Abundance of microplankton in the eastern Mediterranean Sea in March and April 2008 during SES_GR1

The dataset is based on samples taken from 12 stations in Southern Aegean Sea, Northern Aegean Sea, Ionian Sea and Libyan Sea during March-April 2008. 12 Niskin bottles (8lt) made by PVC with rubber coated o rings and stainless steel ss springs. Seawater samples (150 ml) were collected from selected depths of the water column (2, 20, 50, 75, 100 m) for the identification and enumeration of phytoplankton cells (>=5 µm). The samples were fixed with Lugol solution and concentrated to 25 ml by sedimentation. Phytoplankton species abundance was determined with an inverted light microscope (OLYMPUS IX70) according to the Utermohl method (Utermohl, 1958).

Further expansion of the alien seaweed Caulerpa taxifolia var. distichophylla (Sonder) Verlaque, Huisman & Procacini (Ulvophyceae, Bryopsidales) in the Eastern Mediterranean Sea

Date of Acceptance: 27/04/2015 We are grateful to Andreas Antoniou (Dep. of Environment, Ministry of Agriculture, Rural Development & Environment, Cyprus) for his assistance in the preparation of the illustrations. We would also like to thank Dr. Sotiris Orfanidis (NAGREF – Fisheries Research Institute, Kavala, Greece) for his valuable advice and both the DFMR and HSR / HCMR Rhodes crew and George Hatiris for their help in samplings. Special thanks are due to Dinos Leonidou (SeaQuest Divers Cyprus) for accompanying the deep dive for sampling Caulerpa at Cavo Greco. We are grateful to the Total Foundation (Paris) for its funding support to this study within the framework of the project “Brown algal ecology and biodiversity in the eastern Mediterranean Sea” and to the MASTS pooling initiative (Marine Alliance for Science and Technology for Scotland, funded by the Scottish Funding Council and contributing institutions; grant reference HR09011).

(Table 2) Stable carbon and oxygen isotope record of benthic foraminifera of eastern Mediterranean Sea sediment cores

The paleoproductivity, paleo-oxygenation, and paleohydrographic configuration of the southeastern Mediterranean during the late Holocene was reconstructed on the basis of the isotopic composition of the epibenthic Heterolepa floridana, shallow-endobenthic Uvigerina mediterranea, and the deeper endobenthic Bulimina inflata from two high-resolution cores GA-112 (470 m) and GA-110 (670 m). The Delta d13C between H. floridana and U. mediterranea reveals four intervals of enhanced productivity, from 3.3-2.6, 2.3-1.9, 1.5-1.1, and 0.8-0.4 kyr BP, coinciding with increased nutrient supply by the Nile River. The entire basin was well aerated, with oxygen consumption varying between 1.0 and 3.5 mL O2/L. Oxygen consumption increases toward present day, probably because of higher accumulation of total organic carbon at 1.7 kyr BP, coinciding with the appearance of the mesotropic benthic species. The hydrographic configuration of the basin has changed during the course of the last 3.75 kyr. The Levantine Intermediate Water (LIW) deepens below 470 m between 3.3 and 2.0 kyr, and especially between 2.5 and 2.0 kyr. During the last 1.5 kyr, the LIW becomes shallower than 470 m, similar to the present day. The change in the hydrographic configuration reflects changes in evaporation/precipitation ratio and in temperature.

Sr- and Nd-isotopic composition of bulk lithogenic sediments from the Eastern Mediterranean Sea (Table 1)

In order to characterize the provenance of lithogenic surface sediments from the Eastern Mediterranean Sea (EMS), residual (leached) fraction of 34 surface samples have been analysed for their 143Nd/144Nd and 87Sr/86Sr isotope ratios. The sample locations bracket all important entrances of riverine suspended matter into the EMS as well as all sub-basins of the EMS. The combined analyses of these two isotope ratios provide a precise characterization of the lithogenic fraction of surface sediments and record their dilution towards the central sub-basins. We reconstruct provenance and possible pathways of riverine dispersal and current redistribution, assuming more or less homogenous isotopic signatures and flux rates of the eolian fraction over the EMS. Lithogenic sediments entering the Ionian Sea from the Calabrian Arc and the Adriatic Sea are characterized by high 87Sr/86Sr isotope ratios and low epsilon-Nd(0) values (average 87Sr/86Sr=0.718005 and epsilon-Nd(0)=-11.06, n=5). Aegean Sea terrigenous sediments show an average ratio of 87Sr/86Sr=0.713089 (n=5) and values of epsilon-Nd(0)=-7.89 (n=5). The Aegean isotopic signature is traceable up to the southwest, south, and southeast of Crete. The sediment loads entering the EMS via the Aegean Sea are low and spread out mainly through the Strait of Casos (east of Crete). Surface sediments from the eastern Levantine Basin are marked by the highest epsilon-Nd(0) values (-3.3, n=6) and lowest 87Sr/86Sr isotope ratios (average 0.709541, n=6), reflecting the predominant input of the Nile sediment. The influence of the Nile sediment is traceable up to the NE-trending, eastern flank of the Mediterranean Ridge. The characterization of the modern riverine dispersal and eolian flux, based on isotope data, may serve as a tool to reconstruct climate-coupled variations of lithogenic sediment input into the EMS.

Concentrations of major and minor constituents of samples from the lower end of the cores from the eastern Mediterranean Sea (Table 2)

The pore water chemistry of mud volcanoes from the Olimpi Mud Volcano Field and the Anaximander Mountains in the eastern Mediterranean Sea have been studied for three major purposes: (1) modes and velocities of fluid transport were derived to assess the role of (upward) advection, and bioirrigation for benthic fluxes. (2) Differences in the fluid chemistry at sites of Milano mud volcano (Olimpi area) were compiled in a map to illustrate the spatial heterogeneity reflecting differences in fluid origin and transport in discrete conduits in near proximity. (3) Formation water temperatures of seeping fluids were calculated from theoretical geothermometers to predict the depth of fluid origin and geochemical reactions in the deeper subsurface. No indications for downward advection as required for convection cells have been found. Instead, measured pore water profiles have been simulated successfully by accounting for upward advection and bioirrigation. Advective flow velocities are found to be generally moderate (3-50 cm/y) compared to other cold seep areas. Depth-integrated rates of bioirrigation are 1-2 orders of magnitude higher than advective flow velocities documenting the importance of bioirrigation for flux considerations in surface sediments. Calculated formation water temperatures from the Anaximander Mountains are in the range of 80 to 145 °C suggesting a fluid origin from a depth zone associated with the seismic decollement. It is proposed that at that depth clay mineral dehydration leads to the formation and advection of fluids reduced in salinity relative to sea water. This explains the ubiquitous pore water freshening observed in surface sediments of the Anaximander Mountain area. Multiple fluid sources and formation water temperatures of 55 to 80 °C were derived for expelled fluids of the Olimpi area.