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

Life history of turbot in Icelandic waters: Intra- and inter-population genetic diversity and otolith tracking of environmental temperatures

The stock structure of turbot was investigated between samples from S-Norway, the Irish Sea and the Kattegat, using 12 microsatellite loci and compared to the turbot caught in Icelandic waters. Highly significant genetic differentiation was observed between samples from Kattegat and other areas. Significant genetic differentiation was also observed between the Irish Sea sample on one hand and Iceland and S-Norway on the other hand. No significant genetic differentiation was observed between Iceland and S-Norway. Otoliths of 25 turbot, age ranging from 3 to 19 years, were subjected to nearly 300 mass spectrometry determinations of stable oxygen and carbon isotopes. Oxygen isotope composition (δ¹⁸O) in the otolith samples was used to estimate ambient temperature at time of otolith accretion, and yielded estimated temperatures experienced by the turbot ranging from 3 to 15°C. Overall, the genetic analysis indicates panmixia between turbot in Icelandic and Norwegian waters. While the extensive migration of larvae between Norway and Iceland is unlikely, passive drift of turbot larva from other areas (e.g. Ireland) cannot be ruled out. 

A biological survey method applied to seafloor massive sulphides (SMS) with contagiously distributed hydrothermal-vent fauna

Strategies for mitigation of seafloor massive sulphide (SMS) extraction in the deep sea include establishment of suitable reference sites that allow for studies of natural environmental variability and that can serve as sources of larvae for re-colonisation of extracted hydrothermal fields. In this study, we characterize deep-sea vent communities in Manus Basin (Bismarck Sea, Papua New Guinea) and use macrofaunal data sets from a proposed reference site (South Su) and a proposed mine site (Solwara 1) to test the hypothesis that there was no difference in macrofaunal community structure between the sites. We used dispersion weighting to adjust taxa-abundance matrices to down-weight the contribution of contagious distributions of numerically abundant taxa. Faunal assemblages of 3 habitat types defined by biogenic taxa (2 provannid snails, Alviniconcha spp. and Ifremeria nautilei; and a sessile barnacle, Eochionelasmus ohtai) were distinct from one another and from the vent peripheral assemblage, but were not differentiable from mound-to-mound within a site or between sites. Mussel and tubeworm populations at South Su but not at Solwara 1 enhance the taxonomic and habitat diversity of the proposed reference site. © Inter-Research 2012.

A primer for use of genetic tools in selecting and testing the suitability of set-aside sites protected from deep-sea seafloor massive sulfide mining activities

Seafloor massive sulfide (SMS) mining will likely occur at hydrothermal systems in the near future. Alongside their mineral wealth, SMS deposits also have considerable biological value. Active SMS deposits host endemic hydrothermal vent communities, whilst inactive deposits support communities of deep water corals and other suspension feeders. Mining activities are expected to remove all large organisms and suitable habitat in the immediate area, making vent endemic organisms particularly at risk from habitat loss and localised extinction. As part of environmental management strategies designed to mitigate the effects of mining, areas of seabed need to be protected to preserve biodiversity that is lost at the mine site and to preserve communities that support connectivity among populations of vent animals in the surrounding region. These "set-aside" areas need to be biologically similar to the mine site and be suitably connected, mostly by transport of larvae, to neighbouring sites to ensure exchange of genetic material among remaining populations. Establishing suitable set-asides can be a formidable task for environmental managers, however the application of genetic approaches can aid set-aside identification, suitability assessment and monitoring. There are many genetic tools available, including analysis of mitochondrial DNA (mtDNA) sequences (e.g. COI or other suitable mtDNA genes) and appropriate nuclear DNA markers (e.g. microsatellites, single nucleotide polymorphisms), environmental DNA (eDNA) techniques and microbial metagenomics. When used in concert with traditional biological survey techniques, these tools can help to identify species, assess the genetic connectivity among populations and assess the diversity of communities. How these techniques can be applied to set-aside decision making is discussed and recommendations are made for the genetic characteristics of set-aside sites. A checklist for environmental regulators forms a guide to aid decision making on the suitability of set-aside design and assessment using genetic tools. This non-technical primer document represents the views of participants in the VentBase 2014 workshop.

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.

