Glaciers and ice sheets as a biome

We had a lecture today about the cryosphere – the places on Earth where water is in its solid form – and glaciers and ice sheets were introduced as a biome. I found this idea particularly interesting and I was keen to discover a little bit more about it. So, I’ve done a bit of reading and here I’m going to share what I have found with you!

A biome is commonly defined as an area of the planet that can be classified according to the plants and animals that live in it. Temperature, soil, and the amount of light and water all help determine what life exists in a biome. The term itself is something I am familiar with but when I think of it I think of Tropical Rainforests and not glaciers and ice sheets.

When I think of the term 'biome' I think of Tropical Rainforests, not glaciers and ice sheets. Source: National Geographic

Alexandre M. Anesio and Johanna Laybourn-Parry argue that glaciers, ice sheets and the cryosphere are a biome uniquely dominated by microorganisms and active biogeochemical processes that have both local and global impacts. In their paper ‘Glaciers and ice sheets as a biome’, they say that it is time to recognise the cryosphere as one of Earth’s biomes.

The different habitats of the glacial biome

The ice surface

During the melting season, the presence of water provides habitats at the surface of the ice and snow. Distinct communities develop here comprising of species that are tolerant of low temperatures and able to overcome seasonal desiccation (Simon et al., 2009).

Subglacial environments
These habitats are a lot different from the ice surface environments for a number of reasons. Firstly they have a higher rock to water ratio that means the contact time between bedrock and water is much greater and secondly there is a lack of light, which tends to lead to the development of anoxic conditions. These environments dominated by heterotrophic and chemoautotrophic prokaryotes, as well as many fungal species.

Life within ice
Finally it is important to mention that a great deal of biological activity occurs within the ice itself. There are communities of algae, small animals and microbes all living inside the actual glaciers and ice sheets. This has been demonstrated by analysis of ice cores (e.g. Greenland Ice Project).

Ice core analysis has demonstrated that microbes and algae live inside the ice. Source: colorado.edu

Glaciers and ice sheets should be included as a biome
When I think of glaciers and ice sheets I don't picture much green nor many animals running around. However it is important to remember that these habitats support a high diversity of viruses and bacteria. Anesio and Laybourn-Parry (2012) suggest that this may be because a lot of microbial species are adapted to surviving and functioning under low temperature conditions. Despite this only a few studies have investigated the biodiversity of glacial habitats and where attempts have been made they have mostly been based on microscopic observations (e.g. Porazinska et al.,2004). 

The inclusion of glaciers and ice sheets as a biome with unique life adaptations would have wider implications for the conservation of these climate-sensitive ecosystems (Anesio and Laybourn-Parry, 2012). If these environments are not considered as one of Earth's biomes they may not receive the same conservation priority as other sensitive ecosystems. There will be global implications of this. For example the loss of biodiversity may lead to the loss of a pool of genes adapted to surviving and thriving in the cold. 

The loss of biodiversity from the cryosphere could lead to the loss of a pool of genes adapted to surviving in the cold. Source: travelsupermarket.com

In the water

The term is drawing to an end meaning that deadlines are looming. One such deadline that I am working towards at the moment is that of my independent study project. In this project I am investigating and evaluating a range of salinity reconstructions given by numerous proxies taken from a lake sediment core. This means that right now my life involves a lot of ‘palaeo[insert suffix here]’... I have gathered that you can affix pretty much anything on the end of ‘palaeo’ in order to study and make inferences about the past.

However, one such palaeo-combination that I only recently came across was ‘palaeobiodiversity’. I first encountered this paleo- in a paper by Adrian et al.(2009) in which the authors analyse the potential for lakes to act as ‘sentinels’ for climate change. The paper reports that the sensitivity of lakes to climate is well documented and that numerous studies have demonstrated that the physical, chemical, and biological lake properties respond rapidly to climate-related changes (ACIA, 2004). Other authors have suggested that what makes lakes so good at monitoring and recording the effects of climate change, is their high sensitivity to environmental changes as well as the fact that they conveniently integrate changes in the surrounding landscape and atmosphere (Carpenter et al., 2007).

