Day 10

The team

If we ask anybody: which is the color of the sea? The answer will most of the times be: blue. This will be particularly likely for Mediterranean people who enjoy the transparent, crystalline, blue waters of their sea. But we know that the sea is not always blue. If we enter a harbor its color will probably be brownish, or if we stay close to the mouth of a river it will vary from emerald green to dark green. What makes the colors of the sea so different? The answer is obvious: it depends on what is in it, and everybody would give that answer. Then we may ask: what are the mechanisms that make the color changing and can we use them for studying the ocean? The answer is less trivial, because deals with the physics of the light and its interaction with the matter. But we can put it in a simple way. Let us look at the sun ray as beam of small particles, the photons, which when passing through the water can hit a water molecule or a molecule of something dissolved in the water or a suspended particle. In some case the photons can be deviated from their original path and change direction. In some other cases they can just be absorbed with their energy transformed in heat. In both cases the original beam will lose them and will become weaker and weaker. We say that the light gets attenuated traveling in the water. If we then think that not all photons are equal but each of them has a special color then the more one color is absorbed the more the residual light will lack that color. On the other hand the more a color gets deviated form the path the more that color will be seen in the direction where it has been deviated. The colors span from blue to green to yellow to red. So if we have something that absorbs the blue and red light then we will see it as green. But if we have something diffusing the green light then, from specific directions we may again see it green.
So let's go back to the sea. If the water or anything in it absorbs a photon we will loose it and the light beam will become weaker and infinitesimally more colored. But if something is just deviating the photon (we use the word scattering for this process) and some of them will have at the end their path directed upward, i.e., toward the surface then part of them may eventually exit the water and hit our eyes. Are those photons which are more numerous for the colors that have been absorbed the least that let us to perceive what is the color of the water. So we understood that we can see the ocean color because some of the light entering it is eventually diffused back, and the color derives from the properties of the substances in the water. Then we go to the second question. Can we use this information? Of course the answer is yes and we make just an example.
We know that the plants on the land are green. This is because they contain chlorophylls which are green. Also their marine relatives contain chlorophylls and some other substances that are red-brownish. Most of the chlorophyll containing organisms that make photosynthesis just alike their terrestrial sisters are microscopic and live suspended in the water. We name them phytoplankton. And they are green or brown. So if we can measure how intense is the green, which we already know means how much blue and red are absorbed we have a way to know how much phytoplankton is in the sea. This is the clever approach satellites use to monitor everyday all the ocean to assess how much phytoplankton is suspended in it. During Sesame cruise we are measuring the same with an instrument, called underwater spectroradiometer which is tethered to a computer and is left sinking in the water for 100 m or so, and while sinking it measures the intensity of each color at each depth. It does it for the light penetrating from the top and for the light upwelling from the deeper layers (the light that was scattered back). From the analysis of the proportion of different colors in the beam at each depth (we call it a spectrum) it is possible to infer how much phytoplankton there was in the water and also to improve the use of the satellites that see the color of ocean from the sky.

Day 9

Preparing the net for collecting meso-zooplankton (WP2, 200 µm).

Hello to everybody!
Do you remember three days ago we spoke about zooplankton? I hope you do! Today I will tell you how we collect them to study their distribution. The simplest way is to perform a tow with a net, a bit like fishing. However, nets for zooplankton have much smaller mesh size than nets for fish. Why? Because zooplanktonic animals are very small!

I am sure you remember that zooplankton is also very diverse, including animals from different zoological groups and of different sizes. This large biodiversity makes it impossible to study the 'whole' zooplankton communities with a single kind of net, because it would not collect with the same efficiency animals of variable sizes. Actually, zooplankton is conventionally classified according to size classes based on the nets that capture them. Meso-zooplankton, for example, range from 0.2 to 2 mm and are collected by nets with 0.2 mm mesh aperture. Macro-zooplankton is larger than 2 mm are collected with larger nets that have 0.5-1 mm mesh aperture. Finally, micro-zooplankton, mostly represented by protozoans and copepod larvae (nauplii), are better collected by bottles or small nets with tiny mesh aperture (0.02-0.05 mm).

