scholarly journals Phenological shift in swarming patterns of Rhopilema nomadica in the Eastern Mediterranean Sea

2020 ◽  
Vol 42 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Dor Edelist ◽  
Tamar Guy-Haim ◽  
Zafrir Kuplik ◽  
Noa Zuckerman ◽  
Philip Nemoy ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Eastern Mediterranean Sea ◽  
Factors Affecting ◽  
Scientific Debate ◽  
The Public ◽  
Current Spread ◽  
Term Monitoring ◽  
Phenological Shift

Abstract Jellyfish (JF) swarms impact human wellbeing and marine ecosystems. Their global proliferation is a matter of concern and scientific debate, and the multitude of factors affecting (and affected by) their density and distribution merits long-term monitoring of their populations. Here we present an eight-year time series for Rhopilema nomadica, the most prominent JF species swarming the Eastern Mediterranean Sea. Reports were submitted by the public and within it a group of trained participants via an internet website between June 2011 and June 2019. Data collected included species, size, location, ranked amount and stinging. Swarms of R. nomadica prevailed in July and ended in August but were also prominent in winter from January to March. Both observations deviate from past swarming patterns described in the late 1980s, when summer swarms persevered until October and winter swarms were not documented. Climate change (increasing water temperature) and the westwards up-current spread of R. nomadica are discussed as possible explanations for this phenological shift. We further demonstrate how data obtained by Citizen Science is used to develop a swarming indicator and monitor JF in time and space, and propose a forecast based on these observations.

scholarly journals Wave Analysis for Offshore Aquaculture Projects: A Case Study for the Eastern Mediterranean Sea

Climate ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 2
Author(s):  
Flora E. Karathanasi ◽  
Takvor H. Soukissian ◽  
Daniel R. Hayes
Keyword(s):  
Mediterranean Sea ◽  
Wave Height ◽  
Significant Wave Height ◽  
Eastern Mediterranean ◽  
Wave Climate ◽  
Eastern Mediterranean Sea ◽  
Significant Wave ◽  
Offshore Aquaculture

The investigation of wave climate is of primary concern for the successful implementation of offshore aquaculture systems as waves can cause significant loads on them. Up until now, site selection and design (or selection) of offshore cage system structures on extended sea areas do not seem to follow any specific guidelines. This paper presents a novel methodology for the identification of favorable sites for offshore aquaculture development in an extended sea area based on two important technical factors: (i) the detailed characterization of the wave climate, and (ii) the water depth. Long-term statistics of the significant wave height, peak wave period, and wave steepness are estimated on an annual and monthly temporal scale, along with variability measures. Extreme value analysis is applied to estimate the design values and associated return periods of the significant wave height; structures should be designed based on this data, to avoid partial or total failure. The Eastern Mediterranean Sea is selected as a case study, and long-term time series of wave spectral parameters from the ERA5 dataset are utilized. Based on the obtained results, the most favorable areas for offshore aquaculture installations have been identified.

scholarly journals Hydrography in the Mediterranean Sea during a cruise with RV <i>POSEIDON</i> in April 2014

2015 ◽  
Vol 8 (1) ◽  
pp. 427-446
Author(s):  
D. Hainbucher ◽  
V. Cardin ◽  
G. Siena ◽  
U. Hübner ◽  
M. Moritz ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Adriatic Sea ◽  
Eastern Mediterranean ◽  
Intermediate Water ◽  
Strait Of Gibraltar ◽  
Eastern Mediterranean Sea ◽  
German Research ◽  
The Mediterranean ◽  
Long Term Variations

Abstract. We report on data from an oceanographic cruise in the Mediterranean Sea on the German research vessel POSEIDON in April 2014. Data were taken on a west–east section starting at the Strait of Gibraltar and ending south-east of Crete as well on sections in the Ionian and Adriatic Sea. The objectives of the cruise were twofold; long-term variations of the Levantine Intermediate Water (LIW) and the deep water masses of the Eastern Mediterranean Sea were investigated. The measurements include salinity, temperature, oxygen and currents and were conducted with a CTD/rosette system, an underway CTD and an ADCP. The sections are on tracks which have been sampled during several other cruises, thus supporting the opportunity to investigate the long term temporal development of the different variables. The use of an underway CTD made it possible to conduct measurements of temperature and salinity with a high resolution of 6 nm and a vertical resolution of 1 dbar for the upper 800 m of the water column.

