scholarly journals Sponge community variation along the Apulian coasts (Otranto Strait) over a pluri-decennial time span. Does water warming drive a sponge diversity increasing in the Mediterranean Sea?

2019 ◽  
Vol 99 (7) ◽  
pp. 1519-1534 ◽  
Author(s):  
Gabriele Costa ◽  
Giorgio Bavestrello ◽  
Valerio Micaroni ◽  
Maurizio Pansini ◽  
Francesca Strano ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Benthic Communities ◽  
Time Span ◽  
Biodiversity Monitoring ◽  
Sponge Diversity ◽  
Community Variation ◽  
The Mediterranean ◽  
Changes Over Time ◽  
Mass Mortalities

AbstractClimate change and heavy anthropic pressures are giving rise to important modifications in the rocky benthic communities of the Mediterranean Sea. In particular, sponge assemblages have been deeply affected due to the susceptibility of some species to dramatic phenomena such as mass mortalities or widespread variations in the abundance of other species. For this reason, long-term biodiversity monitoring of the sponge assemblages is important for understanding the direction of changes over time. We studied the sponge fauna living off Tricase Porto (Otranto Strait) and compared its composition with the results of a study conducted in the same area 50 years ago. The comparison indicated that the sponge diversity of this area has strongly increased in the last 50 years and a large number of the sponges recorded in the old survey are still present in the recent community. This evidence matches with other results obtained from different localities of the Mediterranean Sea indicating an increase of sponge diversity, possibly due to the present water warming. The description of two new Demosponge species, Diplastrella boeroi sp. nov. and Spirastrella angulata sp. nov., is also provided.

scholarly journals Long-term monitoring programme of the hydrological variability in the Mediterranean Sea: a first overview of the HYDROCHANGES network

Ocean Science ◽  
2013 ◽  
Vol 9 (2) ◽  
pp. 301-324 ◽  
Author(s):  
K. Schroeder ◽  
C. Millot ◽  
L. Bengara ◽  
S. Ben Ismail ◽  
M. Bensi ◽  
...  
Keyword(s):  
Time Series ◽  
Mediterranean Sea ◽  
Sampling Interval ◽  
Global Changes ◽  
Hydrological Variability ◽  
Long Term Monitoring ◽  
The Mediterranean ◽  
Set Up ◽  
Term Monitoring

Abstract. The long-term monitoring of basic hydrological parameters (temperature and salinity), collected as time series with adequate temporal resolution (i.e. with a sampling interval allowing the resolution of all important timescales) in key places of the Mediterranean Sea (straits and channels, zones of dense water formation, deep parts of the basins), constitute a priority in the context of global changes. This led CIESM (The Mediterranean Science Commission) to support, since 2002, the HYDROCHANGES programme (http//www.ciesm.org/marine/programs/hydrochanges.htm), a network of autonomous conductivity, temperature, and depth (CTD) sensors, deployed on mainly short and easily manageable subsurface moorings, within the core of a certain water mass. The HYDROCHANGES strategy is twofold and develops on different scales. To get information about long-term changes of hydrological characteristics, long time series are needed. But before these series are long enough they allow the detection of links between them at shorter timescales that may provide extremely valuable information about the functioning of the Mediterranean Sea. The aim of this paper is to present the history of the programme and the current set-up of the network (monitored sites, involved groups) as well as to provide for the first time an overview of all the time series collected under the HYDROCHANGES umbrella, discussing the results obtained thanks to the programme.

scholarly journals Mediterranean Sea climatic indices: monitoring long term variability and climate changes

2018 ◽  
Author(s):  
Athanasia Iona ◽  
Athanasios Theodorou ◽  
Sarantis Sofianos ◽  
Sylvain Watelet ◽  
Charles Troupin ◽  
...  
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Mediterranean Sea ◽  
Climate Changes ◽  
Salt Content ◽  
Climatic Indices ◽  
In Situ Observations ◽  
The Mediterranean

