Search results for "plank"

Seasonal variations in the stable carbon and nitrogen isotope ratios (13C/12C and 15N/14N) of primary producers and consumers in a western Mediterran…

2003

Stable carbon and nitrogen isotope ratios (13C/12C and 15N/14N) of primary producers and consumers were investigated seasonally throughout 1999, in order to describe the food web in a western Mediterranean coastal lagoon (Lake of Sabaudia, central Italy). Particulate organic matter and algal material (seagrass epiphytes and macroalgae) seem to constitute the main food sources for primary consumers (zooplankton and small benthic invertebrates, respectively) throughout the sampling year, while the seagrass Cymodocea nodosa appears to play a negligible trophic role. As regards the ichthyofauna, carbon stable isotopes differentiated between planktivore and benthivore fish species. However, a be…

The Effect of Temporal Changes and Environmental Trophic Condition on the Isotopic Composition (omega13C and omega15N) of Atherina boyeri (Risso, 181…

2002

δ13C and δ15N of organic matter sources and consumers were employed to analyse trophic differentiation between a benthic consumer, Gobius niger (L., 1758) (Pisces, Osteichthyes), and a pelagic consumer, Atherina boyeri (Risso, 1810) (Pisces, Osteichthyes) in a Mediterranean coastal lagoon (Lake of Sabaudia) in winter and summer 1999. Trophic differences between the two species throughout the two sampling periods were related to the environmental trophic condition (i. e. nutrient and phytopigment concentrations). Although these two fish have different habitats, they both exploited benthic organisms, above all in summer. When the nutrient and phytopigment concentrations were higher (summer), …

Horizontal and vertical food web structure drives trace element trophic transfer in Terra Nova Bay, Antarctica

2019

Abstract Despite a vast amount of literature has focused on trace element (TE) contamination in Antarctica during the last decades, the assessment of the main pathways driving TE transfer to the biota is still an overlooked issue. This limits the ability to predict how variations in sea-ice dynamics and productivity due to climate change will affect TE allocation in the food web. Here, food web structure of Tethys Bay (Terra Nova Bay, Ross Sea, Antarctica) was first characterised by analysing carbon and nitrogen stable isotopes (δ13C, δ15N) in organic matter sources (sediment and planktonic, benthic and sympagic primary producers) and consumers (zooplankton, benthic invertebrates, fish and …

First record and morphological features of Hemidiaptomus (Occidodiaptomus) ingens (Gurney, 1909) (Copepoda Calanoida) in Italy

2004

During a survey, carried out to assess the consistency of microcrustacean fauna inhabiting temporary ponds in Sicily, Hemidiaptomus (Occidodiaptomus) ingens (Gurney, 1909), a large calanoid copepod up to now known only for North-African ponds, Camargue and Corse, was found in the north-western part of the island. Due to its central location in the Mediterranean Sea, Sicily represents a transition zone where several chorological zones of the West Palearctic merge and converge. A brief summary of the existing literature regarding this taxon is given with some morphological considerations on the recently found population which represents the first record for Italy. In particular, the morpholog…

Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and related changes in salinity

2015

According to the Intergovernmental Panel on Climate Change report released in September 2014, unprecedented changes in temperature and precipitation patterns have been recorded globally in recent decades and further change is predicted to occur in the near future, mainly as the result of human activity. In particular, projections show that the Mediterranean climate zone will be markedly affected with significant implications for lake water levels and salinity. This may be exacerbated by increased demands for irrigation water. Based on long-term data from seven lakes and reservoirs covering a geographical gradient of 52 of latitudes and a literature review, we discuss how changes in water le…

Contribution of planktonic and benthic food sources to the diet of the reef-forming vermetid gastropod Dendropoma petraeum in the western Mediterrane…

2012

Abstract In the Mediterranean Sea, the vermetid Dendropoma petraeum (Monterosato, 1884) forms highly biodiverse reefs that have received increasing attention in recent years although very little is known about the food habit of this species. The main goal of this study was to describe the trophic role of planktonic and benthic food sources for D. petraeum . Specimens from three morphological zones of the reef (inner edge, cuvette and outer edge) at two sites with different wave exposure along the north-western coast of Sicily (Italy; western Mediterranean) were compared for δ 13 C and δ 15 N. Isotopic determinations were also carried out on potential food sources identified in epilithon, re…

Year-round variation in the isotopic niche of Scopoli's shearwater (Calonectris diomedea) breeding in contrasting sea regions of the Mediterranean Sea

2022

Top marine predators are key components of marine food webs. Among them, long-distance migratory seabirds, which travel across different marine ecosystems over the year, may experience important year-round changes in terms of oceanographic conditions and availability of trophic resources. We tested whether this was the case in the Scopoli’s shearwater (Calonectris diomedea), a trans-equatorial migrant and top predator, by sampling birds breeding in three environmentally different regions of the Mediterranean Sea. The analysis of positional data and stable isotopes (δ13 C and δ15N) of target feathers revealed that birds from the three regions were spatially segregated during the breeding per…

Tipologica ambiental de los sistemas leniticos de Huinay (Decima Region de Los Lagos, Chile) y distribucion del plancton limnico

2010

Environmental Conditions along Tuna Larval Dispersion: Insights on the Spawning Habitat and Impact on Their Development Stages

2022

Estimated larval backward trajectories of three Tuna species, namely, Atlantic Bluefin Tuna (Thunnus thynnus, Linnaeus, 1758), Bullet Tuna (Auxis Rochei, Risso, 1801) and Albacore Tuna (Thunnus alalunga, Bonnaterre, 1788) in the central Mediterranean Sea, were used to characterize their spawning habitats, and to assess the impact of changes due to the major environmental parameters (i.e., sea surface temperature and chlorophyll-a concentration) on larval development during their advection by surface currents. We assumed that the environmental variability experienced by larvae along their paths may have influenced their development, also affecting their survival. Our results showed that the …

Feeding ecology of the sand smelt, Atherina boyeri (Risso, 1810) (Osteichthyes, Atherinidae), in the western Mediterranean: evidence for spatial vari…

2005

The feeding ecology of the sand smelt Atherina boyeri Risso 1810 (Osteichthyes, Atherinidae) was investigated in a Mediterranean coastal basin (Stagnone di Marsala, Italy) by means of carbon and nitrogen stable isotope ratios. Sampling was carried out seasonally in 1999 in two locations characterised by different depth and vegetal coverage. Throughout the year the sand smelt showed enriched δ 13C and δ 15N values in both sampling locations (δ 13C about −12‰ and δ 15N about 12‰). This result suggests the overall importance of the benthic pathway in the food web leading to A. boyeri. Our isotopic picture is only in partial agreement with stomach content data from the literature. Stomach conte…