scholarly journals Ocean warming is the key filter for successful colonization of the migrant octocoral Melithaea erythraea (Ehrenberg, 1834) in the Eastern Mediterranean Sea

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9355
Author(s):  
Michal Grossowicz ◽  
Or M. Bialik ◽  
Eli Shemesh ◽  
Dan Tchernov ◽  
Hubert B. Vonhof ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Red Sea ◽  
Isotope Composition ◽  
Eastern Mediterranean ◽  
Temperature Range ◽  
Recent Climate ◽  
Carbon Intake ◽  
Successful Colonization ◽  
Metabolic Carbon

Climate, which sets broad limits for migrating species, is considered a key filter to species migration between contrasting marine environments. The Southeast Mediterranean Sea (SEMS) is one of the regions where ocean temperatures are rising the fastest under recent climate change. Also, it is the most vulnerable marine region to species introductions. Here, we explore the factors which enabled the colonization of the endemic Red Sea octocoral Melithaea erythraea (Ehrenberg, 1834) along the SEMS coast, using sclerite oxygen and carbon stable isotope composition (δ18OSC and δ13CSC), morphology, and crystallography. The unique conditions presented by the SEMS include a greater temperature range (∼15 °C) and ultra-oligotrophy, and these are reflected by the lower δ13CSCvalues. This is indicative of a larger metabolic carbon intake during calcification, as well as an increase in crystal size, a decrease of octocoral wart density and thickness of the migrating octocoral sclerites compared to the Red Sea samples. This suggests increased stress conditions, affecting sclerite deposition of the SEMS migrating octocoral. The δ18Osc range of the migrating M. erythraea indicates a preference for warm water sclerite deposition, similar to the native depositional temperature range of 21–28 °C. These findings are associated with the observed increase of minimum temperatures in winter for this region, at a rate of 0.35 ± 0.27 °C decade−1 over the last 30 years, and thus the region is becoming more hospitable to the Indo-Pacific M. erythraea. This study shows a clear case study of “tropicalization” of the Mediterranean Sea due to recent warming.

Local adaptation of a Lessepsian invader species to winter conditions in the Mediterranean Sea

2021 ◽  
Author(s):  
Débora Silva Raposo ◽  
Raphaël Morard ◽  
Christiane Schmidt ◽  
Michal Kucera
Keyword(s):  
Quantum Yield ◽  
Mediterranean Sea ◽  
Red Sea ◽  
Photosynthetic Activity ◽  
Eastern Mediterranean ◽  
Effective Quantum Yield ◽  
Mediterranean Populations ◽  
Cold Temperatures ◽  
Invasion Front ◽  
The Mediterranean

<p>In recent decades the “Lessepsian” migration caused a rapid change in the marine community composition due to the invasion of alien species from the Red Sea into the Mediterranean Sea. Among these invaders is the large benthic foraminifera <em>Amphistegina lobifera</em>, a diatom-bearing species that recently reached the invasion front in Sicily. There it copes with colder winters and broader temperature than in its original source, the Red Sea. It is not yet known how (or if) the population from the invasion front has developed adaptation to this new thermal regime. Understanding the modern marine invasive patterns is a crucial tool to predict future invasive successes in marine environments. Therefore, in this study we aim to evaluate the physiological responses to cold temperatures of <em>A. lobifera</em> populations at three different invasive stages: source (Red Sea), early invader (Eastern Mediterranean) and invasion front (Sicily). For this, we conducted a culturing experiment in which we monitored the responses of the foraminifera (growth, motility) to temperatures of 10, 13, 16, 19°C + control (25°C) over four weeks. To address what is the role of their endosymbionts in the adaptation process, we also monitored their photosynthetic activity (Pulse Amplitude Modulation - PAM fluorometer) during the experiment. The growth rate of the foraminifera was reduced for all populations below 19°C as well as the motility, reduced until 16°C and dropping to zero below 13°C. The response of the endosymbionts was however different. There was a reduced photosynthetic activity of the Red Sea and Eastern Mediterranean populations at colder temperatures observed by the lower maximum quantum yield (Fv:Fm) and effective quantum yield (Y(II)), when compared to their initial levels and to the other treatments. In the meantime, the endosymbionts of the Sicily population stood out with the highest photosynthetic activity (Fv:Fm and Y(II)) in the treatments bellow 13 °C (P < 0.05). In conclusion, we observed that while the host responses were similar between the three populations, the endosymbionts from the invasion front population shows the best performance at colder temperatures. This suggests that the photo-symbiosis has an important role in adaptation, most likely being a key factor to the success of past and future migrations.</p>

scholarly journals Seasonal dynamics of native and invasive Halophila stipulacea populations—A case study from the northern Gulf of Aqaba and the eastern Mediterranean Sea

