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..?

Back to nature: why saving other species could save mankind

Humanity has come a long way from reliance on biologically-derived materials such as wood, bone, antler and fur. Yet this doesn't mean that organic materials have been replaced or many respects surpassed by wholly artificial ones. There are of course new carbon-based materials such as 3D graphene and carbyne that may prove to be the 'ultimate' materials when it comes to properties such as strength, but the history of the past century has shown how natural substances can inspire research too.

Perhaps the most obvious example of this is the hook and loop fastener best known by the trademark Velcro, which is essentially a copy of the burr design on Arctium (burdock) plants. Considering that taxonomists disagree wildly on the global totals of current plant, animal and fungi species - many claiming that less than 20% have been scientifically classified - it seems apparent that nature has plenty more surprises up her sleeve.

Spider silk has long been recognised as an incredibly strong material for its weight, with that generated by many species being up to five times the strength of the equivalent amount of steel. The silk produced by the Madagascan Darwin's bark spider (Caerostris darwini) is ten times stronger than Kevlar, suggesting that bullet-proof clothing manufacturers could do well by investigating it. However, a discovery by an engineering team at Portsmouth University in the UK makes even this seem humdrum: the teeth of limpets are potentially so strong - thanks to a mineral called goethite - that artificial versions of them could be used in high-performance situations, even aircraft components.

In addition to their use in construction, natural substances may prove useful in the development of new pharmaceuticals. I've previously discussed animal defence mechanisms such as that of the bombardier beetle and how small, barely noticed critters such as the peripatus deserve far more investigation. Of course the problem has been that size and aesthetics directly correlate with public attention and newsworthiness, meaning that the likes of the giant panda are used as poster species despite offering little in the way of practical advance for science and technology.

I'm not of course suggesting that species should be judged on the merits of their usefulness to humanity, but that we could probably gain a lot of practical usage from much greater study of the less well known flora and fauna still 'out there'. The resilience of tardigrades is becoming fairly well known, but there are no doubt other seemingly insignificant species with even more astonishing properties. Hydra for example are small, tentacled animals that live in fresh water; thanks to being composed mostly of stem cells they appear to have life cycles that just keep going. There also been limited research on the 'immortal' jellyfish Turritopsis dohrnii; this is surprising, given that the advances in gene splicing technology such as CRISPR-Cas9 and TALEN might lead to important medical breakthroughs, not just glow-in-the-dark pets.

In addition, the race to generate new antibiotics to replace those ineffective against 'superbugs' would suggest any short-cuts that can be taken should be taken. I remember watching a 2006 British murder mystery programme in which people were killed during a hunt for rare South American seeds containing anti-malarial properties. This may be pure fiction, but considering that artemisinin-resistant 'supermalaria' is now on the horizon, the script was somewhat prescient.

The idea behind all this is simple: delving into an existing complex chemical compound is far easier than trying to generate a purely synthetic one from scratch. This is why it is important to conserve small and insignificant species, not just the pandas, elephants and rhinos. Who's to say that a breakthrough medicine or construction material isn't already in existence, just hiding around the corner (or rather, in the genome) of some overlooked species of animal, plant or fungi?

With superbug-beating pharmaceuticals and climate mitigation technology a priority, we're shooting ourselves in the foot if we let an increasing number of unconsidered species became extinct. As I discussed last month all sorts of organisms are now in serious trouble from global amphibian populations via North American snakes and bats to the mighty kauri trees of New Zealand. Just saving a few specimens of doomed species in freezers or formalin is unlikely to be enough: shouldn't we endeavour to minimise species loss for many reasons; and if we must have an economic motive, what about their potential benefit to mankind? Not for nothing has nature been deemed 'the master crafts(person) of molecules' and we lose volumes in that library at own expense.

Valuing the velvet worm: noticing the most inconspicuous of species

Most of the recent television documentaries or books I've encountered that discuss extra-terrestrial life include some description of the weirder species we share our own planet with. Lumped together under the term 'extremophiles' these organisms appear to thrive in environments hostile to most other life forms, from the coolant ponds of nuclear reactors to the boiling volcanic vents of the deep ocean floor.

Although this has rightly gained attention for these often wonderfully-named species (from snottites to tardigrades) there are numerous other lifeforms scarcely noticed by anyone other than a few specialists, quietly going about their unassuming business. However, they may provide a few useful lessons for all of us, including that we should acknowledge there may be unrecognised problems generated when we make rapid yet radical modifications to local environments.

