Search results for "benthic"

Possible influence of Zoophycos bioturbation on radiocarbon dating and environmental interpretation

2002

Abstract In paleoenvironmental studies of marine sediments bioturbation is often neglected and/or only treated as a diffusion-like process affecting only the uppermost sediment with decreasing intensity with depth. Deep dwelling animals, like the Zoophycos producing animal, however, affect the sediment composition by transporting material over vertical distances of up to 1 m below the seafloor. In Arabian Sea sediment cores 70KL, 64KL and 57KL a significant downward transport of particles by Zoophycos can be observed. Within the Zoophycos burrows the faunal composition of both planktonic and benthic foraminiferal assemblages as well as the isotopic signature of foraminiferal carbonate diffe…

Stability and endemicity of benthic diatom assemblages from different substrates in a maritime stream on Byers Peninsula, Livingston Island, Antarcti…

2013

16 páginas, 3 tablas, 9 figuras.

Study of the morphological affinity between two species of benthic foraminifera from restricted environments: Rosalina douvillei (Cushman, 1928) and …

2020

A biometric comparison is carried out on selected tests of the foraminiferal species Rosalina douvillei (Cushman, 1928) and Trichohyalus aguayoi (Bermudez, 1935). The Rosalina douvillei specimens were recovered from the marginal marine Oligocene/Miocene site of Russingen (Mainz Basin, Germany), the lacustrine beds of the lower Miocene site of Bunol (Valencian Community, Spain) and the middle/ upper Miocene site of Fuendetodos (Aragon, Spain). The Trichohyalus aguayoi tests were collected in the current coastal lagoon of Torreblanca and recovered from Holocene cores sampled in the Peniscola marsh and in the coastal lagoon of l’Albufera de Valencia, all them in the Valencian Community (Spain)…

Sedimentary model and high-frequency cyclicity in a Mediterranean, shallow-shelf, temperate-carbonate environment (uppermost Miocene, Agua Amarga Bas…

1996

Uppermost Tortonian to lower Messinian temperate carbonates crop out in the Agua Amarga Basin (SE Spain). They consist of four units. The lower three units can be tentatively assigned to the lowstand systems tract of a fourth-order sequence, constituting in turn the lowstand (‘megatrough unit’), transgressive (‘breccia unit’) and highstand (‘bedded unit’) stages of a higher-order cycle. All these materials were deposited in a small pull-apart basin related to the sinistral Carboneras strike-slip fault system. The best represented is the bedded unit (up to 25 m thick), which consists of bioclastic, bryozoan/bivalve-dominated calcarenites/calcirudites with abundant fragments of echinoids, bar…

Orbitally modulated black shale deposition in the upper Albian Amadeus Segment (central Italy): a multi-proxy reconstruction

2003

Abstract The upper Albian Amadeus Segment, which falls within Oceanic Anoxic Event 1c, exhibits cyclical alternations of marls/black shales and carbonate-rich beds that record evidence of orbital climate and sedimentary dynamics. A combined micropalaeontological (planktic and benthic foraminifera, and palynomorphs) and geochemical (stable isotopes, clay mineralogy, and major element distribution) investigation allowed recognition of a remarkable influence of continental material within the black shales. Moreover, the palaeoproductivity record is characterised by a non-linear response to the orbital forcing. The micropalaeontological and geochemical record suggests that upper Albian bedded c…

The influence of thermal extremes on coral reef fish behaviour in the Persian Gulf

2019

AbstractDespite increasing environmental variability within marine ecosystems, little is known about how coral reef fish species will cope with future climate scenarios. The Arabian/Persian Gulf is an extreme environment, providing an opportunity to study fish behaviour on reefs with seasonal temperature ranges which include both values above the mortality threshold of Indo-Pacific reef fish, and values below the optimum temperature for growth. Summer temperatures in the Gulf are comparable to those predicted for the tropical ocean by 2090-2099. Using field observations in winter, spring and summer, and laboratory experiments, we examined the foraging activity, distance from refugia and res…

Benthic hydroids associated with volcanic structures from Bransfield Strait (Antarctica) collected by the Spanish Antarctic expedition GEBRAP96

2006

During the Spanish Antarctic expedition GEBRAP96 a survey to study the benthic fauna associated with deep volcanic structures in the Bransfield Strait was carried out. Amongst the benthic samples, a small collection of hydroids was gathered. A total of 10 species, most of them Leptothecata, was recorded; only two species of anthoathecates were present. Kirchenpaueriidae and Sertulariidae were the dominant families, and Symplectoscyphus and Oswaldella the predominant genera. Oswaldella niobae sp. nov. is described and figured. Since samples were taken at great depth, the lowest limit of the bathymetrical distribution for several species is distinctly increased. None of the samples showed sig…

Trophic cascades in benthic marine ecosystems: lessons for fisheries and protected-area management

2000

An important principle of environmental science is that changes in single components of systems are likely to have consequences elsewhere in the same systems. In the sea, food web data are one of the few foundations for predicting such indirect effects, whether of fishery exploitation or following recovery in marine protected areas (MPAs). We review the available literature on one type of indirect interaction in benthic marine ecosystems, namely trophic cascades, which involve three or more trophic levels connected by predation. Because many indirect effects have been revealed through fishery exploitation, in some cases we include humans as trophic levels. Our purpose is to establish how wi…

Benthic foraminifera assemblages in coastal marine ecosystem and relationship with metal distribution. A spatial study along Sicilian coasts.

2007

New applications of zoobenthos measurements for risk assessment of chemicals in aquatic ecosystems

2015

Artikkeliväitöskirja. Yhteenveto-osa ja viisi artikkelia. (Artikkelit eivät avoimesti saatavilla.) Article dissertation. An introduction and five articles (not available in this version). Benthic animals in aquatic ecosystems suffer from various anthropogenic pollutants. A challenge in risk assessment of chemicals in aquatic ecosystems (i.e. ecological risk assessment) has been to balance cost-efficiency and effectiveness in detecting early warning signals of chemicals. In this study, hyperspectral imaging and behavioural measurements were evaluated as novel applications for detecting chemical effects on benthic animals, and the reliability of the incidence of chironomid morphological defor…