The ocean absorbs about 25% of anthropogenic CO2 emissions, which alters its chemistry. Among the changes of the carbonate system are an increase in the partial pressure of CO2 (pCO2) and a decline of pH; hence, the whole process is often referred to as ‘ocean acidification’. Many microbial processes can be affected either directly or indirectly via a cascade of effects through the response of ...

Summer blooms of filamentous cyanobacteria, mainly Aphanizomenon sp. and Nodularia spumigena, are characteristic for the Baltic Sea, where they accumulate at the sea surface in calm weather. The chemical microenvironment, and thus the actual growth conditions within these cyanobacterial surface blooms of the Baltic Sea, are largely unknown. Using microsensors, it is shown that photosynthesis is...

Nitrate reductase activity from filamentous, heterocyst-forming cyanobacteria showed a biphasic kinetic behavior with respect to nitrate as the variable substrate. Two kinetic components were detected, the first showing a higher affinity for nitrate (K(m), 0.05-0.25 mm) and a lower catalytic activity and the second showing a lower affinity for nitrate (K(m), 5-25 mm) and a higher (3- to 5-fold)...

Calothrix rhizosoleniae and Richelia intracellularis are heterocystous cyanobacteria found in the tropical oceans. C. commonly live epiphytically on diatom genera Chaetoceros ( C-C ) Bacteriastrum B-C while R. endosymbiotically within Rhizosolenia R-R ), Guinardia G-R Hemiaulus H-R ); although, they occasionally freely (FL- C FL- R ). Both species have much shorter trichomes than other marine f...

The three-dimensional structures of two types of cyanobacterium-dominated microbial mats from meltwater ponds on the McMurdo Ice Shelf were as determined by using a broad suite of complementary techniques, including optical and fluorescence microscopy, confocal scanning laser microscopy, scanning electron microscopy with back-scattered electron-imaging mode, low-temperature scanning electron mi...