Algae Oxygen Production Vs Trees

Algae, Phytoplankton and Chlorophyll

What are Algae?

Algae are aquatic, plant-like organisms. They comprehend a multifariousness of elementary structures, from single-celled phytoplankton floating in the water, to large seaweeds (macroalgae) attached to the body of water floor ⁱⁱ. Algae can be plant residing in oceans, lakes, rivers, ponds and even in snowfall, anywhere on Earth.

So what makes algae only constitute-like, instead of plants? While algae are oft called primitive plants, other terms, like protists, can exist used ⁴. Protist may exist a more than accurate term, peculiarly for the single-celled phytoplankton ^viii. Even so, larger, more circuitous algae, including kelp and chara, are often mistaken for submerged plants.

The difference between these seaweeds and submerged plants is in their structure. Macroalgae are simpler, and attach themselves to the seabed with a holdfast instead of true roots ⁴. Aquatic plants, whether floating, submerged, or emergent (starting in the water and growing out) accept specialized parts such every bit roots, stems and leaves ³. Virtually plants as well have vascular structures (xylem and phloem), which deport nutrients throughout the plant. While algae contain chlorophyll (like plants), they do non accept these specialized structures ⁸.

Algae are sometimes considered protists, while other times they are classified every bit plants or choromists. Phytoplankton are made up of single-celled algae and cyanobacteria.

As algae can exist single-celled, filamentous (string-like) or plant-like, they are often difficult to classify. Most organizations group algae by their main colour (dark-green, red, or brownish), though this creates more than problems than it solves ⁴. The various species of algae are vastly different from each other, not only in pigmentation, just in cellular structure, complication, and called surroundings ^4,5. As such, algal taxonomy is still under debate, with some organizations classifying algae under unlike kingdoms, including Plantae, Protozoa and Chromista ^4,6,8,9. While the overarching kingdom nomenclature is not always agreed upon, the species, genus, family, form and phylum of each alga generally are ⁶.

To farther complicate this nomenclature, unmarried-celled algae oftentimes fall under the wide category of phytoplankton.

What are phytoplankton?

Phytoplankton are microorganisms that migrate virtually in water. They are single-celled, but at times they tin grow in colonies large plenty to be seen by the man eye ^sixteen. Phytoplankton are photosynthetic, meaning they have the power to use sunlight to convert carbon dioxide and water into energy ¹¹. While they are plant-like in this ability, phytoplankton are not plants. The term "single-celled plants" is a misnomer, and should not be used. Instead, phytoplankton can be divided into two classes, algae and cyanobacteria ^ten. These two classes accept the common ability of photosynthesis, merely have different physical structures. Regardless of their taxonomy, all phytoplankton contain at least one form of chlorophyll (chlorophyll A) and thus can acquit photosynthesis for energy.

Phytoplankton, both algae and cyanobacteria, can be establish in fresh or saltwater ¹³. As they need light to photosynthesize, phytoplankton in any environs will bladder near the superlative of the water, where sunlight reaches ¹⁰. Almost freshwater phytoplankton are made up of green algae and cyanobacteria, too known as blueish-green algae ¹³. Marine phytoplankton are mainly comprised of microalgae known every bit dinoflagellates and diatoms, though other algae and cyanobacteria tin can exist nowadays. Dinoflagellates accept some autonomous movement due to their "tail" (flagella), only diatoms are at the mercy of the ocean currents ¹².

Microalgae

In that location are thousands of species of planktonic algae, or microalgae, floating in water all over the world. Green algae, diatoms and dinoflagellates are the about well-known, though other microalgae species include coccolithophores, cryptomonads, gold algae, yellow-green algae and euglenoids ¹. At that place are so many diatoms drifting in the oceans that their photosynthetic processes produce near half of Earth'due south oxygen ⁹. While diatoms and dinoflagellates are forms of planktonic algae, they tin can be incorrectly classified as red or chocolate-brown algae ⁹. Ruby-red and brown algae are not considered phytoplankton as they are non free-floating. True ruby-red and brown algae are rarely single-celled, and remain attached to rock or other structures instead of drifting at the surface ^ane,17. Multicellular greenish algae is besides not considered phytoplankton for the same reasons. To be considered a phytoplankton, the algae needs to use chlorophyll A in photosynthesis, exist single-celled or colonial (a group of unmarried-cells), and alive and dice floating in the water, not attached to any substrate ¹.

