scholarly journals Foraminiferal response to the deposition of insolation cycle 90 sapropel in different Mediterranean areas

2008 ◽  
Vol 27 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Simona Stefanelli ◽  
Lucilla Capotondi
Keyword(s):  
Water Depth ◽  
Benthic Foraminifera ◽  
Adriatic Sea ◽  
Oxygen Depletion ◽  
Recent Theory ◽  
Ionian Sea ◽  
Mediterranean Areas ◽  
Depositional Settings ◽  
Bottom Waters ◽  
Wet Climate

Abstract. Foraminifera were investigated across the sapropel unit corresponding to insolation cycle 90 deposited in three different oceanographic and depositional settings of the Mediterranean Sea (Alboran Sea, South Adriatic Sea and Ionian Sea). The constant presence of benthic foraminifera throughout the sapropels at <2000 m water depth and their absence within the sapropel at greater depth (>3000 m) indicate that the severity of oxygen depletion at the time of sapropel onset increases with increasing water depth.Planktonic and benthic foraminiferal patterns also document an interruption during sapropel deposition, which allows for the recognition of two sapropel phases. In all basins, the short interruption appears to be related to climatic deterioration, which led to the break in stratification and, hence, to the re-oxygenation of bottom waters. Since the interruption of the time-equivalent sapropel intervals has been documented previously in other Mediterranean areas, these data support the recent theory that this interruption must have been a trans-Mediterranean phenomenon and that the interruption records a short excursion out of the periods of wet climate associated with precessional minima.

scholarly journals Deep-Water Cartilaginous Fishes in the Central Mediterranean Sea: Comparison between Geographic Areas with Two Low Impact Tools for Sampling

2021 ◽  
Vol 9 (7) ◽  
pp. 686
Author(s):  
Angela Carluccio ◽  
Francesca Capezzuto ◽  
Porzia Maiorano ◽  
Letizia Sion ◽  
Gianfranco D’Onghia
Keyword(s):  
Adriatic Sea ◽  
Fish Habitat ◽  
Conservation Status ◽  
Abundant Species ◽  
Cartilaginous Fish ◽  
Fish Diversity ◽  
Ionian Sea ◽  
Central Mediterranean ◽  
The North ◽  
North Western

Baited lander represents a low impact technique, an alternative to the traditional trawl sampling for collecting data on fish diversity and abundance, especially for threatened species such as Chondrichthyes living in sensitive habitats. In this study, distribution and abundance of cartilaginous fish were compared between two geographic areas, the southern Adriatic Sea and the north-western Ionian Sea, with two low impact sampling gears, an experimental bottom longline and a baited lander. Species diversity was evaluated by applying ecological indices and difference in mean abundances were tested using multivariate analysis. A total of 13 species of cartilaginous fish were collected. Significant differences in the assemblage recorded in the same area using different sampling tools were detected and no significant differences were detected among different areas explored with the same method. Using longline, the most abundant species collected in both areas was Galeus melastomus, while using lander, the most observed species were Dalatias licha in the southern Adriatic Sea and Hexanchus griseus in the north-western Ionian Sea. According to IUCN classification, of the 13 species collected, 2 are near threatened and 5 are threatened. A better governance of sensitive habitats coinciding with the essential fish habitat for these species would ensure them a better conservation status.

scholarly journals First record of the Combtooth Blenny, Microlipophrys adriaticus (Steindachner & Kolombatovic, 1883) (Pisces, Blenniidae), for the Italian Ionian Sea

Check List ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 1646 ◽  
Author(s):  
F. Tiralongo ◽  
R. Baldacconi
Keyword(s):  
Mediterranean Sea ◽  
Black Sea ◽  
Adriatic Sea ◽  
First Record ◽  
The Black Sea ◽  
Ionian Sea ◽  
Sea Of Marmara ◽  
Limited Distribution ◽  
The North ◽  
The Mediterranean

Microlipophrys adriaticus (Steindachner & Kolombatovic, 1883) is an endemic blenny of the Mediterranean Sea. It is also known from the Sea of Marmara and the Black Sea. However, unlike other species of combtooth blennies, M. adriaticus is a fish with a limited distribution in Adriatic Sea, especially in the north, where it can be common. We report here the first record of this species from the waters of the Ionian Sea.

