When real life imitates testates: a 2019 ‘Testate amoebae in the real world’ calendar?!

Contributed by Matt Amesbury and Alex Whittle

(Real!) testate amoeba photos used with the kind permission of Ferry Siemensma, Microworld, www.arcella.nl

Matt:

As testate amoeba analysts, we all spend countless hours staring down the microscope studying and identifying hundreds upon thousands of shells. Perhaps foolishly, I once added up, out of perverse interest, the number of tests I had counted over the course of a three year project developing palaeo records from three Holocene age cores, a couple of shorter cores and developing a regional transfer function. The total was 130,384.

I still can’t quite decide whether this number amazes or sickens me (!), but it certainly does make it understandable that we should all begin to see the familiar shapes and structures of tests when we close our eyes, in our sleep and even in the real world.

Forward on almost a decade from that count-heavy project and I have moved to the University of Helsinki for a year to work on testates from permafrost peatlands. It’s the weekend and I am enjoying a walk in the local forest with my family. We stop for a snack of ruis sippi; circular, bowl-shaped rye crackers that are popular in Finland. My hand delves into the bag and I pull out a freak cracker with the front still attached. The recognition is immediate … keep reading to find out more!

Alex:

In the true collaborative spirit of our community, a photograph of this most unusual ‘specimen’ soon reaches me back at the University of Exeter. Having myself witnessed a curry resembling my second favourite testate amoeba taxa – Certesella certesi – just weeks before, this starts us wondering … how many other testates are hiding in plain sight, surrounding us in the real world? Others soon followed and we share the first three stories below. (I still deeply regret not taking a photo of the curry!)

Of course, the idea of a ‘Testate amoebae in the real world’ calendar was a natural progression, so please regard this blog as part amusing distraction and part call to arms! Go out into the world, friends and colleagues, find and photograph whatever you can that strongly resembles a testate amoeba and send them in to us!

 

Centropyxis rye-crackeris

1. Centropyxis ‘rye-crackeris’ (Lat: 60.2165°N, Long: 25.0327°E).
Finnish rye crackers generally exhibit a hemispherical boat-shape morphology, adapted to hold some sort of filling. This one obviously had other ideas and preferred to imitate Centropyxis aerophila type, with its test construction of agglutinated rye grains and a sub-terminal aperture. The specimen was found on 13th August 2018 by Matt (and family) whilst stopped for a snack during a walk around the forested tracks and trails near the Viikki campus of the University of Helsinki.

 

Difflugia shroomex

2. Difflugia ‘shroomex’ (Lat: 54.5763°N, Long: -5.9356°W)
Many food stuffs that spend their short lives imitating testate amoebae are secretive and prefer to stay out of the limelight, many being digested by unsuspecting members of the public without ever fulfilling their destiny of being recognised for what they really are. However, some are brazen and do everything they can to be found. One such example is this mushroom amoeba with test of agglutinated breadcrumbs (or Difflugia pulex type) who, astonishingly, infiltrated the lunch buffet on day three (13th September 2018) of the 9th International Symposium on Testate Amoebae (ISTA) held at Riddel Hall, Belfast. Found by Matt, who was distinctly peckish at the time and enjoyed the mushroom very much a short while after this photograph was taken.

Lagenodifflugia vase

3. Lagenodifflugia ‘vase’ (Lat: 64.1447 °N, Long: -21.9423°W)
As a word of caution, it is important to consider that not all everyday testates will be disguised as food items. Indeed, I (Alex) believe the stories above may indicate a particular ‘sampling bias’ by their author! Some are a much less ephemeral presence in everyday life and have invested much more energy into creating permanent tests in the hope of being identified – these are the K-strategists of real life testates. This individual was found by Alex, directly after ISTA9 on a wet and windy evening in late September (23rd) in Reykjavik, Iceland. Considering the location of this record in the Northern Hemisphere, after some initial confusion with Apodera vas, we believe this real-life testate to be imitating Lagenodifflugia vas.

 

Real life testates world map

Distribution of real-life testates currently reported at the time of writing.

 

Remember that real-life testates may be spotted without warning and when you least expect them so keep your eyes peeled and cameras at the ready. We aim to fill the map with finds across the world and let’s not allow any testate genera to go un-represented!

We cannot wait to hear from you – the hotlines for reporting your real-life testate discoveries are: m.j.amesbury@exeter.ac.uk and aw424@exeter.ac.uk

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Testate amoebae from the end of the earth!

Contributed by Matt Amesbury

The moss banks on Green Island on the Antarctic Peninsula provide a vivid green splash amidst the surrounding ice caps, glaciers and icebergs (Photo: Matt Amesbury)

The moss banks on Green Island on the Antarctic Peninsula provide a vivid green splash amidst the surrounding ice caps, glaciers and icebergs (Photo: Matt Amesbury)

The use of testate amoebae as a proxy for past changes in the hydrological status of peatlands has become ever more popular over the past two decades. Studies have been carried out over an increasing geographical range covering most major areas of northern hemisphere peatlands as well as in Patagonia and New Zealand amongst other places south of the equator. Despite this pushing of “amoebal” boundaries, there is one place you might certainly expect to be able to rule out moss-based testate studies: Antarctica.