During this SESAME campaign, we collect meso-zooplankton by performing vertical tows with a standard net (WP2) with 0.2 mm mesh aperture. You can see it in the pictures here attached. This is a 'closing' net, which, thanks to a mechanical device, can be closed at a certain depth and therefore sample zooplankton from a discrete depth layer. During this campaign, we collect samples from three different layers (0-50 m, 50-100m, 100-200 m) to investigate on the vertical distribution of species in the upper water column. Meso-zooplankton tend to be more abundant in these surface waters because phytoplankton, their major food source, are also more abundant in the surface.

Immediately after collection, samples have to be preserved in formaldehyde (to avoid decomposition) and then they will be analyzed using a dissecting microscope. I cannot perform this analysis on board, because the ship moves too much, so I have to do it once back in the institute on land. Lots of work is waiting for me in the few months after the campaign!
Bye bye! Back in a few days, with other news about zooplankton.
Maria Grazia

Day 8 - Bacterial production for boys and girls

My name is Luis and my task on this cruise is the study of Heterotrophic Bacterial Production in marine environments, also called Bacterial Production or simply BP. As the name may suggest this is not an easy topic but in essence we are talking about the the carbon cycle in the marine environment.

Bacteria are very little unicellular organisms, spherical or rod-like, usually less than 1 micrometer in length (a thousandth of a milimeter). They are always present in the seawater, and a single drop can contain from 500 to 15 000 microorganisms! Therefore, bacteria are the most abundant organisms of the whole marine environment. The bacterial activities such as enzymatic transformation, organic matter uptake as well as remineralization are very important for the carbon cycle in the marine ecosystem. The bacteria are only organisms able to use the dissolved organic matter (DOM) produced during photosynthetic processes or introduced in the environment as exogenic substances. They absorb dissolved carbon and make it available as cellular (particulate) organic matter as food for an upper level of the marine food chain. Therefore, bacterial production is the increase of bacterial biomass that occurs in one time unit and the results are expressed as nanograms (a thousand million part of one gram) of bacterial carbon per litre per hour. This amount of carbon may seem insignificant, but if you think of the Mediterranean Sea as a whole, it really represents hundreds of tons of organic matter per day. At this point, you might understand the relevance of the Bacterial Production in carbon cycle studies.

Any preservation method applied to the water samples alters its microbiological characteristics, as a result, to obtain accurately BP results it is essential that the analysis is performed on board immediately after the water samples are taken. Therefore, during an oceanographic cruise, the laboratory is in action 24 hours a day!
Arrivederci
Luis

Day 7

From the Italian research vessel Urania, during the oceanographic campaign in the frame of the European Program SESAME, in the southern Ionian Sea.

Today is the first sunny day since our departure, and we finally see the blue colour of the water and bright light in the sky. Everyone is in a good mood and, thanks to the long transit, we all take the opportunity to rest, read on deck in the sun, or working in the lab but gently.

While resting on the upper deck and watching the sea, I hope to glimpse dolphins playing at the surface, or fish schools crossing our track. But the surface is calm and apparently empty, and I go with my thoughts to the invisible organisms that live into the water column and populate the marine waters in very high numbers from the surface to the bottom. I am talking about zooplankton, the topic of my research work.

During this cruise, I collect zooplankton samples to measure their abundance (as individuals per cubic meter) and biomass (as dry weight and carbon content) and to identify and count the species composition. But I will talk about this project later on, now I would like to introduce you to zooplankton, a quite neglected world to the public, unless in summer jellyfish outbreak and create problems for our beaches.

