Search results for "Oceanography"
showing 10 items of 1567 documents
Major loss of coralline algal diversity in response to ocean acidification
2021
[Abstract] Calcified coralline algae are ecologically important in rocky habitats in the marine photic zone worldwide and there is growing concern that ocean acidification will severely impact them. Laboratory studies of these algae in simulated ocean acidification conditions have revealed wide variability in growth, photosynthesis and calcification responses, making it difficult to assess their future biodiversity, abundance and contribution to ecosystem function. Here, we apply molecular systematic tools to assess the impact of natural gradients in seawater carbonate chemistry on the biodiversity of coralline algae in the Mediterranean and the NW Pacific, link this to their evolutionary h…
Macroalgal responses to ocean acidification depend on nutrient and light levels
2015
Ocean acidification may benefit algae that are able to capitalize on increased carbon availability for photosynthesis, but it is expected to have adverse effects on calcified algae through dissolution. Shifts in dominance between primary producers will have knock-on effects on marine ecosystems and will likely vary regionally, depending on factors such as irradiance (light vs. shade) and nutrient levels (oligotrophic vs. eutrophic). Thus experiments are needed to evaluate interactive effects of combined stressors in the field. In this study, we investigated the physiological responses of macroalgae near a CO2 seep in oligotrophic waters off Vulcano (Italy). The algae were incubated in situ …
The “Seili-index” For The Prediction of Chlorophyll-α Levels In The Archipelago Sea of The Northern Baltic Sea, Southwest Finland
2021
AbstractTo build a forecasting tool for the state of eutrophication in the Archipelago Sea, we fitted a Generalized Additive Mixed Model (GAMM) to marine environmental monitoring data, which were collected over the years 2011–2019 by an automated profiling buoy at the Seili ODAS-station. The resulting “Seili-index” can be used to predict the chlorophyll-α (chl-a) concentration in the seawater a number of days ahead by using the temperature forecast as a covariate. An array of test predictions with two separate models on the 2019 data set showed that the index is adept at predicting the amount of chl-a especially in the upper water layer. The visualization with 10 days of chl-a level predict…
Dualistisches Fortpflanzungsverhalten bei dem protogynen LippfischThalassoma bifasciatum und einige Beobachtungen über dessen Tag-Nacht-Wechsel
1973
1.Thalassoma bifasciatum is a protogynous wrasse with (partial) sexual dimorphism and male dichromatism. Sex-inversion takes place without affecting the color pattern. 2. Males with female-like color dress indulge in group spawning; males with the bright color pattern perform pair spawning. 3. Among the brightly colored males exists a well-established hierarchy. Dominant males only have a particular spawning area in which they spawn daily at a certain time around noon. The spawning area is optically marked by conspicuous behavior of the bright male. Courtship activities towards individual partners are rather superficial. 4. The female has the leading role in pair spawning. In the extremely …
Formation of microbial organic carbonates during the Late Jurassic from the Northern Tethys (Amu Darya Basin, Uzbekistan): implications for Jurassic …
2020
23 pages; International audience; The Late Jurassic was a period of major global carbon cycle perturbations with episodes of anoxia leading to regional accumulation of organic matter in sediments worldwide. The Tubiegatan section (SW Gissar Mountains, Uzbekistan) located in the Northern Tethys, shows atypical organic-rich limestone and marl deposits (up to 6% of total organic carbon) marked by pronounced negative excursions of δ13Ccarb (amplitude of ca. 12‰) and δ13Corg (amplitude of ca. 4‰) recorded during the Middle Oxfordian (Transversarium Zone). A transdisciplinary approach including sedimentology, palynofacies characterization, mineralogy, organic and inorganic geochemistry was carrie…
Greater mitochondrial energy production provides resistance to ocean acidification in "winning" hermatypic corals
2021
Coral communities around the world are projected to be negatively affected by ocean acidification. Not all coral species will respond in the same manner to rising CO2 levels. Evidence from naturally acidified areas such as CO2 seeps have shown that although a few species are resistant to elevated CO2, most lack sufficient resistance resulting in their decline. This has led to the simple grouping of coral species into “winners” and “losers,” but the physiological traits supporting this ecological assessment are yet to be fully understood. Here using CO2 seeps, in two biogeographically distinct regions, we investigated whether physiological traits related to energy production [mitochondrial e…
Vasseuromys rambliensis sp. nov. (Gliridae, Mammalia) from the Ramblian (Lower Miocene) of the Tudela Formation (Ebro basin, Spain)
2012
In this paper, a new species of Vasseuromys, V. rambliensis sp. nov., from the locality Pico del Fraile 1 (PF1, Ebro basin, North-eastern Spain) is described. The association of Ligerimys, Peridyromys murinus and Simplomys simplicidens, and the absence of Eucricetodon and Democricetodon, allows dating of the PF1 locality as Late Ramblian (Early Miocene, MN3, local zone A). Main diagnostic features of V. rambliensis sp. nov. are the presence of four extra ridges in the lower molars, a very reduced anterotropid and a metaloph connected to the posteroloph and not to the protocone. The size and morphology of V. rambliensis sp. nov. are very close to V. bacchius from the upper part of unit MN2, …
La memòria oceànica del clima: El sistema circulatori d'un planeta viu
2013
A principis del segle XVI Leonardo da Vinci comparava els corrents oceànics amb el fl ux de sang d’un cos humà. Actualment disposem d’informació sufi cient per a explorar la idea que la Terra té un sistema circulatori responsable de capturar, transformar i distribuir l’energia solar. El paper dels oceans com a reguladors del clima és extraordinari, realment condicionen el present i el futur del planeta.
Surcotes, tempêtes et risque d’inondation le long du littoral belge : variabilité contemporaine et future (1950-2100)
2010
6 pages; International audience; A l’échelle quotidienne, la hauteur des surcotes à Ostende est quasi-linéairement corrélée à la pressionatmosphérique de surface (PSM) sur la Mer Baltique. Les plus fortes surcotes s’y produisent quand une dépression restestationnaire plusieurs jours sur la Scandinavie synchrone à un renforcement de l’anticyclone des Açores. Cette géographiebarométrique favorise la genèse des forts vents d’afflux de nord-ouest dans la partie sud de la Mer du Nord. Un modèle derégression linéaire permet de simuler de façon robuste la variabilité interannuelle des fortes surcotes à Ostende de 1950 à2000 avec (i) la PSM autour de la Mer Baltique et (ii) le gradient barométrique…
Selection of spawning substratum by European river lampreys (Lampetra fluviatilis) in experimental tanks
2014
The selection of spawning substratum by the river lamprey (Lampetra fluviatilis) was studied in two experimental tanks with different flow conditions. In both tanks, four gravel sizes mixed with 15% sand were available to the test animals. In the tank with the lower current speed, lampreys selected in favour of the finest (2–8 mm) gravel size available against gravel sizes 4–20 mm and 8–40 mm. Selection was also significantly different in the tank with higher current speed where selection against the medium-sized substratum (4–20 mm) was evident, but there were no differences between selection for gravel sizes 2–8 mm, 2–40 mm and 8–40 mm relative to availability. Substratum selection and ob…