially rich in yellow and brown pigments, there is almost no data (Tables 1 and 2).

The above data show that pigment content varies even within the same species. There is evidence that the content of pigments is subject to fluctuations depending on the intensity of light, its quality, the content of nutrients in the medium, the condition of the cell and its age. For example, an abundance of nutrients in the environment with a relatively low light intensity stimulates the productivity of pigments, and conversely, high light intensity with a lack of nutrients in the environment leads to a decrease in the concentration of pigments. With a lack of phosphorus and nitrogen, the content of chlorophyll a can decrease by 2.5-10 times (Finenko, Lanskaya, 1968). It has been established that as cells age, the content of chlorophyll c decreases.

The functions of pigments other than chlorophylls in diatoms have not yet been sufficiently elucidated. Chlorophyll α is the main pigment that absorbs light energy from all rays of the spectrum, and it has two forms that differ in the absorption of light: one of them is excited directly by red light, and the second, in addition, also by the energy transmitted by the auxiliary pigment fucoxanthin (Emerson, Rabinowitch, 1960). The remaining pigments are auxiliary to chlorophyll a, but they also play a relatively important role in photosynthesis. Chlorophyll c has a higher absorption maximum in the blue region than in the red region, and therefore, it is able to utilize light rays of shorter wavelengths, its absorption maximum lies at 520-680 nm and drops to zero at a wavelength of 710 nm, so its absorption more intense in the blue light zone, i.e. at depths of 10-25 m from the water surface, where chlorophyll a is less effective. The role of β-carotene is not clear enough; its absorption spectrum ends abruptly at 500 nm, which indicates its ability to absorb in rays of wavelength 500-560 nm, i.e. in the green-yellow light region (in water at depths of 20-30 m ). Thus, β-carotene transfers the absorbed energy to chlorophyll α (Dutton and Manning, 1941). This is known, for example, for Nitzschia dissipata, which absorbs energy in the green-yellow light region (Wassink, Kersten, 1944, 1946). Brown pigments from the fucoxanthin group have a maximum absorption at a wavelength of about 500 nm and, apparently, ensure photosynthesis of diatoms at depths of 20-50 m by transferring the energy they absorb to chlorophyll. Dutton and Manning (1941), and later Wassink and Kersten (1946) showed that fucoxanthin is the main accessory pigment in diatoms. Light absorbed by fucoxanthin is utilized for photosynthesis almost as efficiently as light absorbed by chlorophyll. This is not observed in green and blue-green algae lacking fucoxanthin. Tanada (1951) also found that in freshwater diatoms Navicula minima var. atomoides fucoxanthin absorbs blue-blue light (450-520 nm) and utilizes it as efficiently as light absorbed by chlorophyll. Hendy (1964) indicates the wavelength of light at which maximum absorption of light occurs by various diatom pigments. In acetone they are as follows (in mmkm): chlorophyll α - 430 and 663-665, chlorophyll c - 445 and 630, β-carotene - 452-456, fucoxanthin - 449, diatoxanthin - 450-452, diadinoxanthin - 444-446, neofucoxanthin A - 448 - 450 and neofucoxanthin B - 448.

The chemistry of photosynthesis in diatoms is apparently somewhat different than in other plant organisms, in which the final product of photosynthesis is carbohydrates, while in diatoms it is fats. Electron microscope studies did not reveal the presence of starch either in the stroma of chloroplasts or near the pyrenoids. Fogg believes that in diatoms the final product of assimilation is also carbohydrates, but in rapidly occurring further metabolic processes they are converted into fats (Collyer and Fogg, 1955; Fogg, 1956). Chemical composition fats in diatoms are unknown neither for assimilation products nor for reserve nutritious oils and oil bodies (Goulon, 1956).

In oceans, seas and freshwater bodies at the surface of the water, conditions for photosynthesis are close to conditions in air environment, but with immersion in depth they change due to changes in the intensity and quality of light. In terms of illumination, three zones are distinguished: euphotic - from the surface to 80 m depth, photosynthesis occurs in it; disphotic - from 80 to 2000 m, here some algae are still found, and aphotic - below, in which there is no light (Das, 1954, etc.). Photosynthesis of marine and freshwater phytoplankton in the surface layer of water has been sufficiently studied both in natural and cultural conditions (Wassink and Kersten, 1944, 1946; Votintsev, 1952; Tailing, 1955, 1957a, 1966; Ryther, 1956; Edmondson, 1956; Ryther , Menzel, 1959; Steemann Nielsen, Hensen, 1959,1961, etc.). In particular, year-round observations in the Black Sea have shown that the highest intensity of phytoplankton photosynthesis coincides with the highest solar radiation. In summer, maximum photosynthesis of phytoplankton is observed from I to 16 hours. (Lanskaya, Sivkov, 1949; Bessemyanova, 1957). In different planktonic species, the maximum intensity of photosynthesis has limits of variation characteristic of a particular species. Wherein great importance has a latitudinal location of water areas (Doty, 1959, etc.).

