The introduction of the paper is really very original as they quote the first description of the dust clouds from the Sahara. The citation is from somebody named Charles Darwin who sail this area on board a ship called H.M.S. Beagle. Below is the text.
lunes, 14 de diciembre de 2009
Dust composition
domingo, 25 de octubre de 2009
Meeting
The IP will give a short talk about the history and objectives of the project for the new members and he will present the dueties before sampling and the sampling program.
Do not forget to e-mail the IP.
lunes, 5 de octubre de 2009
Remember important dust events
miércoles, 29 de julio de 2009
Two interesting papers
martes, 7 de julio de 2009
Saharan Dust Storms and Plankton in the Ocean
As our colleague Gara Frachy saids, they are using the same kind of picture we use here but in their area of research. Perhaps, we follow the same objectives...
This was one of the reasons for the IFM-GEOMAR and other German and UK institutions to establish an observatory on the Cape Verde island Sao Vicente. The Tenatso Observatory now supports long-term measurements of dust and greenhouse gases as well as an oceanographic mooring and regular sampling expeditions by the small Cape Verdean research vessel Islandia.
“We’re testing whether Saharan dust can promote the growth of a particular type of microbe, a cyanobacteria. These cyanobacteria can fertilize the surface of the ocean by fixing the abundant nitrogen gas that is dissolved in seawater”, says Prof. Julie LaRoche from IFM-GEOMAR, co-leader of the expedition.
There is plenty of nitrogen gas in the atmosphere but it needs to be "fixed" so that it turns into a fertilizer which is available to phytoplankton. The enigmatic cyanobacteria UCYN-A seems to be a very special nitrogen fixer. In contrast to other cyanobacteria, it is probably incapable of producing oxygen. This in turns enables it to fix nitrogen during the day while others cannot.
The Trade Winds and frequent dust storms that make this area so important for ocean research also complicate the scientists’ work. Dust samples are collected with filters on top of the atmospheric observatory. The collection of the water samples, however, requires sailing on the Islandia for several hours to the ocean observatory located 130 kilometres offshore in a surrounding water depth of 3600 metres. The samples are returned to laboratories that have been established at Cape Verde’s “National Institute for Fishery Development” where the dust experiments are conducted.
"The working conditions are difficult and some trips on the Islandia are like a roller coaster. But overall it’s a very positive work experience, thanks to our supportive Cape Verdean colleagues, the crew of the Islandia, and the general ambience on the islands “, says Stefanie Sudhaus , Ph.D. student at IFM-GEOMAR and member of the last expedition. Loaded with plenty of data from their experiments and confident that the experiments will deliver new discoveries, the scientists have returned to Kiel. During the expedition they were accompanied by scientists from the Max Planck Institute for Marine Microbiology, the Alfred Wegener Institute for Polar and Marine Research, Leibniz Institute for Baltic Sea Research and the Leibniz Institute for Tropospheric Research.
Research Project at the Cape Verde
Scientists from German and Cape Verdean institutes have started collecting data at Cape Verde Observatory Tenatso in 2008, measurements that they hope to continue in order to follow the effect of global change in the tropical Atlantic Ocean. Their research is part of the SOPRAN project (Surface Ocean Processes in the Anthropocene) that is largely supported by the German Federal Ministry of Education and Research (BMBF).
Nitrogen fixers and UCYN-A
The cyanobacterium UCYN-A doesn’t seem to work like that. It lacks the genes for photosystem II that are needed for the oxygen release and apparently cannot fix carbon dioxide into sugars. Thus, it may utilize light energy in other ways and forgoes photosynthesis, as is normally carried out by land plants and other algae. Although this organism has never been isolated in pure culture, an initial characterization of its genome was published in 2008 by the group of Jonathan Zehr at University of Santa Cruz (Zehr et al. 2008, Science Vol. 322 no. 5904, pp. 1110-1112).
lunes, 22 de junio de 2009
Update
Below some additional papers to update our PhD. Students. The first is about grazing in the Arctic. Very, very interesting. Look at the detailed description of the dilution method. For those who are revising grazing values in the ocean, give a look to this data. Values are not so high as the data given by Calbet and Landry.
For those working in grazing and metabolism of polar mesozooplankton, the paper by Campbell et al. is of interest.