There is a small, unassuming type of creature alive today that differs little from a marine animal present in the Middle Cambrian period around five hundred million years ago. I first read about onychophorans in Stephen Jay Gould's 1989 exposition on the Burgess Shale, Wonderful Life, and although those fossil marine lobopodians are not definitively onychophorans they are presumed to be ancestral. More commonly known by one genus, peripatus, or even more colloquially as velvet worms, there are at least several hundred species around today, possibly many more. The velvet component of their name is due to their texture, but they bear more resemblance to caterpillars than to worms. They are often described as the ‘missing link' between arthropods and worms but as is usually the case this is a wildly inappropriate term in this context of biological classification. The key difference to the Burgess Shale specimens is that today's velvet worms are fully terrestrial: there are no known marine or freshwater species.

Primarily resident in the southern hemisphere, the largely nocturnal peripatus shun bright light and requiring humid conditions to survive. Although there are about thirty species here in New Zealand, a combination of their small size (under 60mm long) and loss of habitat means they are rarely seen. The introduction of predators such as hedgehogs - who of course never meet peripatus in their northern hemisphere home territory - means that New Zealand's species have even more to contend with. Although I frequently (very carefully) look under leaf litter and inside damp logs on bush walks in regions known to contain the genus Peripatoides - and indeed where others have told me they have seen them - I have yet to encounter a single specimen.

There appears to be quite limited research, with less than a third of New Zealand species fully described. However, enough is known about two species to identify their population status as 'vulnerable'. One forest in the South Island has been labelled an 'Area of Significant Conservation Value' thanks to its population of peripatus, with the Department of Conservation relocating specimens prior to road development. Clearly, they had better luck locating velvet worms than I have had! It isn't just the New Zealand that lacks knowledge of home-grown onychophorans either: in the past two decades Australian researchers have increased the number of their known species from just seven to about sixty.

Their uncanny resemblance to the Burgess Shale specimens, despite their transition from marine to terrestrial environments, has led velvet worms to be described by another well-worn phrase, 'living fossils'. However, is this short-hand in any way useful, or is it a lazy and largely inaccurate term? The recent growth in sophisticated DNA analysis suggests that even when outward anatomy may be change little, the genome itself may vary widely. Obviously DNA doesn't preserve in fossils and so any such changes cannot be tracked from the Cambrian specimens, but the genetic variation found in other types of organisms sharing a similar appearance shows that reliance on just external anatomy can be deceptive.

Due to lack of funding, basic taxonomic research, the bedrock for cladistics, is sadly lacking. In the case of New Zealand, some of the shortfall has been made up for by dedicated amateurs, but there are few new taxonomists learning the skills to continue this work - which is often seen as dull and plodding compared to the excitement of, for example, genetics. Most people might say so what interest could there be in such tiny, insignificant creatures as peripatus? After all, how likely would you be to move an ant's nest in your garden before undertaking some re-landscaping? But as shown by the changing terminology from 'food chains' to 'food webs', in most cases we still don't understand how the removal of one species might generate a domino effect on a local ecosystem.

I've previously discussed the over-reliance on 'poster' species such as giant pandas for environmental campaigns, but mere aesthetics don't equate to importance, either for us or ecology as a whole. It is becoming increasingly clear that by weight the majority of our planet's biomass is microbial. Then come the insects, with the beetles prominent both by number of species and individuals. Us large mammals are really just the icing on the cake and certainly when it comes to Homo sapiens, the rest of the biosphere would probably be far better off without us, domesticated species aside.

It would be nice to value organisms for themselves, but unfortunately our market economies require the smell of profit before they will lift a finger. Therefore if their usefulness could be ascertained, it might help generate greater financial incentive to support the wider environment. Onychophorans may seem dull, but there are several aspects to them that is both interesting in itself and might also provide something fruitful for us humans.

Firstly, they have an unusual weapon in the form of a mechanism that shoots adhesive slime at prey. Like spider silk, is it possible that this might prove an interesting line of research in the materials or pharmaceutical industries? After all, it was the prickly burrs of certain plants that inspired the development of Velcro, whilst current studies of tardigrades (the tiny 'water bears' living amongst the mosses) are investigating their near indestructability. If even a single, tiny species becomes extinct, that genome is generally lost forever: who knows what insights it might have led to? Although museum collections can be useful, DNA does decay and contamination leads to immense complexities in unravelling the original organism's genome. All in all, it's much better to have a living population to work on than rely on what can be pieced together post-extinction.