Among diatoms (both planktonic and benthic), there are light-loving and shade-loving species, which have different photosynthesis rates and solar energy utilization rates for the same radiation. In light-loving species, like Cerataulina bergonii(planktonic) and Navicula pennata var. pontica(sublittoral), photosynthesis occurs parallel to radiation and reaches a maximum at noon, and in shade-loving plants - Thalassionema nitzschioides (planktonic) and Nitzschia closterium(tychopelagic) - depression of photosynthesis is observed during the day, and the maximum intensity of this process occurs in the morning and afternoon hours (Bessemyanova, 1959). The same course of photosynthesis is observed in cultures of northern pelagic species Coscinosira polychorda And Coscinodiscus eccentricus(Marshall and Ogg, 1928; Jenkin, 1937). In benthic forms, the intensity of photosynthesis per unit of biomass is significantly higher than in planktonic forms (Bessemyanova, 1959). This is quite natural” because benthic diatoms have large, intensely colored chloroplasts, i.e. total They have much more photosynthetic pigments. Observations have shown that photosynthesis is more active in mobile forms than in immobile ones and is noticeably activated during the period of diatom division (Talling, 1955). Photosynthesis does not stop even in moonlight, but under these conditions, oxygen is released 10-15 times less than during the day. In the upper horizon of the water column, nighttime photosynthesis is only 7-8% of daily (Ivlev, Mukharevskaya, 1940; Subrahmanyan, 1960).

With depth, the light intensity drops sharply. Measurement at various depths in the hall. Puget Sound (north-eastern part of the Pacific Ocean) using a Kunz photoelectric camera showed that the illumination intensity (at the water surface taken as 100%) at a depth of 10 m drops to 9.6%, at a depth of 20 m it is 4%, and at 35 m - 2.4%, practically at this depth it is completely dark (Grein, in: Feldmann, 1938; Gessner, 1955-1959, I). In parallel with the decline in illumination, daylight hours are shortened. In the ocean at latitudes of 30-40° with the greatest transparency of water at a depth of 20 m length summer day about 1 hour, at 30 m - 5 hours, at 40 m - only 5 minutes.

With depth, not only the intensity of illumination and the photoperiod decrease, but the quality of light also changes due to unequal absorption of rays of the solar spectrum of different wavelengths of light. In table Figure 3 shows changes in the absorption of light rays and the color of twilight lighting at different depths.

This table shows that the absorption of light in sea water is inversely proportional to the length of light waves, i.e. the longer the light wavelengths of the spectrum, the faster they are absorbed by water. As light rays are absorbed at appropriate depths, the color of the twilight illumination changes. Both limit photosynthesis at depths. The decrease in the intensity of various rays of the spectrum at different depths in the sea is presented in Table. 4.

The data in this table indicate that some marine brown and red algae can still grow at a depth of 75 m and, probably, deeper under conditions of very high water transparency. As is known, water transparency varies greatly not only in different bodies of water, but also in the same body of water. In the pelagic region of seas and oceans, water is transparent to a depth of 40 to 160 m, and in the marine sublittoral, water transparency drops to 20 m and below. The lower limit of algae distribution is determined by the light intensity at which assimilation and respiration are mutually balanced, i.e., when the so-called compensation point is reached (Marshall, Orr, 1928). Naturally, the compensation point in algae depends on the transparency of the water, the composition of pigments and a number of other factors. In this regard, there is some data for macrophyte seaweeds that have different pigment systems (Levring, 1966), but there is no such information for diatoms (Table 5).

