Ceramium Roth (Ceramiales, Rhodophyta) from Venice lagoon (Adriatic Sea, Italy): Comparative studies of Mediterranean and Atlantic taxa

The cosmopolitan genus Ceramium (Ceramiaceae, Rhodophyta) is a large and systematically complex group. The taxonomy of this genus remains in a chaotic state due to the high degree of morphological variation. Culture studies, suggesting a strong influence of environment on phenotype, and the use of molecular tools have recently questioned the validity of morphological features used in species recognition. Here we compare three Ceramium taxa from Venice lagoon with samples from northwest Europe using the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) and the rbcL-rbcS intergenic spacer combined with morphological observations. A strongly banded species, previously identified as member of a poorly understood and misnamed group, the Ceramium diaphanum complex sensu Feldmann-Mazoyer, is probably conspecific with British samples of Ceramium diaphanum sensu Harvey, for which no valid name has been identified up to now. We show that Ceramium polyceras (Kutzing) Zanardini is a valid name for this species. A fully corticated Ceramium species morphologically resembling C. secundatum differs at the species level from Atlantic C. secundatum; a valid name for this entity is Ceramium derbesii Solier ex Kutzing, described from Mediterranean France. A third species characterized by cortical spines, previously listed as Ceramium ciliation var. robustum (J. Agardh) Mazoyer, is shown to be Ceramium nudiusculum (Kutzing) Rabenhorst, originally described from Venice.

Hydrochemical and isotopic tracing of mixing dynamics and water quality evolution under pumping conditions in the mine shaft of the abandoned Frances Colliery, Scotland.

Since 1995, when pumps were withdrawn from deep mines in East Fife (Scotland), mine waters have been rebounding throughout the coalfield. Recently, it has become necessary to pump and treat these waters to prevent their uncontrolled emergence at the surface. However, even relatively shallow pumping to surface treatment lagoons of the initially chemically-stratified mine water from a shaft in the coastal Frances Colliery during two dynamic step-drawdown tests to establish the hydraulic characteristics of the system resulted in rapid breakdown of the stratification within 24 h and a poor pumped water quality with high dissolved Fe loading. Further, data are presented here of hydrochemical and isotopic sampling of the extended pump testing lasting up to several weeks. The use in particular of the environmental isotopes d18O, d2H, d34S, 3H, 13C and 14C alongside hydrochemical and hydraulic pump test data allowed characterisation of the Frances system dynamics, mixing patterns and water quality sources feeding into this mineshaft under continuously pumped conditions. The pumped water quality reflects three significant components of mixing: shallow freshwater, seawater, and leakage from the surface treatment lagoons. In spite of the early impact of recirculating lagoon waters on the hydrochemistries, the highest Fe loadings in the longer-term pumped waters are identified with a mixed freshwater–seawater component affected by pyrite oxidation/melanterite dissolution in the subsurface system.

High density mangrove plantation enhances surface accretion, surface elevation change, and tree survival in coastal areas susceptible to sea-level rise

Survival, growth, above ground biomass accumulation, soil surface elevation dynamics and nitrogen accumulation in accreted sediments were studied in experimental treatments planted with four different densities (6.96, 3.26, 1.93 and 0.95 seedlings m-2) of the mangrove Rhizophora mucronata in Puttalam Lagoon, Sri Lanka. Measurements were taken over a period of 1171 days and were compared with those from unplanted controls. Trees at the lowest density showed significantly reduced survival, whilst measures of individual tree growth did not differ significantly among treatments. Rates of surface sediment accretion (means ± S.E.) were 13.0 (±1.3), 10.5 (±0.9), 8.4 (±0.3), 6.9 (±0.5) and 5.7 (±0.3) mm yr-1 at planting densities of 6.96, 3.26, 1.93, 0.95, and 0 (unplanted control) seedlings m-2, respectively, showing highly significant differences among treatments. Mean (± S.E.) rates of surface elevation change were much lower than rates of accretion at 2.8 (±0.2), 1.6 (±0.1), 1.1 (±0.2), 0.6 (±0.2) and -0.3 (±0.1) mm yr-1 for 6.96, 3.26, 1.93, 0.95, and 0 seedlings m-2, respectively. All planted treatments appeared to accumulate greater nitrogen concentrations in the sediment compared to the unplanted control, and suggests one potential causal mechanism for the facilitatory effects observed; high densities of plants potentially contribute to the accretion of greater amounts of nutrient rich sediment. While this potential process needs further study, this study demonstrated how higher densities of mangroves enhance rates of sediment accretion and surface elevation, processes that may be crucial in mangrove ecosystem adaptation to sea level rise. There was no evidence that increasing plant density evoked a trade-off with growth and survival of the planted trees. Rather facilitatory effects enhanced survival at high densities, suggesting that local land managers may be able to take advantage of plantation densities to help mitigate sea-level rise effects by encouraging positive soil surface elevation increment, and perhaps even greater nutrient retention to promote mangrove growth and ameliorate nearshore eutrophication in tropical island environments.

