The phosphate and nitrogen compounds found in the waste material that are released into the environment go through some biological processes and are transformed into nourishing salts for the phytoplankton. When there is an increase in temperature, these salts may cause some of the phytoplankton to grow and reproduce excessively. The toxic materials released by some, and the use of excessive oxygen, are harmful to other organisms.

Another example of pollution is related with algae. When the number of microbial plants called algae reaches one million per cubic decimeter (1 million/dm3) of water, the consumption of oxygen required in order to mineralize, and break-down the organic materials found in the water increases, and therefore a compound of toxins which pollute the water, such as hydrogen sulfide (H2S), are released. This pollution can cause the death of fish and other organisms which live in the water. As a result of the reduction in water quality, an increase in the type of algae called cyanobacteria occurs and the biotoxins that they produce threatens human health.

More than forty types of algae produce various toxins. Some of these toxins damage the human liver, some attack the nervous system (particularly the brain), some can cause allergic skin reactions, and some can even induce cancer. The release of domestic, industrial, and agricultural waste and the high percentage of nutrients (such as nitrogen and phosphor compounds) into the aquatic ecosystem can cause an excessive increase of algae in the waters. This algal bloom in fresh water is referred to as eutrophication. In oceans, it is referred to as red tide because the water appears to be a reddish color. Both present a significant environmental problem.

In low doses humans are exposed to these toxins by the consumption of drinking water. In Brazil in 1988, almost 2000 people developed gastroenteritis over a forty day period due to the consumption of drinking water contaminated by these toxins, and eighty-eight of them died. In South Australia, as early as 1878, many sheep, horses, dogs and other animals died as a result of drinking water from Lake Alexandrina, which was covered by scum caused by an aglal bloom called Nodularia spumigena.

Mussels, a delicacy eaten and enjoyed by many, accumulate large amounts of toxins because they feed on phytoplankton. One study found that in fresh water mussels (Mytilus galloprovincialis) that fed on cyanobacteria, almost 10.7 g toxins per gram of bodyweight was accumulated. This is also the case in marine mussels. It has been determined that these toxins in gradually increased concentrations are passed onto organisms higher on the food chain by consumption. Accordingly, we should always consider the potential risk factors before consuming shellfish.

Biotoxins are released into the water after being broken down by algae. Thus, when an algal bloom reaches high levels, there is an increase in the density of toxins in the water. As these toxins dissolve in the water, purifying the contaminated water requires not only expensive, but also advanced technology methods. Unfortunately, it is impossible to remove this waste in many of the existing refining plants. The toxin concentration in drinking and utility water should be reduced in regions where drinking water is obtained from lakes by mixing it with uncontaminated water, particularly during the spring when the algal bloom occurs. Thus, reducing the amount of biotoxins in the water to a level that will cause minimal harm to aquatic organisms should help to reduce the risks to humans.

Many types of waste released into the environment cause damage, which adversely affect humans. Polluting the environment may be easy, but purifying the environment of this pollution is a very difficult task. Indeed, humans were not created to act irresponsibly and destroy the universe in which they are mere guests. On the contrary, the human is a delicate guest with sublime duties. Protecting the natural resources provided for our needs and utilizing these resources in the most productive manner, without disturbing the balance of nature, is a duty of every human on earth.

References

• Pouria S. de Andrade A. 1988. “Fatal microcystin intoxication in haemodialysis unit in Caruaru, Brazil.” Lancet 352:21-26.
• Carmichael W.W., Azevedo S.M.F.O. 2001. “Human fatalities from cyanobacteria: Chemical and biological evidence for cyanotoxins.” Environ. Health Perspect 109: 663-668.
• Codd G.A., Bell S.G., Kaya K., Ward C.J., Beattie K.A., Metcalf J.S. 1999. “Cyanobacterial toxins, exposure routes and human health.” Eur. J. Phycol. 34:405-415.

There are many identified species of phytoplanktons. Phytoplanktons live for a day or two under normal conditions, and when they die they sink to the bottom. As a single-celled organism, phytoplankton is not only one of the main components of marine food chain, it is also assigned with an important role in carbon cycle which keeps atmospheric temperature in balance and the level of oxygen under control. Because of their significance, scientists have always showed considerable attention to phytoplanktons.

Photosynthesis in phytoplanktons

All living things need energy and organic building blocks in order to grow and maintain their lives. Plants transform sunlight into chemical energy and inorganic materials to organic materials. This process is called photosynthesis. Other living organisms consume plants to meet their food and energy needs. Like terrestrial plants, phytoplanktons also have chlorophyll pigments to process photosynthesis. This is how fish and other animals in the oceans obtain their food.