Computerized key to the genus Bursaphelenchus Fuchs, analysis of species clusters based on morphology, using information of insect vectors and associated plants, with a revision of the genus.

The genus Bursaphelenchus includes B. xylophilus (Steiner et Buhrer, 1934) Nickle, 1981, which is of world economic and quarantine importance. Distinction among several species of the pinewood nematodes species complex (PWNSC) is often difficult. Besides standard morphology, morphometrics and molecular biology, new tools are welcome to better understand this group. The computerized (or e-) key of this genus, presented in this communication, includes 74 species (complete list of valid species of the world fauna) and 35 characters, that were used by the taxonomic experts of this group, in the original descriptions. Morphology of sex organs (male spicules and female vulval region) was digitized and classified to distinguish alternative types. Several qualitative characters with overlapping character states (expressions) were transformed into the morphometric indices with the discontinuous ranges (characters of ratios of the spicule dimensions). Characters and their states (expressions) were illustrated in detail and supplied by brief user-friendly comments. E-key was created in the BIKEY identification system (Dianov & Lobanov, 1996-2004). The system has built-algorithm ranging characters depending on their diagnostic values at each step of identification. Matrix of species and the character states (structural part of the e-key database) may be easily transformed using statistical packages into the dendrograms of general phenetic similarities (UPGMA, standard distance: mean character difference). It may be useful in the detailed analysis of taxonomy and evolution of the genus and in its splitting to the species groups based on morphology. The verification of the dendrogram using the information on the species links with insect vectors and their associated plants, provided an opportunity to recognize the five clusters (xylophilus, hunti, eremus sensu stricto, tusciae and piniperdae sensu stricto), which seem to be the natural species groups. The hypothesis about the origin and the first stages of the genus evolution is proposed. A general review of the genus Bursaphelenchus is presented.

