Why tiny organisms can be big news: three stories focused on the smaller scales of life

I've often mentioned how small-scale life is overlooked compared to the larger creatures we share this planet with. Three recent examples concern progressively smaller species and show both how little most people know about such organisms and how such apparently inconsequential life forms can effect our species.

The first example comes from Shropshire in the United Kingdom and occurred last month. A family in Telford came home from holiday to find that the fish in their ornamental tank had died. On cleaning the tank, the toxic fumes that emanated from it were so dangerous as to poison the family, leading to a stay in an isolation ward while their house was sealed off. The agent responsible for this none other than Zoanthid soft corals growing on a tank ornament, which turned out to be palytoxin, for which there is no antidote. Severe cases can lead to death from respiratory or cardiac failure, making it the second most poisonous non-protein substance.

Incidentally, none of the news reports stated if it was the toxin that killed the fish in the aquarium. What is most interesting about this story was that the family were reported as being unaware that the coral was alive, in addition to not receiving a warning from the store they bought the coral from.

I'm uncertain whether they meant that they didn't know that corals are animals rather than plants or whether they considered them as some type of mineral! Either way this sort of lack of fairly basic knowledge about the natural world always fills me with amazement, as I would have thought that a combination of primary school books and David Attenborough documentaries would have supplied this information to just about anyone in the UK today.

Leaving aside the obvious fact that nature is not a harmless mis-en-scene built for the enjoyment of mankind, this example shows just how dangerous even small-scale life can be; proof indeed that you don't have to travel to Australia to come into close contact with highly toxic species. Once gain, global warming may increase such encounters, as since the start of the twenty-first century, the Mediterranean has been experiencing mass poisonings due to algal blooms produced by a palytoxin derivative. Perhaps the moral here is better education before buying a pet!

If NASA's recent announcement of the 2025 Europa Clipper mission comes to fruition we will be one step closer to knowing if there are exotic forms of life in the ice-blanketed ocean of this moon of Jupiter. However, it is possible that our very own Moon might already be harbouring animals of an altogether more terrestrial nature.

The Israeli Beresheet lander crashed there in April this year but news reports have suggested that a few thousand passengers in the form of barely visible tardigrades (no more than 1.2 millimeters long) may have survived, albeit in a dehydrated form of hibernation. Able to survive in a tun state without water and in conditions of intense cold and heat - as well as a high vacuum - these water bears are only susceptible to ultraviolet flux.

Experiments conducted on the International Space Station prove that tardigrades can be rehydrated back to normal after exposure to the outer space environment. The probes demise appears to have been rather fast, so whether the water bears could survive the impact and sudden change in temperature and loss of atmosphere is doubtful. Most news stories seem to play the cuteness factor, with few mentioning that biological contamination of another body could be a breach of international law. Of course, the Moon's lack of atmosphere and liquid water mean any survivors are likely to remain in a tun state unless they can be retrieved in the future.

Tardigrade research may one day aid the development of long-duration space travel and human hibernation. What I'd really like to know about this story is that had Beresheet landed successfully, just what were the plans for the tardigrades anyway? None of the articles I read stated just what sort of scientific experiment they were the unwilling participants in. It's not like they would be able to phone home!

The third story concerns a life form whose individuals are microscopic but none the less important in terms of their environmental impact en masse. Back in 2004, the Waiau River in New Zealand's South Island was found to contain large masses of didymo, a type of freshwater diatom or single-celled algae not known to be native to the Southern Hemisphere, let alone the country. Individual
Didymosphenia geminata, colloquially called 'rock snot', might not be any more than one or two hundred microns long but they are capable of generating clumps and strands of mucus around a meter in size. Other South Island rivers were soon found to be equally contaminated, with other nations ranging from Canada to Chile finding similar proliferation.

What made this outbreak interesting is that algal blooms are usually due to an excess of nutrients entering fresh water sources, primarily from agricultural run-off. In the case of didymo it appears to be quite the opposite, with massive increases in mucus production being generated by a severe lack of phosphorus. Ironically, this means that attempts to reduce nutrient levels in the affected rivers might have only exacerbated the problem. As evidence in favour of this hypothesis, rivers tested in New Zealand's North Island have been shown to contain a combination of high phosphorus and dead didymo cells.

It hasn't even been established beyond doubt as to whether didymo has been accidentally introduced to New Zealand and elsewhere, or whether it has always been a minor, unobtrusive component of the ecosystem previously kept in check. While some environmental departments and organisations seem to prefer the former option - presumably as ammunition in the fight against invasive species - either origin still leads to potential degradation. Smaller insect species that congregate around rivers and streams, such as gnats and midges, tend to increase in numbers at the expense of larger ones such as caddisflies and mayflies. This in turn could have a knock-on effect on freshwater fish, crustacea, and probably wading birds too.

Financially-important human activities are also affected, from commercial fishing to hydroelectric schemes, but there appears to be no method of eradicating didymo without destroying other life in the same river. Therefore it may turn out that the only solution is to pollute rivers with phosphorus in order to keep the diatom population at a minimum!

