Molecular Identification of the Iraqi Aquatic Fern Azolla pinnata and Evaluation of its Efficiency in Reducing CO2 under Various Environmental Conditions

Background: Azolla is one of the fern plants that has great importance in many fields, such as its value as animal feed and its possession of a number of active substances with antimicrobial and antioxidant properties, in addition to its role in consuming carbon dioxide, which has an important role in climate modification. Methods: This study was conducted to determine the optimal conditions for A. pinnata growth and its reduction of carbon dioxide, which has a positive effect in reducing global warming on planet Earth. Azolla pinnata was isolated from the Tigris River-IRAQ and molecularly identified using nucleotide sequence analysis of ITS within 5.8S rRNA gene. Result: Azolla isolated for the first time from the Iraqi environment was molecularly identified to the species level Azolla pinnata strain IRAQ-Tikrit.Has,A.A and registered in NCBI under the accession number PQ836460.1. The results showed a significant increase in CO2 concentration in A. pinnata culture over time when incubated in the dark at 10-40oC. On the other hand, the results revealed a continuous decrease in CO2 concentration with increased light intensity over time. The interaction between A. pinnata growth duration and light intensity, the lowest CO2 concentration reached 375.14 and 362.38 ppm when incubated at light intensity of 10000 lux for 10 days at 20 and 3oC, respectively. The results also showed that there was an increase in the growth of A. pinnata with an increase in the depth of the liquid nutrient medium up to 50 cm, the growth indicators such as absolute growth rate (AGR) and Standing A. pinnata crop (yt) reached 10.53 g/m2/day and 106.42 g/m2 with a decrease in CO2 to 325.64 ppm, with no significant effects on the growth indicators and CO2 concentrations when A. pinnata growing at depths of 60-80 cm. Azolla is one of the biological factors that play a role in reducing carbon dioxide, as it plays an important role in modifying the climate of the Earth’s surface if the standard environmental conditions for its growth are established.