Phytoplankton's Resilience: Polluted Water Growth Explained

Phytoplankton are microscopic plant-like organisms that live in watery environments, both salty and fresh. They are the most powerful ocean organisms as they can use sunlight for energy and grow through photosynthesis. They require nutrients such as nitrate, phosphate, silicate, and calcium, and trace amounts of iron to grow and reproduce. Phytoplankton growth is also influenced by other factors such as water temperature, salinity, depth, wind, and the presence of predators. When conditions are favourable, phytoplankton populations can grow explosively, a phenomenon known as a bloom. These blooms can be triggered by natural causes or pollution, such as agricultural runoff, which provides an abundance of nutrients, creating an ideal environment for phytoplankton to thrive.

Nutrient-rich water from fertiliser runoff

Phytoplankton are microscopic plant-like organisms, also known as algae or microalgae. They are the most powerful ocean organisms as they can use sunlight for energy and grow through photosynthesis. They are a crucial source of oxygen, accounting for almost half of the oxygen in the world. They also serve as food for other organisms in the marine food chain.

Agricultural runoff, a significant source of fertiliser pollution, increases phosphorus and nitrogen concentrations in water bodies, leading to eutrophication. This process creates favourable conditions for phytoplankton, resulting in their rapid growth and the formation of algal blooms. These blooms can be detrimental to water quality and aquatic health, with some species producing toxins that pose risks to both aquatic life and humans.

Iron is another critical factor in phytoplankton growth. While iron is not essential for most plants, it plays a vital role in phytoplankton development. Iron aids an enzyme in phytoplankton that enhances nitrogen uptake, promoting increased algae growth. However, iron depletion in large ocean areas limits phytoplankton growth.

While phytoplankton are essential for the marine ecosystem, an overabundance can lead to problems. Excessive phytoplankton can cause significant increases in pH levels and associated rises in NH3 concentration. These elevated pH conditions favour the growth of blue-green algae, which can dominate the algal community and produce odorous compounds or toxic algal blooms with harmful consequences for aquatic organisms and humans.

Increased water temperature

Phytoplankton are microscopic organisms that live in watery environments, both salty and fresh. They are extremely diverse, ranging from photosynthesizing bacteria (cyanobacteria) to plant-like diatoms and armor-plated coccolithophores. Phytoplankton play a crucial role in the marine food chain and are essential for carbon storage and the oxygen we breathe.

While phytoplankton typically grow well in polluted water due to high concentrations of nutrients from fertilizer or feed inputs, the impact of increased water temperature on their growth is complex and multifaceted. On the one hand, rising temperatures can stimulate phytoplankton metabolic rates, enhancing carbon assimilation and nutrient uptake, and leading to net biomass gain and the initiation of blooms. This is because phytoplankton growth rates can respond more rapidly than those of grazers, allowing their growth to outpace losses by grazing.

However, the relationship between temperature and phytoplankton growth is nuanced and dependent on various factors, including nutrient availability, community composition, and abiotic conditions. While some studies have shown that increasing temperatures can positively influence phytoplankton biomass and productivity, others have found that warmer temperatures can negatively impact their growth. This negative effect is particularly evident in stratified oceans, where warmer, fresher surface waters mix less with the colder, saltier, nutrient-rich deeper waters. As a result, phytoplankton in these areas experience reduced access to nutrients, leading to decreased productivity.

Additionally, the optimal temperature range for phytoplankton growth varies depending on the specific species and community composition. As such, while warmer temperatures may benefit some species, they can exceed the optimal range for others, leading to cellular stress and negative effects on primary production.

In summary, while increased water temperature can stimulate phytoplankton growth and metabolic rates, the overall impact is complex and dependent on a multitude of factors, including nutrient availability, community composition, and environmental conditions. Understanding these complex interactions is crucial for predicting and managing the growth of phytoplankton, particularly in the context of global climate change.

Iron availability

Phytoplankton are microscopic plant-like organisms, also often called algae or microalgae. They are the most powerful ocean organisms as they can use sunlight for energy and grow through the process of photosynthesis. Phytoplankton require nutrients such as nitrate, phosphate, silicate, and calcium, with some species also requiring trace amounts of iron.

The availability of iron in the ocean can vary significantly. In large areas of the ocean, iron concentrations are very low, limiting phytoplankton growth. This is because iron is unusually depleted in water compared to macronutrients like nitrogen and phosphorus.

Agricultural runoff, a major contributor to water pollution, can increase the availability of nutrients such as phosphorus and nitrogen, leading to eutrophication and algal blooms. While iron availability is not directly influenced by agricultural runoff, the increased nutrient concentration can still promote phytoplankton growth.