The Pine Wood Nematode: a personal view

The first report of the disease (“pine wilt disease”) associated with the pinewood nematode, goes back to 1905, when Yano reported an unusual decline of pines from Nagasaki. For a long time thereafter, the cause of he disease was sought, but without success. Because of the large number of insect species that were usually seen around and on infected trees, it had always been assumed that the causal agent would prove to be one of these. However, in 1971, Kiyohara and Tokushike found a nematode of the genus Bursaphelenchus in infected trees. The nematode found was multiplied on fungal culture, inoculated into healthy trees and then re-isolated from the resulting wilted trees. The subsequent published reports were impressive: this Bursaphelenchus species could kill fully-grown trees within a few months in the warmer areas of Japan, and could destroy complete forests of susceptible pine species within a few years. Pinus densiflora, P. thunbergii und P. luchuensis were particularly affected. In 1972, Mamiya and Kiyohara described the new species of nematode extracted from the wood of diseased pines; it was a named Bursaphelenchus lignicolus. Since 1975, the species has spread to the north of Japan, with the exception of the most northerly prefectures. In 1977, the loss of wood in the west of the country reached 80%. Probably as a result of unusually high summer temperatures and reduced rainfall in the years 1978 and 1979, the losses were more than 2 million m3 per year. From the beginning, B. lignicolus was always considered by Japanese scientists to be an exotic pest. But where did it come from? That this nematode could also cause damage in the USA became clear in 1979 when B. lignicolus was isolated in great numbers from wood of a 39 year-old pine tree (Pinus nigra) in Missouri which had suddenly died after the colour of its needles changed to a reddish-brown colour (Dropkin und Foudin, 2 1979). In 1981, B. lignicolus was synonymised by Nickle et al. with B. xylophilus which had been found for the first time in the USA as far back as 1929, and reported by Steiner and Buhrer in 1934. It had originally been named Aphelenchoides xylophilus, the wood-inhabiting Aphelenchoides but was recognised by Nickle, in 1970,to belong in the genus Bursaphelenchus. Its common name in the USA was the "pine wood nematode" (PWN. After its detection in Missouri, it became known that B. xylophilus was widespread throughout the USA and Canada. It occurred there on native species of conifers where, as a rule, it did not show the symptoms of pine wilt disease unless susceptible species were stressed eg., by high temperature. This fact was an illuminating piece of evidence that North America could be the homeland of PWN. Dwinell (1993) later reported the presence of B. xylophilus in Mexico. The main vector of the PWN in Japan was shown to be the long-horned beetle Monochamus alternatus, belonging to the family Cerambycidae. This beetle lays its eggs in dead or dying trees where the developing larvae then feed in the cambium layer. It was already known in Japan in the 19th century but in the 1930s, it was said to be present in most areas of Japan, but was generally uncommon. However, with the spread of the pine wilt disease, and the resulting increase of weakened trees that could act as breeding sites for beetles, the populations of Monochamus spp. increased significantly In North America, other Monochamus species transmit PWN, and the main vector is M. carolinensis. In Japan, there are also other, less efficient vectors in the genus Monochamus. Possibly, all Monochamus species that breed in conifers can transmit the PWN. The occasional transmission by less efficient species of Monochamus or by some of the many other beetle genera in the bark or wood is of little significance. In Europe, M. galloprovincialis and M. sutor transmits the closely related species B. mucronatus. Some speculate that these two insect species are “standing by” and waiting for the arrival of B. xylophilus. In 1982, the nematode was detected and China. It was first found in dead pines near the Zhongshan Monument of Nanjing (CHENG et. al. 1983); 265 trees were then killed by pine wilt disease. Despite great efforts at eradication in China, the nematode spread further and pine wilt disease has been 3 reported from parts of the provinces of Jiangsu, Anhui, Guangdong, Shandong, Zhejiang and Hubei (YANG, 2003). In 1986, the spread of the PWN to Taiwan was discovered and in 1989, the nematode was reported to be present in the Republic of Korea where it had first been detected in Pinus thunbergii and P. densiflora. It was though to have been introduced with packing material from Japan. PWN was advancing. In 1984, B. xylophilus was found in wood chips imported into Finland from the USA and Canada, and this was the impetus to establish phytosanitary measures to prevent any possible spread into Europe. Finland prohibited the import of coniferous wood chips from these sources, and the other Nordic countries soon followed suit. EPPO (the European and Mediterranean Plant Protection Organization) made a recommendation to its member countries in 1986 to refuse wood imports from infested countries. With its Directive of 1989 (77/93 EEC), the European Community (later called the European Union or EU) recognised the potential danger of B. xylophilus for European forests and imposed restrictions on imports into the Europe. PWN was placed on the quarantine list of the EU and also of other European countries. Later, in 1991, a dispensation was allowed by the Commission of the EU(92/13 EEC) for coniferous wood from North America provided that certain specified requirements were fulfilled that would prevent introduction.

Bursaphelenchus pinophilus Brzeski & Baujard, 1997 (Nematoda: Parasitaphelenchinae) associated with nematangia on Pityogenes bidentatus (Herbst, 1783) (Coleoptera: Scolytinae), from the Czech Republic

