Aquatic invasive alien species – top issues for their management. Outcomes from the IFI/EIFAAC conference “Freshwater Invasives – Networking for Strategy”

In November 2014, a new EU Regulation to address Invasive Alien Species (IAS) and protect biodiversity was published. This entered into force across the EU in January 2015. The aim of the Regulation is to ‘prevent the introduction of, control or eradicate alien species which threaten ecosystems, habitats or species’. In an effort to provide focus to the Regulation prior to its publishing and to identify the major issues relating to Invasive Alien Species in Europe, the views of invasive species experts from around the world were sought. These were consolidated at an international conference (Freshwater Invasives - Networking for Strategy (FINS)) that was held in Ireland in April 2013. A major outcome from this meeting of experts was the production of the Top 20 IAS issues that relate primarily to freshwater habitats but are also directly relevant to marine and terrestrial ecosystems. This list will support policy makers throughout the EU as preparations are made to implement this important piece of legislation. A further outcome from the conference was the formation of an expert IAS Advisory Group to support EIFAAC in its work on invasive species

Freshwater Reservoir Effects on the Re-Dating of the Eurasian Steppe Cultures: New Data for the Prehistoric Sites of Kazakhstan and South of Siberia

Freshwater reservoir effects (FRE) can cause a major problem with radiocarbon dating human skeletal material in the Eurasian steppe. Recent research has demonstrated that, for the Eneolithic to Early Bronze Age sites of North-Eastern Kazakhstan, the maximum fish-herbivore freshwater reservoir offset observed equals 301±47 14C yrs, as such indicating that 14C dates from aquatic and human samples from the area apparently need to be interpreted with caution as they are likely to be affected by the offset. The current paper presents the new data on the FRE of the Eneolithic to the Early Iron Age sites of Kazakhstan and South of Siberia.

Spatial and temporal variability of the freshwater reservoir effect (FRE) in lacustrine sediments in a cold climate zone, Northwest Territories (Canada)

Climate variability along the 600 km Tibbitt to Contwyoto Winter Road (TCWR) in central Northwest Territories is poorly understood. With the transportation of goods from Yellowknife to the mines projected to increase significantly as new mines open, it is critical that planners and mine developers have reasonable data on the future viability of the road, as alternative transportation costs (e.g. air transport) are prohibitively high.

The research presented here is part of a paleoclimate study based on the analysis of multiple proxy data derived from freeze cores in lakes along the TCWR.

A validated UPLC–MS/MS method for the surveillance of ten aquatic biotoxins in European brackish and freshwater systems

Over the past few decades, there has been an increased frequency and duration of cyanobacterial Harmful Algal Blooms (HABs) in freshwater systems globally. These can produce secondary metabolites called cyanotoxins, many of which are hepatotoxins, raising concerns about repeated exposure through ingestion of contaminated drinking water or food or through recreational activities such as bathing/ swimming. An ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) multi-toxin method has been developed and validated for freshwater cyanotoxins; microcystins-LR, -YR, -RR, -LA, -LY and -LF, nodularin, cylindrospermopsin, anatoxin-a and the marine diatom toxin domoic acid. Separation was achieved in around 9 min and dual SPE was incorporated providing detection limits of between 0.3 and 5.6 ng/L of original sample. Intra- and inter-day precision analysis showed relative
standard deviations (RSD) of 1.2–9.6% and 1.3–12.0% respectively. The method was applied to the analysis of aquatic samples (n = 206) from six European countries. The main class detected were the hepatotoxins; microcystin-YR (n = 22), cylindrospermopsin (n = 25), microcystin-RR (n = 17), microcystin-LR (n = 12), microcystin-LY (n = 1), microcystin-LF (n = 1) and nodularin (n = 5). For microcystins, the levels detected ranged from 0.001 to 1.51 mg/L, with two samples showing combined levels above the guideline set by the WHO of 1 mg/L for microcystin-LR. Several samples presented with multiple toxins indicating the potential for synergistic effects and possibly enhanced toxicity. This is the first published pan European survey of freshwater bodies for multiple biotoxins, including two identified for the first time; cylindrospermopsin in Ireland and nodularin in Germany, presenting further incentives for improved monitoring and development of strategies to mitigate human exposure.