Global effects

The larger the world’s phytoplankton population, the more carbon dioxide gets pulled from the atmosphere through photosynthesis. Carbon dioxide is responsible for as much as 50% of the total greenhouse effect. There is a divine wisdom behind existence of phytoplanktons in big populations which help with the adjustment of carbon dioxide level in the atmosphere and thereby the greenhouse effect.

Phytoplanktons have an interactive relationship with their environment. This interactive relationship either increases or decreases the population of phytoplanktons in accordance with environmental changes. Scientists have found that a given population of phytoplankton can double once per day. Large populations of this organism, sustained over long periods of time, could significantly lower atmospheric carbon dioxide levels and, in turn, lower average temperatures. Populations of this marine plant will grow or diminish rapidly in response to changes in its environment. Changes in the trends for a given phytoplankton population-such as its density, spatial distribution, and rate of population growth or diminishment-will alert scientists that environmental conditions are changing there.

Phytoplanktons and sulfur cycle

Dimethylsulfide (DMS) is a sulfuric compound which is synthesized by phytoplanktons. This compound has an important role in softening climate and cloud formation. It has a peculiar odor and although it is frequently perceived as a harmfully polluting chemical, it fulfills a very important task within the bio-geo-chemical cycle on Earth. In order to better recognize climate changes on a global scale and to develop smarter environmental politics, we need to know more about this gas compound.

The production of DMS is dependent upon co-existence of various organisms. Some species of phytoplanktons synthesize the dimethylsulfoniopropionate (DMSP) molecule, from which DMS is broken down. Bacteria and phytoplanktons participate in this break down which assimilates DMSP into DMS or other compounds. Some of the produced DMS vaporizes into the atmosphere from the salty sea water and become tropospheric sulfate gas after oxidization. Consequently, this gas plays a direct role in the global radiation balance by the upward scatter of solar radiation, and an indirect role as cloud condensation nuclei (CCN). Clouds affect the Earth’s radiation balance and thereby greatly influence its temperature and climate. DMS represents 95% of the natural marine flux of sulfur gases to the atmosphere, and scientists estimate that the flux of marine DMS supplies about 50% of the global biogenic source of sulfur to the atmosphere.

In order for the sulfuric cycle in nature to continue, it is necessary that sulfuric compounds are transferred from the ocean to land through the atmosphere. DMS, the source for 95% of natural sulfuric gas coming from the oceans, served as cloud condensation nuclei and helps carry sulfuric compounds move to the land with rain.

DMS emissions that originate from phytoplanktons play a significant role in climate formations. One third of the radiation coming from the sun reflects back into the space from the clouds, ice, and snow. The remaining two thirds is absorbed to some extent by the atmosphere, and to a greater extent by oceans and rocks. This energy is converted to heat some of which is later reflected by land and ocean as ultraviolet rays towards the space warming the atmosphere. If the Earth intakes more energy than it loses, the end result is global warming; the opposite is global cooling.

The size of clouds and water driblets indicate global climate changes. The more cloud condensation nuclei (CCN), the smaller the water droplets and the denser a cloud. This, in turn, influences the cloud’s radioactivity.

DMS containing chemical reactions from poles to tropical waters are important for us to estimate man-based and natural effects on the chemistry of atmosphere and the climate more accurately. It sounds somewhat weird for us that we first destroy the environmental balance God has established before we try to discover what we have done using the natural laws He has enjoined.

References

• Norris, K.B., 2003. “Dimethylsulfide emission: Climate control by marine algae?” ASFA: Aquatic Sciences and Fisheries Abstracts, http://www.csa. com/discoveryguides/dimethyl/overview.php
• http://www.oceansonline.com/phytoplankton.htm
• http://www.sciencephotolibrary.com
• http://www.cedareden.com/phyto.html

These tiny and mysterious creatures of the water are called Plankton; included in these are passively floating or weakly swimming animals and plants. The word plankton comes from the Greek word “planktos,” which means “to drift.” The plankton that drifts in the ocean currents are among the most abundant creatures of the planet. A bowl of water taken from an ocean consists of millions of these tiny organisms; they cannot be perceived by the naked eye. The only way to really become familiar with these creatures is to find them and observe them with the help of a video scope or a microscope. Many marine plants and animals go through a stage in their life cycle when they are plankton, but they ultimately outgrow this stage. These types of creatures are called meroplankton. Unlike meroplankton, holoplankton are tiny creatures which live their whole life as plankton.