Finally, those working in the Oxygen Minimum Zone have to read this paper by Dr. Escribano from Chile.
domingo, 14 de junio de 2009
More and more papers
sábado, 6 de junio de 2009
Interesting paper
jueves, 28 de mayo de 2009
Dilution method
lunes, 11 de mayo de 2009
More interesting papers
To those working in fish larvae and fisheries oceanography, the trailer of a coming review paper by Edward Houde about one of the most important issues in oceanography: recruitment variability. Once we have the paper, we will announce its publication. Please, keep your interest in our blog.
jueves, 7 de mayo de 2009
Dear Mr. President
miércoles, 6 de mayo de 2009
Nice paper about microzooplankton grazing
See feeding currents in copepods
The paper of today is a recent publication by Isabel Reche and co-workers about the effect of Saharan dust on bacterial biomass and production in lakes. Interesting to our work in the ocean.
miércoles, 22 de abril de 2009
Some more references
New paper by Lidia Yebra in Deep-Sea Research I (congratulations Lidia). The publication is related to the mesoscale physical variability and AARS activity of zooplankton as a proxy for growth rate.
sábado, 18 de abril de 2009
Some interesting references
Probably somebody working in top-down effects in the ocean would be interested in this paper. This is a clear message.
This paper was sent by Marta Moyano (thank you) and it is an interesting review about recruitment and Hjort´s hypothesis. Important for those interested in fisheries oceanography.
Finally, another interesting paper by Jaspers et al. about metazoan microzooplankton in the Indian Ocean. Interesting for those wishing to know more and more about those tiny organisms, but especially for those thinking about to build an apparatus to concentrate microzooplankton from a Niskin bottle. Somebody has to ask Dr. Jaspers because the description of the toy is not already published.
viernes, 10 de abril de 2009
New Blog for the WG in Biological Oceanography
Today I announce the start of a new blog for the biological oceanography working group of the University of Las Palmas. Therefore, I strongly recommend to change to this new blog (biologicaloceanography.blogspot.com), because in a short time we will have access to the different projects of the group and you can easily see if a new entry has been posted and when... In fact, this Lucifer blog is announced right now in the new blog. So, general information will be shown in the biological oceanography blog, while the more specific information about each project will appear in their respective blogs. Long life to the new blog!!
Santiago
jueves, 9 de abril de 2009
Migrations into the Ocean's Interior
martes, 7 de abril de 2009
sábado, 4 de abril de 2009
Blue Planet Deep Sea Part III
Today, we continue with the Blue Planet chapter about the Deep Sea soap opera. Enjoy the video.
viernes, 3 de abril de 2009
Losing my time
And now, the part II of the Blue Planet video about the "Dwellers of Darkness" (nice name for a band of rock and roll). Impressive. See the nice pictures of the flashing copepods.
Finally, somebody in the lab said yesterday that this blog is my way to lose my time. Now, I wonder if I am happy losing my time and the answer is... yes!! So, for him the video of Crazy Train (nothing related to Theodore) and his song "Losing my time".
miércoles, 1 de abril de 2009
Blue Planet Deep Sea Part I
...
Yes, I will not change anymore.
The photographer was worst than me.
The only girl on board
And the promised abstract.
Now, a nice video (part I is 10 min) about the animals which promote the lunar cycles we are studying. This an impressive document about the "dwellers of darkness". Compulsory for the members of the Lucifer Team.
lunes, 30 de marzo de 2009
Playing for change
...
...
Por último, un interesante video y una hermosa canción. Espero que la disfruten.
Playing For Change | Song Around The World "Stand By Me" from Concord Music Group on Vimeo.
viernes, 27 de marzo de 2009
Lutz Postel farewell cake
Lutz Postel
The staff engaged in a big science discussion
Gerhard Herndl came specially for the party from the Neitherlands to say goodby to Lutz and to test the cake. He also gave some lectures during his spare time.
Annelli (Lutz Postel´s wife) also came from Germany for the farewell party and to convince Lutz to forget Las Canteras Beach and go back to Germany. Thanks for the cake!!
The staff really very happy after the cake (and some drinks).
