At present rates of population expansion and climate change, lake eutrophication will increase by 25 to 200 percent by 2050 and double or quadruple by 2100. Second, higher storms and runoff will increase nutrient losses from land to inland waterways. Third, as the climate heats, so will the lakes. The increased evaporation caused by warmer temperatures will further increase the amount of water lost through runoff and evaporative loss.
The more nutrients that enter our waters from agricultural and urban sources each year, the more algae can grow in them. Algae use up oxygen when they photosynthesize, leaving little or no oxygen for fish to breathe. They also produce a lot of waste that consumes additional oxygen. Fish are particularly vulnerable to oxygen shortages because they need oxygen all the time. If there isn't enough oxygen, then the fish will either have to move away from the contamination or die.
Climate change will also cause larger numbers of fish to be killed by other predators as they try to move into new territories. These animals depend on stable temperatures and abundant food supplies to reproduce successfully. As the climate changes, so will their choices about where to live and eat, which could lead to mass extinction events.
Finally, global warming will increase the amount of heat absorbed by oceans, which will cause more ocean acidification.
Water temperatures will rise, but dissolved oxygen levels will fall. What does an increase in eutrophication tell scientists who are investigating a body of water? Algae growth will accelerate, reducing oxygen levels. The algae consume nutrients that would otherwise promote growth of other organisms, so the increase in algal growth also reduces biodiversity.
Eutrophication occurs when nutrient levels in water become high enough for algae to flourish and produce toxins instead of plants. Toxins can be harmful or deadly for humans and other animals. Nutrients include nitrogen and phosphorus, which usually come from human activity such as farming and sewage disposal. When these nutrients flow into lakes and oceans they can cause algae to bloom and die back before blooms even have a chance to reproduce. As the name suggests, eutrophication can be beneficial in small amounts, but when it occurs extensively it can have negative effects on the health of the waterway. Fish kills, reduced biodiversity, and increased risk of cancer due to greater exposure to toxic chemicals are all problems that can arise from eutrophication.
Scientists use biomarkers in water samples to detect changes in ecosystems caused by eutrophication. Biomarkers are substances found in living things that reveal their presence and condition. Scientists can identify specific types of algae, for example, by measuring their DNA with molecular markers.
This causes a rise in the development of aquatic plants. If this occurs frequently, the lake or pond will begin to fill with more algae and plants. The aquatic system eventually transforms into a terrestrial habitat. This is called eutrophication.
Eutrophication happens when excess nitrogen or phosphorus enters a water body. This results in excessive plant growth that absorbs large amounts of oxygen from the water. Without enough oxygen, other organisms cannot survive in the water. Fish become endangered as well as other living things such as worms and insects.
Eutrophication can be caused by agricultural runoff, sewage discharge, and littering. These sources of pollution add excess nutrients to lakes and ponds. As these elements accumulate in the water, they stimulate the growth of algae and other plants. This increases the amount of sediment and debris being dumped into our waters. It's important to prevent contamination from reaching our oceans because this would cause great harm for many species that depend on ocean ecosystems for survival.
Eutrophication has been affecting freshwater bodies around the world. Many scientists believe that we are already past the point of no return for many systems. The effects of increased acidity, reduced oxygen levels, and biodiversity loss are already visible in many areas that have been studied in detail.
"Eutrophication is defined as the enrichment of water by nutritional salts, which produces structural changes in the ecosystem, such as increased production of algae and aquatic plants, depletion of fish species, general worsening of water quality, and other impacts that restrict and prevent usage."
As nutrient levels increase in lakes, other changes will occur. Algae growth will be encouraged, reducing sunlight penetration and causing further oxygen depletion. The amount of toxic substances produced by algae also increases as their growth is not restricted by low nutrients levels. Toxic substances released into the lake include ammonia, hydrogen sulfide, and phosphorus compounds. These can be harmful or fatal if consumed in sufficient quantities.
Lakes become more acidic as acid rain and other pollutants dissolve calcium carbonate from rocks and shells found in the lake's shoreline. The resulting calcium ions are less soluble than the sodium ions from sodium chloride (common salt). As a result, more calcium carbonate remains on the surface of the lake where it can damage ecosystems and cause problems for people who swim in them. Calcium carbonate deposits may also build up on boats, causing chipping and pitting. This is called "saltwater corrosion".
Lakes become more fertile as they get more depleted of nutrients. This is because there's more nitrogen and phosphorous available to support plant growth. More plants mean more algae growth, which causes more depletion of nutrients.
Increased development of aquatic vegetation, phytoplankton, and algal blooms disturbs the ecosystem's regular functioning, creating a range of difficulties, including a shortage of oxygen required for fish and shellfish survival. Eutrophication also reduces the value of rivers, lakes, and recreational opportunities. Aquatic plants have evolved ways to tolerate increased nutrient levels in their ecosystems, but this tolerance can lead to overgrowth that blocks light and air spaces, reducing water quality further.
Aquatic plants play an important role in removing nitrogen from the environment through photosynthesis, thereby reducing nitrate concentrations in water bodies. This process is called "nitrogen fixation" and is useful because nitrates are toxic to many organisms at high concentrations. The more aquatic plants there are in an area, the lower the risk of nitrate contamination in the water.
In addition to reducing nitrogen concentrations in water bodies, aquatic plants also reduce phosphorus levels. Phosphorus is another essential element for healthy plants and ecosystems, but too much can be harmful. Like nitrogen, phosphorus can cause problems if it reaches toxic levels for plants. Phosphorus comes in two forms: orthophosphate and pyrophosphate. Orthophosphate is found in soil and enters waterways via agricultural activity. Pyrophosphate is a by-product of organic matter decomposition and adds weight to sediment, which can clog riverbeds and hinder aquatic plant growth.