Phytoplankton come up in many dissimilar structures, but all except for cyanobacteria are algae. Collage adapted from drawings and micrographs by Sally Bensusen, NASA EOS Project Science Office

Cyanobacteria: Blue-Green Algae

Despite their power to conduct photosynthesis for energy, blueish-green algae are a blazon of bacteria. This means that they are single-celled, prokaryotic (simple) organisms. Prokaryotic means that the blue-green alga practice not have a nucleus or other membrane-bound organelles within their jail cell wall ⁵.

Cyanobacteria are the only bacteria that contain chlorophyll A, a chemical required for oxygenic photosynthesis (the same process used by plants and algae) ^1,xiv. This process uses carbon dioxide, water and sunlight to produce oxygen and glucose (sugars) for energy. Chlorophyll A is used to capture the free energy from sunlight to help this procedure. Other leaner can be considered photosynthesizing organisms, merely they follow a different process known as bacterial photosynthesis, or anoxygenic photosynthesis ¹⁴. This process uses bacteriochlorophyll instead of chlorophyll A ¹⁹. These bacteria cells utilize carbon dioxide and hydrogen sulfide (instead of water) to industry sugars. Leaner cannot use oxygen in photosynthesis, and therefore produce energy anaerobically (without oxygen) ¹⁸. Cyanobacteria and other phytoplankton photosynthesize as plants practice, and produce the same sugar and oxygen for use in cellular respiration.

In 2011, Lake Erie experienced the worst blueish-greenish algae bloom in decades (Photo Credit: MERIS/NASA; processed by NOAA/NOS/NCCOS )

In addition to chlorophyll A, bluish-light-green algae too contain the pigments phycoerythrin and phycocyanin, which give the bacteria their blueish tint (hence the name, blue-green algae) ^xv. Despite not having a nucleus, these microorganisms do contain an internal sac called a gas vacuole that helps them to bladder near the surface of the water ¹³.

What is chlorophyll?

Chlorophyll is a color pigment found in plants, algae and phytoplankton. This molecule is used in photosynthesis, as a photoreceptor ²⁰. Photoreceptors blot light energy, and chlorophyll specifically absorbs energy from sunlight ¹⁵. Chlorophyll makes plants and algae appear green because it reflects the greenish wavelengths establish in sunlight, while absorbing all other colors.

The different forms of chlorophyll blot slightly different wavelengths for more than efficient photosynthesis.

Nevertheless, chlorophyll is not actually a single molecule. There are 6 dissimilar chlorophylls that have been identified ^1,22. The dissimilar forms (A, B, C, D, Due east and F) each reflect slightly different ranges of greenish wavelengths. Chlorophyll A is the main molecule responsible for photosynthesis ^ane,15. That ways that chlorophyll A is found in every single photosynthesizing organism, from land plants to algae and cyanobacteria ⁱ. The additional chlorophyll forms are accompaniment pigments, and are associated with different groups of plants and algae and play a role in their taxonomic confusion. These other chlorophylls nonetheless absorb sunlight, and thus aid in photosynthesis ²⁰. As accompaniment pigments, they transfer any energy that they absorb to the chief chlorophyll A instead of direct participating in the process ^1,21.

Chlorophyll B is mainly found in land plants, aquatic plants and green algae ¹. In virtually of these organisms, the ratio of chlorophyll A to chlorophyll B is iii:1 ²¹. Due to the presence of this molecule, some organizations volition group the greenish algae into the Plant Kingdom. Chlorophyll C is found in red algae, brown algae, and dinoflagellates ¹⁵. This has lead to their classification under the Kingdom Chromista ⁴. Chlorophyll D is a modest paint found in some ruby algae, while the rare Chlorophyll Eastward has been institute in yellow-greenish algae. Chlorophyll F was recently discovered in some cyanobacteria virtually Australia ²². Each of these accessory pigments will strongly absorb different wavelengths, so their presence makes photosynthesis more efficient ²⁰.