Anyway, in the context of salinity variations in lake water I am afraid I hadn’t given much thought to how palaeolimnology (that’s the reconstruction of past lake environments) could be useful for studying biodiversity. So when I was introduced to palaeobiodiversity in that paper I thought that it would be interesting to learn more about this palaeo- (I’ll stop saying palaeo now, it gets annoying).

Irene Gregory-Eaves and Beatrix E. Beisner give a particularly useful contribution to the study of freshwater biology in their paper ‘Palaeolimnological insights for biodiversity science: an emerging field’. In this paper, the authors argue that palaeolimnology offers unique insights into biodiversity science, and the article highlights both its potential and limitation in providing further understanding of biodiversity dynamics.

What role will palaeolimnology play in the future of biodiversity science?

They write this article in the context of a growing need for scientists and policy makers to understand, predict and manage the consequences of rapid global declines in biodiversity (MillenniumAssessment, 2005). It could be argued that one of the greatest tools for prediction is the past, and I suppose that past trends are the underlying principle behind those fancy climate models developed by the likes of the IPCC (although I don’t know much about models and to be honest I don’t have much of a desire to venture into that section of the library so don’t quote me on this). With this in mind, as well as the fact that lakes make such good sentinels of climate change (Adrian et al.,2009), it makes perfect sense to me that palaeolimnology is used to understand and predict changes in global biodiversity.

As I said, the authors evaluate the role of palaeolimnology in biodiversity science. Palaeolimnology allows the researcher to focus on a single ecosystem, studying the way it changes over time (Gregory-Eaves and Beisner, 2011). This is a key advantage to anyone wishing to infer past changes in biodiversity in a particular area. Another benefit of using palaeolimnology to study biodiversity is the sheer timescale that can be studied. Investigators are able to quantify community responses to environmental changes over centuries, and even millennia! Clearly this would not be achieved by conducting any field-based survey typical of studies of biodiversity.

However, as is usually the case, for every benefit there is a limitation. Not all organisms preserve in sediments meaning that it is often difficult for investigators to find an identifiable remain to record. This is especially problematic for organisms that produce siliceous microfossils (e.g. diatoms) in lakes that are poor in silicate or are very alkaline (Stoermer et al.,  1985).

 

Diatom preservation is not as good in lakes that are poor in silicate

The application of palaeolimnological methods to the field of biodiversity science is a relatively new thing. However initial studies suggest that there is perhaps an exciting future to be had. For example, several studies are beginning to provide an insight into the drivers of community assembly and recovery. In this respect it seems likely that we’ll be seeing a lot more of palaeolimnology in biodiversity in the future!

NestWatch

Following on from last week's post, I wanted to highlight the importance of citizen science and the role it is playing in climate change science. The video below gives a good insight into one such citizen science project. NestWatch is a nationwide monitoring programme that has been designed by scientists at Cornell University. The aim of the project is to study the current condition of breeding birds and how breeding behaviour may be changing as a result of climate change and habitat degradation. 

                                   

Citizen Science

About a month ago I attended a lunch hour lecture held by Professor Kate Jones. In her lecture 'Technology for Nature', Professor Jones discussed the concept of citizen science and introduced the work of the Extreme Citizen Science research group here at UCL. This was the first I had heard of citizen science until a few weeks later when it featured on Countryfile. I realise that it is extremely topical at the moment and I am interested to find out more about it!

In a review of citizen science commissioned by the UK Environmental Observation Framework (UK-EOF), scientists from the NERC Centre for Ecology and Hydrology (CEH) and the Natural History Museum, London defined citizen science as:

            “…volunteer collection of biodiversity and environmental information which contributes to expanding our knowledge of the natural environment, including biological monitoring and the collection or interpretation of environmental observations.” (Roy et al., 2012).

In short citizen science is the involvement of volunteers in science. According to Roy et al. (2012), participation with environmental science and natural history is not a new thing. It has a long history dating back much further than the latest iOS update. In 1993 Paul Feyerabend philosopher of science, called for a full “democratisation of science”. He claimed that scientists are no better at science than anyone else (Pfeifer et al., unpublished). “Long history”?! “1993”?! Well I feel OLD! Moving swiftly on… Over the past decade there has been a rapid increase in the diversity and scale of citizen science and this is partly due to the development of smartphone apps, which have enabled a revolution in data collection.

