{"id":110,"date":"2017-07-13T13:52:39","date_gmt":"2017-07-13T12:52:39","guid":{"rendered":"http:\/\/www.oceanblogs.org\/m139\/?p=110"},"modified":"2017-07-13T19:50:32","modified_gmt":"2017-07-13T18:50:32","slug":"algae-and-sand","status":"publish","type":"post","link":"https:\/\/www.oceanblogs.org\/m139\/2017\/07\/13\/algae-and-sand\/","title":{"rendered":"Algae and Sand"},"content":{"rendered":"

Dear interested reader, colleagues, friends and families,<\/p>\n

for the moment, let us focus on the water surface rather than the deep sea: We found stretches of brown algae across the ocean surface (Image 1). Free-floating brown algae like Sargassum<\/em> are distributed worldwide in warm seas. In summer 2015 in the Caribbean, it was reported as the \u201cSargassum crisis\u201d, which led to the accumulation of algae along the shores in response to rising temperatures of the ocean and the change of ocean currents due to climate change. What must have been just malodorous for tourists, is fascinating for us today. We were glad to salvage three exemplars of Sargassum<\/em>\u00a0(Image 2,3) and observe all the life under the microscope (Image 4). Lots of organisms use the brown algae as food, substrate, locomotion vehicle and shelter. It will be interesting, whether the living community on the Sargassum<\/em> will change under different pressure conditions.<\/p>\n

Now let us step aside the water surface and look at the RV Meteor. The ship\u2019s rail is covered with a thin layer of iron-rich sand, which was transported here over thousands of kilometres with the wind from the Sahara Desert (Image 5). Up to 90 % of the iron in the North Atlantic comes from the dust of the Sahara and promotes the carbon fixation by phytoplankton (microscopic algae), which needs the iron for photosynthesis. Phytoplankton is responsible for 45 % of the primary production of the Earth (about 50 x 109<\/sup> tonnes carbon per year), which in turn feeds zooplankton (animals up to few millimetres in size) and subsequently fish and whales. The drop of atmospheric CO2 <\/sub>concentrations, thus the reduction of the greenhouse gas, leads to the cooling of the planet.<\/p>\n

Your M139 team<\/p>\n

–<\/p>\n

Liebe interessierte Leser, Kollegen, Freunde und liebe Familien,<\/p>\n

f\u00fcr einen Augenblick konzentrieren wir uns nicht nur auf die Tiefsee sondern auch auf die Wasseroberfl\u00e4che: Immer wieder sehen wir lange Stra\u00dfen von Braunalgen \u00fcber den Ozean ziehen (Bild 1). Freischwimmende Braunalgen wie Sargassum<\/em> kommen weltweit in w\u00e4rmeren Meeren vor. Hier in der Karibik wurde im Sommer 2015 \u00fcber die sogenannte \u201eSargassum-Krise\u201c berichtet, in der vermutlich durch ansteigende Temperaturen des Ozeans und ver\u00e4nderte Str\u00f6mungen durch den Klimawandel vermehrt Algen an die K\u00fcste gesp\u00fclt wurden. Was f\u00fcr Strandtouristen wegen der Faulgase nur zu einem \u00fcbelriechenden Erlebnis gef\u00fchrt haben muss, freute uns heute, da wir drei Sargassum<\/em>-Exemplare bergen (Bild 2,3) und das Leben darauf unter dem Mikroskop beobachten konnten (Bild 4). Viele Organismen nutzen die Braunalge als Nahrungssubstrat, Fortbewegungsmittel und Schutz. Es wird weiterhin interessant sein, ob sich die Lebensgemeinschaften auf dem Sargassum<\/em> bei unterschiedlichen Druckverh\u00e4ltnissen ver\u00e4ndern.<\/p>\n

Bewegen wir uns nun von der Wasseroberfl\u00e4che weg und betrachten die FS Meteor. Die Reling des Schiffes tr\u00e4gt eine d\u00fcnne Schicht aus eisenhaltigem Sand, der viele Tausende Kilometer \u00fcber die Winde von der Sahara-W\u00fcste hierher transportiert wurde (Bild 5). \u00dcber 90 % des Eisens im Nordatlantik stammt vom Staub der Sahara und f\u00f6rdert die Kohlenstofffixierung \u00fcber Phytoplankton (mikroskopische Algen), welches das Eisen f\u00fcr die Photosynthese ben\u00f6tigt. Phytoplankton ist f\u00fcr 45 % der Prim\u00e4rproduktion der Erde verantwortlich (etwa 50 x 109<\/sup> Tonnen Kohlenstoff pro Jahr), welches Nahrung f\u00fcr Zooplankton (Tiere bis wenige Millimeter Gr\u00f6\u00dfe) und sp\u00e4ter Fische und Wale bietet. Durch die Reduzierung der atmosph\u00e4rischen CO2<\/sub>-Konzentration, also die Verringerung von Treibhausgasen, wird der Planet k\u00fchler.<\/p>\n

Ihr M139-Team<\/p>\n

\"\"

Image 1 | Free-floating brown algae (Sargassum<\/em>) in the Caribbean. (Photo: Johannes Werner)<\/p><\/div>\n

 <\/p>\n

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Image 2 | Fishing Sargassum<\/em>. (Photo: Johannes Werner)<\/p><\/div>\n

 <\/p>\n

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Image 3 | Sargassum<\/em> in the net. (Photo: Johannes Werner)<\/p><\/div>\n

 <\/p>\n

\"\"

Image 4 | Living community on the surface of Sargassum<\/em>, here: Bryozoa with tentacles (Moostierchen mit Tentakeln). (Photo: Johannes Werner)<\/p><\/div>\n

 <\/p>\n

\"\"

Image 5 | Iron-rich sand originating from the Sahara Desert on the RV Meteor in the Caribbean. (Photo: Johannes Werner)<\/p><\/div>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Dear interested reader, colleagues, friends and families, for the moment, let us focus on the water surface rather than the deep sea: We found stretches of brown algae across the ocean surface (Image 1). Free-floating brown algae like Sargassum are distributed worldwide in warm seas. In summer 2015 in the Caribbean, it was reported as […]<\/p>\n","protected":false},"author":183,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-110","post","type-post","status-publish","format-standard","hentry","category-deep-sea"],"_links":{"self":[{"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/posts\/110","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/users\/183"}],"replies":[{"embeddable":true,"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/comments?post=110"}],"version-history":[{"count":3,"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/posts\/110\/revisions"}],"predecessor-version":[{"id":118,"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/posts\/110\/revisions\/118"}],"wp:attachment":[{"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/media?parent=110"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/categories?post=110"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.oceanblogs.org\/m139\/wp-json\/wp\/v2\/tags?post=110"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}