Other Color Pigments

Each pigment absorbs and reflects dissimilar wavelengths, but they all act as accessory pigments to chlorophyll A in photosynthesis.

Chlorophyll is not the merely photosynthetic paint found in algae and phytoplankton. There are also carotenoids,and phycobilins (biliproteins). These accompaniment pigments are responsible for other organism colors, such equally yellow, red, blue and brown. Similar chlorophylls B, C, D, Eastward and F, these molecules amend light energy absorption, just they are non a primary part of photosynthesis. Carotenoids tin can be found in nearly every phytoplankton species, and reflect yellow, orangish and/or cherry-red calorie-free ¹⁵. In that location are 2 phycobilins establish in phytoplankton: phycoerythrin and phycocyanin. Phycocyanin reflects blue light and is responsible for blue-green alga's mutual proper name – blue-dark-green algae. Phycoerythrin reflects ruby light, and tin be institute in red algae and cyanobacteria.

Some algae will appear green despite the presence of these accessory pigments. But as in plants, the chlorophyll in algae has a stronger relative assimilation than the other molecules. Like a dominant trait, the more intense, reflected greenish wavelengths can mask the other, less-reflected colors ^twenty. In green algae, chlorophyll is also found at a higher concentration relative to the accessory pigments. When the accessory pigments are more concentrated (such as in cerise algae, chocolate-brown algae and blue-green alga), the other colors can be seen ²³.

What is Photosynthesis?

Photosynthesis is the process past which organisms use sunlight to produce sugars for energy. Plants, algae and blue-green alga all comport oxygenic photosynthesis ^1,14. That means they require carbon dioxide, water, and sunlight (solar energy is nerveless by chlorophyll A). Plants and phytoplankton use these iii ingredients to produce glucose (sugar) and oxygen. This sugar is used in the metabolic processes of the organism, and the oxygen, produced as a byproduct, is essential to nearly all other life, underwater and on country ^i,24.

Photosynthesis uses h2o, carbon dioxide and sunlight to produce free energy and oxygen.

Underwater Photosynthesis

Phytoplankton drifting nigh beneath the surface of the water still carry out photosynthesis. This process can occur every bit long as enough calorie-free is available for the chlorophyll and other pigments to blot. In the ocean, light tin attain as far as 200m below the surface ²⁵. This region where sunlight can accomplish is known equally the euphotic zone. Phytoplankton and other algae tin can be plant throughout this zone.

What Affects Photosynthesis?

As light is required for photosynthesis to occur, the corporeality of light bachelor will bear on this process. Photosynthetic product peaks during the day and declines afterward nighttime ²⁴. However, not all light tin can exist used for photosynthesis. Only the visible light range (blue to ruby) is considered photosynthetically active radiation ¹. Ultraviolet light has too much free energy for photosynthesis, and infrared light does not have enough. If phytoplankton are exposed to too much UV light, the excessive solar energy can break molecular bonds and destroy the organisms' Dna ²⁷.

Blue and red light are used more than efficiently in photosynthesis.

Within the visible calorie-free spectrum, chlorophyll strongly absorbs red and blue light while reflecting light-green light ⁴⁸. This is why phytoplankton, specially cyanobacteria, can thrive at the bottom of the euphotic (sunlit) zone, where only blue light tin can reach. As bluish light is both high in energy and strongly absorbed by chlorophyll, it can be used effectively in photosynthesis.

Turbidity, or the presence of suspended particles in the water, affects the amount of light that reaches into the water ¹. The more sediment and other particles in the water, the less light volition exist able to penetrate. With less light bachelor, photosynthetic production volition decrease. In turbid h2o, photosynthesis is more likely to occur at the h2o's surface than on the lakebed, as more light is available. .

Temperature affects the photosynthetic rates of dissimilar algae.

Water temperature will also touch photosynthesis rates ¹. As a chemical reaction, photosynthesis is initiated and sped up past heat ²⁶. Equally photosynthesis production increases, then will phytoplankton reproduction rates ¹³. This factors into the big, seasonal swings of phytoplankton populations ^xiii. Nevertheless, the extent to which temperature affects photosynthesis in algae and blue-green alga is dependent on the species. For all phytoplankton, photosynthetic product volition increase with the temperature, though each organism has a slightly unlike optimum temperature range ⁱ. When this optimum temperature is exceeded, photosynthetic activity will in turn be reduced. Also much rut will denature (break down) the enzymes used during the process, slowing down photosynthesis instead of speeding it up ²⁶.

