Search results for "STABLE-ISOTOPE"
showing 10 items of 14 documents
Drivers of shell growth of the bivalve, Callista chione (L. 1758) - Combined it environmental and biological factors
2018
WOS:000426027100014; Seasonal shell growth patterns were analyzed using the stable oxygen and carbon isotope values of live-collected specimens of the bivalve Callista chione from two sites in the Adriatic Sea (Pag and Cetina, Croatia). Micromilling was performed on the shell surface of three shells per site and shell oxygen isotopes of the powder samples were measured. The timing and rate of seasonal shell growth was determined by aligning the delta O-18(shell)-derived temperatures so that the best fit was achieved with the instrumental temperature curve. According to the data, shells grew only at very low rates or not at all during the winter months, i.e., between January and March. Shell…
Periphyton support for littoral secondary production in a highly humic boreal lake
2016
Steep stratification and poor light penetration in highly humic lakes typically restrict oxygenated littoral areas to narrow lake margins. However, in some instances, surrounding floating vegetation mats can sustain highly productive periphyton and more diverse invertebrate communities than pelagic areas. Little is known about how these littoral food webs function or the extent to which the pelagic and littoral food webs are coupled. We added 15N-labeled ammonium nitrate to the floating moss mat surrounding the littoral zone of Mekkojärvi, a small highly humic and fishless lake in southern Finland. Our goal was to increase the δ15N values of periphyton to investigate the diets of littoral i…
Fundamental questions and applications of sclerochronology: Community-defined research priorities
2020
WOS:000582677500029; International audience; Horizon scanning is an increasingly common strategy to identify key research needs and frame future agendas in science. Here, we present the results of the first such exercise for the field of sclerochronology, thereby providing an overview of persistent and emergent research questions that should be addressed by future studies. Through online correspondence following the 5th International Sclerochronology Conference in 2019, participants submitted and rated questions that addressed either knowledge gaps or promising applications of sclerochronology. An initial list of 130 questions was compiled based on contributions of conference attendees and …
Trophic interactions between introduced lake trout (Salvelinus namaycush) and native Arctic charr (S. alpinus) in a large Fennoscandian subarctic lake
2014
Introduced fishes may have major impacts on community structure and ecosystem function due to competitive and predatory interactions with native species. For example, introduced lake trout (Salvelinus namaycush) has been shown to replace native salmonids and induce major trophic cascades in some North American lakes, but few studies have investigated trophic interactions between lake trout and closely related native Arctic charr (S.alpinus) outside the natural distribution of the former species. We used stomach content and stable isotope analyses to investigate trophic interactions between introduced lake trout and native Arctic charr in large subarctic Lake Inarijarvi in northern Finland. …
Environmental controls on benthic food web functions and carbon resource use in subarctic lakes
2019
Climate warming and consequent greening of subarctic landscapes increase the availability of organic carbon to the detrital food webs in aquatic ecosystems. This may cause important shifts in ecosystem functioning through the functional feeding patterns of benthic organisms that rely differently on climatically altered carbon resources. Twenty-five subarctic lakes in Finnish Lapland across a tree line ecotone were analysed for limnological and optical variables, carbon (delta C-13) and nitrogen (delta N-15) stable isotope (SI) composition of surface sediment organic matter (OM) and fossil Chironomidae (Diptera) remains to examine environmental controls behind chironomid functional feeding g…
Microwear and isotopic analyses on cave bear remains from Toll Cave reveal both short-term and long-term dietary habits
2019
Dietary habits of the extinct Ursus spelaeus have always been a controversial topic in paleontological studies. In this work, we investigate carbon and nitrogen values in the bone collagen and dental microwear of U. spelaeus specimens recovered in Level 4 from Toll Cave (Moia, Catalonia, NE Iberian Peninsula). These remains have been dated to > 49,000 C-14 BP. The ability of both proxies to provide data on the diet of U. spelaeus at different times in the life-history (isotopes: average diet of life; microwear: last days/weeks before death), allows us to generate high-resolution and complementary data. Our results show lower values (delta C-13 & delta N-15) in cave bears than in strict herb…
Complementary methods assessing short and long-term prey of a marine top predator ‒ Application to the grey seal-fishery conflict in the Baltic Sea.
2019
The growing grey seal (Halichoerus grypus) population in the Baltic Sea has created conflicts with local fisheries, comparable to similar emerging problems worldwide. Adequate information on the foraging habits is a requirement for responsible management of the seal population. We investigated the applicability of available dietary assessment methods by comparing morphological analysis and DNA metabarcoding of gut contents (short-term diet; n = 129/125 seals, respectively), and tissue chemical markers i.e. fatty acid (FA) profiles of blubber and stable isotopes (SIs) of liver and muscle (mid- or long-term diet; n = 108 seals for the FA and SI markers). The methods provided complementary inf…
Multi-isotopic and trace element evidence against different formation pathways for oyster microstructures
2021
Geochimica et cosmochimica acta 308, 326-352 (2021). doi:10.1016/j.gca.2021.06.012
Allochthony, fatty acid and mercury trends in muscle of Eurasian perch (Perca fluviatilis) along boreal environmental gradients
2022
Environmental change, including joint effects of increasing dissolved organic carbon (DOC) and total phosphorus (TP) in boreal northern lakes could potentially affects food web energy sources and the biochemical composition of organisms. These environmental stressors are enhanced by anthropogenic land-use and can decrease the quality of polyunsaturated fatty acids (PUFAs) in seston and zooplankton, and therefore, possibly cascading up to fish. In contrast, the content of mercury in fish increases with lake browning potentially amplified by intensive forestry practises. However, there is little evidence on how these environmental stressors simultaneously impact beneficial omega-3 fatty acid …
Contrasting shell growth strategies in two Mediterranean bivalves revealed by oxygen-isotope ratio geochemistry: The case of Pecten jacobaeus and Gly…
2019
International audience; High-resolution stable-isotope ratio data (delta O-18, delta O-18) were used to study growth strategies of two bivalve species, Pecten jacobaeus (calcitic shell) and Glycymeris pilosa (aragonitic shell) from the North Adriatic Sea. The principal objectives of this study were to identify the period of the year when the growth line is formed in the shell of two target species, to identify the main growing season of these two species, to identify the environmental drivers of shell growth, and to evaluate the potential applicability of delta O-18 and delta O-18 values for the reconstruction of environmental variability. Samples were collected from the North Adriatic Sea …