Wild green wall. Punta Arenas, Chile
On the few
occasions someone has pointed a microphone at me and asked why I 'chose to
study moss', I've found myself struggling to respond. I imagine they expect a heroic
answer, like when people say they wanted to be an astronaut since a child, or
experienced an epiphany and felt drawn to a life on stage!
Now that I
stop to think about it, I stumbled upon moss possibly in much the same way
others have found themselves studying this tiny – but important and fascinating
– plant.
My path
took a mossy turn as I contemplated a PhD in Australia after an undergraduate
degree in biology, topped by an Honours project in conservation genetics on a
rare native plant. To assess potential PhD projects, I drew up a list of
criteria that included, amongst others, developing new skills; a friendly lab
or research group; and potential for an experimental approach.
I didn't
really mind what taxa it was, but I happily settled on a moss project that fit
the bill – tweaking and nipping it until it was my own. The starting point was
the potential for mossy biocrusts on green roofs, but I felt not enough was
known about how moss survives more generally in the urban environment, so I
back-pedalled a little. City life involves changes in light, hydrology,
pollution and substrate. How do these effect the biodiversity of moss? Now that
I'm firmly focused on moss, there are many reasons I enjoy studying it.
My colleague, Flavia Ferrari from Brazil keeps her distance from the wild life while recording moss communities on King George Island
I like the
way moss makes me think about concepts like scale, water relations and
surviving stresses. The fact it is so small, and its leaves just one cell
thick, means it can rely on the process of diffusion to obtain water and
minerals. This in turn affects where it thrives - particularly in the urban
environment where it can exploit small niches like pavement cracks, dimples in
road surfaces or skeletal soils. Rhizoids suffice where larger plants require
the vascular tissues of roots.
Desiccation
tolerance - described as the ability to dry without dying – is surely one of
the most amazing qualities of bryophytes, found in different degrees among
these plants. It involves a carefully choreographed sequence of events, where
plant sugars create glass-like coverings that protect macromolecules like DNA
or proteins, which would otherwise crack and crumble in a totally dry state. Desiccation
tolerance was associated with those first steps of land colonisation by plants,
adding an evolutionary note whenever I take a hand lens to tuft of moss and watch
it rehydrate. I never tire of seeing twisted dried leaves unfurl, sighing open
with just a spray of water.
Like other
bryophytes, mosses are often overlooked. But once you notice them, they draw
you in, then, with newly found moss-attuned vision, you realise that moss is a
member of many ecosystems, whether woodland, urban or even beachside. Now that I study moss, I have an eye out for
it everywhere I go. Is that moss I see growing in this playground on plastic
turf? Yes - moss reminds us that wild processes occur all around us, whether we
take notice or not. On the cusp of micro and macro, it has the ability to alter
your perception of the world.
After the fire. Australia
When I get
asked what I'm doing when I'm out and about in the suburbs, it's nice to be
able to share some basic facts about moss. Usually, people think of it as only
found in moist habitats, so they are surprised to learn that desert mosses
inhabit our city pavements. But as members of the IAB will be well aware, moss
is both ubiquitous and picky. Ubiquitous in that there are thousands of species
(10 000 at least according to the Tree of Life Web Project) and these grow in
an astonishing variety of places: among other biocrust organisms (such as lichen,
fungi, bacteria) in deserts; on trees in rainforests and on ground that is
newly exposed, as glaciers retreat in Antarctica. But picky too, in that substrate
– the kind of rock, for instance – also largely dictates whether a particular
species can grow there. For example, I'm looking at moss on an urban gradient
on three substrates - pavement cracks, asphalt dimples (such as car park edges)
and soil in grassy green spaces. The species vary according to substrate
(albeit with a few that have wide ranges and can tolerate all three). But
whether it's the CBD or Antarctica, where moss grows depends on a combination
of factors including microclimate (the humidity, temperature and so on, at the
scale it matters to a moss) and microtopography.
Science is
my second career (my first career focus was publishing) and one of the reasons
I turned back to biology was to go into the field and experience places I
otherwise would not have the opportunity to visit. Moss, albeit small, has not
disappointed on this front. Travelling for conferences has allowed me to
witness the micro 'mountains' of biocrusts in Utah, urban moss and night
markets in Shenzhen, and the wonderful IAB/iMOSS conference in Madrid's Royal
Botanic Garden last year (hot on the heels of the SEB in Seville). Visiting the
Prado was a highlight. Little moss there, it's true, but Goya's May 3rd moved
me to tears. The field trip to the Parque Regional de la Cuenca Alta del
Manzanares provided a special opportunity to see numerous dry adapted moss
species in the wild. Early last year, in February 2020, moss took me camping in
Antarctica, and I delivered the moss back to Australia in the form of samples
from sites on King George Island glacier retreat. The samples now sit in a
freezer in Wollongong, awaiting analysis for C13, which will show what
conditions were like as it grew, and possibly C14 for dating purposes.
Currently,
however, my research is taking me out into the suburbs of Wollongong, a coastal
city in NSW, where watching closely for moss also makes me appreciate neighbourhoods
I wouldn't usually visit, whether it's the expansive beaches of Windang in the
south, or the bourek shops in the migrant suburb of Cringila.
So next
time I'm asked, ‘why do you study moss?’ I now have a ready answer: for its
rich research potential; because it's thought-provoking philosophically; and because
it leads me to places near and far.
The surprising colours of urban moss
Written by Alison Haynes
PhD Candidate (University of Wollongong), Australia
Twitter
Instagram
No comments:
Post a Comment