In addition to insufficient light in the aquarium, a lack of certain nutrients can lead to poor plant growth and even death. However, too much nutrients can also lead to problems. And if only one plant nutrient is missing, the plant cannot optimally absorb the other, sufficient nutrients either. And weakened plants can also assert themselves less successfully against the competition of other plants in the aquarium or defend themselves against the growth of algae.
Of course, every species of aquatic plant has a specific need for light and nutrients and reacts differently to too little or too much. More information can be found in the introduction and the respective profile of the individual aquarium plants. But there are some general symptoms that indicate a deficiency in certain nutrients, minerals and trace elements. However, there is also multiple damage in which the individual symptoms overlap and can no longer be clearly assessed.
How to detect deficiency symptoms of the individual nutrients
Here are the most important functions and deficiency symptoms of the individual nutrients and trace elements (in alphabetical order of the elements):
Boron (chemical symbol B)
Boron is involved in the structure of cell membranes, the formation of flowers and the development of roots. If there is a lack of boron, young plants begin to cripple and the formation of roots is severely restricted.
Calcium is important for the structure of cellulose and the cell membrane, although aquatic plants need less supporting tissue and therefore less calcium than land plants due to their higher buoyancy. Calcium also acts as an ion pump, promoting the transport of substances through the cell membrane and activating enzymes. If there is a calcium deficiency, the first damage is visible on new leaves and especially on the leaf edges.
Iron is an important component of chlorophyll and is therefore jointly responsible for the photosynthetic performance of plants. If there is a lack of iron, what is known as chorosis occurs. Due to the lack of chlorophyll, the leaves become yellowish and increasingly translucent. If there is too much iron, however, the leaves turn brown. Aquarium plants with reddish leaves have an additional need for iron. Red-leaved cultivars often only turn reddish when there is sufficient iron in the water, otherwise they remain green.
Potssium activates various enzymes. Defects are visible through damage to the leaf edges of the aquarium plants.
Magnesium like the element iron, is a building block of chlorophyll. It also activates various enzymes. Damage caused by a magnesium deficiency is first visible in the middle of the leaves. They spread out in the form of a marbled pattern.
Manganese also activates various enzymes. Lack of manganese causes damage to the edges of the leaves.
Molybdenum is an essential element of various enzymes that are involved in the reduction of nitrate. If there is a lack of molybdenum, the leaves of adult aquatic plants turn blue-green.
Nitrogen is an important element in amino acids and DNA and RNA (the nucleic acids).
Phosphorous is an element that is involved in the construction of membranes, nucleic acids and adenosine triphosphate (ATP). ATP is the main energy carrier in plant cells. If there is a lack of phosphorus, the aquatic plants remain small and turn gray-green or reddish in color.
Zinc is even involved in around 60 enzymes. A deficiency in zinc is first seen by damage between the nerves of the leaves.
These elements, which are essential for aquarium plants – here simply stated as atoms – are mostly in the form of ions (e.g. P as soluble orthophosphate), molecules (n in amino acids, proteins or their fragments, the peptides), complex chelate compounds (such as iron in Chlorophyll).