Search results for "Water"
showing 8 items of 9348 documents
Water chemistry, zooplankton and benthos in small lakes within the distribution area of the rare European pool frog Pelophylax lessonae (Camerano) in…
2020
Summary In June 2018, water chemistry, benthos and zooplankton were investigated in 7 small lakes/ ponds within the key area of the European pool frog Pelophylax lessonae (Camerano) in Norway. The geographic distribution of the Norwegian population is minor, limited to a very few small lakes in the county of Agder in southernmost Norway. Since the species is thermophilic, reproduction success only occurs in warm summers. Accordingly, the pool frog is one of the most rare vertebrates in Norwegian fauna, classified as critically endangered in the Norwegian red list. A breeding program is today established in order to rescue this species.The article deals with potential biotope challenges most…
Relationship between trophic state and plankton community structure in 21 Sicilian dam reservoirs
1994
The relationship between the trophic state of 21 Sicilian dam reservoirs and their taxonomic community structure of phytoplankton (87 taxa) as well as zooplankton (45 taxa) have been examined by means of cluster analysis performed using annual average biomass values. The phytoplankton community structure was closely connected with the trophic state of the reservoirs, whereas the zooplankton community structure was related to hydrological regimes peculiar to the individual water bodies and not to the trophic state. © 1994 Kluwer Academic Publishers.
Stable carbon and oxygen isotope fractionation in bivalve (Placopecten magellanicus) larval aragonite
2008
Abstract The relationship between stable isotope composition (δ13C and δ18O) in seawater and in larval shell aragonite of the sea scallop, Placopecten magellanicus, was investigated in a controlled experiment to determine whether isotopes in larval shell aragonite can be used as a reliable proxy for environmental conditions. The linear relationship between δ13CDIC and δ13Caragonite (r2 = 0.97, p δ 13 C DIC = 1.15 ( ± 0.05 ) ∗ δ 13 C aragonite - 0.85 ( ± 0.04 ) The relationship between δ13CDIC and δ13Caragonite described for P. magellanicus resulted in larval shell aragonite that was depleted on average by 1.82‰ (SD = 0.22‰, range = 1.1–2.1‰) from predicted equilibrium values based on the r…
Unraveling environmental histories from skeletal diaries — Advances in sclerochronology
2013
High-resolution proxy archives from aquatic settings are essential to better understand processes and mechanisms of global change. During the last decade, it has become increasingly evident that calcified tissues of bivalve mollusks and cold-water corals, in particular, can significantly increase our knowledge of seasonal to multi-decadal paleoclimate and paleoenvironmental variability in the extratropical oceans and coastal marine settings. Daily, tidal, fortnightly and annual growth patterns of periodically formed skeletal hard parts provide a means to place the proxy record in a precise temporal context. Their extreme longevity coupled with the running similarity between growth increment…
Carbon cycle and sea-water palaeotemperature evolution at the Middle-Late Jurassic transition, eastern Paris Basin (France).
2014
14 pages; International audience; A very high-resolution carbon and oxygen stable isotope analysis (bulk-carbonate) of a biostratigraphically well-constrained Callovian-Oxfordian series is provided here for the first time. The homogeneity of the clayey series and the weak diagenetic alteration allow the isotopic signal variations to be considered as primary in origin. A prominent and brief negative excursion in the δ13C curve (−2‰), occurring at the start of the Middle Callovian (Jason Zone - Obductum Subzone) and correlated regionally, suggests a possible methane release. The increasing δ13C values thereafter up to the Early Oxfordian, concomitant with a warming episode, highlight the buri…
Темпоральные аспекты моделирования и прогнозирования в экологии
1986
Межведомственный тематический сборник научных трудов по концептуальным, методологическим и методическим вопросам формализации временных отношений (темпоральности) в биоэкологическом прогнозировании, при моделировании экосистемы и ее биотических элементов. Тематика сборника в определенной мере отражает широкий диапазон и многогранность проблемы темпорализма в биоэкологии.
Охрана, экология и этология животных
1986
В сборнике представлены материалы по фаунистическому составу, распространению и экологии редких видов животных, а также видов, имеющих хозяйственное значение, даются рекомендации по увеличению численности редких животных.
The “genetic erosion” of the soil ecosystem
2013
Abstract This paper takes into consideration the influence of human activities on the loss of pedodiversity in a Mediterranean area due to large scale farming. In particular it examines the quantitative and qualitative soil changes in a period of 53 years (from 1955 to 2008) evaluating the loss of soil diversity at soil subgroups level of the USDA Soil Taxonomy system. The following indices were used: richness; Shannon’s diversity index; Simpson diversity index; Shannon’s evenness index; Simpson’s evenness index. In this case study, considering what we observed in time, the human intervention in soil transformation could increase the diversity in the landscape in an initial phase, but forwa…