Under equal lighting conditions, the compensation point in algae of different divisions depends on the function of their pigments. In blue-green algae (having pigments: chlorophylls a and b, β-carotene, ketocarotenoid, myxoxanthophyll) the compensation point is at a depth of about 8 m, in green algae (pigments: chlorophylls a and b, β-carotene, xanthophyll) - about 18 m, and in brown and red algae, which have additional pigments in addition to chlorophyll, carotene and xanthophyll (brown ones have phycoxanthin, red ones have phycoerythrin and phycocyan), the compensation point drops significantly below 30 m.

In some species of diatoms of the sublittoral Black Sea, the compensation point, apparently, can drop to a depth of 35 m. Modern methods for collecting sublittoral diatoms do not provide an accurate indicator of the living conditions of individual species. Based on the latest data, a general pattern of distribution of subtidal diatoms across depths has been established. In the sublittoral conditions of the Black Sea they live to a depth of about 30 m (Proshkina-Lavrenko, 1963a), in the Mediterranean Sea - to a depth of 60 m (Aleem, 1951), which is quite natural when the water transparency in this sea is 60 m. There are indications of habitation diatoms up to 110 m (Smyth, 1955), up to 200 m (Bougis, 1946) and up to 7400 m (Wood, 1956), with Wood stating that living diatoms (usually subtidal) have been found at this depth marine species together with freshwater ones!). The data of the last two authors is unreliable and requires verification.

The compensation point for the same species of diatom is not constant; it depends on the geographical latitude of the species, the season of the year, water transparency and other factors. Marshall and Opp (Marshall, Orr, 1928) experimentally established, lowering a culture of diatoms to different depths in the bay (Loch Striven; Scotland), that Coscinosira polychorda in summer it has a compensation point at a depth of 20-30 m, and in winter near the surface of the water. They obtained similar results for Chaetoceros sp.

Benthic diatoms undoubtedly exhibit chromatic adaptation, which explains the ability of many of them to live at a certain range of depths under conditions of changing spectral light and its intensity; it is possible that they have different races (some species Amphora, Carrtpylodiscus, Diploneis, Navicula). It has been experimentally established that the process of adaptation to lighting intensity occurs quite quickly. For example, a freshwater immobile planktonic diatom Cyclotella meneghiniana adapts to lighting from 3 thousand to 30 thousand lux within 24 hours, it is able to withstand significantly higher light intensity - up to 60 thousand lux and even up to 100 thousand lux (Jorgensen, 1964a, 1964b). Photosynthetic apparatus of mobile subtidal species ( Tropidoneis, Nitzschia) adapts to lighting conditions at the depths of their habitat of 1-3 m, where the light intensity ranges from 10 to 1% (Taylor, 1964). In general, a large literature is devoted to the issue of chromatic adaptation in diatoms (Talling, 1955, 1957a; Ryther, 1956; Ryther, Menzel, 1959; Steemann Nielsen, Hensen, 1959; Jørgensen, 1964a).

Planktonic diatoms can live much deeper than sublittoral ones, which is mainly due to the greater transparency of water in the pelagic zone. It is known that in the seas and oceans, diatom plankton extends to depths of 100 m or more. In the Black Sea at a depth of 75-100 m, phytoplankton consists of Thalassionema nitzschioides and several types Nitzschia, and here they live in much greater numbers than in the 0-50 m layer of water (Morozova-Vodyanitskaya, 1948-1954). Many types Nitzschia, as is known, easily switch from autotrophic nutrition to mixotrophic and heterotrophic. Apparently, planktonic species that live in the disphotic and aphotic zones of the seas have the same property; they create deep-sea shadow plankton. However, Steemann Nielsen and Hensen (1959) consider surface phytoplankton as “light” under conditions of radiation intensity of 600-1200 lx and as “shadow” under conditions of low radiation: 200-450 lx. According to these researchers, winter surface phytoplankton in temperate zone is a typical "shadow". However, winter phytoplankton consists of late autumn and early spring species, which cannot be classified as “shadow” species. It should be recognized that the problem of phytosynthesis in diatoms is still at the initial stage of research, and on many pressing issues of this problem there is only fragmentary and unverified data.

Oceans and seas occupy 71% (more than 360 million km2) of the Earth's surface. They contain about 1370 million km3 of water. Five huge oceans - Pacific, Atlantic, Indian, Arctic and Southern - are connected to each other through the open sea. In some parts of the Arctic and Southern Oceans, a permanently frozen continental shelf has formed, extending from the coast (shelf ice). In slightly warmer areas, the sea freezes only in winter, forming pack ice (large floating ice fields up to 2 m thick). Some marine animals use the wind to travel across the sea. Physalia ("Portuguese man-of-war") has a gas-filled bladder that helps catch the wind. Yantina releases air bubbles that serve as her float raft.