Plankton are also classified as either plant plankton or animal plankton. Phytoplankton is the scientific name for plant plankton, whereas zooplankton is the term used for animal plankton. Phytoplankton are usually smaller than zooplankton and it is hard to observe them even under the microscope. Most of the food chains in the ocean begin with phytoplankton, which are eaten by tiny zooplankton. These tiny zooplankton in turn are eaten by larger animals living under the water, including sharks and blue whales.

Since plankton are at the bottom of most of the food chains in the ocean, anything that causes damage to their lives may effect many other organisms. Losing large numbers of plankton may affect the abundance of krill, which is the main diet of whales. Phytoplankton produce oxygen that people breathe; therefore a decrease in the number of phytoplankton may cause problems for human beings. Most plankton live near the surface of the oceans. Pollution, especially that caused by chemical pollutants, has a direct impact on the water at the surface. This is a great threat to plankton populations. Plankton are not only critical for their role in the food chain, but they are also important for their usage in the production of valuable minerals. Ancient deposits of plankton, which were buried under the seafloor and later mined, have become important sources of oil, shale, and many other valuable minerals.

Like land plants, phytoplankton fix carbon through photosynthesis, making it available for higher trophic levels.¹ The major environmental factors influencing phytoplankton growth are temperature, light, and availability of nutrients. Phytoplankton can undergo rapid population growth or “algal blooms” when water temperatures rise in the presence of excess nutrients. While increased phytoplankton populations provide more food to organisms at higher trophic levels, too much phytoplankton can harm the overall health of the oceans. During these blooms, most of the phytoplankton die and sink to the bottom, where they decompose. This process depletes the bottom waters of dissolved oxygen, which is necessary for the survival of other organisms, including fish and crabs.

Major groups of phytoplankton include: diatoms, golden-brown algae, green algae, blue-green algae, dinoflagellates and crypto monads. Phytoplankton are being used as indicators of environmental conditions within the oceans because their populations are especially sensitive to changes in nutrient levels and other water quality conditions.

Zooplankton are planktonic animals that range in size from microscopic rotifers to macroscopic jellyfish. Their distribution within the oceans is governed by salinity, temperature and food availability. The zooplankton community is composed of both primary consumers, which eat phytoplankton, and secondary consumers, which feed on other zooplankton. Zooplankton can be classified into three size classes: Microzooplankton-protozoans and rotifers, Mesozooplankton-including copepods and invertebrate larvae, and Macrozooplankton-including amphipods, shrimp, fish larvae, and jelly fish. Zooplankton, like phytoplankton, are excellent indicators of environmental conditions within the oceans, because they are sensitive to changes in water quality.

The most common animal in the plankton group is the copepod. There are more than 7,500 species of copepods. Copepods are small shrimp-like animals.

Copepods have appendages that are used like paddles for movement. They eat diatoms and other plankton and in turn are eaten by other, larger, drifters. A single copepod can eat an average of 200,000 diatoms a day.

Amphipods, which are the main diet of the gray whale, look like a cross between a shrimp and an isopod. The amphipod typically ranges in size from 2 to 50 mm, although a few may be larger. Amphipods are common in aquatic ecosystems throughout many parts of the world, inhabiting marine, brackish, and freshwater environments. A few species also live in terrestrial ecosystems.

One of the most interesting plankton species is the barnacle. It lives in the upper zone of the oceans where the water only comes at high tide. The appearance of a barnacle is rather deceptive. At first glance it looks like a mollusk, but when you observe the larva of the barnacle the truth becomes clear. Barnacles cause serious problems on the hulls of ships and buoys.

Jellyfish, which are basically nothing more than a large stomach with long tentacles, are also plankton. Their tentacles have stingers on them which they use to catch and paralyze food and then bring it to their stomachs. They move through the water by pumping their stomachs. For the most part they move up and down in the water, letting the currents carry them from side to side.

Copepods, amphipods, jellyfish, and barnacles are some of the most abundant and well-known examples of plankton. The oceans of the world contain a world of tiny organisms; most of them invisible to the human eye and yet these are the basis for nearly all the life in the sea. Our awareness of these tiny creatures will help enhance our appreciation of God’s uniqueness and greatness. The more we learn about the mysteries of the deep, the more we believe in the existence of God.

Footnote

1. Trophic levels: Producer, primary consumer, secondary consumer, tertiary consumer.