Calcareous nannoplanktons are present in today's oceans significantly (Young & Bown, 1997, Thibault et al., 2012). As Coccolithophores, they are among the calcareous marine phytoplankton that live in oceanic waters and light seawater. Many have thought that the function of Coccolithus is light for photosynthesis for Coccolithophores (Gartner & Bukry, 1969). Coccolithophores, due to having chlorophyll, make the necessary food by themselves. Coccolithophores are involved in the preparation of biochemical limestones. Calcareous nannoplanktons emerged from the Norian and Rhaetian ages, during the Triassic as very primitive and simple organisms. These organisms spread in all seas and oceans during the Jurassic and Cretaceous periods and reached their development in the Cenozoic. Calcareous nannoplanktons found from the current Triassic period to the recent era and the benefits of their study in the fields of paleontology, paleoecology, and biogeochemistry are of great importance.
Researchers such as Jalili and Hadavi (1399); Hadavi (1387); Martini (1971); Kassler (1971) and Hilbert et al. (1981) conducted studies on the sediments of the Persian Gulf. Bioluminescence properties in seawater from bacteria that live in seawater. These bacteria are Photorhabdus, Shewanella, Vibrio, and Aliivibrio, which produce luciferase enzyme and live in the body of nannoplankton. The accumulation of nannoplankton near the shores at night causes the waters to glow. By presenting detailed studies in the fields of biology, paleontology, and microbiology, this research clarifies the role of nannoplankton in the current and past ecosystems. The purpose of this study is to investigate and understand the spread of calcareous micro-organisms in four strategic regions of the Persian Gulf and the relationship with their bioluminescence characteristics in this region.
Materials and Methods
This study was carried out in the identification of Holocene calcareous nannoplankton (Megaline) in four regions of the Persian Gulf. Eight samples were collected and studied from the surface waters of the western and southern Hormuz Island in Feb. 2018 and Feb. 2023, the beaches of Bushehr in, April 2017; the coral beaches of Kish Feb. 2018, and the west of Lawan Island in August 2021. These studies are carried out based on the determination of the species based on systematics and a series of PCR tests to investigate the bioluminescence characteristics of bacteria in BHI agar and BHI broth to determine the volume of the luciferase enzyme that causes bioluminescence.
Results and discussion
Analysis and samples of eight areas indicate that this nannoplankton can withstand high temperatures (more than 17 degrees Celsius), characteristics that were expected to be achieved due to the special weather conditions and high evaporation in the Persian Gulf.
Studies also show that many species of tropical limestones such as Coccolithus palgicus, Gephyrocapsa oceanica، Helicosphaera carteri ، Reticulofenestra minutula ،Cyclicargolithus abisectus، Syracosphaera pulchra ،Pseudoemiliania ovata، Gephyrocapsa ericsonii ،Retecapsa angustiforata و Emiliania huxleyi are present in these areas. These species help regulate carbon in marine ecosystems and play a significant role in the environmental cycle.
Among the available nannoplankton from Nannoliths, Diatomite, Heterococcoliths, and Holococcolithes, in total, 41 species from 14 genera were identified. You can also see diatoms that live in marine environments.
Microbiology and biology studies on Persian Gulf water samples have shown the presence of a group of light-producing bacteria including Photorhabdus, Shewanella, Vibrio, and Aliivibrio that live in the seas. These bacteria produce luciferase enzyme and thus produce light in the visible range. In this study, only in one of the samples related to the waters of Lawan Island, very little of the optical characteristics of these samples can be seen, and the reason for this is the inappropriate storage of the waters for the test sample.
Conclusions
This study has been conducted on the biological diversity of calcareous nannoplankton from the seawaters of four regions and eight samples of the Persian Gulf, from the western and southern Hormuz Island in February 2018 and February 2023, the beaches of Bushehr in, April 2017; the coral beaches of Kish February 2018, and the west of Lawan Island in August 2021. In this research, 41 species of 14 genera of calcareous nannoplanktons were identified, which shows the richness and biological diversity in these areas.
Species with high abundance such as Gephyrocapsa oceanica, Helicosphaera carteri, Coccolithus plagicus, and Emiliania huxleyi, Holococcolithes were observed. These findings are very important because some of these species that originated from the Paleocene or Cretaceous periods such as Coccolithus plagicus, Retecapsa angustiforata, and Braarudosphaera bigelowii are still present in the seas of the present era. They can provide valuable information on the environmental history of the Persian Gulf. Also, PCR tests were performed to determine the presence of bioluminescence agents in the samples. Despite the evidence of a small presence of light-producing bacteria such as Vibrio and Aliivibrio that produce luciferase enzyme, they exist in seawater. According to the richness of nannoplankton observed, it can be concluded that Persian Gulf waters have the highest level of primary productivity and nutrients are sufficient to support different microbial and planktonic populations