The average depth of water in the oceans is 4000 m, but in some ocean depressions it can reach 11 thousand m. Under the influence of wind, waves, tides and currents, ocean water is in constant motion. Waves raised by the wind do not affect deep water masses. This is done by the tides, which move water at intervals corresponding to the phases of the moon. Currents carry water between oceans. Surface currents, moving, slowly rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

Ocean bottom:

Most of the ocean floor is flat, but in some places mountains rise thousands of meters above it. Sometimes they rise above the surface of the water in the form of islands. Many of these islands are active or extinct volcanoes. Through central part At the bottom of a number of oceans there are mountain ranges. They are constantly growing due to the outpouring of volcanic lava. Each new flow that carries rock to the surface of underwater ridges forms the topography of the ocean floor.

The ocean floor is mostly covered with sand or silt - they are brought by rivers. In some places there are hot springs, from which sulfur and other minerals are deposited. The remains of microscopic plants and animals sink from the surface of the ocean to the bottom, forming a layer of tiny particles (organic sediment). Under pressure from overlying water and new sediment layers, the loose sediment slowly turns into rock.

Oceanic zones:

In depth, the ocean can be divided into three zones. In the sunny surface waters above - the so-called photosynthetic zone - most ocean fish swim, as well as plankton (a community of billions of microscopic creatures that live in the water column). Beneath the photosynthetic zone lie dimly lit Twilight Zone and the deep cold waters of the zone of darkness. Fewer life forms are found in the lower zones - mainly carnivorous (predatory) fish live there.

In most of the ocean water the temperature is approximately the same - about 4 °C. As a person dives deeper, the pressure of water on him from above constantly increases, making it difficult to move quickly. On great depths oh, besides, the temperature drops to 2 °C. The light becomes less and less until finally, at a depth of 1000 m, complete darkness reigns.

Life at the surface:

Plant and animal plankton in the photosynthetic zone provide food for small animals, such as crustaceans, shrimp, as well as juvenile starfish, crabs and other marine life. Away from sheltered coastal waters, the fauna is less diverse, but many fish and large mammals- for example, whales, dolphins, porpoises. Some of them (baleen whales, giant sharks) feed by filtering the water and swallowing the plankton contained in it. Others (white sharks, barracudas) prey on other fish.

Life in the depths of the sea:

In cold, dark waters ocean depths hunting animals are able to detect the silhouettes of their victims in the dimmest light, barely penetrating from above. Here, many fish have silvery scales on their sides: they reflect any light and camouflage the shape of their owners. Some fish, flat on the sides, have a very narrow silhouette, barely noticeable. Many fish have huge mouths and can eat prey that is larger than them. Howliods and hatchetfish swim with their large mouths open, grabbing whatever they can along the way.

The world's oceans cover more than 70% of the Earth's surface. It contains about 1.35 billion cubic kilometers of water, which is about 97% of all the water on the planet. The ocean supports all life on the planet and also makes it blue when viewed from space. Earth is the only planet in our solar system, which is known to contain liquid water.

Although the ocean is one continuous body of water, oceanographers have divided it into four main regions: Pacific, Atlantic, Indian and Arctic. Atlantic, Indian and Pacific Oceans merge into icy waters around Antarctica. Some experts identify this area as the fifth ocean, most often called the Southern Ocean.

To understand ocean life, you must first know its definition. The phrase "marine life" covers all organisms living in salt water, which includes a wide variety of plants, animals and microorganisms such as bacteria and.

There is a huge variety of marine species that range from tiny single-celled organisms to giant blue whales. As scientists discover new species, learn more about the genetic makeup of organisms, and study fossil specimens, they decide how to group ocean flora and fauna. The following is a list of the major types or taxonomic groups of living organisms in the oceans:

  • (Annelida);
  • (Arthropoda);
  • (Chordata);
  • (Cnidaria);
  • Ctenophores ( Ctenophora);
  • (Echinodermata);
  • (Mollusca)
  • (Porifera).

There are also several types of marine plants. The most common ones include Chlorophyta, or green algae, and Rhodophyta, or red algae.

