Assessing fish quality status in transitional waters,within the European Water Framework Directive: Setting boundary classes and responding to anthropogenic pressures

Validation of the AZTI's Fish Index (AFI), proposed for the Basque Country (northern Spain), in assessing fish quality within the Water Framework Directive (WFD), is undertaken. The response to anthropogenic pressure is investigated, in setting the boundaries between the different quality status classes. Hence, 12 estuaries were sampled, at different frequencies, between 1989 and 2007, by means of a beam trawl. Significant (p < 0.0001) correlations were found between the AFI and oxygen saturation and ammonia. Oxygen quality standards are used to set boundaries between quality classes. Then, the AFIs obtained are compared with different anthropogenic pressures, including urban and industrial discharges, engineering works and dredging. The effects of the removal of some of these pressures are also studied. The total number of pressures within an estuary shows significant (p < 0.009) negative correlation with AFI, explaining between 51 and 62% of the variability in fish quality. The impact of pressures upon fish and demersal assemblages is detected as required by the WFD. Nonetheless, further investigation and intercalibration of the methods used, are necessary.     

Structure, ordering and cation interactions in Ca-free P2 1 /c clinopyroxenes

A suite of 14 synthetic Ca-free P2 ₁ /c low-clinopyroxenes of compositions across the enstatite-ferrosilite (En-Fs) join have been studied by X-ray powder diffraction and Mössbauer spectroscopy. The crystal structure of one sample with composition X _Fs=0.39 was determined by single-crystal X-ray diffraction. The powder diffraction data show that there is no significant (<0.25% at X _Fs=0.5) excess volume of mixing on the enstatite-ferrosilite join. The molar volumes are described by V=31.261(17)+1.677(23) X _Fs cm³.mol(MSiO₃)^–1. The linear behaviour of volume with composition arises from the compensating effects of non-linear changes in the unit-cell parameters with composition. Unweighted fits to the data yielded the relationships: a=9.6100(15)+0.105(2)X _Fs, b=8.8156(28)+0.218(12)X _Fs+0.0481(117)X ² _Fs , c?=5.1702(4)+0.0879(21)X _Fs–0.0214(21)X ² _Fs , β=108.345(8)+0.947(30)X _Fs–0.805(26)X ² _Fs . The strong positive deviation of β from linearity is directly correlated to the difference in site occupancies between M1 and M2 as determined by Mössbauer spectroscopy and arises directly from the expansion of M2-O1 and M2-O3 bonds upon initial substitution of Fe for Mg in enstatite. The hyperfine parameters from Mössbauer spectra are consistent with variations in the average local environment as recorded by the X-ray data. Asymmetric line broadening of the Mössbauer spectra provides evidence for next-nearest neighbour effects, and is consistent with no significant clustering of Fe or Mg within the samples.     

Constraining Holocene sea levels using U‐Th ages of phreatic overgrowths on speleothems from coastal caves in Mallorca (Western Mediterranean)

Phreatic overgrowths on speleothems (POS) are carbonate formations deposited at the water table of caves in unique karstic coastal settings having morphologies that can be directly related to sea level at the time of formation. The U‐Th ages of calcite and aragonite overgrowths collected from the modern water table in coastal caves on Mallorca (Cova de Cala Varques A and Cova des Pas de Vallgornera) were determined using high‐precision MC‐ICPMS techniques. U‐Th ages indicate that phreatic carbonate deposition occurred between ca 2·8 and at least 0·6 ka BP and are in accord with an archeologically estimated age of 3·7–3·0 ka BP for a drowned prehistoric construction at a depth of 1 m below current sea level in a cave from the same area. Speleothem δ¹³C and δ¹⁸O and chemical composition of cave pools provide supportive evidence that POS reflect mixing between seawater and brackish water table. Copyright © 2010 John Wiley & Sons, Ltd.     