The zooplankton communities are made by all animals that live in suspension within the water column. The terms 'plankton' means 'floating'. Zooplankton is very diverse group because it is comprised of all zoological phyla, from protozoans (e.g. ciliates, foraminifers, radiolarians,..) to vertebrates (e.g. eggs and larvae of fish), also covering a large size spectrum (from a few tens of microns to certain large jellyfish over a meter in length). All these very different animals have common features that represent adaptations to living in suspension. For example, the body density is reduced by small dimensions (e.g. in crustaceans) or increased water content (e.g. up to 90% of the body in gelatinous zooplankton such as jellyfish).

Among planktonic crustaceans, the most numerous are copepods, the so called 'insects of the sea', because of their similar features in terms of life history traits, some biological and ecological traits and their role in food webs. Copepods are very abundant and rich in species and, considering their distribution in the large oceanic volumes, they likely represent the most numerous metazoans on Earth. In many copepod species, the body is ornamented by numerous and various appendages, like long feathered setae, which decrease the body density but also represent sensory structures that allow these tiny animals to perceive their prey, predators and mates in the surrounding environment. Most zooplankters are transparent to be invisible to visual predators and many are bioluminescent.

Zooplankton plays an important role in marine ecosystems, because it is a key element in the pelagic food webs and contribute to biogeochemical fluxes. Zooplankters are omnivore consumers; most of them feed preferentially on autotrophic phytoplankton while a few are preferential carnivorous. They are preyed on by fish, birds and marine mammals and contribute to the carbon flux through the marine biota.

Ooops! Bell rings now announcing dinner time. We'll keep talking about zooplankton (and phytoplankton) during over the next few days.
Bye everybody and see you soon!
Maria Grazia Mazzocchi, Stazione Zoologica Anton Dohrn di Napoli

Day 6

Dear readers,
We are now directed toward station 17, or as we technically call it S-IT2-017. We are in the southern Ionian Sea, closer to Libya than to Italy, and we are lucky to have reached this point. In the past days, in fact, the captain was afraid that we may have to turn back toward the Sicilian coast due to bad weather forecasts, but such weather has not materialized, despite all the meteorological bulletins.

I am Benedetto and I am part of the research group of the Zoological Station of Naples, what is also commonly knows as 'the aquarium', although its role is rather greater that just fish expositions. There are three of us from Naples onboard: Grazia, Maurizio, that is the cruise chief scientist, and I. With Maurizio, we specialise in two domains: the bio-optics and the characterization of the photosynthetic plankton. Don't be afraid, I am going to explain it better.

In bio-optics, we deal with the light in the surface layer of the sea. We measure how light characteristics change trying to investigate the causes and predict the effects on the organisms. To reach this objective, we use two instruments that are casted at a depth of about 100 meters: the first is the 'Satlantic', a torpedo-shaped sensor, that measures the quantity and quality (we can think of it as the light colour) of solar light that reaches different depths; the second is called AC-9 and it takes measurements at different depths as well, but, unlike 'Satlantic', it emits light itself that is then received by a sensor, and in this way we can directly measure how much light is absorbed by the water itself.

The second target of our investigation is the characterization of phytoplankton, the tiny aquatic organisms responsible for photosynthesis. Like plants on ground, they use light to grow and with this energy they sustain all the bigger organisms encountered in the sea, all the way up to fish. So, it is easy to imagine how important this phytoplankton is. To study it, we filter sea water and, once back on land, we analyze the filters for different pigments (chlorophyll and its variations), molecules indicating the presence of various phytoplankton species.

Of all deployments, the funniest part is when we put the 'Satlantic' in the water. We coordinate with walkie talkies: Maurizio is in front a computer screen, in the laboratory, and I am on the stern (at the rear of the vessel) putting the instrument in the water. The captain does not always have full confidence in me so he comes on the stern too, to make sure everything goes well. Instrument deployment from the stern of the ship is always a negotiating situation: I would like to slow down the ship to optimize measurements and the captain wants to go faster so as to avoid the instrument going into the screw of the ship. At the end, he has to take the final decision, but we always find a compromise.

