Search results for "Reef"

Implication of the biofilm ageing for the settlement of the vermetid gastropod Dendropoma cristatum (Biondi 1857)

2016

Dendropoma cristatumreefs are key-intertidal habitats of the central Mediterranean. Knowledge onD. cristatumbiology is presently scant, particularly on its early life stage. The development of embryos occurs inside the maternal shell, and the crawling larvae settle on hard substrates shortly after hatching. Epilithic biofilm is known to have implications in the settlement of many marine invertebrates; however whether biofilm plays a role in driving the vermetid settlement is unknown. In this study the microbial assemblage ageing is tested as apotentialtriggerforD. cristatumsettlement. A field experiment was set-up to compare the larval settlement rate on removable limestone cubes (5x5x2 cm)…

Settlement performance of the Mediterranean reef-builders Dendropoma cristatum (Biondi 1859) in response to natural bacterial films

2018

The gastropod Dendropoma cristatum is a biogenic engineer of the central Mediterranean, forming reefs along the lower rocky intertidal fringe with a remarkable ecological role. To understand whether reef-associated biofilm cultivable bacterial and biofilm ageing may trigger the settlement of the juvenile snails, a combination of laboratory techniques and field experiments was used. Reef-associated biofilm cultivable bacteria were isolated, and a settlement-choice experiment was performed in situ on artificial biofilms composed of i) a mixture of six biofilm-forming selected isolates, ii) all the cultivable bacteria, and iii) 13-, 23-, 32-day old biofilms formed under naturalconditions. Overall,sett…

Artificial Reefs in North-West Sicily: Comparisons and Conclusions

2000

The most notable features of the biotic colonization and fishing yield of artificial reefs are a straightforward response to local environmental conditions. When applying this assumption to the artificial reefs of north-west Sicily, the features that distinguish the reefs from each other are largely consistent with the major hydrographic characteristics of the Gulf of Castellammare, the Bay of Carini and the Gulf of Palermo. The differences in environmental conditions in the three biotopes have made it possible to compare the colonization of artificial reefs in unpolluted oligotrophic water (Bay of Carini), eutrophic water (Gulf of Palermo) and water with heavy siltation rates (Alcamo Marin…

Biogenic habitat shifts under long-term ocean acidification show nonlinear community responses and unbalanced functions of associated invertebrates

2019

Este artículo contiene 8 páginas, 4 figuras.

Deep-water stromatolites andFrutexites Maslov from the early and Middle Jurassic of S-Germany and Austria

1993

Despite extensive discussions during the last 20 years stromatolites are still used by many geologists as unequivocal indicators of very shallow-water conditions. We investigated four stratigraphic units from the Lower and Middle Jurassic of southern Germany (Posidonien-Schiefer, Amaltheen-Ton) and of the Northern Calcareous Alps (Adneter Kalk, Klauskalk), which were formerly interpreted as shallow marine sediments by some authors due to the occurrence of stromatolites. Our interpretations of the macro-, micro- and ultrafacies of these sediments are not compatible with shallow-water settings. We therefore propose a deep-marine, aphotic origin of these stromatolites. Former interpretations o…

A Triassic carbonate platform edge in the Sciacca zone: implications for the accretion of the Maghrebian chain in southwestern Sicily

2008

Probing the Multiple Structures of Vaterite through Combined Computational and Experimental Raman Spectroscopy.

2014

First-principles Raman spectra have been computed for several new vaterite structural models that have been recently proposed, and compared with spectra recorded on a set of biogenic, geological and synthetic samples. This set includes new measurements collected on Herdamania momus spicules (Great Barrier Reef, Queensland, Australia), which are known to have purity and crystallinity that are higher than for other biogenic samples. Overall, due to the close structural connection between the various models, the computed Raman spectra are found to be broadly similar. However, the spectra obtained for the two most stable models (monoclinic C2 and trigonal P3221, corresponding to two different p…

Calcification is not the Achilles' heel of cold-water corals in an acidifying ocean

2015

Ocean acidification is thought to be a major threat to coral reefs: laboratory evidence and CO2 seep research has shown adverse effects on many coral species, although a few are resilient. There are concerns that cold-water corals are even more vulnerable as they live in areas where aragonite saturation (?ara) is lower than in the tropics and is falling rapidly due to CO2 emissions. Here, we provide laboratory evidence that net (gross calcification minus dissolution) and gross calcification rates of three common cold-water corals, Caryophyllia smithii, Dendrophyllia cornigera, and Desmophyllum dianthus, are not affected by pCO2 levels expected for 2100 (pCO2 1058 ?atm, ?ara 1.29), and nor a…

Nondipolar Structures With Threefold Symmetry For Nonlinear Optics

1997

Mediterranean bioconstructions along the Italian coast

2018

Marine bioconstructions are biodiversity-rich, three-dimensional biogenic structures, regulating key ecological functions of benthic ecosystems worldwide. Tropical coral reefs are outstanding for their beauty, diversity and complexity, but analogous types of bioconstructions are also present in temperate seas. The main bioconstructions in the Mediterranean Sea are represented by coralligenous formations, vermetid reefs, deep-sea cold-water corals, Lithophyllum byssoides trottoirs, coral banks formed by the shallow-water corals Cladocora caespitosa or Astroides calycularis, and sabellariid or serpulid worm reefs. Bioconstructions change the morphological and chemicophysical features of prima…