Noctilucales

An order of marine dinoflagellates known for their bioluminescence

Overview

Noctiluca scintillans, a bioluminescent dinoflagellate

The Noctilucales are an order of dinoflagellates, a group of single-celled organisms that are primarily marine plankton. They are known for their ability to produce bioluminescence, a phenomenon where living organisms emit light. This light is often visible at night in the ocean, creating a glowing effect on the water's surface.

Characteristics

Noctilucales are unique among dinoflagellates due to their large size and lack of thecal plates, which are common in other dinoflagellates. They possess a large vacuole and a single flagellum, which they use for movement. The most well-known species within this order is Noctiluca scintillans, often referred to as "sea sparkle" due to its bright luminescence.

Bioluminescence

The bioluminescence in Noctilucales is caused by a chemical reaction involving the enzyme luciferase and the substrate luciferin. When disturbed, these organisms emit a blue-green light, which can be seen in the ocean at night. This light is thought to serve as a defense mechanism, deterring predators by startling them or attracting larger predators to consume the smaller ones.

Ecology

Noctilucales are found in oceans worldwide, often in coastal regions. They are heterotrophic, feeding on other plankton, including phytoplankton and small zooplankton. During periods of high nutrient availability, they can form large blooms, which may be visible from the shore as glowing patches in the water.

Impact on the Environment

While the bioluminescence of Noctilucales is a natural and often beautiful phenomenon, large blooms can have negative impacts on marine ecosystems. These blooms can lead to oxygen depletion in the water, affecting other marine life. Additionally, some species within the order can produce toxins that are harmful to fish and other marine organisms.

Related pages

• Dinoflagellate
• Bioluminescence
• Marine plankton