Marine Life Adaptations

From the perspective of a land animal like us, the ocean can be a harsh environment. However, marine life is adapted to life in the ocean. Characteristics that help organisms thrive in marine environment, include the ability to regulate salt intake, organs for obtaining oxygen (for example, fish gills), resist high blood pressure water, adaptation to lack of light. Animals and plants that live in the intertidal zone deal with extreme temperatures, sunlight, wind and waves.

There are hundreds of thousands of species sea ​​life, from tiny zooplankton to giant whales. The classification of marine organisms is very variable. Each is adapted to its specific habitat. All oceanic organisms are forced to interact with several factors that do not pose problems for life on land:

  • Regulating salt intake;
  • Obtaining oxygen;
  • Adaptation to water pressure;
  • Waves and changes in water temperature;
  • Getting enough light.

Below we look at some ways to survive marine flora and fauna in this environment, which is very different from ours.

Salt regulation

Fish can drink salt water and remove excess salt through the gills. Seabirds also drink sea ​​water, and excess salt is removed through the “salt glands” into the nasal cavity and then shaken out by the bird. Whales do not drink salt water, but receive the necessary moisture from their bodies, which they feed on.

Oxygen

Fish and other organisms that live underwater can obtain oxygen from the water either through their gills or through their skin.

Marine mammals must come to the surface to breathe, so whales have breathing holes on the top of their heads, allowing them to inhale air from the atmosphere while keeping most of their body submerged.

Whales are able to remain underwater without breathing for an hour or more, as they use their lungs very efficiently, filling up to 90% of their lung capacity with each breath, and also store unusually a large number of oxygen in the blood and muscles during diving.

Temperature

Many ocean animals are cold-blooded (ectothermic), and their internal body temperature is the same as their environment. The exception is warm-blooded (endothermic) marine mammals, which must maintain a constant body temperature regardless of water temperature. They have a subcutaneous insulating layer consisting of fat and connective tissue. This layer subcutaneous fat allows them to maintain their internal body temperature approximately the same as that of their terrestrial relatives, even in the cold ocean. The bowhead whale's insulating layer can be more than 50 cm thick.

Water pressure

In the oceans, water pressure increases by 15 pounds per square inch every 10 meters. While some sea ​​creatures rarely change water depth, long-swimming animals such as whales, sea turtles and seals travel from shallow waters to great depths in a few days. How do they cope with pressure?

It is believed that the sperm whale is capable of diving more than 2.5 km below the ocean surface. One adaptation is that the lungs and chest shrink when diving to great depths.

The leatherback sea turtle can dive to more than 900 meters. Folding lungs and a flexible shell help them withstand high water pressure.

Wind and waves

Intertidal animals do not need to adapt to high blood pressure water, but must withstand strong wind and wave pressure. Many invertebrates and plants in this region have the ability to cling to rocks or other substrates and also have hard protective shells.

While large pelagic species such as whales and sharks are not affected by storms, their prey may be displaced. For example, whales hunt copepods, which can be scattered across different remote areas during strong wind and waves.

sunlight

Organisms that require light, such as tropical Coral reefs and associated algae are found in small, clear waters easily transmitting sunlight.

Because underwater visibility and light levels can change, whales do not rely on vision to find food. Instead, they find prey using echolocation and hearing.

In the depths of the ocean abyss, some fish have lost their eyes or pigmentation because they simply are not needed. Other organisms are bioluminescent, using light-producing organs or their own light-producing organs to attract prey.

Distribution of life in the seas and oceans

From the coastline to the deepest seabed, the ocean is teeming with life. Hundreds of thousands of marine species range from microscopic algae to the blue whale that has ever lived on Earth.

The ocean has five main zones of life, each with unique adaptations of organisms to its particular marine environment.

Euphotic zone

The euphotic zone is sunlit top layer ocean, up to approximately 200 meters in depth. The euphotic zone is also known as the photic zone and can be present in both lakes with seas and the ocean.

Sunlight in the photic zone allows the process of photosynthesis to occur. is the process by which some organisms convert solar energy and carbon dioxide from the atmosphere into nutrients(proteins, fats, carbohydrates, etc.), and oxygen. In the ocean, photosynthesis is carried out by plants and algae. Seaweeds are similar to land plants: they have roots, stems and leaves.