2020 ◽  
Vol 162 ◽  
pp. 103205 ◽  
Author(s):  
Hung Manh Nguyen ◽  
Ioannis Savva ◽  
Periklis Kleitou ◽  
Demetris Kletou ◽  
Fernando P. Lima ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Seasonal Dynamics ◽  
Eastern Mediterranean ◽  
Gulf Of Aqaba ◽  
Eastern Mediterranean Sea ◽  
Halophila Stipulacea

scholarly journals Determination of the copper isotope composition of seawater revisited: A case study from the Mediterranean Sea

2019 ◽  
Vol 511 ◽  
pp. 465-480 ◽  
Author(s):  
Isabelle Baconnais ◽  
Olivier Rouxel ◽  
Gabriel Dulaquais ◽  
Marie Boye
Keyword(s):  
Mediterranean Sea ◽  
Isotope Composition ◽  
Copper Isotope ◽  
The Mediterranean

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.

Using solitary ascidians to assess microplastic and phthalate plasticizers pollution among marine biota: A case study of the Eastern Mediterranean and Red Sea

2019 ◽  
Vol 138 ◽  
pp. 618-625 ◽  
Author(s):  
Gal Vered ◽  
Aviv Kaplan ◽  
Dror Avisar ◽  
Noa Shenkar
Keyword(s):  
Red Sea ◽  
Eastern Mediterranean ◽  
Marine Biota

scholarly journals Seasonal dynamics of phytoplankton and bacterioplankton at the ultra-oligotrophic southeastern Mediterranean Sea

2021 ◽  
Author(s):  
Tom Reich ◽  
Tal Ben-Ezra ◽  
Natalya Belkin ◽  
Anat Tsemel ◽  
Dikla Aharonovich ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Red Sea ◽  
Seasonal Dynamics ◽  
Eastern Mediterranean ◽  
Western Mediterranean ◽  
Bacterial Productivity ◽  
The North ◽  
Chemical Conditions ◽  
South Pacific Gyre ◽  
Physical And Chemical

The Eastern Mediterranean Sea (EMS) is an ultra-oligotrophic, enclosed basin strongly impacted by regional and global anthropogenic stressors. Here, we describe the annual (2018-19) dynamics of phyto- and bacterioplankton (abundances, pigments and productivity) in relation to the physical and chemical conditions in the photic water column at the offshore EMS water (Station THEMO-2, ~1,500m depth, 50km offshore). Annual patterns in phytoplankton biomass (as chlorophyll a), primary and bacterial productivity differed between the mixed winter (January-April) and the thermally stratified (May-December) periods. Prochlorococcus and Synechococcus numerically dominated the picophytoplankton populations, with each clade revealing different temporal and depth patterns, while pico-eukaryotes (primarily haptophytes) were less abundant, yet likely contributed significant biomass. Integrated primary productivity (~32 gC m-2 y-1) was lower compared with other well-studied oligotrophic locations, including the north Atlantic and Pacific (HOT and BATS observatories), the western Mediterranean (DYFAMED observatory) and the Red Sea, and was on-par with the ultra-oligotrophic South Pacific Gyre. In contrast, integrated bacterial production (~11 gC m-2 y-1) was similar to other oligotrophic locations. Phytoplankton seasonal dynamics were reminiscent of those at BATS and the Red Sea, suggesting an observable effect of winter mixing in this ultra-oligotrophic location. These results highlight the ultra-oligotrophic conditions in the EMS and provide, for the first time in this region, a full-year baseline and context to ocean observatories in the region.

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