Abstract. We present a new product composed of a set of thermohaline climatic indices from 1950 to 2015 for the Mediterranean Sea such as decadal temperature and salinity anomalies, their mean values over selected depths, decadal ocean heat and salt content anomalies at selected depth layers as well as their long times series. It is produced from a new high-resolution climatology of temperature and salinity on a 1/8° regular grid based on historical high quality in situ observations. Ocean heat and salt content differences between 1980–2015 and 1950–1979 are compared for evaluation of the climate shift in the Mediterranean Sea. The spatial patterns of heat and salt content shifts demonstrate in greater detail than ever before that the climate changes differently in the several regions of the basin. Long time series of heat and salt content for the period 1950 to 2015 are also provided which indicate that in the Mediterranean Sea there is a net mean volume warming and salting since 1950 with acceleration during the last two decades. The time series also show that the ocean heat content seems to fluctuate on a cycle of about 40 years and seems to follow the Atlantic Multidecadal Oscillation climate cycle indicating that the natural large scale atmospheric variability could be superimposed on to the warming trend. This product is an observations-based estimation of the Mediterranean climatic indices. It relies solely on spatially interpolated data produced from in-situ observations averaged over decades in order to smooth the decadal variability and reveal the long term trends with more accuracy. It can provide a valuable contribution to the modellers' community, next to the satellite-based products and serve as a baseline for the evaluation of climate-change model simulations contributing thus to a better understanding of the complex response of the Mediterranean Sea to the ongoing global climate change. The product is available here: https://doi.org/10.5281/zenodo.1210100.

scholarly journals Stochastic bioeconomic modelling of alternative management measures for anchovy in the Mediterranean Sea

2010 ◽  
Vol 67 (6) ◽  
pp. 1291-1300 ◽  
Author(s):  
Christos D. Maravelias ◽  
Richard Hillary ◽  
John Haralabous ◽  
Efthymia V. Tsitsika
Keyword(s):  
Mediterranean Sea ◽  
Aegean Sea ◽  
Optimal Level ◽  
Fishing Mortality ◽  
Alternative Management ◽  
Management Measures ◽  
Bioeconomic Modelling ◽  
The Mediterranean ◽  
Age Structured

Abstract Maravelias, C. D., Hillary, R., Haralabous, J., and Tsitsika, E. V. 2010. Stochastic bioeconomic modelling of alternative management measures for anchovy in the Mediterranean Sea. – ICES Journal of Marine Science, 67: 1291–1300. The purse-seine fishery for anchovy in the Aegean Sea consists of two main fleet segments (12–24 and 24–40 m vessels); this paper investigates economically and biologically preferable effort and capacity scenarios for the fishery. Attention is paid to a bioeconomic analysis of fleets composed of segments with varying levels of efficiency (in terms of catch rate) and costs (fixed and variable) and the role this might play in optimal effort allocation at a fleet level. An age-structured stochastic bioeconomic operating model for Aegean anchovy (Engraulis encrasicolus) is constructed. It attempts to account robustly for the multiple uncertainties in the system, including (i) the effort–fishing mortality relationship, (ii) the selectivity, and (iii) the stock–recruit dynamics of the population. A method is proposed for determining the economically optimal level of long-term effort in a fishery such as this, with similar characteristics in terms of stock dynamics, fishery, and markets. Lower values of effort and capacity are predicted to yield greater future profit when viewing the fleet in its entirety, but even lower values may be advisable to maintain the long-term biological integrity of the stock. The results may prove useful in balancing the productivity of the stock with the harvesting capacity of the fleet, while managing to ensure the long-term profitability of the fleet along with the sustainability of the resource.

scholarly journals Mediterranean Tropical-Like Cyclones in Present and Future Climate

2014 ◽  
Vol 27 (19) ◽  
pp. 7493-7501 ◽  
Author(s):  
Leone Cavicchia ◽  
Hans von Storch ◽  
Silvio Gualdi
Keyword(s):  
Climate Change ◽  
Mediterranean Sea ◽  
Tropical Cyclones ◽  
Dynamical Evolution ◽  
Climate Change Scenarios ◽  
Moderate Increase ◽  
High Resolution Data ◽  
The Mediterranean ◽  
The One