Close up of Polytrichum strictum moss growing on Green Island (Photo: Matt Amesbury)

Close up of Polytrichum strictum moss growing on Green Island (Photo: Matt Amesbury)

Only a tiny 0.3% of the Antarctic continent is ice free, yet in parts of this seemingly minute slither, the climate is just about amenable enough to have permitted the formation of deep moss banks; accumulations of moss that grow a few millimetres each year and are then frozen stiff over the winter months only to thaw out in the short Austral summer and accumulate a little further. The most extensive moss banks are to be found on Elephant Island, located just off the northern tip of the Antarctic Peninsula. Here, the banks are almost three metres deep and around four to five thousand years old. At the other end of the scale, almost ten degrees of latitude further south at Lazarev Bay on Alexander Island as the Antarctic Peninsula begins to merge into the continental mass, comparatively tiny moss banks of only 40 cm depth still cling on to a dubious existence.

The rugged surface topography of a moss bank on Green Island (Photo: Matt Amesbury)

The rugged surface topography of a moss bank on Green Island (Photo: Matt Amesbury)

Work is currently underway to exploit these moss banks as a palaeoclimatic archive. The Antarctic Peninsula has warmed by 3°C since the 1950s making it one of the most rapidly warming parts of the globe, but there is comparatively little terrestrial palaeoclimate data to put this temperature rise into a longer-term perspective. Could this be where testate amoebae step into the fray once more?

The pioneering work of the British Antarctic Survey’s Humphrey Smith laid the foundations of knowledge on Antarctic testate amoeba throughout the 1970s and 80s. His work painstakingly analysed and recorded the distribution and ecology of moss bank Protozoan communities from the sub-Antarctic Islands (mainly on Signy and Elephant Islands) as well as the Antarctic Peninsula itself and latterly in sites spanning the entire circumference of the Antarctic continent. Taxonomic diversity was relatively low with the same few familiar faces cropping up over and again, perhaps most frequently the taxa Corythion dubium.

Campsite on Green Island with blue-eyed cormorants and the creaking icebergs just offshore as our only companions (Photo: Matt Amesbury)

Campsite on Green Island with blue-eyed cormorants and the creaking icebergs just offshore as our only companions (Photo: Matt Amesbury)

So when we began working in the region in 2012 we were faced with a lot of testate unknowns, especially in terms of their abundance, diversity and distribution in core samples; all of Smith’s work had been on surface samples. To date, we’ve counted assemblages from a range of locations ranging from the southerly extent of moss banks at Lazarev Bay to Elephant Island in the north. In some locations the concentration of tests is low enough to make counting rather unfeasible but in other places we have been able to produce records with relatively high diversity (for Antarctica!) and evidence of switching between taxa, suggesting that the method can be applied in the traditional sense that it is in more temperate regions. Corythion dubium remains the best friend of the Antarctic testate counter, being abundant and dominant in most profiles. But it is joined by Assulina, Difflugia, Euglypha, Pseudodifflugia, Trinema and Valkanovia taxa, as well as some as yet unidentified tests (pictures included – please get in touch if you recognise any!)

The ubiquitous Corythion dubium, found in abundance in most Antarctic Peninsula sites.

The ubiquitous Corythion dubium, found in abundance in most Antarctic Peninsula sites.

In our work at Lazarev Bay, recently published in Current Biology, we used the testate concentration profile as part of a multi-proxy record alongside carbon stable isotope discrimination and measures of moss growth rates and accumulation. The testate profile here, at the limits of moss bank growth, was swamped with C. dubium to the almost complete exclusion of other taxa but concentration values showed a rapid increase coherent with changes in the other proxies and with the recorded temperature changes in the region since the 1950s. C. dubium is a taxa that shows a wide range of recorded sizes in the literature, but morphometric work we have embarked on suggests it may be possible to consistently split these size fractions, perhaps offering more information on past changes than we currently realise.

Three examples of an a yet to be confirmed test from Ardley Island, Antarctic Peninsula.

Three examples of a yet to be confirmed test from Ardley Island, Antarctic Peninsula.

With such a relatively blank canvas of testate research in the Antarctic Peninsula and so much still to learn, there is a lot left to do and there are certainly more questions than answers at present. But even so, it is a remarkable testament to these fascinating organisms that they survive and flourish at the end of world (well, give or take a few degrees of latitude!).

Reference

Royles, J., Amesbury, M. J., Convey, P., Griffiths, H., Hodgson, D. A., Leng, M. J. and Charman, D. J. 2013. Plants and soil microbes respond to recent warming on the Antarctic Peninsula. Current Biology 23, 1702-1706.

About the author

Matt Amesbury is a Research Fellow at the University of Exeter.  He is a testate amoebae analyst with broad interests in Holocene climate change and peatland palaeoecology.  He is currently working on peat from New Zealand as well as moss banks in Antarctica. He is co-founder of the website Bogology which aims to share the science of peatlands and past climate change in a light-hearted and accessible way. He’d love you to visit him there.