José Miguel González-Correa

Echinoderms as indicators of brine discharge impacts

Abstract Echinoderms are osmoconformer organisms and are expected to be very sensitive to brine discharges. The objective of this study is to examine the use of echinoderms as early warning indicators of the impact of brine discharges and its application in the management of desalination discharges. We sampled using visual census along transect lines, for nine consecutive years and in three different stations, i.e. before the seawater reverse osmosis desalination plant began operating and thereafter. One year after the plant operation, echinoderms disappeared from the localities affected by the desalination brine. When the desalination brine was diluted with seawater prior to discharge, it was observed a recovery of echinoderm densities in these localities. Therefore, echinoderm populations may be used as early indicators to monitor impacts associated with a desalination brine discharge, but also to detect a possible recovery of a previously impacted area when additional mitigation measures to reduce the ...

Short-term effect of beach replenishment on a shallow Posidonia oceanica meadow

Putative perturbations on a Posidonia oceanica meadow produced by recent artificial beach nourishment were evaluated in relation to four undisturbed meadows. Temporal variations of putative impacted location vs. control locations of environmental (light availability and sediment features), plant (associated epiphytes, silt-clay fraction attached to epiphytes, herbivore attack, non-structural carbohydrate reserves) and structural parameters (cover and density) of meadows were tested by asymmetrical analysis of variance beyond BACI (Before/After, Control/Impact). Additionally, two asymmetrical analyses of variance were used to test for differences in vegetative growth of horizontal rhizomes (leaf production, horizontal rhizome growth, biomass production and net secondary rhizome recruitment) before and after beach replenishment. Environmental effects induced by dumping works were only detected in connection with a higher silt-clay deposition rate. This increase was consistent with the increase of silt-clay cover attached to epiphytes. As a consequence of silt-clay smothering, a decrease of filter feeding epiphytes, starch reserves, shoot surface and shoot biomass was observed. The sensitivity of plants to sediment inputs, leads us to recommend avoidance of dumping or sediment movement in the vicinity of P. oceanica meadows.

Evaluation of the viability of Posidonia oceanica transplants associated with a marina expansion

In March 2005, a preliminary Posidonia oceanica transplantation was carried out as a restoration measure prior to enlargement of a marina. Seagrass sods of approximately 1 m 2 surface area and 40 cm depth (including rhizome and sediment) were cut free from the area expected to be impacted by harbor expansion. These fragments were transferred to nearby areas lacking P. oceanica, viz. in bare areas within the nearest meadows and at the same depth as the donor site (;10 m). The present work was carried out with the aim of evaluating the feasibility of this technique through estimating the vitality of transferred plants (measured as density and cover) for comparison with plants from a nearby meadow with similar conditions. There was a high level of mortality among transplants and a considerable degradation of the shoots that remained alive at the time of the sampling. When results were expressed in terms of global density, the rate of survival of transplanted shoots decreased to 15% (50 vs. 361 shoots m -2 of meadow in transplant and control plots, respectively). These results indicate that transplant techniques for P. oceanica on a large scale are not feasible.

Comparison between the marine soundscape of recreational boat mooring areas with that of a pristine area in the Mediterranean: Evidence that such acoustic hot-spots are detrimental to ecologically sensitive habitats

We investigated the potential to use passive acoustics to access the impact of recreational boat mooring areas on ecologically sensitive habitats in the Western Mediterranean. One important consequence of the tourist industry in the region is that it targets the most pristine and ecologically sensitive habitats. Underwater sounds were recorded in mooring areas in Ibiza, Formentera and Tabarca harbors during high use and low use seasons and compared to recordings in the Tabarca Marine Protected area. At each location, we recorded sounds during 20 min at three different sites, for three random sampling times during the day. The percent of time occupied by selected biological (drums and croaks) and anthropogenic sounds (boat and mooring chain noises), and call rates of selected fish sounds were measured and compared among sites and seasons. Biological sounds contributed significantly less to the soundscape in mooring areas during the tourist season, and to the reserve in both seasons. Our study demonstrates ...