pollution Archives - EcoEvo@TCD

20/08/2015

Microplastics: a macro-problem for remote islands in the South Atlantic?

Dr Dannielle Green from the Biogeochemistry Research Group in Geography is about to return from an adventure in the South Atlantic where she was hunting for microplastics in some of the world’s most remote islands.

Plastic debris can be found in every country around the world and larger items like plastic bags and bottles can have obvious impacts, such as entanglement, ingestion and suffocation of seabirds, turtles and mammals. But even when plastic breaks down, it persists as small pieces called “microplastics” and in this form can still cause harm to a wide range of marine organisms who unwittingly eat it. Microplastics have been found in marine waters all over the globe but sampling has mostly focused on areas adjacent to large human populations, very little is known about concentrations in remote islands like Ascension Island and the Falkland islands. In collaboration with Dr David Blockley from the South Atlantic Environmental Research Institute (SAERI), Dr Dannielle Green from Trinity College Dublin, Ireland flew out to the South Atlantic to assess the situation.

Eerily desolate but beautiful Ascension island

Water samples were taken from a range of sites around Ascension Island and the Falklands and every site was found to contain microplastics. In fact, the concentrations found were surprisingly high.

Taking water samples in the only glass bottles available... Pimm's bottles! — Taking water samples in the only glass bottles available… Pimm’s bottles!

Dr Green presented her work to the Falkland islanders by giving a public lecture at the Chamber of Commerce which was well attended with a mixed audience including government officials, fishermen, the general public and the local television crew. She explained the potential issues of microplastic pollution and a thoughtful discussion about solutions later ensued with input from the audience.

Dannielle presenting her results at the Chamber of Commerce in Stanley.

Microplastics can absorb toxic substances from the water column. In this way, they can become like “pills” of concentrated toxic chemicals that could be consumed by creatures like worms, shellfish, fish and mammals and can be transferred through the food web.

Pollution of natural habitats by microplastics is a global problem that we are only just beginning to understand, but it is one that is expected to get worse as plastic production continues to rise. Dr Green’s research explores the wider effects of microplastics on marine ecosystems. Through this work, she hopes to provide scientifically sound recommendations that will feed into policy and help protect our ecosystems.

Author

Dannielle Green

Photo credits

https://www.indiegogo.com/projects/save-our-seas-from-the-microplastic-threat#/story and Dannielle Green

27/02/2015

Land – spare or share?

The debate on what is better for the environment and by extension many ecosystem services, high intensity conventional farming using large amounts of fertiliser and pesticides on mostly homogenous areas or low intensity possibly organic farming in a heterogeneous landscape seems to be a no-brainer. High intensity farms are pressing into natural habitats, pesticides are impacting pollinators and natural pest controls such as beetles or spiders (Hole et al., 2005, Biological Conservation) and the overuse of fertilisers are contaminating ground and surface water leading to eutrophication and even drinking water pollution.

However, on a larger scale this question seems to be more difficult to answer. The problem is that in theory, and most of the recent scientific literature supports the hypothesis that the product yield of organic farming is lower by 5 to 34 % (e.g. De Ponti et al., 2012, Agricultural Systems; Seifert et al., 2012, Nature). In return, to maintain the production levels, more land has to be devoted to agriculture, potentially destroying natural habitat. This leaves the following question: On a landscape scale, what is environmentally better, a large area of organic farming with a decent environmental footprint, or a mosaic of intensive farming and high quality natural habitat?

This debate is still ongoing and far from concluded. In their paper Grau et al. (2013, Current Opinion in Environmental Sustainability) showed that current research is still conflicting, especially since results vary quite a bit when looking at different taxa in different landscapes. On one side sparing supporters point out that in addition to the already mentioned higher land-availability, the higher yield will potentially reduce the per yield impact of farming (e.g. the greenhouse gas emissions per ton grain harvested).

On the other side supporters of sharing point out, that apart from the already mentioned effects of intensive farming on ecosystem services, there should at least be a bold question mark added to the statement that increasing yield will actually lead to land being made available for natural habitat. Land might become available for urban sprawl instead, especially in times of high property prices people might be drawn into a more rural/suburban setting, or the land may not leave agriculture at all but rather be used of agricultural expansion.

So what is the better solution? We don’t know yet. The most likely answer is neither. The best strategy will be dependent on factors on all spatial scales, from disturbance resistance of present taxa, to environmental conditions such as climate and soil type up to socio-economic issues such as land planning. Still the debate has been most beneficial to science. It has sparked multiple excellent large scale research projects that boosted the understanding of landscape scale impacts of farming on ecosystem services, and how regional-scale agricultural management can best benefit ecosystem services and by default ourselves.

Author

Jesko Zimmermann, zimmerjr[at]tcd.ie

Photo credit

wikimedia commons

19/12/201203/01/2013

Smoking nests

We all know that cigarettes and smoking are bad for you. However, a recent Biology Letters paper which was featured on BBC Nature suggests that the discarded remains of cigarette butts may help to maintain the health of some urban birds.

Researchers from the National Autonomous University of Mexico found that smoked cigarette butts incorporated into house sparrow and house finch nests may act as parasite repellents. Nests which included high numbers of cigarette butts had fewer parasites. A further experiment involving heat traps to attract parasites indicated that the anti-parasitic properties of the cigarettes seemed to be related to their nicotine content which is only released after the cigarettes have been smoked. This doesn’t necessarily mean that the birds use cigarette butts as an adaptive anti-parasite strategy. Cellulose in the butts is an effective thermal insulator so any anti-parasite effects may be a fortuitous coincidence. The authors suggest that future behavioural choice tests could be used to determine whether birds can distinguish and preferentially include smoked cigarette butts in their constructions.

The paper is an interesting contribution to the growing fields of urban ecological and wildlife research. More than half of the world’s population now lives in urban areas so it is increasingly important to understand the ecological effects of this changing environment. Wildlife and urban areas are not always a happy mix – we have all seen the squished remains of a hedgehog’s attempt to cross a busy road. However, as this paper shows, sometimes urban animals can adopt novel behaviours which appear to have positive consequences.

However, I can’t see the paper being used to counteract anti-cigarette butt litter campaigns any time soon!

Author

Sive Finlay: sfinlay[at]tcd.ie

Photo credit

wikimedia commons