Peridiniales

Peridiniales

Peridinium digitale, a species within the order Peridiniales

Peridiniales is an order of dinoflagellates, a group of single-celled organisms that are primarily aquatic and photosynthetic. They are part of the larger group known as Alveolata, which also includes ciliates and apicomplexans. Dinoflagellates are notable for their two distinct flagella and their role in marine and freshwater ecosystems as primary producers and as part of the plankton community.

Characteristics

Peridiniales are characterized by their armored plates, which are composed of cellulose and form a protective covering known as the theca. These plates are arranged in a specific pattern that is used to identify different species within the order. The cells of Peridiniales are typically biflagellate, with one flagellum encircling the cell in a groove called the cingulum, and the other trailing behind the cell in a groove called the sulcus.

Ecology

Members of the order Peridiniales are found in both marine and freshwater environments. They play a crucial role in the food web as primary producers, converting sunlight into energy through photosynthesis. Some species are also capable of mixotrophy, obtaining nutrients by ingesting other organisms in addition to photosynthesis.

Peridiniales can form blooms, which are large concentrations of dinoflagellates that can sometimes be harmful to aquatic life and humans. These blooms are often referred to as red tides due to the discoloration of the water caused by the high density of pigmented cells.

Reproduction

Reproduction in Peridiniales can occur both sexually and asexually. Asexual reproduction is the most common and occurs through binary fission, where the cell divides into two identical daughter cells. Sexual reproduction involves the fusion of two cells to form a zygote, which can then undergo meiosis to produce new individuals.

Importance

Peridiniales are important indicators of environmental change and are used in paleoclimatology to study past climate conditions. Their fossilized remains, known as dinocysts, are found in sedimentary records and provide valuable information about historical ocean conditions.

Related pages

• Dinoflagellate
• Alveolata
• Plankton
• Red tide