Mysterious foam on South Australian beaches caused by bloom of tiny but toxic algae | Shauna Murray and Greta Gaiani for the Conversation

CPictures of dead seadragons, fish and octopus were washed on the beaches of southern Australia – and Disturb reports Among the “more than 100” surfers and beach pioneers with influenza-like symptoms after swimming or just breathing in the sea spray-attracted international anxiety last week.

Speculation ranged around the potential cause of pollution and algae to unusual bacterial infections or viruses. We can reveal that the perpetrator was a small type – but harmful – from the named algae called Carne Mikimotoy.

The government of southern Australia sent water samples from the beach of Waitpinga, Petre Cove Beach, Encounter Bay Boat Ramp and Persons Headland on Tuesday. We studied water under a microscope and extracted the DNA for genetic analysis.

Our results have revealed large numbers of small harmful algae – each of them only 20 microns (where one thousand mm of microscope is from millimeters). While relatively common in Australian coastal waters, it blooms K. Mikimotii It only occurs intermittently. But harmful algae flowers are similar and kill fish because of K. Mikimotii It happened in the past, like 2014 Bloom In Coffin Bay, southern Australia. The latter will not be the last.

Harmful algae flowers

Microbial algae occurs naturally naturally in sea water all over the world.

They are also called vegetable plankton because they float in the water column and a light -acting column like plants. “Phyto” comes from the Greek word of the plant and “plankton” comes from the Greek word Wander, which relates to its floating movement with the oceanic, tide and carrots.

Like plants on Earth, fine flying or vegetable plankton in the ocean that picks up sunlight and produces up to half of the oxygen in our atmosphere. There are more than 100,000 different types of microscopes. Each liter of sea water usually contains a mixed group of these different types of algae.

But under certain circumstances, it can accumulate just one type of microal algae in one area and dominates other regions. If we are lucky, it may be dominant species that produce a toxin or have a harmful effect.

This can be caused by the so -called “blaming of harmful algae” problems for people and marine life such as fish, invertebrates such as crabs, and even marine mammals such as whales and seals.

There are hundreds of different types of harmful algae. Each of them produces its own type of poison with a specific toxic effect.

Most of these toxic chemical compounds produced by harmful algae are well known, including nerve toxins that affect the brain. But others are more complicated, and toxic mechanisms are not well understood. This can make it difficult to understand the factors that lead to the death of fish and other marine life. Unfortunately, toxins from K. Mikimotii It is located in this last category.

presentation Carne Mikimotoy

Species responsible for recent events in southern Australia, K. MikimotiiIt causes harmful algae flowers in Asia, Europe, South Africa and South America, as well as Australia and New Zealand. These flowers caused fish deaths, and some also caused difficulties to breathe for some beach pioneers.

The most root of these K. Mikimotii Flowers have occurred in China during the past two decades. In 2012, more than 300 square kilometers of sea ear farms were affected, causing about $ 525 million in Missing production.

Explanation of toxic effects

Microleum algae can be damaged by fish and shellfish, which prevents them from breathing. This is the main cause of death. But some studies have also found commercial damage to the digestive system and liver From fish.

Tests using gills of fish clearly show the exciting poisonous effect of K. Mikimotii. When the fish cells were subjected to sound K. Mikimotii Cells, after 3.5 hours, have died more than 80 % of fish cells.

Fortunately, the poison does not last yet K. Mikimotii The cells are dead. So as soon as the flowering ends, the marine environment can recover at a relative speed.

It is partly due to the production of algae for “interactive oxygen types”, and interactive forms of oxygen molecules that can cause cell deaths in high doses. K. Mikimotii Cells may also produce fat molecules (fat) that cause some toxic effects.

Finally, very thick flowers can reduce microscopic algae from the amount of dissolved oxygen in the water column, which means less oxygen for other marine life.

The effects of human health are not well known, but they may relate to interactive types of oxygen being irritated.

K. Mikimotii Cells can also produce “Mucilage”, a type of mysterious thick material made of complex sugars, which can accumulate bacteria within. This could cause “sea foam”, which was clear on the beaches last week.

Questions remain unprocessed

A question for many people is whether the increasing water temperatures are opening K. Mikimotii probably.

Another concern is whether the flow of nutrients from farms, cities and aquatic biology can cause more harmful algae flowers.

Unfortunately, at least for Australia, the answer to these questions is that we do not know yet. Although we know that some harmful algae flowers increase when the surface flow of the nutrients is higher, others really prefer a fewer nutrients or cold temperatures.

We know that the warmer species of water It moves south along the Australian coastChanging the types of vegetables abundant and distribution.

While it can cause some precise flowering A beautiful biological spin to see itAnd others like K. Mikimotii It can cause irritation in the skin and respiratory system.

If you notice colored water, fish mortality, or excessive sea foam along the coast or in a mouth, avoid hunting or swimming in the area and notify the local primary industry or environmental authorities in your state.

• Shona Murray is a scientific professor at the University of Sydney (UTS) and Greta Gayani, post -PhD, UTS. This article The original appeared in the conversation