Influence of restoration methods on the longevity of changes in the thermal and oxygen dynamics of a degraded lake

2015 ◽  
Vol 44 (1) ◽  
Author(s):  
Jolanta Grochowska ◽  
Renata Brzozowska ◽  
Michał Łopata ◽  
Julita Dunalska
Keyword(s):  
Oxygen Depletion ◽  
Artificial Circulation ◽  
Anaerobic Conditions ◽  
Lake Volume ◽  
Depletion Rate ◽  
Bottom Waters ◽  
Phosphorus Inactivation ◽  
The City ◽  
Oxygen Dynamics ◽  
Content Of Oxygen

AbstractThe study was conducted on Lake Długie, located in the city of Olsztyn, which for 20 years received raw domestic sewage (400 m3 per day). After preliminary conservation operations, the lake was restored by artificial circulation and phosphorus inactivation methods. During artificial circulation, water temperature in the whole lake volume was equalized. The disconnection of the compressor stimulated the return to typical thermal parameters in the lake. Phosphorus inactivation did not affect the thermal regime in the lake. Artificial circulation caused an increase in the oxygen content in the whole lake, lowered the oxygen-depletion rate during stagnation, and shortened the duration of anaerobic conditions in the near-bottom waters. Phosphorus inactivation did not directly affect the content of oxygen. However, after the coagulant was added to the lake, the oxygenation of the water was further improved owing to the depressed photosynthesis caused by drastically reduced availability of phosphate for primary producers.

scholarly journals Oxygen depletion in subarctic peatland thaw lakes

2017 ◽  
Vol 3 (2) ◽  
pp. 406-428 ◽  
Author(s):  
Bethany N. Deshpande ◽  
Frédéric Maps ◽  
Alex Matveev ◽  
Warwick F. Vincent
Keyword(s):  
Dissolved Oxygen ◽  
Ice Cover ◽  
Oxygen Depletion ◽  
Freshwater Ecosystems ◽  
In Situ Sensors ◽  
Modelling Studies ◽  
Bottom Waters ◽  
Bacterial Decomposition ◽  
Permafrost Thawing ◽  
Thaw Lakes

Permafrost thawing and erosion results in the enrichment of northern lakes by soil organic matter. These allochthonous inputs favour bacterial decomposition and may cause the draw-down of dissolved oxygen to anoxic conditions that promote methanogenesis. Our objective in the present study was to determine the seasonal variations in dissolved oxygen in a set of permafrost peatland lakes in subarctic Quebec, Canada, and to relate these changes to metabolic rates, ice cover, and mixing. The lakes had high dissolved organic carbon concentrations, and their surface waters in summer had greenhouse gas concentrations that were up to one (CO2) to three (CH4) orders of magnitude above air-equilibrium values, indicating their strongly heterotrophic character. Consistent with these observations, the peatland lakes had elevated rates of bacterial production and oxygen consumption. Continuous measurements of oxygen by in situ sensors and of ice cover by automated field cameras showed that the lakes became fully anoxic shortly after freeze-up. The waters were partially re-oxygenated by mixing events in spring and fall, but in one lake, the bottom waters remained anoxic throughout the year. These observations provide a foundation for subsequent biogeochemical and modelling studies of peatland thaw lakes as an abundant class of Arctic freshwater ecosystems.

Marine alien Mollusca in Italy: a critical review and state of the knowledge

2012 ◽  
Vol 92 (6) ◽  
pp. 1357-1365 ◽  
Author(s):  
Fabio Crocetta
Keyword(s):  
Critical Review ◽  
Adriatic Sea ◽  
First Record ◽  
Extensive Literature ◽  
Tyrrhenian Sea ◽  
Ionian Sea ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Definition Of ◽  
Molluscan Species

The state of the knowledge about the marine alien molluscan species from Italy is provided based on a critical review of records compiled from an extensive literature survey and from unpublished data obtained from 2005 to 2010. Based on the IUCN definition of ‘alien’, 35 molluscan taxa (18 Gastropoda, 16 Bivalvia and 1 Cephalopoda) are reported here, for each of which the following data (collected up to December 2010) are provided: published and unpublished records from the coastal and offshore territorial seawaters of Italy, including lagoons, within the 14 biogeographical sea divisions covering the Italian shores, date of first record, most plausible vector(s) of introduction and establishment status. The southern Ionian Sea, the northern Adriatic Sea and the eastern-central Tyrrhenian Sea resulted to be the areas most affected by alien molluscan introductions. The rate of records of new alien species (evaluated on the basis of live findings) is quite uniform over five decades, with six to eight species recorded per decade. The analysis of the vectors showed shipping/maritime transport to be the most common vector of introduction (40%), followed by trade (24%). Nineteen alien molluscan species (54%) were considered as established in Italy.

Abyssal benthic foraminifera in the eastern equatorial Pacific (IODP EXP 320) during the middle Eocene

2013 ◽  
Vol 87 (6) ◽  
pp. 1160-1185 ◽  
Author(s):  
Hiroyuki Takata ◽  
Ritsuo Nomura ◽  
Akira Tsujimoto ◽  
Boo-Keun Khim ◽  
Ik Kyo Chung
Keyword(s):  
Water Depth ◽  
Benthic Foraminifera ◽  
Middle Eocene ◽  
Accumulation Rate ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Ocean Drilling Program ◽  
Integrated Ocean Drilling Program ◽  
Eastern Equatorial Pacific ◽  
Study Interval