Abstract The Mediterranean has been identified as one of the most responsive regions to climate change. It has been conjectured that one of the effects of a warmer climate could be to make the Mediterranean Sea prone to the formation of hurricanes. Already in the present climate regime, however, a few of the numerous low pressure systems that form in the area develop a dynamical evolution similar to the one of tropical cyclones. Even if their spatial extent is generally smaller and the life cycle shorter compared to tropical cyclones, such storms produce severe damage on the highly populated coastal areas surrounding the Mediterranean Sea. This study, based on the analysis of individual realistically simulated storms in homogeneous long-term and high-resolution data from multiple climate change scenarios, shows that the projected effect of climate change on Mediterranean tropical-like cyclones is decreased frequency and a tendency toward a moderate increase of intensity.

scholarly journals Physical and biogeochemical parameters of the Mediterranean Sea during a cruise with RV <i>Maria S. Merian</i> in March 2018

2020 ◽  
Vol 12 (4) ◽  
pp. 2747-2763
Author(s):  
Dagmar Hainbucher ◽  
Marta Álvarez ◽  
Blanca Astray Uceda ◽  
Giancarlo Bachi ◽  
Vanessa Cardin ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Spatial And Temporal Scales ◽  
Circulation Patterns ◽  
Report Data ◽  
Zonal Section ◽  
The Mediterranean ◽  
Biogeochemical Parameters ◽  
Anthropogenic Contributions

Abstract. The last few decades have seen dramatic changes in the hydrography and biogeochemistry of the Mediterranean Sea. The complex bathymetry and highly variable spatial and temporal scales of atmospheric forcing, convective and ventilation processes contribute to generate complex and unsteady circulation patterns and significant variability in biogeochemical systems. Part of the variability of this system can be influenced by anthropogenic contributions. Consequently, it is necessary to document details and to understand trends in place to better relate the observed processes and to possibly predict the consequences of these changes. In this context we report data from an oceanographic cruise in the Mediterranean Sea on the German research vessel Maria S. Merian (MSM72) in March 2018. The main objective of the cruise was to contribute to the understanding of long-term changes and trends in physical and biogeochemical parameters, such as the anthropogenic carbon uptake and to further assess the hydrographical situation after the major climatological shifts in the eastern and western part of the basin, known as the Eastern and Western Mediterranean Transients. During the cruise, multidisciplinary measurements were conducted on a predominantly zonal section throughout the Mediterranean Sea, contributing to the Med-SHIP and GO-SHIP long-term repeat cruise section that is conducted at regular intervals in the Mediterranean Sea to observe changes and impacts on physical and biogeochemical variables. The data can be accessed at https://doi.org/10.1594/PANGAEA.905902 (Hainbucher et al., 2019), https://doi.org/10.1594/PANGAEA.913512 (Hainbucher, 2020a) https://doi.org/10.1594/PANGAEA.913608, (Hainbucher, 2020b) https://doi.org/10.1594/PANGAEA.913505, (Hainbucher, 2020c) https://doi.org/10.1594/PANGAEA.905887 (Tanhua et al., 2019) and https://doi.org/10.25921/z7en-hn85 (Tanhua et al, 2020).

scholarly journals New historical data for long-term swordfish ecological studies in the Mediterranean Sea

2021 ◽  
Vol 13 (12) ◽  
pp. 5867-5877
Author(s):  
Brian R. MacKenzie ◽  
Teresa Romeo ◽  
Piero Addis ◽  
Pietro Battaglia ◽  
Pierpaolo Consoli ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Fishery Management ◽  
Data Availability ◽  
Knowledge Based ◽  
Time Period ◽  
Before And After ◽  
Trap Fishery ◽  
History Of ◽  
The Mediterranean