Phytoplankton, microscopic organisms that include plants, algae and bacteria, also live in the euphotic zone. Billions of microorganisms form huge green or blue patches in the ocean, which are the foundation of oceans and seas. Through photosynthesis, phytoplankton are responsible for producing almost half of the oxygen released into the Earth's atmosphere. Small animals such as krill (a type of shrimp), fish and microorganisms called zooplankton all feed on phytoplankton. In turn, these animals are eaten by whales, large fish, seabirds and humans.

Mesopelagic zone

The next zone, extending to a depth of about 1000 meters, is called the mesopelagic zone. This zone is also known as the twilight zone because the light within it is very dim. The lack of sunlight means that there are virtually no plants in the mesopelagic zone, but large fish and whales dive there to hunt. The fish in this area are small and luminous.

Bathypelagic zone

Sometimes animals from the mesopelagic zone (such as sperm whales and squid) dive into the bathypelagic zone, which reaches depths of about 4,000 meters. The bathypelagic zone is also known as the midnight zone because light does not reach it.

Animals that live in the bathypelagic zone are small, but they often have huge mouths, sharp teeth and expanding stomachs that allow them to eat any food that falls into their mouths. Much of this food comes from the remains of plants and animals descending from the upper pelagic zones. Many bathypelagic animals do not have eyes because they are not needed in the dark. Because the pressure is so high, it is difficult to find nutrients. Fish in the bathypelagic zone move slowly and have strong gills to extract oxygen from the water.

Abyssopelagic zone

The water at the bottom of the ocean, in the abyssopelagic zone, is very salty and cold (2 degrees Celsius or 35 degrees Fahrenheit). At depths of up to 6,000 meters, the pressure is very strong - 11,000 pounds per square inch. This makes life impossible for most animals. The fauna of this zone, in order to cope with the harsh conditions of the ecosystem, has developed bizarre adaptive features.

Many animals in this zone, including squid and fish, are bioluminescent, meaning they produce light through chemical reactions in their bodies. For example, the anglerfish has a bright appendage located in front of its huge, toothy mouth. When the light attracts small fish, the anglerfish simply snaps its jaws to eat its prey.

Ultra Abyssal

The deepest zone of the ocean, found in faults and canyons, is called the ultra-abyssal. Few organisms live here, such as isopods, a type of crustacean related to crabs and shrimp.

Such as sponges and sea cucumbers thrive in the abyssopelagic and ultra-abyssal zones. Like many sea ​​stars and jellyfish, these animals depend almost entirely on the settling remains of dead plants and animals called marine detritus.

However, not all bottom dwellers depend on marine detritus. In 1977, oceanographers discovered a community of creatures on the ocean floor feeding on bacteria around openings called hydrothermal vents. These vents lead hot water, enriched with minerals from the depths of the Earth. The minerals feed unique bacteria, which in turn feed animals such as crabs, clams and tube worms.

Threats to marine life

Despite relatively little understanding of the ocean and its inhabitants, human activity has caused enormous harm to this fragile ecosystem. We constantly see on television and in newspapers that yet another marine species has become endangered. The problem may seem depressing, but there is hope and many things each of us can do to save the ocean.

The threats presented below are not in any particular order, as they are more pressing in some regions than others, and some ocean creatures face multiple threats:

  • Ocean acidification- If you've ever owned an aquarium, you know that the correct pH of the water is an important part of keeping your fish healthy.
  • Changing of the climate- we constantly hear about global warming, and for good reason - it negatively affects both marine and terrestrial life.
  • Overfishing is a worldwide problem that has depleted many important commercial species fish.
  • Poaching and illegal trade- despite laws passed to protect marine life, illegal fishing continues to thrive to this day.
  • Nets - marine species from small invertebrates to large whales may become entangled and die in abandoned fishing nets.
  • Garbage and pollution- various animals can become entangled in debris, as well as in nets, and oil spills cause enormous damage to most marine life.
  • Habitat loss- As the world's population grows, human pressure on coastlines, wetlands, kelp forests, mangroves, beaches, rocky shores and coral reefs, which are home to thousands of species, increases.
  • Invasive species - species introduced into a new ecosystem can cause serious harm to their native inhabitants, since due to the lack of natural predators they may experience a population explosion.
  • Seagoing vessels - ships can cause fatal damage to large marine mammals, and also create a lot of noise, carry invasive species, destroy coral reefs with anchors, and lead to the release of chemical substances into the ocean and atmosphere.
  • Ocean noise - there is a lot of natural noise in the ocean that is an integral part of this ecosystem, but artificial noise can disrupt the rhythm of life of many marine inhabitants.