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Pseudo-nitzschia australis
Pseudo-nitzschia australis is a pennate diatom found in temperate and sub-tropic marine waters, such as off the coast of California and Argentina. This diatom is a Harmful Micro Algae that produces toxic effects on a variety of organisms through its production of domoic acid, a neurotoxin. Toxic effects have been observed in a variety of predatory organisms such as pelicans, sea lions, and humans. If exposed to a high enough dose, these predators will die as a result, and there is no known antidote. The potential indirect mortality associated with P. australis is of great concern to humans as toxic algae blooms, including blooms of P. australis, continue to increase in frequency and severity over recent years. Blooms of P. australis are believed to result from high concentrations of nitrates and phosphates in stream and river runoff, as well as coastal upwelling, which are also sources of other harmful algae blooms.
From the article Pseudo-nitzschia australis on Wikipedia (CC BY-SA), quoted section by section
Description
Pseudo-nitzschia australis are a part of the genus which are bilaterally symmetrical diatoms with a protective cell wall layer called a silica. Their body plan is such that cells overlap with adjacent cells, allowing them to form chains. The cells are needle shaped, and the overlap between cells can be between one-third to one-half each cell length. Their total body length can be from 68-144 μm long and their width can range from 3-8 μm wide.
Wikipedia: “Morphology”
Range & habitat
These diatoms in a neritic zone meaning that they reside in shallow parts of the ocean with a depth ranging from 0 to 170 meters deep. Their temperature range is from around -1 °C to 29 °C. They can live in temperate and subtropical waters. Common distributions are the American West Coast, Australia, New Zealand, and North Atlantic Ocean.
Wikipedia: “Habitat”
What it does
Pseudo-nitzschia australis can reproduce both sexually and asexually by binary fission. Sexual reproduction occurs by auxo-sporulation in which gametes fuse to form a zygote. Sexual reproduction has also been found to correlate with higher levels of domoic acid production Population growth of this species is seasonal and can depend on the amount of water upwelled and nutrient concentrations present off of the coast.
Wikipedia: “Life cycle”
Toxicity
Domoic acid can cause Amnesic Shellfish Poisoning (ASP) in humans that eat them. ASP is only a concern when algae in the ecosystem increases to high levels during an algal bloom. Shellfish are susceptible to accumulation of toxins due to their morphology as filter feeders. When they filter feed algae containing domoic acid, they can have accumulation of this toxin in their tissue. The poison has been detected in organisms such as mussels, oysters and clams and crabs. Physical symptoms in humans from ASP include diarrhea, nausea, vomiting, and abdominal cramps. Neurological symptoms can include headaches, disorientation, dizziness, short-term memory loss, coma and death. Cooking organisms which have accumulated domoic acid will not reduce their toxicity.
Wikipedia: “Amnesic shellfish poisoning”
Where it lives
Recorded sightings
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geo-referenced records in GBIF, from museums, herbaria and field observers.
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In the stacks
Searching the stacks…
Every page naming Pseudo-nitzschia australis in the Biodiversity Heritage Library →
This page is assembled live from iNaturalist, GBIF, Wikipedia, the Source Library and the Internet Archive. It is not yet part of the hand-edited codex. iNaturalist taxon 320114.