Why are Phytoplankton Important?

Microscopic phytoplankton play some of the biggest roles in climate control, oxygen supply and food production. These single-celled organisms are responsible for more than 40% of World's photosynthetic production ²⁸. That process uses up carbon dioxide, which helps regulate CO2 levels in the atmosphere, and produces oxygen for other organisms to live ²⁸.

Oceanic Food Spider web

Phytoplankton create their ain energy from sunlight. All other organisms swallow them, whether straight or indirectly as a carbon source.

Phytoplankton make up the foundation of the oceanic food web. A food spider web is a complex net of organisms and food chains (who-eats-who). To survive, every living affair needs organic carbon ²⁹. Organic carbon can be institute in many different things including sugars (glucose = C6H12O6), plants and animals. Phytoplankton produce their required saccharide through photosynthesis. As they are able to produce their ain energy with the assistance of light, they are considered autotrophic (self-feeding). Phytoplankton and other autotrophs are called primary producers, and brand upwardly the lesser of the food web ¹¹. These organisms are chosen "primary" considering all other organisms rely on them (directly or indirectly) as a food source ²⁹.

Phytoplankton are generally consumed by zooplankton and pocket-sized marine organisms like krill. These creatures are then consumed past larger marine organisms, such as fish ^29,30. This chain continues up to apex predators, including sharks, polar bears and humans.

Oxygen Production

Plants, algae and cyanobacteria all engage in oxygenic photosythesis (top equation), which means that they require water and release oxygen. Precambrian leaner used hydrogen sulfide instead of water (lesser equation) and did non release oxygen as a byproduct.

During the photosynthetic procedure, phytoplankton produce oxygen equally a byproduct. Due to their vast and widespread populations, algae and cyanobacteria are responsible for approximately one-half of all the oxygen found in the ocean and in our atmosphere ^x. Thus oceanic lifeforms not merely feed off the phytoplankton, but besides require the dissolved oxygen they produce to alive.

Earlier plants, algae and phytoplankton used water for photosynthesis, bacteria used H2S and other organic compounds to set up CO2 ³¹. Early cyanobacteria were the outset organism to employ water to gear up carbon ³¹. The use of H2O introduced costless oxygen (O2) into the surroundings every bit a byproduct. The start of oxygenic photosynthesis was a turning point for Earth's history. This process slowly inverse the inert Precambrian temper into the oxygen-rich environment known today ³¹. Though microscopic, early cyanobacteria take made a permanent touch on the Globe'southward environs.

Carbon Fixation and the Climate

In improver to providing food and oxygen for nearly all life on Globe, phytoplankton assistance to regulate inorganic carbon (carbon dioxide) in the atmosphere ¹⁷. During photosynthesis, carbon dioxide and water molecules are used to make saccharide for energy. The process of incorporating inorganic carbon into organic carbon (glucose and other biologically useful compounds) is called carbon fixation, and is part of the biological carbon pump ¹¹.

Equally carbon fixation and oxygen production are function of the aforementioned procedure, the extent of phytoplankton's participation is on the same calibration. Phytoplankton consume a similar amount of carbon dioxide every bit all land plants combined ¹¹. While phytoplankton can pull carbon dioxide from the temper or the body of water, it will take a similar event. CO2 that is taken from the h2o is replaced past CO2 from the temper, thanks to Henry'southward police force (the dissolved gas content of h2o is proportional to the pct of gas in the air above it ³². This consumption helps keep carbon dioxide levels in check, reducing its presence as a greenhouse gas ²⁸.

Algae and blue-green alga help to regulate the climate past fixing carbon dioxide from the atmosphere. This carbon is then consumed or decomposed by other organisms, making its way through the cycle until information technology is released every bit dissolved carbon dioxide in water or deposited in sediment.