The occurrence of Bursaphelenchus species in the Czech Republic is poorly known, the first report of the genus being made by Kubátová et al. (2000) who reported the association of B. eremus with the hyphomycetous microfungus, Esteya vermicola, and the bark beetle, Scolytus intricatus, collected from Quercus robur, in central Bohemia. To date, four other species have been reported from the country, namely B. fungivorus (Braasch et al., 2002), B. hofmanni (see Braasch, 2001), B. mucronatus (see Braasch, 2001) and B. vallesianus (Gaar et al., 2006). More recently, a survey for Bursaphelenchus species associated with bark- and wood-boring insects in the Czech Republic identified B. pinophilus Brzeski & Baujard, 1997 from the Moravia region. Although this represents a new country record, it was also associated with nematangia on the hind wings of a new insect vector. A total of 404 bark- and wood-boring insects were collected from declining or symptomatic trees and screened for the presence of Bursaphelenchus. Bark and longhorn beetles were captured manually after debarking parts of the trunk displaying symptoms of insect attacks. Longhorn beetle larvae were also collected together with logs cut from the trunk. Logs were kept at room temperature in the laboratory until insect emergence. Each adult insect was individually dissected in water and examined for nematodes. All nematodes resembling dauer juveniles of Bursaphelenchus were collected and identified by molecular characterisation using a region of ribosomal DNA (rDNA) containing the internal transcribed spacer regions ITS1 and ITS2. ITS-RFLP analyses using five restriction enzymes (AluI, HaeIII, HinfI, MspI, RsaI) were performed to generate the species-specific profile according to Burgermeister et al. (2009). Species identification was also confirmed by morphological data after culture of the dauers on Botrytis cinerea Pers. ex Ft., growing in 5% malt extract agar. During this survey, only species belonging to the Curculionidae, subfamily Scolytinae, revealed the presence of nematodes belonging to Bursaphelenchus. Dauers of this genus were found aggregated under the elytra in nematangia formed at the root of the hind wings (Fig. 1). The dauers were identified from 12 individuals of Pityogenes bidentatus (Herbst, 1783) (Coleoptera: Scolytinae) collected under the bark of Pinus sylvestris trunks. Each insect carried ca 10-100 dauers. The ITS-RFLP patterns of the dauers so obtained confirmed the identification of B. pinophilus associated with this insect species. Bursaphelenchus pinophilus has been found mainly in Europe and has been reported from various countries such as Poland (Brzeski & Baujard, 1997), Germany (Braasch, 2001), and Portugal (Penas et al., 2007). The recent detection of this species associated with dead P. koraiensis in Korea (Han et al., 2009) expands its geographical distribution and potential importance. It has been found associated only with Pinus species, but very little is known about the insect vector. The bark beetle, Hylurgus ligniperda, was initially suggested as the insect vector by Pe-nas et al. (2006), although the nematode associated with this insect was later reclassified as B. sexdentati by morphological and molecular analysis (Penas et al., 2007). According to the literature, P. bidentatus has been cited as a vector of Ektaphelenchus sp. (Kakuliya, 1966) in Georgia, and an unidentified nematode species in Spain (Roberston et al., 2008). Interestingly, B. pinophilus was found in the nematangia formed at the root of the hind wings of P. bidentatus. Although this phenomenon is not so common in other Bursaphelenchus species, B. rufipennis has been found recently in such a structure on the hind wings of the insect Dendroctonus rufipennis (Kanzaki et al., 2008). Although other nematode species (e.g., Ektaphelenchus spp.) are frequently found associated within the same nematangia (see Kanzaki et al., 2008), in this particular case, only dauers of B. pinophilus were identified. The association between B. pinophilus and P. bidentatus represents the first report of this biological association and the association with the Scolytinae strengthens the tight and specific links between this group of Bursaphelenchus species and members of the Scolytinae (Ryss et al., 2005).

Ecotoxicological tests using Chironomus riparius

Os sistemas aquáticos naturais podem estar sujeitos frequentemente a entrada de tóxicos, quer seja através da lixiviação dos campos agrícolas ou da descarga por parte de unidades industriais. Avaliar o impacto potencial destes contaminantes nos sistemas aquáticos é muito importante, porque pode promover consequências sérias no balanço ecológico dos ecossistemas. Os efeitos de níveis sub-letais destes tóxicos nas populações aquáticas são detectados, em muitos casos, somente após diversas gerações, dependendo da espécie e do contaminante. O comportamento animal é considerado como sendo a primeira linha de defesa perante estímulos ambientais, e pode ser uma representação de alterações fisiológicas no organismo, sendo portanto um indicador excelente de alterações ambientais. O desenvolvimento dos sistemas de aviso prévio que integram parâmetros comportamentais pode ajudar a prever mais rapidamente possíveis alterações ao nível das populações naturais, do que a utilização de testes ecotoxicológicos padrão com a mesma finalidade. O conhecimento acerca de possíveis implicações devido a alterações comportamentais, em organismos bentónicos e em populações do campo sujeitas a tóxicos, é ainda escasso. Sabendo isto, neste estudo pretendeu-se investigar como o comportamento de Chironomus riparius – usando um biomonitor em tempo real – e outros parâmetros tais como crescimento, emergência de adultos, bioacumulação e biomarcadores, são afectados pela exposição a imidacloprid e ao mercúrio, que foram seleccionados como contaminantes. Os resultados demonstraram que a exposição às concentrações sub-letais de imidacloprid afecta o crescimento e o comportamento dos quironomídeos e que estes organismos podem recuperar de uma exposição curta ao insecticida. O comportamento que corresponde à ventilação de C. riparius revelou-se como um parâmetro mais sensível do que a locomoção e do que as respostas bioquímicas, quando as larvas foram sujeitas ao imidacloprid. Larvas de C. riparius expostas a concentrações sub-letais de mercúrio apresentaram uma tendência de diminuição de actividade comportamental, em testes com concentrações crescentes do tóxico; o crescimento das larvas foi também prejudicado, e as taxas de emergência de adultos e o tempo de desenvolvimento apresentaram retardamento. Estes organismos podem bioacumular rapidamente o mercúrio em condições de não alimentação e apresentam uma lenta depuração deste metal. Estes efeitos podem, em último caso, conduzir a prováveis repercussões ao nível da população e das comunidades. As reduções em actividades comportamentais, mesmo em concentrações baixas, podem diminuir a quantidade de tempo gasta na procura de alimento, produzindo efeitos aos níveis morfo-fisiológicos, e assim afectar severamente o desempenho dos quironomídeos no ambiente. O uso destes factores comportamentais como um parâmetro ecotoxicológico sub-letal relevante ao nível da toxicologia aumentará a versatilidade dos testes, permitindo uma resposta comportamental mensurável e quantitativa ao nível do organismo, utilizando uma avaliação não destrutiva, e assim certificando que esta aproximação pode ser usada em testes ecotoxicológicos futuros.

