ZOOLOGY- On dinoflagellates causing red tides... ?

Question

" Noctiluca" and "Gonyaulax" both are dinoflagellates causing Red tides in sea... can u pls tell me is they r related or r they same or 2 different organisms both exbiting red tide formation ???

thnx for answering :)

Answer 1

"NO"

Answer 2

i dont know

Answer 3

Dinoflagellates sometimes bloom in concentrations of more than a million cells per millilitre. Some species produce neurotoxins, which in such quantities kill fish and accumulate in filter feeders such as shellfish, which in turn may pass them on to people who eat them. This phenomenon is called a red tide, from the color the bloom imparts to the water. Some colorless dinoflagellates may also form toxic blooms, such as Pfiesteria. It should be noted that not all dinoflagellate blooms are dangerous. Bluish flickers visible in ocean water at night often come from blooms of bioluminescent dinoflagellates, which emit short flashes of light when disturbed.

Dinoflagellate cysts are found as microfossils from the Triassic period, and form a major part of the organic-walled marine microflora from the middle Jurassic, through the Cretaceous and Cenozoic to the present day. Because some species are adapted to different surface water conditions, these fossils from sediments can be used to reconstruct past surface ocean conditions (Sluijs et al., 2005). Arpylorus, from the Silurian of North Africa was at one time considered to be a dinoflagellate cyst, but this palynomorph is now considered to be part of the microfauna (Arthropoda). It is possible that some of the Paleozoic acritarchs also represent dinoflagellates.

The Noctilucales are a peculiar order of marine dinoflagellates. They differ from most others in that the mature cell is diploid and its nucleus does not show a dinokaryotic organization. These cells are very large, from 1 to 2 millimetres in diameter, and are filled with large buoyant vacuoles. Some may contain symbiotic green algae, but there are no chloroplasts. Instead, they feed on other plankton, and there is usually a special tentacle involved in ingestion.

Noctilucales reproduce mainly by fission, but sexual reproduction also occurs. Each cell produces numerous gametes, which resemble more typical athecate dinoflagellates and have the dinokaryotic nuclei. Evidence suggests that they diverged from most other dinoflagellates early on, and they are generally placed in their own class.

The most common species is Noctiluca scintillans, also called N. miliaris. It is usually bioluminescent when disturbed, as are various other dinoflagellates, and large blooms can sometimes be seen as flickering lights on the ocean.

Gonyaulax causes massive industrial damage. Gonyaulax is one of the dinoflagellates responsible for the advent of red tides. During red tides, many fishes, whales, manatees, and shorebirds have died in massive numbers because of the anoxic conditions produced by dinoflagellate blooms. The toxin of Gonyaulax can also directly poison marine animals who are at the top of the food pyramid. Gonyaulax is a primary producer in the food web.

Dinoflagellates may be small, but they have power in numbers! They are one of the chief constituents of the marine planktonic community, which is responsible for the majority of photosynthetic carbon fixation in the ocean. These ubiquitous, chorophyll-bearing protists thus comprise the base of the food web. As primary producers they support all major marine organisms, including those that are exploited for human consumption.

Gonyaulax cysts may indicate petroleum reserves. Dinoflagellates have long been pervasive in ocean life. Due to such an illustrious history, they have been useful to the fossil fuel industry. Dead plankton fallen to the sea floor has been transformed into petroleum compounds over the course of millions of years, due to the pressure of increasing layers of sediment. Thus dinoflagellate fossilized cysts are thought to indicate locations of petroleum reserves.

Gonyaulax poisons have medical applications. Paradoxically, Gonyaulax toxins can be beneficial. Research is currently being conducted regarding the use of chemically modified saxitoxin in the treatment of nerve and heart disorders. In addition, saxitoxin may have future importance as a local anesthetic. Entertainment value of bioluminescence! Gonyaulax gives us the gift of bioluminescence. Their night-time light displays have enchanted seafarers around the world since the beginning of time.

Hope I could help.