Search results for "ocean"
showing 10 items of 2919 documents
Molecular Phylogeny of Tintinnid Ciliates (Tintinnida, Ciliophora)
2012
We investigated the phylogeny of tintinnids (Ciliophora, Tintinnida) with 62 new SSU-rDNA sequences from single cells of 32 marine and freshwater species in 20 genera, including the first SSU-rDNA sequences for Amphorides, Climacocylis, Codonaria, Cyttarocylis, Parundella, Petalotricha, Undella and Xystonella, and 23 ITS sequences of 17 species in 15 genera. SSU-rDNA phylogenies suggested a basal position for Eutintinnus, distant to other Tintinnidae. We propose Eutintinnidae fam. nov. for this divergent genus, keeping the family Tintinnidae for Amphorellopsis, Amphorides and Steenstrupiella. Tintinnopsis species branched in at least two separate groups and, unexpectedly, Climacocylis branc…
Small-scale patches of detritus as habitat for invertebrates within a Zostera noltei meadow
2021
Abstract Seagrass detritus can attract numerous invertebrates as it provides food and substrate within the meadow or in adjacent environments. Nonetheless, several factors could modify the invertebrate response to this habitat. In this study, we tested if epifaunal colonisation of Zostera noltei detritus was related to substrate availability rather than food and whether colonising assemblages were similar according to the meadow structural complexity. Litterbags filled with natural or artificial detritus were deployed within an eelgrass meadow in a Mediterranean coastal lagoon (Thau lagoon, France). Colonisation appeared to be driven by the presence of detritus, with similar assemblages in …
Volcanic CO2 seep geochemistry and use in understanding ocean acidification
2020
AbstractOcean acidification is one of the most dramatic effects of the massive atmospheric release of anthropogenic carbon dioxide (CO2) that has occurred since the Industrial Revolution, although its effects on marine ecosystems are not well understood. Submarine volcanic hydrothermal fields have geochemical conditions that provide opportunities to characterise the effects of elevated levels of seawater CO2 on marine life in the field. Here, we review the geochemical aspects of shallow marine CO2-rich seeps worldwide, focusing on both gas composition and water chemistry. We then describe the geochemical effects of volcanic CO2 seepage on the overlying seawater column. We also present new g…
Temporal and spatial patterns of trawl fishing activities in the Adriatic Sea (Central Mediterranean Sea, GSA17)
2020
Abstract Trawl fishing activities have occurred for centuries on large spatial scale in the entire Mediterranean Sea, and today they are considered as one of the main and widespread causes of anthropogenic disturbance and habitat alteration in the marine environment. In order to delineate when, where and how marine ecosystems have been perturbed and to implement ecosystem-based management strategies, the identification and investigation of the spatial and temporal distribution of fishing effort and the fleet dynamics play a key role. In this context, Geospatial Technologies such as the Automatic Identification System (AIS) could represent a useful tool. The aim of the present work is to rec…
Seaweed fails to prevent ocean acidification impact on foraminifera along a shallow-water CO2 gradient
2014
Ocean acidification causes biodiversity loss, alters ecosystems, and may impact food security, as shells of small organisms dissolve easily in corrosive waters. There is a suggestion that photosynthetic organisms could mitigate ocean acidification on a local scale, through seagrass protection or seaweed cultivation, as net ecosystem organic production raises the saturation state of calcium carbonate making seawater less corrosive. Here, we used a natural gradient in calcium carbonate saturation, caused by shallow-water CO2 seeps in the Mediterranean Sea, to assess whether seaweed that is resistant to acidification (Padina pavonica) could prevent adverse effects of acidification on epiphytic…
Small-scale variability in geomorphological settings influences mangrove-derived organic matter export in a tropical bay
2017
Abstract. Organic matter (OM) exchanges between adjacent habitats affect the dynamics and functioning of coastal systems, as well as the role of the different primary producers as energy and nutrient sources in food webs. Elemental (C, N, C : N) and isotope (δ13C) signatures and fatty acid (FA) profiles were used to assess the influence of geomorphological setting in two climatic seasons on the export and fate of mangrove OM across a tidally influenced tropical area, Gazi Bay (Kenya). The main results indicate that tidal transport, along with riverine runoff, plays a significant role in the distribution of mangrove organic matter. In particular, a marked spatial variability in the export of…
Geochemical survey of Levante Bay, Vulcano Island (Italy), a natural laboratory for the study of ocean acidification
2013
Abstract Shallow submarine gas vents in Levante Bay, Vulcano Island (Italy), emit around 3.6t CO2 per day providing a natural laboratory for the study of biogeochemical processes related to seabed CO2 leaks and ocean acidification. The main physico-chemical parameters (T, pH and Eh) were measured at more than 70 stations with 40 seawater samples were collected for chemical analyses. The main gas vent area had high concentrations of dissolved hydrothermal gases, low pH and negative redox values all of which returned to normal seawater values at distances of about 400 m from the main vents. Much of the bay around the vents is corrosive to calcium carbonate; the north shore has a gradient in s…
Ocean acidification does not impair predator recognition but increases juvenile growth in a temperate wrasse off CO2seeps
2017
8 pages, 4 figures, supplementary data https://doi.org/10.1016/j.marenvres.2017.10.013
Trophic flexibility of the Atlantic blue crab Callinectes sapidus in invaded coastal systems of the Apulia region (SE Italy): A stable isotope analys…
2017
Abstract The Atlantic blue crab Callinectes sapidus is recognized as an Invasive Alien Species in the Mediterranean Sea. However, its trophic role and feeding flexibility in invaded benthic food webs have been addressed only recently. Here, field samplings were conducted in winter and summer in five coastal systems of the Apulia region (SE Italy), three located on the Ionian Sea (Mar Piccolo, Torre Colimena, and Spunderati) and two on the Adriatic Sea (Acquatina and Alimini Grande). Captured blue crabs were weighed and had their δ 13 C and δ 15 N isotopic signatures measured; their trophic level (TL) was estimated using the mussel Mytilus galloprovincialis as isotopic baseline. C. sapidus a…
Responses of marine benthic microalgae to elevated CO2
2011
Increasing anthropogenic CO emissions to the atmosphere are causing a rise in pCO concentrations in the ocean surface and lowering pH. To predict the effects of these changes, we need to improve our understanding of the responses of marine primary producers since these drive biogeochemical cycles and profoundly affect the structure and function of benthic habitats. The effects of increasing CO levels on the colonisation of artificial substrata by microalgal assemblages (periphyton) were examined across a CO gradient off the volcanic island of Vulcano (NE Sicily). We show that periphyton communities altered significantly as CO concentrations increased. CO enrichment caused significant increa…