Toxicity assessment of essential metals in aquatic detritivores

Os contaminantes provenientes quer de fontes naturais quer como consequência da atividade humana, têm contribuído para a degradação dos ecossistemas aquáticos. Entre estes encontram-se os metais que podem, ou não ser essenciais mediante o papel que desempenham no metabolismo dos organismos. O cobre e o zinco são exemplos de metais essenciais, contudo quando atingem concentrações elevadas podem tornar-se tóxicos. Os detritívoros aquáticos desempenham um papel fundamental na decomposição da matéria orgânica, alimentando-se de carcaças e partes de plantas que caem nos cursos de água. Assim, estes organismos permitem que o ciclo dos nutrientes se complete e servem como elo de ligação entre todos os grupos funcionais do ecossistema mantendo o seu equilíbrio estrutural e funcional. Sendo a matéria orgânica a sua principal fonte de energia estão sujeitos à contaminação existente no meio, pelo que é de todo o interesse proceder-se à avaliação dos efeitos da toxicidade de metais nestes organismos. Uma vez que as diferenças comportamentais consequentes desta exposição podem originar variações na densidade e diversidade, o que se refletirá a nível das comunidades, originando alterações na estrutura e funcionamento do ecossistema. Tendo em vista a avaliação dos efeitos da contaminação por metais em detritívoros, o principal objetivo deste trabalho foi comparar a sensibilidade a metais essenciais de dois detritivoros aquáticos, o camarão Atyaephyra desmarestii e o anfípode Echinogammarus meridionalis. Para tal, avaliaram-se os efeitos do cobre e do zinco a diferentes níveis de organização biológica. Primeiro, foram determinadas as preferências alimentares de A. desmarestii e E. meridionalis considerando tanto a área das folhas como a contaminação por metais das folhas. Em seguida, avaliaram-se os efeitos do cobre e do zinco na sobrevivência e inibição alimentar de ambas as espécies. Finalmente, avaliaram-se os efeitos destes mesmos metais a nível bioquímico utilizando uma bateria de biomarcadores que incluiu enzimas de stresse oxidativo, o sistema de defesa antioxidante e as colinesterases. Ambos os organismos não mostraram preferência em relação a folhas de área diferente. A presença de uma maior ou menor concentração de metais essenciais no alimento não teve qualquer influência na sua escolha pelo alimento (contaminado ou não). Os ensaios agudos de cobre e zinco mostraram que o cobre é mais tóxico para ambas as espécies do que o zinco. O camarão demonstrou ser mais sensível ao zinco que o anfípode, tendo este sido mais sensível ao cobre ( CL50 do cobre para A. desmarestii foi de 0,128 mg.l-1 e o de E. meridionalis foi de 0,050 mg.l-1; os valores correspondentes para o zinco foram 7,951 e 11,860 mg.l-1, respectivamente. Em relação aos efeitos subletais, o cobre teve efeitos notórios na taxa de alimentação de E. meridionalis, mas não afectou a de A. desmarestii. No que diz respeito à exposição ao zinco, ambas as espécies parecem apresentar tendência para inibir a alimentação. A caracterização das colinesterases revelou que a principal forma presente em ambas as espécies é a acetilcolinesterase, a qual que não foi afetada pela presença dos metais, no caso do camarão, mas parece ser inibida pelo zinco no caso do anfípode. O cobre inibiu o sistema de defesa enzimático de ambas as espécies, sem sinais de danos lipídicos. Para além disto, inibiu uma das enzimas antioxidantes (GPx) do anfípode. Apesar de não ter ocorrido dano lipídico após exposição ao cobre, observou-se um ligeiro aumento dos níveis das LPO, o que pode ser indicativo de uma potencial existência de dano oxidativo, como resultado da falha do sistema de defesa antioxidante. Por outro lado, o zinco induziu o sistema de defesa em E. meriodionalis prevenindo o dano lipídico. Enquanto em A. desmarestii o sistema enzimático antioxidante não respondeu, tendo ocorrido dano celular oxidativo considerando-se, assim, que o sistema de defesa antioxidante do camarão pode ser comprometido por exposição a metais. Ainda que os danos celulares oxidativos tivessem ocorrido a baixas concentrações de zinco. A exposição a este metal também induziu a actividade da GST de E. meriodionalis. Considerando que a taxa de alimentação foi severamente reduzida no caso deste organismo, o zinco parece ser o metal cuja concentração no ecossistema requer maior atenção. Integrando as respostas dos biomarcadores parece também evidente que A. desmarestii responde de uma maneira geral a maiores concentrações dos dois metais, enquanto a resposta de E. meridionalis ocorre a concentrações inferiores. Pelo que, E. meridionalis parece ser mais sensível ao nível bioquímico. Neste trabalho, os dois detritívoros, com ligeiras diferenças no modo como utilizam a matéria orgânica disponível, apresentam diferenças na sensibilidade aos metais essenciais a vários níveis de organização biológica, sendo o zinco o metal que poderá causar maior preocupação a nível bioquímico, enquanto o cobre parece ser o mais tóxico ao nível do organismo, causando mortalidade a concentrações mais baixas.