Abstract. Management of marine fisheries and ecosystems is constrained by knowledge based on datasets with limited temporal coverage. Many populations and ecosystems were perturbed long before scientific investigations began. This situation is particularly acute for the largest and commercially most valuable species. We hypothesized that historical trap fishery records for bluefin tuna (Thunnus thynnus Linnaeus, 1758) could contain catch data and information for other, bycatch species, such as swordfish (Xiphias gladius Linnaeus, 1758). This species has a long history of exploitation and is presently overexploited, yet indicators of its status (biomass) used in fishery management only start in 1950. Here we examine historical fishery records and logbooks from some of these traps and recovered ca. 110 years of bycatch data (1896–2010). These previously neglected, but now recovered, data include catch dates and amounts in numbers and/or weights (including individual weights) for the time period before and after major expansion of swordfish fisheries in the Mediterranean Sea. New historical datasets such as these could help understand how human activities and natural variability interact to affect the long-term dynamics of this species. The datasets are online and available with open access via three DOIs, as described in the “Data availability” section of the article.

scholarly journals Mediterranean Sea climatic indices: monitoring long-term variability and climate changes

2018 ◽  
Vol 10 (4) ◽  
pp. 1829-1842 ◽  
Author(s):  
Athanasia Iona ◽  
Athanasios Theodorou ◽  
Sarantis Sofianos ◽  
Sylvain Watelet ◽  
Charles Troupin ◽  
...  
Keyword(s):  
Time Series ◽  
Mediterranean Sea ◽  
Climate Changes ◽  
Salt Content ◽  
Climatic Indices ◽  
Long Time ◽  
In Situ Observations ◽  
The Mediterranean

Abstract. We present a new product composed of a set of thermohaline climatic indices from 1950 to 2015 for the Mediterranean Sea such as decadal temperature and salinity anomalies, their mean values over selected depths, decadal ocean heat and salt content anomalies at selected depth layers as well as their long time series. It is produced from a new high-resolution climatology of temperature and salinity on a 1∕8∘ regular grid based on historical high-quality in situ observations. Ocean heat and salt content differences between 1980–2015 and 1950–1979 are compared for evaluation of the climate shift in the Mediterranean Sea. The two successive periods are chosen according to the standard WMO climate normals. The spatial patterns of heat and salt content shifts demonstrate that the climate changes differently in the several regions of the basin. Long time series of heat and salt content for the period 1950 to 2015 are also provided which indicate that in the Mediterranean Sea there is a net mean volume warming and salinification since 1950 that has accelerated during the last two decades. The time series also show that the ocean heat content seems to fluctuate on a cycle of about 40 years and seems to follow the Atlantic Multidecadal Oscillation climate cycle, indicating that the natural large-scale atmospheric variability could be superimposed onto the warming trend. This product is an observation-based estimation of the Mediterranean climatic indices. It relies solely on spatially interpolated data produced from in situ observations averaged over decades in order to smooth the decadal variability and reveal the long-term trends. It can provide a valuable contribution to the modellers' community, next to the satellite-based products, and serve as a baseline for the evaluation of climate-change model simulations, thus contributing to a better understanding of the complex response of the Mediterranean Sea to the ongoing global climate change. The product is available in netCDF at the following sources: annual and seasonal T∕S anomalies (https://doi.org/10.5281/zenodo.1408832), annual and seasonal T∕S vertical averaged anomalies (https://doi.org/10.5281/zenodo.1408929), annual and seasonal areal density of OHC/OSC anomalies (https://doi.org/10.5281/zenodo.1408877), annual and seasonal linear trends of T∕S, OHC/OSC anomalies (https://doi.org/10.5281/zenodo.1408917), annual and seasonal time series of T∕S, OHC/OSC anomalies (https://doi.org/10.5281/zenodo.1411398), and differences of two 30-year averages of annual and seasonal T∕S, OHC/OSC anomalies (https://doi.org/10.5281/zenodo.1408903).

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