In addition, for such tiny creatures, velvet worms have developed complex social structures; is it possible that analysis of their brains might be useful in computing or artificial intelligence? Of course it is unlikely - and extinction is nothing if not natural - but the current rate is far greater than it has been outside of mass extinctions. Losing a large and obvious species such as the Yangtze River dolphin (and that was despite it being labelled a ‘national treasure') is one thing, but how many small, barely-known plants and animals are going the same way without anyone noticing? Could it be that right now some minute, unassuming critter is dying out and that we will only find out too late that it was a vital predator of crop-eating pests like snails or disease vectors such as cockroaches?

It has been said that ignorance is bliss, but with so many humans needing to be fed, watered and treated for illness, now more than ever we need as much help as we can get. Having access to the complex ready-made biochemistry of a unique genome is surely easier than attempting to synthesise one from scratch or recover it from a long-dead preserved specimen? By paying minimal attention to the smallest organisms that lie all around us, we could be losing so much more than just an unobtrusive plant, animal or fungus.

We can't save every species on the current endangered list but more attention could be given to the myriad of life forms that get side-lined by the cute and cuddly flagship species, usually large animals. Most of us would be upset by the disappearance of the eighteen hundred or so giant pandas still left in the wild, but somehow I doubt their loss would have as great an impact on the surrounding ecosystem than that of some far less well known flora or fauna. If you think that's nonsense, then consider the vital roles that bees and dung beetles play in helping human agriculture.

Although the decimation of native New Zealand wildlife has led to protective legislation for all our vertebrates and a few famous invertebrates such as giant weta, the vast majority of other species are still left to their own devices. That's not to say that the ecosystems in most other countries are given far less support, of course. But without funding for basic description and taxonomy, who knows what is even out there, never mind whether it might be important to humanity? Could it be that here is a new field for citizen scientists to move into?

Needless to say, the drier climes brought on by rising temperatures will not do peripatus any favours, thanks to its need to remain in damp conditions. Whether by widespread use of the poison 1080 (in the bid to create a pest-free New Zealand by 2050) or the accidental importation of a non-native fungus such as those decimating amphibians worldwide and causing kauri dieback in New Zealand, there are plenty of ways that humans could unwittingly wipe out velvet worms, etal. So next time you watch a documentary on the demise of large, familiar mammals, why not spare a thought for all those wee critters hiding in the bush, going about their business and trying to avoid all the pitfalls us humans have unthinkingly laid for them?

Backyard bonanza: collating stats for a predator-free future

I've previously discussed how a lack of understanding of statistics can cause consumers to make poor choices, so it would seem that increasing the public's understanding of them can only be a good thing. Therefore, along the lines of New Zealand's annual garden bird survey, I decided to do a bit of citizen science. My aim was to record the highest number of each fauna species seen at one time, either actually in my garden or seen from my garden. The time frame was a calendar year, so as to take into account seasonal migrations and food availability. As an aside, it might have been easier to count flora (after all, it doesn't move very fast) but with Auckland being the weediest city in the world and my floral knowledge much weaker than my recognition of fauna, I opted for the easier option of any animal that I could see without using a microscope.

A meta-analysis released this month states that almost twenty-five percent of birds on the IUCN Red List of Threatened Species are being affected by climate change. In addition, with last years' announcement to make New Zealand predator-free by 2050, such surveys might be useful for locating concentrations of introduced pest species. In a way, I'm providing a guide that anyone can follow with the minimum of effort (hint, hint). So here are my results, followed by some more information:

Class/species	Native/self-introduced	Number seen
Insecta
Ant (unknown species)	Yes	Numerous
Asian paper wasp	No	3
Black field cricket	Yes	4
Bumble bee	No	1
Bush cockroach	Yes	14
Cabbage tree moth	Yes	7
Cabbage white butterfly	No	2
Cicada	Yes	2
Click beetle	Yes	2
Common bag moth	Yes	1
Crane fly	Yes	1
European earwig	No	1
Ground beetle	Yes	2
Honey bee	No	1
Housefly	No	7
Ladybird	Yes	2
Monarch butterfly	Yes	17
Shield bug	Yes	3
South African praying mantis	No	22
Tree weta	Yes	18
Arachnida
Bird dropping spider	Yes	1
Black cobweb spider	Yes	1
Black house spider	Yes	1
Daddy long-legs	Yes	3
Jumping spider	Yes	1
Nurseryweb spider	Yes	1
Slater spider	Yes	1
White tail spider	No	1
Annelida
Earthworm	No	5
Tiger worm	No	Numerous
Hexapoda
Springtail	No	Numerous
Chilopoda
Centipede	Yes	3
Mollusca
Common garden snail	No	9
Reptilia
Rainbow skink	No	2
Aves
Australasian hawk	Yes	1
Blackbird	No	2
Black headed gull	Yes	3
Eastern rosella	No	4
Fantail	Yes	2
Goldfinch	No	3
Greenfinch	No	2
House sparrow	No	14
Myna bird	No	4
Rock pigeon	No	5
Silvereye	Yes	7
Song thrush	No	1
Spotted dove	No	1
Starling	No	4
Tui	Yes	1
Mammalia
Cat	No	2
Chicken	No	1
Dog	No	1
Hedgehog	No	1
Mouse	No	1
Rabbit	No	1

The first thing that seems obvious is just how many non-native species I observed, some deliberate introductions whilst others accidentally brought to New Zealand, but all within the past two centuries.