Now I have to say goodbye because it's time to clean the instruments, and that takes lots of time and care...
Bye bye

Day 5

Hello dear friends!!
Even if are the 3 a.m., I want to tell you what have we done in this sea day!!
My name is Irene and this is my first experience on board of a oceanographic ship. I carry out my activity of specialistic thesist on the premises of biophisic' institute of CNR (national council of researches) Pisa's section. My work consist in measurement of optical proprieties, in particulary absorbiment and fluorescence of Organic Dissolved Matter present in samples taked in different oceanographic campaignes.
I'm sure that you, as me in the first time, don't know exactly what is this organic dissolved matter
So, the DOM (abbreviated name) have many origins, for example:
- possible death of vegetal and animal organisms living in the sea
- the �'lunch crumbes''of some predator and herbivor organisms
- fecal pellets of marine animals
Ok, now that the idea of what is the DOM is more clear, an other possible question can be..."why this is so important in marine environment??" Mainly it is converterted in new nurients by chemical reactions carry out by smaller organisms as bacteria, virus, protists. These new nutrients are reabsorbed by photosynthetic organisms, as fitoplancton, turn off the food chain.
In this night full of sparkling stars, we have sampled in a station off the greek coasts.
In these days the sea has been rough but being its a kind soul allow us to do our works.
The marine water samples taked throught rosette system are strained and then are kept at 5�C in the refrigerator. The real important analysis of them will be made in CNR Pisa laboratory.
So, the time of dreams is now arrived and my eyes are starter to close.
Goodnight guys and we see again at next adventure!..bye bye

Day 4

Hello, dear friends!
Welcome on board the Italian research vessel Urania!
We are now navigating toward the middle of the Ionian Sea, along the track planned in the SESAME Project.
Our research team is formed by myself, Giuseppe Civitarese, and my colleague Stefano Cozzi. We are two chemical oceanographers of the CNR - Istituto di Scienze Marine of Trieste (Italy) and our research interest can be viewed as a mixture of physics, chemistry and biology (oceanography really is a interdisciplinary matter!).
We study the distribution and behaviour of some basic biogeochemical compounds, namely nitrite, nitrate, phosphate, and silicate also known as nutrients, and dissolved oxygen, in different marine environments. In addition, we are interested in other parameters, such as total dissolved phosphorus (TDP) and nitrogen (TDN), pH and Alkalinity.
At any station, we collect samples in the water column with a multisampler, the so-called “rosette". This is a complex mechanical and electronical device equipped with a probe (CTD which stands for Conductivity Temperature Depth) that is able to record continuously some environmental parameters (temperature, salinity, fluorescence, ...). The rosette also has 24 twelve-litres bottles that collect water at different depths.
After we collect our water samples we store them at different temperatures (ambient temperature, +5 C, -20 C, according to the experiment) so that they can be analyzed in our laboratories back on land. Here on the ship, we only analyze the dissolved oxygen in the sea water.
Well, you are now wondering why we study these parameters...
Nutrients represent the first level of the marine food web, since they contain the basic elements, such as nitrogen (N), phosphorus (P) and silicate (Si), which are necessary for the growth of phytoplankton, the autotrophic producers. The dissolved organic compounds (TDN and TDP) are the forms of N and P resulting from the assimilation and other processes operated by the marine biota.
So, nutrients and organic compounds are fundamental components of the food web and their study allow us to better understand some basic ecological aspects of the sea.
In addition, nutrients, together with dissolved oxygen, are useful in tracing the water masses of the Mediterranean and their evolution through space and time.
Due to climate change and the “warming" phase we are experiencing, it is particularly important to assess the ability of the Mediterranean Sea to trap the excess of the major "greenhouse effect" agent released by human activity in the atmosphere, CO2. The sea dissolves the CO2 or releases it to the atmosphere through a complex series of chemical reactions (modulated by the physics and by the biology of the sea) called “the carbonate system". The pH and the Alkalinity are two important parameters of the marine carbonate system. Through their precise determination along the water column we will be able to better assess the carbon content of the sea and its dynamics.
Apart from the work, it's really funny to participate on an oceanographic cruise. We wish you enjoy this experience too...
Well, now it's late. Our rosette is coming back from the abyssal Mediterranean (about 4 km deep!). It's time to work!