Towards an ocean biogeochemical modelling framework for long-term transient simulations with a focus on the Eastern Mediterranean Sea 

2021 ◽  
Author(s):  
Katharina Six ◽  
Uwe Mikolajewicz
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Ocean Model ◽  
Early Holocene ◽  
Max Planck ◽  
Model Framework ◽  
Eastern Mediterranean Sea ◽  
Modelling Framework ◽  
First Results

&lt;p&gt;Sediment archives of the Eastern Mediterranean Sea (EMed) indicate very different physical and biogeochemical conditions during the LGM and the early Holocene than for present day. The ultimate goal of the here presented project is to disentangle the controlling processes of the circulation in the EMed over the last deglacial period by applying a regional ocean model including biogeochemistry covering the entire Mediterranean Sea. This model setup will be driven by downscaled forcing fields from a simulation with the paleo version of Max Planck Institute Earth System Model (pMPI-ESM) spanning from 26 to 0 kaBP.&amp;#160; pMPI-ESM has unique features like automatic bathymetry adjustment due to sea level rise and transient river routing. Despite its coarse model resolution, pMPI-ESM simulations catch the humid period of the early Holocene with corresponding increased Nile river discharge, a relevant driver for the conditions in the EMed. Thus, we are convinced that pMPI-ESM can provide a long-term transient and consistent forcing which is appropriate for our aims.&lt;/p&gt;&lt;p&gt;Here we present first results to evaluate the performance of our regional model driven by the downscaled forcing from pMPI-ESM. Main characteristics of the present day Mediterranean circulation are well captured such as locations of deep water formation, Mediterranean and Black Sea fresh water budgets, and the baroclinic transports through the Strait of Gibraltar.&amp;#160; We test our model framework for different time slices of deglaciation.&lt;/p&gt;

scholarly journals Functional Exoenzymes as Indicators of Metabolically Active Bacteria in 124,000-Year-Old Sapropel Layers of the Eastern Mediterranean Sea

2000 ◽  
Vol 66 (6) ◽  
pp. 2589-2598 ◽  
Author(s):  
Marco J. L. Coolen ◽  
Jörg Overmann
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Correction Method ◽  
Bacterial Cells ◽  
Eastern Mediterranean Sea ◽  
Intermediate Layers ◽  
Strong Adsorption ◽  
Active Bacteria

ABSTRACT Hydrolytic exoenzymes as indicators of metabolically active bacteria were investigated in four consecutive sapropel layers collected from bathyal sediments of the eastern Mediterranean Sea. For comparison, the organic carbon-poor layers between the sapropels, sediment from the anoxic Urania basin, and sediments of intertidal mud flats of the German Wadden Sea were also analyzed. The sapropel layers contained up to 1.5 · 108 bacterial cells cm−3, whereas cell numbers in the intermediate layers were lower by a factor of 10. In sapropels, the determination of exoenzyme activity with fluorescently labeled substrate analogues was impaired by the strong adsorption of up to 97% of the enzymatically liberated fluorophores (4-methylumbelliferone [MUF] and 7-amino-4-methylcoumarin [MCA]) to the sediment particles. Because all established methods for the extraction of adsorbed fluorophores proved to be inadequate for sapropel sediments, we introduce a correction method which is based on the measurement of equilibrium adsorption isotherms for both compounds. Using this new approach, high activities of aminopeptidase and alkaline phosphatase were detected even in a 124,000-year-old sapropel layer, whereas the activity of β-glucosidase was low in all layers. So far, it had been assumed that the organic matter which constitutes the sapropels is highly refractory. The high potential activities of bacterial exoenzymes indicate that bacteria in Mediterranean sapropels are metabolically active and utilize part of the subfossil kerogen. Since a high adsorption capacity was determined not only for the low-molecular-weight compounds MUF and MCA but also for DNA, the extraordinarily strong adsorption of structurally different substrates to the sapropel matrix appears to be the major reason for the long-term preservation of biodegradable carbon in this environment.

scholarly journals Comparison of Hydrocarbon-Degrading Consortia from Surface and Deep Waters of the Eastern Mediterranean Sea: Characterization and Degradation Potential

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2246
Author(s):  
Georgia Charalampous ◽  
Efsevia Fragkou ◽  
Konstantinos A. Kormas ◽  
Alexandre B. De Menezes ◽  
Paraskevi N. Polymenakou ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Oil Spills ◽  
Eastern Mediterranean ◽  
Sole Source ◽  
Eastern Mediterranean Sea ◽  
Deep Waters ◽  
Degradation Rates ◽  
Polycyclic Aromatic ◽  
Set Up

The diversity and degradation capacity of hydrocarbon-degrading consortia from surface and deep waters of the Eastern Mediterranean Sea were studied in time-series experiments. Microcosms were set up in ONR7a medium at in situ temperatures of 25 °C and 14 °C for the Surface and Deep consortia, respectively, and crude oil as the sole source of carbon. The Deep consortium was additionally investigated at 25 °C to allow the direct comparison of the degradation rates to the Surface consortium. In total, ~50% of the alkanes and ~15% of the polycyclic aromatic hydrocarbons were degraded in all treatments by Day 24. Approximately ~95% of the total biodegradation by the Deep consortium took place within 6 days regardless of temperature, whereas comparable levels of degradation were reached on Day 12 by the Surface consortium. Both consortia were dominated by well-known hydrocarbon-degrading taxa. Temperature played a significant role in shaping the Deep consortia communities with Pseudomonas and Pseudoalteromonas dominating at 25 °C and Alcanivorax at 14 °C. Overall, the Deep consortium showed a higher efficiency for hydrocarbon degradation within the first week following contamination, which is critical in the case of oil spills, and thus merits further investigation for its exploitation in bioremediation technologies tailored to the Eastern Mediterranean Sea.

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