Natural events, such as El Niño and La Niña, can also impact iron availability and phytoplankton growth. During El Niño, phytoplankton productivity in the equatorial Pacific declines as the easterly trade winds that drive upwelling grow still or reverse direction. In contrast, La Niña enhances phytoplankton growth by increasing the upwelling of nutrient-rich deep water.

Overall, iron availability is a critical factor in the growth of phytoplankton, and its presence or absence can have a significant impact on the health and abundance of these microscopic organisms.

Carbon dioxide removal

Phytoplankton are microscopic plant-like organisms, also known as algae or microalgae. They are the most powerful organisms in the ocean because they can use sunlight for energy and grow through photosynthesis. They are responsible for almost half of the oxygen in the world and are an important part of the marine food chain.

Phytoplankton absorb nutrients from water to grow, including nitrate, phosphate, silicate, and calcium. They also require trace amounts of iron, which is a huge factor in promoting phytoplankton growth. Iron helps a specific enzyme pick up nitrogen, which stimulates growth. Phytoplankton growth is also influenced by other factors, such as water temperature and salinity, water depth, wind, and the presence of predators.

Phytoplankton play a crucial role in carbon dioxide removal. They consume carbon dioxide from the water and release oxygen during photosynthesis. This process helps to increase the pH of the water, making it more alkaline. When carbon dioxide is depleted, phytoplankton will use bicarbonate as a carbon source for photosynthesis. This process has a significant impact on the water's alkalinity and pH, which can affect the health of aquatic species.

The growth of phytoplankton can be influenced by natural events and human activities. For example, during El Niño events, phytoplankton productivity in the equatorial Pacific declines due to changes in trade winds, while La Niña events enhance phytoplankton growth by increasing upwelling in the same region. Human activities, such as agricultural runoff, can also contribute to increased nutrient concentrations in water, leading to eutrophication and algal blooms. While some blooms are harmless, others may produce toxins that can be harmful to both aquatic life and humans.

The ability of phytoplankton to remove carbon dioxide from the water and atmosphere has led to the idea that they could be a solution to climate change. Some people have even suggested creating personal phytoplankton tanks or pools to capture carbon dioxide and store it in a holding facility. However, it is important to note that too much phytoplankton can also cause problems, as they can produce harmful algal blooms and release toxins.

Ammonia nitrogen removal

Identification of Ammonia Sources

It is important to identify the sources of ammonia nitrogen pollution to effectively remove it. Common sources include municipal wastewater, industrial runoff, agricultural activities, and fish farms. For example, urea from urinal discharge in municipal wastewater quickly dissociates into ammonia or ammoniacal nitrogen.

Treatment Processes

Several treatment processes are available for removing ammonia from wastewater. These can be categorized into two main groups:

• Pollution Elimination: This includes biological processes (aerobic and anaerobic), adsorption, chemical oxidation, and combustion.
• Concentration Reduction: Methods such as flocculation, precipitation, ultrafiltration, nanofiltration, reverse osmosis, and evaporation are used to reduce the concentration of ammonia in wastewater.

Specific Techniques

• Air Stripping: This is one of the most widely used methods for removing ammonia from wastewater. It involves passing air through the water to strip out the ammonia.
• Ion Exchange: This process utilizes ion exchange resins to remove ammonia ions from the water.
• Breakpoint Chlorination: By adding chlorine to the wastewater, ammonia is converted into chloramines, which are less harmful.
• Biological Nitrification-Denitrification: This biological process involves converting ammonia into nitrate through nitrification and then reducing the nitrate to nitrogen gas through denitrification.
• Natural Minerals: Natural minerals like zeolite and activated carbon can be used to adsorb and remove ammonium ions from water.
• Struvite Precipitation: Removing nitrogen through struvite (MgNH4PO4 × 6H2O) precipitation is effective but limited by factors such as pH, temperature, and ion concentrations.

Role of Phytoplankton

Phytoplankton play a crucial role in removing ammonia nitrogen from water. They absorb nutrients, including ammonia, for growth and photosynthesis. However, overabundant phytoplankton can cause issues, such as increases in pH and associated rises in NH3 concentration, favouring the growth of certain algae.

Preventative Measures

To reduce ammonia nitrogen pollution, it is essential to regulate the use of fertilisers and manage fish farms and aquaculture operations properly. Additionally, technologies like BIOBOX® can remove ammonium from drinking water with high yields.

Frequently asked questions