Metagenomic characterisation of the viral community of lough neagh, the largest freshwater lake in Ireland

Lough Neagh is the largest and the most economically important lake in Ireland. It is also one of the most nutrient rich amongst the world's major lakes. In this study, 16S rRNA analysis of total metagenomic DNA from the water column of Lough Neagh has revealed a high proportion of Cyanobacteria and low levels of Actinobacteria, Acidobacteria, Chloroflexi, and Firmicutes. The planktonic virome of Lough Neagh has been sequenced and 2,298,791 2×300 bp Illumina reads analysed. Comparison with previously characterised lakes demonstrates that the Lough Neagh viral community has the highest level of sequence diversity. Only about 15% of reads had homologs in the RefSeq database and tailed bacteriophages (Caudovirales) were identified as a major grouping. Within the Caudovirales, the Podoviridae and Siphoviridae were the two most dominant families (34.3% and 32.8% of the reads with sequence homology to the RefSeq database), while ssDNA bacteriophages constituted less than 1% of the virome. Putative cyanophages were found to be abundant. 66,450 viral contigs were assembled with the largest one being 58,805 bp; its existence, and that of another 34,467 bp contig, in the water column was confirmed. Analysis of the contigs confirmed the high abundance of cyanophages in the water column.

Development of release methods for critically endangered freshwater pearl mussels (Margaritifera margaritifera)

Biodiversity loss is a global problem with freshwater bivalves considered amongst the most
endangered biota. The freshwater pearl mussel, Margaritifera margaritifera, is declining
throughout its range owing to habitat degradation and overexploitation. In most of its range,
populations are regarded as reproductively non-functional which has led to the development
of captive breeding programmes. A novel method of releasing M. margaritifera was trialled,
with captive-bred juveniles being released into the rivers caged in ‘mussels silos’ (protective
concrete domes with ventilation creating upwelling to ensure water through flow). We
released 240 juvenile mussels and survival and growth rates were monitored for 18 months
post-release for three size classes: A (13.01-20.00mm); B (10.01-13.00mm); and C (4.01-
10.00mm). We explicitly tested two experimental treatments; one where sediment was added
to each silo (allowing mussels to orientate and burrow) and one without sediment. Survival
by the end of the experiment at month 18 was significantly higher for the largest size class at
97% (though growth was lowest in this cohort), and lowest for the smallest size class at 61%
(though growth was highest in this cohort). Survival and growth were unaffected by the
experimental treatment suggesting that adding sediment offered no advantage. Growth was
positively correlated with both water temperature and the particle size of suspended solids
(both of which were collinear, peaking in summer). There are a large number of ex situ
breeding programmes for freshwater pearl mussels throughout Europe and our finding
suggest that the use of ‘mussel silos’ could be a useful tool to protecting juvenile mussels
allowing them to be released at a relatively early stage of development, minimising the risk of
domestication.

Assessing the Legacy of Red Mud Pollution in a Shallow Freshwater Lake: Arsenic Accumulation and Speciation in Macrophytes

Little is known about long-term ecological responses in lakes following red mud pollution. Among red mud contaminants, arsenic (As) is of considerable concern. Determination of the species of As accumulated in aquatic organisms provides important information about the biogeochemical cycling of the element and transfer through the aquatic food-web to higher organisms. We used coupled ion chromatography and inductively coupled plasma mass spectrometry (ICP-MS) to assess As speciation in tissues of five macrophyte taxa in Kinghorn Loch, UK, 30 years following the diversion of red mud pollution from the lake. Toxic inorganic As was the dominant species in the studied macrophytes, with As species concentrations varying with macrophyte taxon and tissue type. The highest As content measured in roots of Persicaria amphibia (L.) Gray (87.2 mg kg-1) greatly exceeded the 3 - 10 mg kg-1 range suggested as a potential phytotoxic level. Accumulation of toxic As species by plants suggested toxicological risk to higher organisms known to utilise macrophytes as a food source.