This is far from the first time that I have discussed small-scale life but the issues raised by these three stories show yet again that we maintain traditional scale prejudice at our peril. Whether it is a single household experiencing (potentially fatal) poisoning to widespread changes in freshwater environments, we need better public education - and probably far more funding for international research - in order to minimise the problems generated at scales usually beneath our gaze. When it comes down to the crunch, such organisms have a far greater impact on the global ecosystem than all the endangered pandas, elephants and rhinos combined. As for those lunar tardigrades, I wonder how they are getting on..?

Anti-avian ingenuity: the numerous ways to minimise airport bird strikes

The widespread installation of wind turbines over the past three decades has generated a new ecologically unfriendly phenomenon, namely wild birds being killed by turbine sails. Although it could cause maintenance issues - and of course it's not good news for the birds themselves, the increasing density of air travel means far higher numbers of bird strikes are likely to occur in the much smaller turbines of jet engines, predominantly around airports.

I've previously written about how urban environments appear to generate wildlife somewhat smarter than rural equivalents. In contrast, airports seem to be a very poor choice for birds to inhabit, suggesting that the loss of natural environments coupled with the relatively undeveloped land around airport perimeters is causing birds to congregate in such precarious places.

It's somewhat ironic that such an environmentally unfriendly technology as air travel is inadvertently providing habitats for wild birds, but as urban sprawl increases animals are forced to live wherever they can find, even areas as seemingly unsuitable as runway taxiways and safety areas. As aircraft increase in size and speed but decrease in engine noise, it may be that aviation technology is contributing to the problem. In addition, waterfowl are attracted by the fresh water storage ponds found near runways for use in firefighting or drainage. Therefore, despite the noise, pollution, changes to local weather patterns and the obstacles in the form of the aircraft themselves, airports worldwide have found themselves becoming home to or visited by flocks of numerous bird species.

With over forty bird strikes every day, the cost to the global airline industry surpasses US$1 billion per year. So what is being done to reduce or remove this threat? The range of options is both ingenious and proof that birds are a formidable opponent, so here is a brief summary of popular methods:

1. Removing food and water sources
2. Audio repellents
3. Chemical repellents
4. Fake fire and pyrotechnics
5. Baited traps
6. Real and fake predators
7. Removing and culling birds

1) Reducing bird foodstuffs involves a variety of techniques that aren't exactly the height of eco-friendliness. Any vegetation that might be a food source for local bird species, such as fruit- or seed-bearing trees and bushes may be removed. One step further is to replace any grass areas with a non-local variety that is less attractive to native birds.

A substantially less environmentally-friendly approach has been the regular use of insecticides to remove food sources for insectivorous birds and even distributing poison to remove potential raptor prey such as rabbits. Open water storage ponds within airports have been netted to prevent waterfowl from landing on them, but camouflage has also been developed specifically to minimise the attractiveness of large bodies of water.

2) Some airports such as Singapore's Changi play bird distress and/or raptor calls to scare birds away. A less subtle method has been the regular discharge of loud sounds generated by sonic cannon such as propane exploders. However, evidence suggests that birds soon become accustomed to these.

3) As an antithesis to the removal of food sources described above, adding chemical repellents to airport vegetation is now being used. Since 2010, New Zealand airports have been using a a locally-developed grass, which contains an endophyte fungus that reduces insect numbers and makes birds sick. This may prove to be easier to implement than natural chemical repellents imported from agribusiness, such as methyl anthranilate and anthraquinone, which require sophisticated, ongoing and locally-tailored programmes to maintain effectiveness.

4) Although it might sound high-tech, the use of wind-blown metallic streamers that simulate fire have been found to only fool birds for short periods. Likewise, the use of lasers, flare launchers and other live pyrotechnic devices serve to acclimatise local wildfowl to sudden noise and light. After all, the birds are already congregating around noisy aircraft for much of the day!

5) For airports frequented by raptors, live prey such as pigeons can serve as bait for sophisticated traps that notify staff once they have been triggered. The problem then is where to release the bird of prey so that it doesn't return to the original area.

6) The opposite of the previous method is to swamp the locality with trained predators, from dogs to raptors, in order to convince birds to nest elsewhere. The predators don't have to always be live, either: in the USA, fake coyotes have been used in wetlands to keep birds away from flight paths.

7) If all other methods fail, there are several time-consuming alternatives that could be used as a last resort. Firstly, birds can be caught and moved to regions far from airports. Naturally, this requires collaboration with wildlife experts and/or rangers. As a guaranteed solution, culling may also be allowed, although this is hardly going to endear most people to a sector that, essential though it is, has a rather poor environmental record.

One potential smart solution for civilian aviation has been developed for the Royal Netherlands Air Force, which involves constant radar monitoring of wildfowl so that pilots can adjust their take-off and landing flight paths. Apart from lack of the technology at airports, each airport would need long-term trials to determine the appropriate adjustments with regard to local bird populations and their behaviour.

From what I've learnt while researching this issue, there is probably no single solution suitable for all airports; a suite of methods is required, tailored for each one depending on the local landscape, climate and of course bird species - the latter being wily and unpredictable adversaries. Clearly, there's a long way to go if such drastic solutions as culling the birds themselves and poisoning the wider ecosystem are seen as valid options. It looks as if more research is required before the danger to both airliners and birds can be reduced, although I doubt if it could ever be completely eliminated; nature is just too unpredictable!