When carbon dioxide is consumed, the carbon molecules become incorporated into the phytoplankton's structure, allowing the organism to function and abound ¹¹. If the phytoplankton is not eaten by some other organism (passing on the carbon up the food chain), then it will sink into the ocean when it dies. Equally with other detritus (non-living organic material), the phytoplankton will exist decomposed by bacteria, and the carbon is either released back into the ocean as dissolved carbon dioxide or somewhen deposited into the seafloor sediment ³³. Thanks to phytoplankton, this biological carbon pump removes approximately 10 trillion kilograms (x gigatonnes) of carbon from the atmosphere every yr, transferring information technology to the ocean depths ¹¹.

In climate terms, this process helps to maintain global surface temperatures ¹¹. Without this cycle, atmospheric CO2 would ascent approximately 200 ppm (current levels are effectually 400 ppm) ^33,34. Fifty-fifty pocket-sized changes in phytoplankton populations could have an event on the temper and world climate ¹¹.

Typical Levels and Factors that Influence Productivity

Phytoplankton populations and their subsequent photosynthetic productivity will fluctuate due to a number of factors, most of which are part of seasonal changes ³⁰. The largest influence on phytoplankton levels is nutrient scarcity ^xiii. While sunlight levels affect productivity, nutrient levels touch on phytoplankton growth and populations. While any one phytoplankton just lives for a few days, a population smash tin can terminal for weeks under the correct conditions ¹¹.

As phytoplankton populations abound and shrink seasonally, typical concentrations vary non only past location simply from month to calendar month ^thirty. Expected levels should be based on local, seasonal data from previous years. While changes within the aforementioned calendar year are normal, populations should stay consequent with previous seasonal fluctuations from year to year. If phytoplankton concentrations are abnormally high or low for a season, it may indicate other water quality concerns that should be addressed.

Sunlight Influence

Dissolved oxygen concentrations will increase during the day due to photosynthesis production and decline at night after the lord's day sets and the phytoplankton engage in respiration instead.

Phytoplankton crave sunlight for photosynthesis. If sunlight is express, phytoplankton productivity volition decrease. This can be seen in a daily cycle as oxygen levels fluctuate with light levels throughout the twenty-four hour period. However, if sunlight is unavailable or minimal for an extended menstruum of time, aquatic life will consume dissolved oxygen quicker than phytoplankton can restore it, leading to a plummet in dissolved oxygen levels ¹. Phytoplankton are responsible for much of the dissolved oxygen found in surface waters ^ten. As oxygen is required for fish and other aquatic organisms, a decrease in photosynthesis productivity is detrimental to aquatic populations. Without phytoplankton, the oxygen supply of the bounding main would be cutting in half. In both fresh and saltwater, a lengthy decrease in phytoplanktonic productivity tin can pb to a fish kill (massive fish die-off) ⁱ.

Although phytoplankton require sunlight for photosynthesis and oxygen production, too much light can exist harmful to photosynthetic production. Ultraviolet light from the sun can impairment the phytoplanktons' DNA, inhibiting the photosynthetic pathway ³⁵. On very bright days, UV-B radiations can diminish photosynthesis by 8.2% ³⁵. This is why photosynthesis rates height during the morning, and subtract at noon (when the radiations levels are highest) ⁱ.

Food Influence

Eutrophication is caused by an increment in nutrient levels. This can lead to an algal bloom and tin can cause low levels of dissolved oxygen.

While phytoplankton rely on photosynthesis to produce saccharide for free energy, they yet need other nutrients to abound and reproduce ⁷. These nutrients are typically phosphorus, nitrogen and iron, though some species as well crave silicon, calcium and other trace metals ^11,thirteen. The more nutrients (particularly phosphorus) that are present in a body of h2o, the more than algae and phytoplankton that will grow ⁷. An increase in the nutrient concentration of a torso of water is called eutrophication ¹³. Eutrophication is often an indicator of agricultural runoff, which tin can raise phosphorus and nitrogen concentrations to very high levels. If there are also many nutrients, the algae will class a bloom, which tin be very detrimental to water quality and aquatic health ⁷.

The lack of iron in the open up ocean limits phytoplankton growth ¹⁰. Nitrogen and phosphorus are also deficient away from coastlines, and can be limiting factors besides ^xiii. Notwithstanding, ocean circulation can crusade an upwelling, which moves deep, food-rich water up into the photic (sunlight zone), replacing the nutrient-depleted surface h2o ^xxx. Upwelling, seasonal ice melts and agricultural runoff can all increment food levels, leading to an increase in phytoplankton populations.