Now for some interesting comments about how statistics can be (mis)interpreted:

1) The method I chose to order the table by could affect how easy it is to find key points of interest. Alphabetical order is familiar but is simply a well-known form of cataloging. Therefore it can be seen as a neutral form of presentation, not emphasising any particular pattern of the results. Had I ordered by native/non-native, it might have become more apparent how many of the latter bird species there are. If I had ordered all species in one list by this method, rather than in separate classes, the pattern would have been obscured again. So simply by selecting a certain order, results can appear to support a certain notion.

2) How useful is this data if it lacks supporting information? By this, I mean factors that might affect the count: Is it a common or garden (yes, that's a pun) location or an highly unusual one? Is the locale urban or rural? What are the surroundings? How big is the garden and how much vegetation is there? Is the vegetation primarily native or non-native? I could go on like for this ages, but clearly to get a more sophisticated understanding of the causes behind the figures, this information is necessary. Even then, two locations that are almost identical to a casual observer might appear profoundly different from the vantage point of say, earthworms. I will admit to (a) having built 2 weta motels and a bug motel; and (b) feeding silvereyes in winter; and (c) having made a tui sugar water feeder that has been totally ignored. Go figure!

3) Are there any other obvious factors that could affect wildlife? How managed is the location? Are chemicals such as weedkiller used or is the garden solely organic? Again, this can have a massive effect on wildlife, such as pesticides that remove insects at the base of food webs. On the one hand, if mine is an organic garden surrounding by neighbours who spray their foliage, then it could be an island of suitability in a comparatively barren terrain. But alternatively, if most of the neighbourhood isn't fauna-friendly, how likely would my garden get visited even on the off-chance by animals that can't live in the wider area?

4) Of course there's also contingency within natural selection. For example, quite by chance some species can survive on foods not native to their ecosystem. Although stick insect numbers in New Zealand were drastically reduced thanks to DDT, gardens don't need to contain their native food plants in order to support them. In the south-west of England, three species of accidentally-introduced New Zealand stick insect have flourished for decades on the likes of roses! Also, unusual events can affect populations: in this case, the two rainbow skinks appeared several months' after laying some ready lawn so I can only assume their eggs arrived with the turf, the previous five years having seen no skinks whatsoever.

5) When it comes to surveys, timing is also important. As you might expect, most of my observations took place during the day, with the only nocturnal ventures being on clear nights when using my telescope. The moths and hedgehogs were mostly seen at night, whilst had I included birds I could hear as well as see, then a morepork would have been added to the list. Again a simple prejudice, in this case sight over sound, has skewed the statistics. The large number of mantises were not adults but nymphs all hatching from a single ootheca. As for the monarch butterflies, they were a combination of caterpillars, chrysalis and adults, having appeared in much greater numbers this year than previous, despite no additional swan plants (their only food). Interesting, a clump of twenty or so mature swan plants a few streets away hasn't yielded any monarchs in any of the three stages. Presumably, predators such as wasps are responsible.

The sheer randomness of nature is exciting, but doesn't exactly help to uncover why populations are such as they are found via small-scale studies. Oh, and further to the damage invasive species have wrought on native wildlife, you may be interested to learn that none of the mammals belonged to me, the cats and dog being owned by friends and neighbours whilst the rabbit was an escapee from a dozen houses away!

6) Finally, there's the scale prejudice. Although I have a basic microscope, I didn't include such tiny wonders as tardigrades and bdelloid rotifers, even though garden moss and leaf litter respectively has revealed these wee critters. My page of nature photographs shows this prejudice, with microscopic fauna getting their own page.

So, what can we learn from this, apart from the large number of non-native species commonly found in Auckland? Perhaps that raw data can be presented in ways to obscure patterns or suggest others, should the publisher have an agenda. Furthermore, without access to highly detailed meta data, the statistics by themselves tell only a small part of the story and as such are open to wide-ranging interpretation by the reader. Therefore the next time you read about some percentage or other, remember that even without manipulation or omission, survey data is not necessarily pure, unsullied and free of bias.