Impact of natural events on metal bioaccumulation in Anemonia sulcata

Samples of Anemonia sulcata were collected in 2022 from different areas of the Canary Islands affected by different natural contamination sources, such sandstorms, submarine volcanic activity, continuous rainfall, upwelling and dinoflagellate blooms. Significant differences were observed between the zones for the metals and trace elements analyzed (Al, Zn, Cd, Pb, Ni, Co, Fe, B, Cu, Mg and Li). Anemones from volcanic areas showed higher levels of Cd, Pb and Ni. Individuals from sandstorm areas showed elevated levels of Al, Zn and Fe. Samples collected from areas affected by upwelling processes had higher concentrations of Cu, Mg and Li. Finally, the areas affected by dinoflagellates showed lower levels of Zn, Pb, Fe, Mg and Li. The study reveals how natural phenomena dramatically influence metal accumulation in A. sulcata, which is of great value for anticipating and managing potential problems associated with public health.

High-resolution characterization of intertidal areas and lowest astronomical tidal surface by use of Sentinel-2 multispectral imagery and hydrodynamic modeling: Case-study in Cadiz Bay (Spain)

In intertidal areas, the zonation is determined by factors such as sea-level and topography. For this reason, a mixed methodology for the characterization (topography, extension, and zonation) of maximum intertidal areas is presented, based upon multispectral satellite imagery, hydrodynamic modeling, and in situ measurements. The methodology is applied and validated in the inner Cadiz Bay (SW Spain) as a case study. Satellite-derived waterlines were vertically referenced by tide-gauge measurements of sea-level; the resulting partial topography of intertidal areas was integrated into available hydrographic/topographic data to elaborate a high-resolution (10 m) model grid from which hydrodynamic simulations were conducted. Model results for lowest and highest tidal level situations were used to characterize the maximum intertidal areas within the inner Cadiz Bay, as well as the lowest astronomical tidal surface (LAT). The obtained LAT, referenced with respect the chosen geoid and/or ellipsoid, was identified with the vertical reference surface for Hydrography (VRSH) in this environment, complementing and improving the official VRSH presently being developed for Spanish waters. Obtained results show errors of the order of 1 cm for sea-level amplitudes and <1 min for the main tidal lags when comparing with tide-gauge data. Further applications of this exportable, relatively fast, low-cost, and accurate methodology are outlined.

Relative abundances of benthic foraminifera in response to total organic carbon in sediments: Data from European intertidal areas and transitional waters

We gathered total organic carbon (%) and relative abundances of benthic foraminifera in intertidal areas and transitional waters from the English Channel/European Atlantic Coast (587 samples) and the Mediterranean Sea (301 samples) regions from published and unpublished datasets. This database allowed to calculate total organic carbon optimum and tolerance range of benthic foraminifera in order to assign them to ecological groups of sensitivity. Optima and tolerance range were obtained by mean of the weighted-averaging method. The data are related to the research article titled “Indicative value of benthic foraminifera for biomonitoring: assignment to ecological groups of sensitivity to total organic carbon of species from European intertidal areas and transitional waters” [1].

High salinity and UVR synergistically reduce the photosynthetic performance of an intertidal benthic diatom

The intertidal flat is an important intermediate ecosystem characterized by abrupt fluctuations of some environmental factors. As a major contributor to coastal primary productivity, benthic diatoms have to cope up with these fluctuating conditions, such as variations in salinity and light. In this study, we used a typical benthic diatom, Nitzschia sp., to investigate how the photosynthetic performance of a benthic species responded to coupled stresses of high salinity and simulated sunlight. Results showed that their responses were largely dependent on the spectra of light they received. Further, ultraviolet radiation (UVR) interacted with high salinity more effectively than photosynthetically active radiation (PAR), which synergistically reduced the photochemical performance of photosystem II (PSII). The different responses to PAR and UVR were mainly attributed to the repair processes of PSII. Under high salinity, particularly for cells exposed to UVR, the repair rate was significantly lower than those under the control treatment. The present work suggests that UVR, rather than PAR, could be more important in influencing the benthic diatom under high salinity conditions.