Assessing the benthic quality status of the Bohai Bay (China) with proposed modifications of M-AMBI

Multivariate AZTI's Marine Biotic Index (M-AMBI) was designed to indicate the ecological status of European coastal areas. Based upon samples collected from 2009 to 2012 in the Bohai Bay, we have tested the response of variations of M-AMBI, using biomass (M-BAMBI) in the calculations, with different transformations of the raw data. The results showed that the ecological quality of most areas in the study indicated by M-AMBI was from moderate to bad status with the worse status in the coastal areas, especially around the estuaries, harbors and outfalls, and better status in the offshore areas except the area close to oil platforms or disposal sites. Despite large variations in nature of the input data, all variations of M-AMBI gave similar spatial and temporal distribution patterns of the ecological status within the bay, and showed high correlation between them. The agreement of new ecological status obtained from all M-AMBI variations, which were calculated according to linear regression, was almost perfect. The benthic quality, assessed using different input data, could be related to human pressures in the bay, such as water discharges, land reclamation, dredged sediment and drilling cuts disposal sites. It seems that M-BAMBI were more effective than M-NABMI (M-AMBI calculated using abundance data) in indicating human pressures of the Bay. Finally, indices calculated with more severe transformations, such as presence/absence data, could not indicate the higher density of human pressures in the coastal areas of the north part of our study area, but those calculated using mild transformation (i.e., square root) did.     

The effect of seawater magnesium on natural fluorescence during estuarine mixing,and implications for tracer applications

Natural fluorescence, which is thought to result from low molecular weight humic and fulvic compounds, can be used as a tracer to distinguish between individual river waters. Natural fluorescence exhibits conservative mixing with seawater, except for a slight fluorescence increase which is sometimes observed in the low salinity range (0–5‰). This increase is not due to the inner filter effect (internal quenching). Laboratory experiments can reproduce this low-salinity natural fluorescence increase. Of the major seawater ions, only magnesium can cause a similar natural fluorescence increase. Variation in sample pH, ionic strength, or particle content cannot explain the natural fluorescence increase, nor does it appear to be related to the estuarine flocculation of humic material. Addition of seawater magnesium to the fluorescent material with subsequent loss of hydrogen ions could enhance fluorescence by adding crosslinking to the structure. Replacement of a fluorescence-depressing metal like copper or iron by magnesium could also enhance fluorescence, essentially by removing the quenching effect of the metal. Experimental data in this study are consistent with both of these possible mechanisms. Calcium also enhances fluorescence, however the effect of seawater calcium during estuarine mixing is not as apparent as the magnesium effect. The implications of this low-salinity natural fluorescence increase with respect to estuarine and coastal tracer applications depend on whether individual rivers mix in the high or low salinity region of an estuary or coastal area.     

Climate change and summer mass tourism: the case of Spanish domestic tourism

This paper investigates the impact of climate change on destination choice decisions in a context of domestic coastal tourism in Spain. Destinations are characterized in terms of travel cost and coastal ‘attractors’, such as temperature and beach-related attributes. By means of a discrete choice model based on the random utility theory, these variables are used to explain the observed pattern of interprovincial domestic trips, showing trade-offs between temperature and attractiveness in the probability of a particular destination being chosen. The model is used to investigate the impact of two climate change scenarios on the allocation of domestic tourism within Spain. The findings show that while Spain’s northern colder provinces would benefit from rising temperatures, provinces in the south would experience a decrease in the frequency of trips.     

Tectonic evolution of the Málaga Basin (Betic Cordillera). Regional implications

Abstract

During the Neogene (uppermost Aquitanian-Lower Burdigalian, Tortonian and Pliocene), three successive marine episodes took place in the present-day Malaga Basin. The first of these affected a wide area of the Belic Internal Zones and was brought to an abrupt conclusion by the westward displacement of these Zones, together with important horizontal movements associated with N70-100 direction strike-slip faults and the superposition of materials from the Campo de Gibraltar. The two other marine episodes were clearly controlled by vertical movements of NW-SE and NK-SW faults, caused by a clear E-W distension which, according to regional data, was associated with some compression in an approximately N-S direction. The area has also been affected, although to a lesser extent, by the uplift of the Betic Cordillera from the Upper Miocene to the present day.