Four new exotic red seaweeds on European shores

We report the occurrence of four red macroalgae new to Europe. Two species were unambiguously determined to the species level with a DNA barcoding approach, while the remaining two species could only be assigned to a genus. Gelidium vagum was found in the Oosterschelde estuary (the Netherlands). Gracilariopsis chorda, Chondracanthus sp. and Solieria sp. were found in the Gulf of Morbihan in Brittany (France); Solieria sp. was also subsequently observed in the Thau Lagoon (France). Gelidium vagum and Gracilariopsis chorda are species originating from the north-western Pacific, around the Japanese archipelago. Phylogenetic analyses also show a likely Pacific origin for Chondracanthus sp. and Solieria sp. Three of these species are likely to have been introduced after 2008, indicating some active transport pathways between the Pacific and the north-eastern Atlantic. These findings also underline the importance of consistent and continuous local expertise (versus rapid assessment) in early warning systems.

After the Aznalcóllar mine spill:arsenic, zinc, selenium, lead and copper levels in the livers and bones of five waterfowl species

In April 1998, a holding lagoon containing pyrite ore processing waste, failed and released 5-6 million m3 of highly polluting sludge and acidic water. Over 2650 ha of the internationally important Doñana Natural Park became contaminated, along with <100 ha of the more pristine Doñana National Park. In order to assess the affect of the spill on waterfowl from Doñana, bone and liver samples from 124 individuals have been analysed for As, Pb, Cu, Zn and Se. Five species have been studied, from the Rallidae (rails), Anatini (dabbling ducks) and Aythyini (pochards) families. Geometric mean bone concentrations 2-3 months after the spill were in the order of Zn > Cu > Pb > Se > As, while liver concentrations were in the order of Zn > Cu > Se > Pb > As. Dry weight bone concentrations ranged from n.d-1.76 mg kg(-1) As, 109.4-247.6 mg kg(-1) Zn, 0.06-1.27 mg kg(-1) Se, n.d-134.11 mg kg(-1) Pb, and 2.18-8.92 mg kg(-1) Cu. Wet weight liver concentrations ranged from n.d-0.34 mg kg(-1) As, 29.8-220.1 mg kg(-1) Zn, 0.15-0.85 mg kg(-1) Se, n.d-3.80 mg kg(-1) Pb, and 7.30-742.96 mg kg(-1) Cu. The most important factor related to the accumulation of these metals was commonly species; however, location and sex also had important effects on liver As levels, location and age affected Cu levels, while Zn and Pb were affected by age, sex and location. Birds from Natural Park areas were found to have significantly higher levels of bone Zn, Pb and Cu, and liver As and Cu than birds from National Park areas. Female birds had higher liver As, Zn and Pb than males; whilst adults appeared to have lower bone As and Zn but higher liver Pb than chicks/juveniles. Although metal concentrations were elevated in certain individuals, in the majority of birds studied, they did not reach levels widely considered to be toxic. However, it would appear that As and Cu liver levels (which may be indicative of short-medium term pollutant exposure) were elevated in waterbirds which died in the spill contaminated Natural Park, 2-3 months after the disaster.

Arsenic levels in the soils and macrophytes of the 'Entremuros' after the Aznalcóllar mine spill

In April 1998, a holding lagoon containing pyrite ore processing waste rich in arsenic, failed and released 5-6 million m(3) of highly polluting sludge and acidic water. Over 2700 ha of the internationally important Doñana National and Natural Parks were contaminated. The area of Natural Park to sustain the greatest impact was known as the Entremuros. This paper presents 0-5 cm soil monitoring data from the Entremuros, from sampling campaigns 6 and 18 months after the disaster; as well as macrophyte root, rhizome and stem data from samples taken 18 months after the spill. Results show a clear, decreasing, north-south arsenic soil pollution trend, both 6 and 18 months after the spill, and suggest a small reduction in total soil arsenic levels occurred over time; although a significant increase in extractable arsenic is also noted. The two macrophytes (Typha dominguensis and Scirpus maritimus) studied herein are not accumulating arsenic in stem parts, however, accumulation of arsenic on iron plaque on the roots of these plants may be occurring. Further work is recommended in order to determine the ecotoxicological significance of this process in relation to the avian food-chains of Doñana, and elsewhere.

The distribution of arsenic in soils affected by the Aznalcóllar mine spill, SW Spain

In April 1998, a holding lagoon containing pyrite ore processing waste, failed and released an estimated 5-6 million m(3) of metal rich sludge and acidic waters into the Rio Guadiamar, SW Spain. Over 2700 ha of the internationally important Doñana National and Natural Parks were contaminated. The sludge component of the waste contained up to 0.6% arsenic. This paper presents an extensive set of 0-5 cm soil analyses results from samples taken 6-8 months after the spill. Data are presented on pseudo-total arsenic levels in these samples, and on arsenic removed by both single batch and sequential extraction techniques. Pseudo-total levels of arsenic in the sludge ranged from 1521 to 3510 mg kg(-1), and a mean 4.4% of this was found to be extractable using 2.5% acetic acid. Soils in the Guadiamar Valley and Entremuros areas (those worst affected by the spill) were found to contain 85.4-782 mg kg(-1) and 7.1-196 mg kg(-1) pseudo-total arsenic, respectively. The mean acetic acid extractable component in these areas was 2.5% and 4.9%, respectively. Background pseudo-total arsenic levels in the soils of the area have been found to be 4.2-13.6 mg kg(-1). Rapid input of acidic waters, and the acidic nature of the sludge itself, may have caused depletion of Mg, Na and K, and to a lesser extent Mn, Ca and PO(4) in the upper 5 cm of the worst affected soils. Sequential extraction results suggest clear As-Fe associations, and possible As-Mn associations within the more soluble phases.