Typical Freshwater Levels

In temperate fresh waters, growth is express in winter because low-cal and temperatures are depression. A large increase in the jump commonly occurs as calorie-free conditions improve and water begins to mix ⁱ. In the summer, phytoplankton flourish until the nutrient supply begins to run depression. In tropical lakes, the phytoplankton distribution is fairly abiding throughout the yr and seasonal population changes are frequently very small ¹. In temperate and subpolar waters, the seasonal fluctuations are normally fairly big. Fluctuations in population also occur if agricultural runoff brings boosted nutrients into a sea.

Typical Saltwater Levels

Saltwater phytoplankton can be found all over the earth, living in the photic (sunlit zone) of the ocean. Cyanobacteria prefer to live virtually the lesser of this zone, closest to the nutrient-rich deep h2o while withal receiving enough sunlight for photosynthesis ¹. Still, in any marine environment, phytoplankton populations vary non only by season but by region.

Phytoplankton can be found along coastline and areas of upwelling. Data: Average chlorophyll concentration July 2002- May 2010, MODIS,(Photo Credit: NASA, Jesse Allen & Robert Simmon)

Algae blooms tin occur nigh the poles in the leap, when at that place is enough of sunlight and the melting sea water ice leaves behind nutrient-rich freshwater ^thirty. This melting process also fuels the oceanic convection, or circulation ³⁸. In coastal and open-ocean environments, oceanic circulation is responsible for phytoplankton concentrations.

This circulation can cause upwelling (bringing nutrient-rich water to the surface) and instigates phytoplankton transportation. Similar bounding main ice melting, upwelling is a seasonal occurrence. The extent and location of upwells are based on wind patterns, which cause currents beyond the globe ^xi. Surface water is carried away from coastlines by currents, and is replaced by cold, nutrient-rich water from below ³⁷.

In many littoral regions, southerly winds cause this littoral upwelling in late summer and autumn ³⁶. As upwelling brings nutrient-rich water up to the surface, phytoplankton blooms often appear at this fourth dimension. Oceanic apportionment and upwelling ensures that the coastal environments have the highest rates of main production in the ocean ^xiii. Tides, flooding and currents all encourage college nutrient levels in the photic zone ¹³.

Consequences of Unusual Levels

Phytoplankton are an of import aspect of a healthy torso of water. Algae and blue-green alga help to provide oxygen and food for aquatic organisms ¹². As a key component, an imbalance of phytoplankton levels can cause major problems. If too many nutrients are available, it can trigger an algal bloom ¹². Algal blooms and overproduction of phytoplankton can crusade toxic red tides and fish kills. On the other manus, phytoplanktonic productivity can exist limited by a lack of required reactants such as sunlight. This decrease in productivity can also lead to fish kills ³.

Algal Blooms and Cerise Tides

Algal bloom in Lake Erie, July 22, 2011. (Credit: National Oceanic and Atmospheric Administration)

An algal bloom is a sudden increment in the concentration of phytoplankton. During a bloom, clear h2o tin go covered with phytoplankton inside days ³⁹. These algal blooms tin can grow large plenty to exist seen from a satellite, covering hundreds of foursquare kilometers ^eleven. Algal blooms come in many colors from light-green to red, brownish, blue, white or purple ⁴³.

Under the right atmospheric condition, algal blooms tin can last one week to an entire summertime, despite the brusk, few-twenty-four hours life span of phytoplankton ¹¹. A single bloom will only terminal ane to two weeks, as the phytoplankton population will die without the proper oxygen and nutrient levels. However, if the water conditions stay favorable, successive blooms tin can occur and announced to be ane continuous population ³⁹. Algal blooms are most common in late summer and early on fall.

What Causes an Algal Blossom?