Silver nanoparticles flow in an aquatic trophic chain

Silver nanoparticles (AgNP) have been produced and applied in a variety of products ranging from personal care products to food package containers, clothing and medicine utilities. The antimicrobial function of AgNP makes it very useful to be applied for such purposes. Silver (Ag) is a non-essential metal for organisms, and it has been historically present in the environment at low concentrations. Those concentrations of silver increased in the last century due to the use of Ag in the photographic industry and lately are expected to increase due to the use of AgNPs in consumer products. The presence of AgNP in the aquatic environment may pose a risk for aquatic species, and the effects can vary from lethal to sublethal effects. Moreover, the contact of aquatic organisms with AgNP may not cause immediately the death of individuals but it can be accumulated inside the animals and consequently transferred within the food chain. Considering this, the objective of this work was to study the transfer of silver nanoparticles in comparison to silver ions, which was used as silver nitrate, within an aquatic food chain model. To achieve this goal, this study was divided into four steps: the toxicity assessment of AgNP and AgNO3 to aquatic test-species, the bioaccumulation assessment of AgNP and AgNO3 by Pseudokirchneriella subcapitata and Daphnia magna under different exposure scenarios, and finally the evaluation of the trophic transfer of Ag through an experimental design that included the goldfish Carassius auratus in a model trophic chain in which all the species were exposed to the worse-case scenario. We observed that the bioconcentration of Ag by P. subcapitata is mainly driven by ionic silver, and that algae cannot internalize these AgNPs, but it does internalizes dissolved Ag. Daphnia magna was exposed to AgNP and AgNO3 through different exposure routes: water, food and both water and food. The worse-case scenario for Daphnia Ag bioaccumulation was by the joint exposure of contaminated water and food, showing that Ag body burdens were higher for AgNPs than for AgNO3. Finally, by exposing C. auratus for 10 days through contaminated water and food (supplied as D. magna), with another 7 days of depuration phase, it was concluded that the 10 days of exposure were not enough for fish to reach a plateau on Ag internal concentration, and neither the 7 days of elimination were sufficient to cause total depuration of the accumulated Ag. Moreover, a higher concentration of Ag was found in the intestine of fish when compared with other organs, and the elimination rate constant of AgNP in the intestine was very low. Although a potential for trophic transfer of AgNP cannot be suggested based in the data acquired in this study, there is still a potential environmental risk for aquatic species.

