Using valve gape analysis to compare sensitivity of native Mytilus edulis to invasive Magallana gigas when exposed to heavy metal contamination.

Coastal ecosystems are ecologically and economically important but are under increasing pressure from numerous anthropogenic sources of stress. Both heavy metal pollution and invasive species pose major environmental concerns that can have significant impacts on marine organisms. It is likely that many stresses will occur simultaneously, resulting in potential cumulative ecological effects. The aim of this study was to compare the relative resilience of an invasive oyster Magallana gigas and a native mussel Mytilus edulis to heavy metal pollution, utilising their valve gape response as an indicator. The gape activity of bivalves has been utilised to monitor a range of potential impacts, including for example oil spills, increased turbidity, eutrophication, heavy metal contamination etc. In this study, Hall effect sensors were used on both the native blue mussel (M. edulis) and the pacific oyster (M. gigas), invasive to Ireland. Mussels were shown to be more responsive to pollution events than oysters, where all heavy metals tested (copper, cadmium, zinc, lead) had an effect on transition frequency though significant differences were only observed for lead and cadmium (Control; > Copper, p = 0.0003; >lead, p = 0.0002; >Cadmium, p = 0.0001). Cadmium had an apparent effect on mussels with specimens from this treatment remaining closed for an average of 45.3% of the time. Similarly, significant effects on the duration of time mussels spent fully open was observed when treated with lead and cadmium (Control; > lead, p = 0.03, > cadmium, p = 0.02). In contrast, oysters displayed no significant difference for any treatment for number of gapes, or duration spent open or closed. Though there was an effect of both zinc and copper on the amount of time spent closed, with averages of 63.2 and 68.7% respectively. This indicates oysters may be potentially more resilient to such pollution events; further boosting their competitive advantage. Future mesocosm or field studies are required to quantify this relative resilience.

Ammonia emissions from agriculture and their contribution to fine particulate matter: A review of implications for human health.

Atmospheric ammonia (NH3) released from agriculture is contributing significantly to acidification and atmospheric NH3 may have on human health is much less readily available. The potential direct impact of NH3 on the health of the general public is under-represented in scientific literature, though there have been several studies which indicate that NH3 has a direct effect on the respiratory health of those who handle livestock. These health impacts can include a reduced lung function, irritation to the throat and eyes, and increased coughing and phlegm expulsion. More recent studies have indicated that agricultural NH3 may directly influence the early on-set of asthma in young children. In addition to the potential direct impact of ammonia, it is also a substantial contributor to the fine particulate matter (PM2.5) fraction (namely the US and Europe); where it accounts for the formation of 30% and 50% of all PM2.5 respectively. PM2.5 has the ability to penetrate deep into the lungs and cause long term illnesses such as Chronic Obstructive Pulmonary Disease (COPD) and lung cancer. Hence, PM2.5 causes economic losses which equate to billions of dollars (US) to the global economy annually. Both premature deaths associated with the health impacts from PM2.5 and economic losses could be mitigated with a reduction in NH3 emissions resulting from agriculture. As agriculture contributes to more than 81% of all global NH3 emissions, it is imperative that food production does not come at a cost to the world's ability to breathe; where reductions in NH3 emissions can be easier to achieve than other associated pollutants.

Mapping ammonia risk on sensitive habitats in Ireland.

The aim of this study was to provide a simple, cost-effective, risk-based map of terrestrial areas in Ireland where environmental quality may be at risk from atmospheric ammonia. This risk-based approach identifies Natura 2000 sites in Ireland at risk from agricultural atmospheric ammonia, collating best available data using Geographical Information Systems (GIS). In mapping ammonia risk on sensitive habitats (MARSH), the method identifies sources of ammonia, classifying them on a scale of risk from 0 to 5. These sources are subsequently summed based on a weighting determined by their contribution to national emissions divided by their potentially impacted area. A Pearson's correlation coefficient of 0.72 allows for concentrations from United Kingdom's FRAME modelling to be applied to the MARSH model, which are corrected based on recent monitoring. Applying Designation Weighted Indicators (DWI), the MARSH model predicts that 80.7, 34.3 and 5.9% of Natura 2000 sites in Ireland may exceed ambient concentrations of 1, 2, and 3 µg/m3, respectively. A Nitroindex map of Ireland based on available lichen records was also developed and is presented as part of this study. This Nitroindex was used to identify areas where impacts have already been recorded, thus informing the classification of sites "at-risk". The combination of both the MARSH and Nitroindex models ascertains which Natura 2000 sites are most at risk, thereby providing valuable data to relevant authorities. The MARSH model acts as a first step towards screening and assessing Natura 2000 sites most at risk from atmospheric ammonia, providing a tool to demonstrate compliance with the National Emissions Ceilings Directive.