At that place are several causes that tin can contribute to an algal bloom. These blooms can occur seasonally, after an upwelling of nutrient-rich water, or due to pollution such every bit agricultural runoff. In both cases, the water becomes saturated with nutrients, creating an ideal environment for phytoplankton productivity ³⁶. Even natural causes can trigger an algal bloom, such every bit a rainstorm followed by warm, sunny weather condition ⁱ. Rain tin contribute runoff, or encourage the mixing of nutrient-depleted and nutrient-rich layers of water. When food levels rise, phytoplankton growth is no longer nutrient-limited and a bloom may occur ¹³.

Red Tides

Cerise Tide, June 22, 2009. (Credit: National Oceanic and Atmospheric Assistants)

If a phytoplankton concentration stays steady afterwards the initial bloom, it may go a red tide. While some blooms are harmless, others may produce toxins that endanger aquatic life and humans. This harmful algal bloom is known every bit a red tide. While reddish tides specifically refer to harmful algal blooms (HABs), they are ofttimes simply associated with the discoloration due to a large concentration of phytoplankton ^53,43. Although known as a ruby tide, the discoloration from a harmful algal bloom is not always red. The colour of the tide depends on the pigments nowadays in the phytoplankton ³⁶. In some cases, the bloom cannot be seen by the human eye, though it is all the same releasing toxins ⁴³.

Crimson tides and the toxins they release tin have a directly or indirect impact on the health of humans and other organisms. Some species of phytoplankton tin suffocate fish during a blossom by clogging or irritating the fishes' gills, preventing them from taking in oxygen ⁵³. These harmful algal blooms can as well crusade shellfish poisoning in humans and other adverse effects ¹³. Even during not-toxic algal blooms, the aquatic environs tin can be compromised. Massive levels of phytoplankton respiration and decomposition tin can reduce dissolved oxygen to unsustainable levels, resulting in the deaths of other aquatic creatures ¹³.

Toxins

The phytoplankton that cause a carmine tide are usually comprised of dinoflagellates, diatoms or cyanobacteria. Certain species of these phytoplankton can incorporate harmful toxins that can affect humans and other animals. At normal levels, heterotrophic leaner in the water break downwards the toxins in these organisms before they can get dangerous ⁵¹. When an algal bloom appears, the concentration of toxins increases faster than the bacteria can break it down.

Mussels, clams and other mollusks tin accumulate toxins from phytoplankton.

Some of these toxins cause mild problems if consumed past humans, such every bit headaches and upset stomachs, while others tin cause serious neurological and hepatic symptoms that can lead to death ⁵¹. These effects can be caused by direct or indirect contact with an algal bloom. Directly exposure can occur from swimming or drinking affected h2o. Indirect contact tin occur from eating animals that have been exposed to the toxic flower, particularly shellfish.

Shellfish are susceptible to toxins because they are filter feeders. Filter feeders ingest food by taking upwardly the water surrounding them and then filtering out what they do non wish to ingest ⁵². This method accumulates toxins inside the shellfish system. Organisms that swallow the shellfish (including humans) are consuming the concentrated toxins, which can achieve mortiferous levels ⁵².

Filamentous Algal Blossom

Filamentous algae is a drove of microscopic algae that clumps together in strings and mats at the surface of the h2o ^vii. These accumulations tin can vary from a pocket-size, woolly patch well-nigh shore to a widespread, slimy green covering. Filamentous algae are ofttimes referred to as swimming scum, and appear in eutrophic (food-rich) bodies of water. More often than not, filamentous algae are more of a nuisance than a danger ⁷. They are somewhat more than controllable in that the algae clumps can be physically removed from the h2o ^7,44. While big filamentous algal blooms will terminate sunlight from penetrating the water and reaching submerged plants, the biggest threat associated with them is oxygen depletion ⁴⁴.

Oxygen Depletion and Fish Kills

If an algal flower appears, a fish kill tin occur shortly thereafter due to the ecology stresses caused by the flower. A fish impale, as well known every bit a fish die-off is when a large concentration of fish die. The most common cause of this event is lack of oxygen ⁴⁵.

If a phytoplankton population grows to an excessive corporeality, the amount of usable oxygen in the h2o can be depleted ⁴⁵. Oxygen depletion has two algal-flower-related causes: respiration and decomposition. Algae and blue-green alga consume oxygen at night (respiration) when there is non lite for photosynthesis ⁴⁴. If there is a blossom, the phytoplankton and other aquatic organisms (like fish) can consume more than oxygen than is produced. Besides, if big portions of the algal flower dice off at once, bacteria will commencement to consume oxygen in guild to decompose the dead algae. This tin can reduce oxygen concentrations to below sustainable levels. If oxygen levels become as well low, fish and other aquatic creatures may die ⁴⁴.

