Ecosystem engineers are plants and micro-organisms that are able to tailor their living environment to their needs. Examples of ecosystem engineers include floating aquatic plants such as duckweed, which seals off the water surface when it occurs in high concentrations. By doing so, the plant blocks the gas exchange between the water system and the atmosphere. The oxygen in the water system begins to deplete, as oxygen is used by organisms that are active in the submerged soil and the layer of water is not replenished. Under such low-oxygen conditions, the availability of important nutrients in the water such as phosphate and ammonium can increase drastically, which is beneficial to the growth of the duckweed.
What does biogeochemical water purification involve?
The organic material that organisms deposit when they die is 'recycled' and reduced by bottom-dwellers (such as fungi and bacteria) into elements from which the organic material was originally constructed. The speed and manner in which this occurs is largely dependent on environmental conditions (warm or cold, wet or dry, presence or absence of oxygen, etc.). This determines which nutrients are retained in the environment and which naturally occur in the environment. By intervening in the abiotic conditions, it is possible to control the availability of nutrients in the environment and therefore to control the water quality. This is the principle behind biogeochemical water purification.
What is biogeochemistry?
Biogeochemistry is the study of the origins and share of organic material in the environment on a molecular level. Micro-organisms decompose organic material of both natural and anthropogenic origin found in the environment. The presence and absence of oxygen in the environment is very important in this process, as it has a large impact on how the organic material is converted and how the resultant minerals are formed.
What does 'biobased' mean?
The biobased economy describes an economy in which fossil fuels such as oil and gas are replaced by renewable raw materials. These alternatives are mostly produced using biomass from plants. The biobased economy is an economy in which food for humans and animals, chemicals, materials, fuels for transport, electricity and heat are produced from 'green' raw materials in an economical and sustainable fashion.
What is biofertiliser?
Biofertiliser is fertiliser which is produced from natural raw materials or organic material. Using biofertiliser can improve the quality of the soil. Biofertilisers help to support a rich variety of bottom-dwelling organisms and more effectively retain water and nutrients.
What is phosphate and why does this have to be reused?
Phosphorus is a crucial mineral for all life on Earth: it is present in each cell of every organism, in which it is used for energy metabolism and other biological processes. Approximately 1% of the weight of the human body is comprised of phosphorus. A handful of phosphorus mines are scattered across the globe, most of which in the USA, China and Morocco. Phosphorus is a finite resource - primarily because the materials accumulate on agricultural land after usage and end up in sewage sludge from waste water treatment installations - and most is burnt and extracted from the agricultural cycle. In addition to this, a large proportion is deposited by erosion in lake beds, coastal zones and the ocean. The growing world population requires more food. The demand for artificial fertiliser, and therefore phosphate, is increasing correspondingly. A 'phosphate peak' is forecast for around 2030. From that moment on, it will become increasingly expensive and challenging to mine phosphate. Between 2070 and 2110, it is estimated that the global supply of phosphorus currently known to exist will be exhausted. An exhaustion of phosphate supplies could entail significant geopolitical tensions. In light of this, the reuse of phosphate is of crucial strategic importance.