We report on the faunal transition of benthic foraminifera during the middle Eocene at Site U1333 (4862 m water depth, 3,560–3,720 m paleo-water depth) of Integrated Ocean Drilling Program Expedition 320 in the eastern equatorial Pacific Ocean. During the period ∼41.5–40.7 Ma, which includes carbonate accumulation event 3 (CAE-3), the benthic foraminiferal accumulation rate (BFAR) increased gradually and then it declined rapidly. In contrast, BFAR was considerably lower during ∼40.7–39.4 Ma, corresponding to the middle Eocene climatic optimum (MECO), and then it increased during ∼39.3–38.4 Ma, including CAE-4. Diversity (E [S200]) was slightly lower in the upper part of the study interval than in the lower part. The most common benthic foraminifera were Nuttallides truempyi, Oridorsalis umbonatus, and Gyroidinoides spp. in association with Globocassidulina globosa and Cibicidoides grimsdalei during the period studied. Quadrimorphina profunda occurred abundantly with N. truempyi, O. umbonatus, and G. globosa during ∼39.4–38.4 Ma, including CAE-4, although this species was also relatively common in the lower part of the study interval. Virgulinopsis navarroanus and Fursenkoina sp. A, morphologically infaunal taxa, were common during ∼38.8–38.4 Ma, corresponding to the late stage of CAE-4. Based on Q-mode cluster analysis, four sample clusters were recognized and their stratigraphic distributions were generally discriminated in the lower and upper parts of the study interval. Thus, there was only a small faunal transition in the abyssal eastern equatorial Pacific during the middle to late-middle Eocene. The faunal transition recognized in this study may be related to recovery processes following intense carbonate corrosiveness in the eastern equatorial Pacific during MECO.

scholarly journals Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)

2017 ◽  
Vol 14 (23) ◽  
pp. 5607-5632 ◽  
Author(s):  
Ulrich Kotthoff ◽  
Jeroen Groeneveld ◽  
Jeanine L. Ash ◽  
Anne-Sophie Fanget ◽  
Nadine Quintana Krupinski ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Environmental Parameters ◽  
Ocean Drilling Program ◽  
Marginal Seas ◽  
Integrated Ocean Drilling Program ◽  
Depositional Settings ◽  
Shelf Seas ◽  
Bottom Waters ◽  
Baltic Proper ◽  
The Baltic

Abstract. Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial), paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059) over the past  ∼  8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index) show that lacustrine conditions occurred in the Little Belt until  ∼  7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish–marine conditions of the Littorina Sea stage (more saline and warmer) occurred within  ∼  200 years when the connection to the Kattegat became established after  ∼  7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg  /  Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86) can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant changes in depositional settings: in the case of our study, the change from freshwater to marine conditions. Our study shows that particular caution has to be taken when applying and interpreting proxies in coastal environments and marginal seas, where water mass conditions can experience more rapid and larger changes than in open ocean settings. Approaches using a multitude of independent proxies may thus allow a more robust paleoenvironmental assessment.

scholarly journals A Late Palaeocene–Early Eocene benthic foraminiferal record from Bovlstrup, Denmark, showing a remarkable agglutinated fauna

1997 ◽  
Vol 16 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Gitte Vestergaard Laursen ◽  
Søren Blegvad Andersen
Keyword(s):  
Water Depth ◽  
Benthic Foraminifera ◽  
Oil Well ◽  
Overlying Water ◽  
Sea Floor ◽  
Low Diversity ◽  
Foraminiferal Record ◽  
Clay Formation ◽  
Detailed Record ◽  
Dense Sampling

Abstract. The Bovlstrup well, Denmark, provides a detailed record of benthic foraminifera from the Upper Palaeocene and Lower Eocene deposits. The investigated interval spans four litho-units: an informal Grey Clay unit, the Holmehus Formation, the Ølst Formation and the Røsnæs Clay Formation (Danian?–Ypresian). Five interval zones based on benthic foraminifera have been established. Three of these zones (Zones 2, 3, and 4) contain exclusively agglutinated faunas. No foraminifera have previously been found in the Ølst Formation (Late Thanetian–Early Ypresian), but at Bovlstrup the formation contains a remarkable low-diversity agglutinated fauna (Zone 4). A programme of relatively dense sampling yielded information that may be lost in commercial oil well analysis. The five foraminiferal zones at Bovlstrup are correlated to established North Sea zonations, and the recognition of the faunas of Zones 3 and 4 leads to the conclusion that the zonation of King (In: Jenkins, D. G. &amp; Murray, J. W. (Eds), Stratigraphical Atlas of Fossil Foraminifera, Ellis Horwood, 1989) can be refined.The benthic faunas indicate changes in the bottom environment both at the sea floor and within the overlying water mass. A transition from a calcareous fauna to an agglutinated fauna is interpreted as the result of a change from a neutral to a slightly acidic environment at the sea floor. There is a fluctuation in water depth through the studied section with a minimum water depth during the Thanetian and Early Ypresian. Volcanic ash layers in the Ølst Formation presumably resulted in low pH values, thereby causing the extreme low diversity of the benthic foraminiferal faunas.

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