Some are claiming the Victorian lockdown was too late, saying the rate of spread was already suppressed before it started. But that misses the point that slowing flight arrivals was responsible for most of the suppression up to that point, but that wasn’t going to stop the rising cases of community transmission. To judge if lockdown works, we need to look at domestic spread.
The graph that matters are the new daily cases, and even more so, the graph of daily new cases due to of community transmission (below).
Victoria started a major lockdown on March 24th when schools were largely closed (except to essential workers) and only essential services were allowed to run. We see daily new cases peaked 11 days later, almost exactly as expected (with the same delay as Japan, Germany, Italy, Spain, South Korea and Norway). The 12 day average expected lag comes from a five day average incubation and then a roughly seven day lag for new cases to get into breathing trouble and get tested as such.
Victoria, All Daily New Cases | Source: Covid19data
Most of the early spread was from foreign arrivals
Only highly specialized bacteria can carry out the degradation of brown algae with the help of more than hundred enzymes
Max Planck Institute for Marine Microbiology
You may like them or not, but almost everyone knows them: brown algae such as Fucus vesiculosus, commonly known as bladderwrack, grow along the entire German coast. Giant kelp like Macrocystis or Sargassum grow closely together along the coasts but can also form floating aggregates that can cover the Atlantic from west to east. Some ecologists see this this very productive ecosystem as a marine counterpart to rainforests on land. In these algal forests, large amounts of carbon dioxide are stored, making them an important part of the global carbon cycle.
Andreas Sichert from the Max Planck Institute for Marine Microbiology dedicated his PhD to the question how brown algae can be such a good sink of carbon: “Main constituents of algal biomass are their cell walls – a tight network of proteins and long-chained sugars. When the algae die, we actually have little clue about the fate of algal biomass in the ocean, for example which compounds are degraded fast or slowly”.
Firm and flexible
The Atlantic coast is not a cozy habitat. Tides, wind and waves demand special adaptations from the inhabitants of this harsh environment. Brown algae developed a special cell wall structure, making them both firm and flexible, and enabling the plant to successfully withstand heavy currents and waves. A major component of the cell walls is the polysaccharide fucoidan, a long-chained sugar accounting for about a quarter of algal dry mass. Likely, fucoidan can regulate the water content of the cell wall which protects brown algae from drying out at low tide.
What role this sugar plays in the long degradation process of brown algae was analyzed by scientists from the research group Marine Glycobiology at the Max Planck Institute for Marine Microbiology and the MARUM, Center for Marine Environmental Sciences at the University of Bremen. For their study, they cooperated with colleagues from the Massachusetts Institute of Technology, from the University of Greifswald and from the University of Vienna. “It was already known that microbial communities hydrolyze fucoidan slower than other algal polysaccharides and thus fucoidan might act as carbon sink” says Andreas Sichert from the Max Planck Institute for Marine Microbiology, first author of the study, published in the scientific journal Nature Microbiology in May 2020. “Usually, polysaccharides are a favorite energy source for bacteria, but the reason why fucoidan should be barely digestible remained unclear”.
Only specialists degrade this sugar
So far, the fucoidan degradation pathways were only partially known, but it was evident that they involve a substantial number of enzymes either distributed within a microbial community or housed within individual, highly specialized bacteria. The scientists from Bremen examined the latter theory and analyzed newly isolated bacteria of the genus Lentimonas, belonging to the phylum Verrucomicrobia. Even the isolation of these Lentimonas bacteria was challenging. “From initially more than thousand colonies, only one was able to degrade fucoidan in the end,” remembers Christopher H. Corzett from the Massachusetts Institute of Technology, first author of the study next to Andreas Sichert.
“We could show that Lentimonas acquired a remarkably complex machinery for the degradation of fucoidan that uses about one hundred enzymes to liberate the sugar fucose – a part of fucoidan”, says Jan-Hendrik Hehemann, leader of the research group Marine Glycobiology. „This is probably one of the most complicated biochemical degradation pathways for natural material that we know of.” Fucose is then metabolized via a bacterial microcompartment, a proteinaceous shell that shields the cell from the toxic intermediate lactaldehyde. „The need for such a complex catabolic pathway underpins the recalcitrance of fucoidans for most marine bacteria and it shows that only highly specialized organisms in the ocean are able to break down this algal sugar,” says Hehemann. „This can explain the slower turnover of the algal biomass in the environment and suggests that fucoidans sequester carbon in the ocean.”
Potential for pharmacology
Scientists are also interested in enzymes for fucoidan degradation because it may be a pharmacologically active molecule that shows similar effects to heparin in blood clotting. “Enzymes that specifically fragment fucoidan and thus help to characterize its structure are of great scientific interest because they enable researchers to understand the effects of fucoidan and to open up these marine sugars for biotechnological applications,” says Thomas Schweder, participating microbiologist from the University of Greifswald.
Denmark will not consider how to raise taxation of greenhouse gas emissions until fall because of the current economic uncertainty, Minister for Climate, Energy and Utilities Dan Jorgensen says.
In 2019 Denmark set itself some of the world’s most ambitious environmental goals; they include a 70% reduction in greenhouse gas emissions by 2030, compared to 1990 levels. The EU’s target, by contrast, is for a 40% reduction by 2030, an objective that Jorgensen has said is not sufficiently ambitious.
It will be impossible to reach the country’s goal without looking at a fundamental overhaul of the Danish economy that puts a larger price on pollution, Jorgensen said in an interview Wednesday, but “the middle of an unprecedented crisis where thousands and thousands of Danes are losing their jobs, and companies are closing down” is not a good time to raise taxes.
A report released in March by the government-appointed Danish Council on Climate Change recommended increasing carbon taxation, but Jorgensen said that a tax covering the whole of society would be extremely complex and that there is no such model out there that is ready to implement.
The government is planning a broad overhaul of its tax system, he said, but this has been sidetracked by the coronavirus crisis.
“Like [boxer] Mike Tyson said, everybody has got a plan until he gets hit in the face,” said Jorgensen. “That’s what happened to us.”