Assessing the effectiveness of chemical treatment with nanomaterials in improving the quality of different industrial effluents

Industrial activities are the major sources of pollution in all environments. Depending on the type of industry, various levels of organic and inorganic pollutants are being continuously discharged into the environment. Although, several kinds of physical, chemical, biological or the combination of methods have been proposed and applied to minimize the impact of industrial effluents, few have proved to be totally effective in terms of removal rates of several contaminants, toxicity reduction or amelioration of physical and chemical properties. Hence, it is imperative to develop new and innovative methodologies for industrial wastewater treatment. In this context nanotechnology arises announcing the offer of new possibilities for the treatment of wastewaters mainly based on the enhanced physical and chemical proprieties of nanomaterials (NMs), which can remarkably increase their adsorption and oxidation potential. Although applications of NMs may bring benefits, their widespread use will also contribute for their introduction into the environment and concerns have been raised about the intentional use of these materials. Further, the same properties that make NMs so appealing can also be responsible for producing ecotoxicological effects. In a first stage, with the objective of selecting NMs for the treatment of organic and inorganic effluents we first assessed the potential toxicity of nanoparticles of nickel oxide (NiO) with two different sizes (100 and 10-20 nm), titanium dioxide (TiO2, < 25 nm) and iron oxide (Fe2O3, ≈ 85x425 nm). The ecotoxicological assessment was performed with a battery of assays using aquatic organisms from different trophic levels. Since TiO2 and Fe2O3 were the NMs that presented lower risks to the aquatic systems, they were selected for the second stage of this work. Thus, the two NMs pre-selected were tested for the treatment of olive mill wastewater (OMW). They were used as catalyst in photodegradation systems (TiO2/UV, Fe2O3/UV, TiO2/H2O2/UV and Fe2O3/H2O2/UV). The treatments with TiO2 or Fe2O3 combined with H2O2 were the most efficient in ameliorating some chemical properties of the effluent. Regarding the toxicity to V. fischeri the highest reduction was recorded for the H2O2/UV system, without NMs. Afterwards a sequential treatment using photocatalytic oxidation with NMs and degradation with white-rot fungi was applied to OMW. This new approach increased the reduction of chemical oxygen demand, phenolic content and ecotoxicity to V. fischeri. However, no reduction in color and aromatic compounds was achieved after 21 days of biological treatment. The photodegradation systems were also applied to treat the kraft pulp mill and mining effluents. For the organic effluent the combination NMs and H2O2 had the best performances in reduction the chemical parameters as well in terms of toxicity reduction. However, for the mine effluent the best (TiO2/UV and Fe2O3/UV) were only able to significantly remove three metals (Zn, Al and Cd). Nonetheless the treatments were able of reducing the toxicity of the effluent. As a final stage, the toxicity of solid wastes formed during wastewater treatment with NMs was assessed with Chironomus riparius larvae, a representative species of the sediment compartment. Certain solid wastes showed the potential to negatively affect C. riparius survival and growth, depending on the type of effluent treated. This work also brings new insights to the use of NMs for the treatment of industrial wastewaters. Although some potential applications have been announced, many evaluations have to be performed before the upscaling of the chemical treatments with NMs.

Amino acid requirements of white seabream (Diplodus sargus) larvae: effects on growth and performance

Tese dout., Aquacultura, Universidade do Algarve, 2008

Ecology of the early life-history stages of shad Alosa fallax fallax (Lacépède, 1803) in the River Mira, with a note on Alosa spp. larvae in the River Guadiana

Tese dout., Ecologia, Universidade do Algarve, 2006

Ontogeny of behavioural abilities in temperate reef fish larvae

Tese de dout., Ciências do Mar, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010