Smartphones have revolutionised data collection

However, it seems that not everyone is rushing to the app store. The involvement of the public in scientific research is still disputed by many. For example, in 1993 (‘oh I remember it well’), The US House of Representatives voted to ban the National Biological Survey from accepting the services of volunteers (BBC, 15.03.2011). It seems only right to list the pros and cons of citizen science!

Strengths of citizen science

• Involves and empowers a participating public
• Contributes to our scientific knowledge base 
• Helps organisations prioritise action and investment 
• Raises people's awareness of environmental issues and their local environment
• Can be used to present global issues, e.g. the impacts of climate change or biodiversity loss, in a way that is locally relevant and meaningful 
• Allows for more research to be accomplished globally
• Connects people in a worldwide environmental movement 

Citizen science raises people's awareness of their local environment

Weaknesses of citizen science

• Data sets are often dismissed as inconsistent because they were collected by non-professional scientists 
• Data requires validation and calibration 
• High cost in the development of smartphone apps
• People who don't have access to/choose not to engage with technology are excluded

The review reached a number of conclusions about the value of citizen science. It found that:

• The development of technologies such as smartphone apps was "revolutionising citizen science"
• The quality of the data collected by citizen scientists had the potential to be excellent however this was not fully recognised by all researchers and policymakers
• It is a cost-effective way of collecting environmental data 
• There is huge potential to make more use of citizen science in the future 

My feelings are mostly positive when it comes to citizen science. I think that using technology as a platform to raise people’s awareness of environmental issues is both practical and exciting. I think that this could be a way of finally getting people to engage and connect with global environmental issues such as climate change and loss of biodiversity in a way that is meaningful and locally relevant.

However I am concerned that by using relatively new technologies such as smartphone apps, citizen science is something that is not open to everyone. I think that it is important for developers to be aware that by increasing the reliance on high-tech solutions they may be excluding an increasing proportion of the public who may be keen to participate in citizen science. I think the solution is to promote different forms of citizen science, for example I think there is a lot to be gained from groups of volunteers conducting field surveys in their local areas. Certainly I think citizen science should increase connection and interaction in the local community as well as collaboration in the global community, as promoted by technology.

Click here for further information about the role citizen science is playing in the study of UK biodiversity. 

The need for a new kind of ecology

In her article published in nature last week, Georgina Mace - president of the British Ecological Society and professor at and director of the Centre for Biodiversity and Ecosystems here at UCL – argues that a fresh approach to ecology is needed if we are going to tackle the global environmental challenges that the world faces today. She says that climate change and the loss of biodiversity and ecosystem services demand a new kind ecology, a kind that focuses on how whole communities interact with people and the physical environment at the landscape level. 

Advances in ecology in the past century have hugely improved our understanding of species interactions, population dynamics, food-web dynamics and how organisms adapt to their local environments. For example, Schmitz and Barton (2013) reported that climate change might alter abiotic conditions such as temperature and precipitation, which in turn could alter the life-cycle timing of predator and prey species and the nature of their interactions. However, there are few general theories for how multiple species respond to factors such as disease or changing climate at the community level and Georgina Mace considers this to be a major problem for global-change science.

In the article, Georgina talks specifically about the need to integrate ecological processes into models simulating Earth systems. In their current state, Earth systems models are unable to account for ecological processes such as feedbacks and thresholds due to a lack of long-term ecological studies. This limits the validity of such models considerably and so impairs our understanding of how biodiversity will respond to climate change in the future. Drew Purves and colleagues argue that analogous general ecosystem models (GEMs) could radically improve our understanding of the biosphere and could inform policy decisions about biodiversity and conservation. Considering how valuable and effective general circulation models have been in improving understanding of how the climate system works, to me it seems absolutely essential that analogous GEMs are developed. 

Finally, Georgina emphasises the need for data sharing and collaboration, and a greater focus on meta-analyses and synthesis. These approaches are fundamental for the identification of general trends, such as the effect of temperature change on animal dispersal. Innovations in citizen-science such as the monitoring of ash-dieback in Europe may be the key to unlocking this new kind of ecology. In my next post I want to explore and review the role that citizen-science is playing in scientific research and really get to grips with this latest trend!

