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).

Abundance of phytoplankton in the Marmara Sea collected during the Bilim 2 cruise in April 2008

The dataset is composed of 48 samples from 17 stations. The phytoplankton samples were collected by 5l Niskin bottles attached to the CTD system. The sampling depths were selected according to the CTD profiles and the in situ fluorometer readings. The samples (50 ml sea water) were preserved with prefiltered (0.2 micron) glutardialdehyde solution (1.5 ml of commercial glutardialdehyde (25%)) into dark colored glass bottles. Preserved samples were poured into 10 or 25 ml settling chambers (Hydro-Bios) for cells to settle on the bottom over a day. Species identification and enumeration were done under an inverted microscope (Olympus IX71). At least 400 specimen were tried to be counted in each sample.

Abundance of phytoplankton in the Cilician Basin during the Bilim 2 cruise in September 2008

The dataset is composed of 20 samples from 14 stations. The phytoplankton samples were collected by 5l Niskin bottles attached to the CTD system. The sampling depths were selected according to the CTD profiles and the in situ fluorometer readings. The samples (50 ml sea water) were preserved with prefiltered (0.2 micron) glutardialdehyde solution (1.5 ml of commercial glutardialdehyde (25%)) into dark colored glass bottles. Preserved samples were poured into 10 or 25 ml settling chambers (Hydro-Bios) for cells to settle on the bottom over a day. Species identification and enumeration were done under an inverted microscope (Olympus IX71). At least 400 specimen were tried to be counted in each sample.

A stereo-image analysis JAVA software with links to executable and source code

Scientists planning to use underwater stereoscopic image technologies are often faced with numerous problems during the methodological implementations: commercial equipment is too expensive; the setup or calibration is too complex; or the imaging processing (i.e. measuring objects in the stereo-images) is too complicated to be performed without a time-consuming phase of training and evaluation. The present paper addresses some of these problems and describes a workflow for stereoscopic measurements for marine biologists. It also provides instructions on how to assemble an underwater stereo-photographic system with two digital consumer cameras and gives step-by-step guidelines for setting up the hardware. The second part details a software procedure to correct stereo-image pairs for lens distortions, which is especially important when using cameras with non-calibrated optical units. The final part presents a guide to the process of measuring the lengths (or distances) of objects in stereoscopic image pairs. To reveal the applicability and the restrictions of the described systems and to test the effects of different types of camera (a compact camera and an SLR type), experiments were performed to determine the precision and accuracy of two generic stereo-imaging units: a diver-operated system based on two Olympus Mju 1030SW compact cameras and a cable-connected observatory system based on two Canon 1100D SLR cameras. In the simplest setup without any correction for lens distortion, the low-budget Olympus Mju 1030SW system achieved mean accuracy errors (percentage deviation of a measurement from the object's real size) between 10.2 and -7.6% (overall mean value: -0.6%), depending on the size, orientation and distance of the measured object from the camera. With the single lens reflex (SLR) system, very similar values between 10.1% and -3.4% (overall mean value: -1.2%) were observed. Correction of the lens distortion significantly improved the mean accuracy errors of either system. Even more, system precision (spread of the accuracy) improved significantly in both systems. Neither the use of a wide-angle converter nor multiple reassembly of the system had a significant negative effect on the results. The study shows that underwater stereophotography, independent of the system, has a high potential for robust and non-destructive in situ sampling and can be used without prior specialist training.

Surface spectral albedo complementary to ROV transmittance measurements at 6 ice stations during POLARSTERN cruise ARK-XXVII/3 (IceArc) in 2012

The dataset consists of spectra and photogrpahs of the surface (sea ice and melt ponds) obtained in the Central Arctic during the Polarstern cruise ARK-XXVII/3 at 6 ice stations. The spectra were measured with a portable spectroradiometer ASD FieldSpecPro 3. The photographs were taken with a digital camera Olympus C765 in the "Auto" mode. The measurements have been performed every 10 meters along 100 m ROV transects (transects used for underice ROV flights) where available. Otherwise the albedo measurements have been done at the selected cites complementary to point transmitance measurements or at cites featuring characteristic sea ice surface.