The people feeding "ad libitum" and Javier performing an ancient language from the Canary Islands, the Gomeran whistling
Lutz Postel and Ted Packard advising about the right way to cut the cake in order to avoid loosing enzymatic activity and therefore the taste.
martes, 24 de marzo de 2009
Lohafex
Report
The results of the transects showed that our patch was indeed fairly homogeneous within its boundaries, which were sharply delineated to the south and along its sides, but was trailing a long tail of diluted water to the north. The pteropod swarm was not encountered again but the VPN images (the camera system attached to the CTD) showed that there were about twice as many copepods (Calanus simillimus) per square metre inside the patch compared to outside. Even more striking were the high densities of their main predators – the amphipod Themisto gaudichaudii – we had found at 3 previous in-stations: their numbers ranged from 30 to 138 specimens per square metre. Imagine that many 2 – 3 cm large beetles living off tens of thousands of 2 mm long aphids (the equivalent of C. simillimus densities), themselves feeding on the plants on a square metre of garden and you have an impression of the biomass of larger zooplankton maintained by our patch. At our latitude the amount of sunlight available to the plants is the same as in a cloudy August in northern Europe, so, although the plankton are distributed over a deep water column, the analogy is justified.
We found several species of amphipods in the RMT tows but Themisto was by far the most abundant. They are tough, active animals, equipped with a range of grappling, sharply hooked legs in the front and paddle-like legs on their abdomen with which they scurry about in the buckets in which the net catches are emptied. It is a voracious carnivore that evidently feeds on other large zooplankton such as salps, chaetognaths (arrow worms) but also the local euphausiids (cousins of the better known krill of the south). Small groups even attacked the tiny fishes (myctophids) in the net catches, reducing them to skeletons in tens of minutes. In feeding experiments on board they also captured and ate copepods. They are visual predators with large compound lenses on top of the head (the translucent “caps” in the picture) indicating that they hunt by looking for prey above them, silhouetted against the weak light of the night sky. The black spots on the sides of the head in the picture are actually the retinas below the lenses. In the virtual absence of fishes (we caught very few mesopelagic fishes in the night net tows), amphipods are the only visual predators on plankton in this stretch of ocean, so the amazing transparency of their potential prey - from copepods to salps and chaetognaths – is witness to their predation pressure and their acute eye sight.
Calanus simillimus Photo: G. Mazzochi. AWI.
Amphipod numbers increased within the patch in the weeks following fertilization and by the middle of the experiment there were ten times more inside it than outside. They probably roam about in swarms and presumably entered our patch from the sides and stayed within it because of the higher copepod (C. simillimus) density. Previous experiments have also found higher copepod densities within iron-fertilized patches compared to outside. Since copepods, unlike amphipods and krill, are too small to swim into the patch horizontally, they are believed to congregate within it by adjusting their patterns of daily vertical migration. They feed on plankton in the surface layer only during the night and descend to a depth of around 100 m (demonstrated by the VPN images) where they spend the day, presumably invisible to visual predators. Their light sensors (they do not have lenses, so cannot see images) enable them to determine the appropriate depth, which depends on the depth of light penetration, which in turn depends on the amount of light-absorbing particles, particularly phytoplankton, in the surface layer. If surface and deeper layers move at different speeds then copepods spending the day at deeper depths, i.e. under a more transparent surface layer will be transported away from it. If they encounter a surface layer with more plankton, they will stay higher up during the day and hence add to the population already there. At this stage we cannot judge whether the VPN data are representative but will have to wait until the copepods in the net catches are counted and the relative movements of surface and deeper water layers in the patch have been analysed. So we cannot yet say what attracted the amphipods to the patch.
Amphipod Themisto gaudichaudii. Photo: Humberto González, UACh-COPAS. AWI.
Comentarios
viernes, 20 de marzo de 2009
Iron solubility
lunes, 16 de marzo de 2009
La otra versión del efecto de los aerosoles saharianos
domingo, 15 de marzo de 2009
Tan importante como la ciencia
martes, 10 de marzo de 2009
Phytoplankton survival clouded by dust particles
Aerosols can kill as well as nourish ocean organism.
Katharine Sanderson
Tiny ocean-dwelling organisms called phytoplankton, which lock up vast amounts of atmospheric carbon, could be under threat from microscopic particles of copper suspended in aerosols.