How do you Measure Phytoplankton?

While phytoplankton concentrations tin be measured by sampling, this tin be difficult and time-consuming. Plankton nets exercise not e'er catch the smallest of phytoplankton, and do non provide an authentic guess of water volume ^forty. Box or tube traps offer an verbal book, only crave lab sedimentation or settling chambers to concentrate the algae population for counting ⁴¹. Furthermore, phytoplankton can be establish at multiple depths in the water column, which requires multiple sampling efforts and risks missing layers of phytoplankton in between sample depths ⁴⁰. The primary advantage of sampling phytoplankton is the power to analyze and place the species present ⁴¹.

Measuring Chlorophyll

An easier and more efficient method is to use a chlorophyll sensor. Every bit all phytoplankton accept chlorophyll A, a chlorophyll sensor can be used to observe these organisms in-situ ⁴¹. In addition to providing immediate data, information technology can be used for continuous or long-term monitoring and recording. However, as a chlorophyll sensor assumes all algae and cyanobacteria have the aforementioned levels of chlorophyll A, it just provides a crude estimate of biomass ⁴¹. It also cannot be used to place specific species.

Even with its limitations, in-situ chlorophyll measurements are recommended in Standard Methods for the Test of Water and Wastewater to estimate algal populations ³². Chlorophyll sensors are also an in-situ method for determining the trophic state (nutrient-rich, stable, or food-poor) of an aquatic system ⁴⁷. A high chlorophyll measurement is an indicator of eutrophication.

Chlorophyll is measured in micrograms per liter (µg/fifty). Chlorophyll sensors rely on fluorescence to estimate phytoplankton levels based on chlorophyll concentrations in a sample of water ⁴⁷. Fluorescence means that when the chlorophyll is exposed to a high-free energy wavelength (approximately 470 nm), it emits a lower energy light (650-700 nm) ⁴⁷. This returned light can and then exist measured to determine how much chlorophyll is in the water, which in turn estimates the phytoplankton concentration. These estimates are and so used to develop parameter limits for bodies of water. As an example, the New Hampshire Department of Ecology Services provides the following chlorophyll guidelines for river quality: a chlorophyll measurement below 7 µg/l is inside a desirable range. 7-xv µg/l is less than desirable, while over fifteen µg/l is considered problematic ⁴².

Measuring Blue-Green Algae

Blue-green algae, or cyanobacteria, are the only phytoplankton that contain phycocyanin and phycoerythrin, making the pigments good indicators of the corporeality of cyanobacteria in a ocean ¹⁵. While chlorophyll measurements can be used to guess unabridged phytoplankton populations en masse, the accompaniment pigments phycocyanin and phycoerythrin can exist measured to estimate blue-green alga concentrations specifically. Marine cyanobacteria have higher levels of phycoerythrin, while freshwater species have dominating amounts of phycocyanin.

Like chlorophyll sensors, blue-green algae sensors rely on fluorescence to observe the pigment concentration ⁴⁹. Phycoerythrin sensors use a wavelength effectually 540 nm, while phycocyanin sensors emit a wavelength at 600 nm ⁵⁰. Due to the differences in secondary paint concentrations between species, it is recommended to use the phycocyanin BGA sensor in freshwater applications, and the phycoerythrin BGA sensor in saltwater ^49,fifty.

Cite This Work

Fondriest Environmental, Inc. "Algae, Phytoplankton and Chlorophyll." Fundamentals of Environmental Measurements. 22 Oct. 2014. Web. < https://www.fondriest.com/environmental-measurements/parameters/water-quality/algae-phytoplankton-and-chlorophyll>.

Boosted Data

• Measurement Methods
• Chlorophyll Sensors
• Applications
• References

Algae Oxygen Production Vs Trees,

Source: https://www.fondriest.com/environmental-measurements/parameters/water-quality/algae-phytoplankton-chlorophyll/

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