Hedgeucation

Hedgerows originated and coexist with agriculture. They tell the story of the countryside and farming traditions over many centuries. Some hedgerow systems in the UK date back to prehistoric times, and most were well established by the Anglo-Saxon period. They were originally planted to contain livestock, mark boundaries or to fulfil Parliamentary Enclosure Acts. Hedgerows are a defining feature of the British landscape, forming part of our cultural and landscape heritage. They are really something to be proud of!

Britain's hedgerow landscape

The importance of hedgerows for biodiversity

The length of UK hedgerows is estimated to be 506 thousand miles. This makes them by far the largest nature reserve in the UK! In present day agricultural landscapes, hedgerows are considered to have many important ecological functions. They serve as refuges for species that were once widespread but are now restricted to uncultivated field margins. Hedgerows also provide a range of regulatory services, buffering against soil erosion and preventing the movement of surface water flow and particulate movement.

They're in decline!

Agricultural modernisation was responsible for considerable changes in both agricultural practices and landscape structure in the UK. We have seen a huge decline in the traditional hedgerow network landscape during the last century. This degradation of the rural landscape that has elapsed as a result of agricultural intensification represents the decline of hedgerow habitats and in my opinion this is a really serious impoverishment of the British landscape.

The condition of the UK's hedgerows is under threat. Local hedgerow surveys show that only 41% of hedgerows are in favourable condition. What is it that is threatening our hedgerows? Well, studies show that nutrient enrichment is the single most important reason for poor condition, with 38% of surveyed hedgerows failing on this criterion.

Contemporary agriculture is highly dependent on external outputs and high fertiliser rates are required to give high yields. Herbicides and pesticides are applied to suppress weeds and to control pests. However, unfortunately the devices that are used to apply these fertilisers and agrochemicals are not very good at getting it only on the crop and so non-target areas such as hedgerows are regularly hit! The nutrient enrichment that occurs as a result of this drift has been shown to modify plant community organisation in hedgerows.

Agrochemical drift poses a huge threat to hedgerow biodiversity

What can be done?

Well the answer is relatively simple... Many scientists are now advocating the incorporation of conservation headland at the edge of intensively farmed fields. A conservation headland is an area at the edge of a field that receives reduced agrochemical and fertiliser inputs. Scientists have shown that this is sufficient to reduce non-target deposition significantly and thus prevent loss of biodiversity in our hedgerows.

I hope that reading this post has enabled you to reconsider your opinion of hedgerows. They do seem like modest features that happen to just be there however they are hugely important for biodiversity. I sincerely hope that their prevalence in the British countryside persists for centuries to come. 

Save the date!

This week I want to introduce a topic that really interests me and that I feel really strongly about. Like many other final year degree students I am frequently asked what I am doing my dissertation on and I have to say I have received some funny looks when I tell people I'm doing it on hedgerows. I believe that the ecological importance of the hedgerow is severely underestimated, hence why I'm preaching to you now (and in a 12,000 word document that I will hand in some time in April...). Perhaps I'm becoming a bit of a 'hedge-hugger' but I honestly do believe that is a lot to be learnt from these (seemingly boring) linear features.

Having lived in rural Staffordshire all my life - with the exception of the last 3 years which i've spent in the metropolis that is London (pardon my human geography) - the way the hedgerow organises the countryside, marking ownership and dividing land types, has always intrigued me. The high surface area-volume ratio of the hedgerow means that it is mostly edge habitat and this renders it susceptible to interference from surrounding agricultural practices. Agricultural mechanisation, increasing herbicide and fertiliser use and increasing cultivation, have all led to a deterioration of Britain's hedgerow network. This will have severe implications for biodiversity in agrarian landscapes.

I have a lot of reading to sift through before I present you with a proper blog post about hedgerows, but because this topic means so much to me I thought I would officially invite you to read my next post.

Friday 15th November **Hedgerows** 

(I'm still working on an exciting title)

Featuring...

Importance of hedgerows for biodiversity and

Reasons for their decline in Britain

Here's me investigating the effects of grazing on hedgerows