Atmospheric aerosols, suspensions of small particles in the air that can be man-made or natural, provide the oceans and resident phytoplankton with nutrients. The particles deliver nitrogen, phosphorous and iron in particular to phytoplankton, which are a vital source of food for marine life.
But now Adina Paytan, a marine scientist at the University of California, Santa Cruz, and her colleagues have found that air samples from different areas of the world are toxic to the most common phytoplankton species, Synechococcus.
Paytan incubated seawater phytoplankton in flasks filled with different samples of aerosol-rich air. "We wanted to find out how aerosol deposition impacts the phytoplankton community," Paytan explains. "Our hypothesis was that adding the aerosol will add nutrients to the incubation flasks and the phytoplankton will grow happily."
This is exactly what Paytan saw for aerosol samples being blown in from the Arabian Peninsula or Europe to the sampling point above a beach south of Eilat, Israel, at the Gulf of Aqaba, in the northern Red Sea. But when phytoplankton were exposed to samples of aerosols that had arrived from the Sahara Desert in Africa, some of them died. "We were very surprised," Paytan says.
The different aerosol samples were analysed to see what was in them, and the Saharan samples had lots of copper and other metals, as well as high levels of nitrate, ammonium and phosphate, also present in the Aqaba samples as well as in samples from Europe. Copper was the prime suspect and follow up experiments showed that when exposed to differing amounts of copper particles alone, the Synechococcus phytoplankton suffered, although another phytoplankton, Prochlorococcus, was not affected. The research is published in the Proceedings of the National Academies of Sciences1.
Knowledge gap
Paytan's paper is a useful reminder that atmospheric deposits supply nutrients and contaminants together, says Tim Jickells, an environmental scientist from the University of East Anglia, Norwich, UK. "We need to understand the combined effect of all these inputs on the system and recognize that this effect will be different in different places and affect different phytoplankton species differently," he says.
He points out that much needs to be done to understand these processes. For example, he says that copper in aerosols can be made safe by being bound up with organic ligands in the ocean, and in Paytan's experiments these processes were not accounted for fully. "If you increase the copper loading [in the ocean] slightly over a long time you might get a different response," Jickells suggests.
"All we know is that from the analytes we measured in our samples, copper is known to be toxic, and when we did controlled lab additions we found toxicity thresholds in concentrations similar to what we measured in the field," says Paytan. She admits that the other toxins present might be to blame, and this needs more investigation. "But regardless if it is copper or not, there is no way to get around the fact that the specific aerosol sample caused a negative effect," she says. "So something in this aerosol was toxic."
Copper concentrations in aerosols around the world vary, but are set to rise in areas downwind of fast-developing Asian countries, such as India and China. Aerosol composition varies from region to region, as do phytoplankton populations, which further complicates the picture.
The experiments highlight how little is known about interactions between land, the atmosphere and the ocean through aerosols, says Paytan. "In short, the land-air-ocean interactions through aerosol deposition are a lot more complicated than the simple paradigm 'dust equals iron, equals phytoplankton growth'," she adds.
References
1. Paytan, A. et al. Proc. Natl. Acad. Sci. doi:10.1073/pnas.0811486106 (2009).
lunes, 9 de marzo de 2009
lunes, 2 de marzo de 2009
Estimados Luciferinos:
Esta simpática chilena nos ha hecho llegar algunas fotos de bichos antárticos. Merece la pena verlas:
...
...
...
Para finalizar y no olvidarnos del proyecto que embarga esta página, les relatamos los objetivos principales del proyecto y la posición de las estaciones que vamos a muestrear. ¿Cuándo? Ya lo veremos.
Lucifer Goals:
(1)The vertical mixing and the consequent planktonic bloom in the oceanic subtropical waters around the Canary Islands
(2)The influence of the lunar cycle observed in zooplankton in the transport of organic carbon towards the mesopelagic zone
(3)The process of natural fertilization with iron promoted by the deposition of Saharan dust which is produced in several events during winter around the Canary Islands, coinciding with the vertical mixing and the planktonic lunar cycles
(4)Food web dynamics from end to end: Is there cascade effects?
Hasta la próxima.