Ciao!

Day 3

Deployment of the rosette

Good afternoon everybody!
We take advantage of this short break to tell you about our activities during this hard working day. We are Gabriella Cerrati and Stefano Salvi, and we work for ENEA (Italian National Agency for new Technologies, Energy and the Environment). During this Oceanographic Cruise organized in the framework of SESAME project, we are responsible for:
The determination of organic carbon, nitrogen (N) and phosphorus (P) in sea water particles at different depths, from the surface to the bottom, in 10 sampling locations in the Ionian Sea.
Measuring Cesium (137Cs) contamination along a water vertical profile at 5 sampling locations. This Cesium isotope is radioactive and originates from the Chernobyl accident in 1986.

It is Sunday morning but nevertheless we woke up at 3:45am and arrived on S-IT2-003 sampling station 45 minutes later. We collect our samples with a particular device called "Rosette" (see picture) that allows us to acquire some proprieties of the water column (salinity, temperature, etc.) as it is lowered, and to collect water samples at discrete depths during the ascent.
To measure organic carbon, Nitrogen and Phosphorus content, about 5 litres of sea water are filtrated and all the particulates in it are collected on a glass microfibre filter, which is then stored at 20 °C for further analysis in the lab back on land.
The Cesium isotope, 137Cs, is extracted from approximately 20 litres of sea water through a selective precipitation, and stored in a plastic PVC bottle to be carried back to the lab.

Operations on this station finished at about 11:00am, just in time for lunch and a little rest because ... at 15 o'clock in the afternoon we will arrive to the next sampling station!
Bye!!

Day 2

This morning at the sunrise the group of the OGS (National Oceanographic Institute of Trieste) started the research operations of this oceanographic cruise positioning a deep measuring mooring at the seafloor (850m depth) in the area to the Otranto Strait. This mooring is anchored at the bottom and has a subsurface buoy that maintains in a vertical position, from the sea bottom upwards, a series of instruments positioned a different depths. This instruments measure every 15 minutes the physical properties of the sea, e.g. currents, temperature and salinity that allow to characterize the different water masses.

After one year, during a similar research cruise, we will return to the same location to recover this mooring. This will be possible by sending an acoustic signal into the sea; the mooring will receive the order to release the instrument chain from the anchor so that all the instruments will be spined up to the sea surface. The instruments will be taken onboard and all the data will be downloaded, giving us the possibility to describe and better understand the water masses exchange occurred during this period between the Ionian and the Adriatic seas through the Otranto Strait.

Day 1

The italian Research Vessel URANIA

Good evening my name is Maurizio Azzaro and I am a researcher at the Institute for the Marine Coastal Environment of Messina. As the chief scientist of the SESAME IT2 cruise, I will care of both the scientific and logistic organization of the survey. Moreover I’ll perform the measurements of microbial respiratory rates along the entire water column. The cruise in the Ionian Sea is starting with a 24 h delay. This morning we took aboard the scientific instrumentations of the Research Teams of this Leg. 16 scientist from several Italian scientific Institutions (CNR-IAMC, CNR-ISMAR, CNR-IBF, OGS, SZN, ENEA) will be working on this project. Our group gets on well together because we worked in the past in several multidisciplinary national and international projects. A couple of hours ago we met to plan the research activities and to assign the lab locations. In this moment we are preparing the laboratories and there is a big excitement as we feel like beginning the cruise. We plan to sail today at 6:05 p.m. Launching of a mooring in the Southern Adriatic Sea (Lat. 40° 49.94’ N; Long 018° 40.79’ E), is planned tomorrow at 6:00 a.m, before of the start of the samplings in the Ionian Sea.