In Situ Quantification of Biological N Production Using Naturally Occurring NN.

We describe an approach for determining biological N production in soils based on the proportions of naturally occurring NN in N. Laboratory incubation experiments reveal that biological N production, whether by denitrification or anaerobic ammonia oxidation, yields proportions of NN in N that are within 1‰ of that predicted for a random distribution of N and N atoms. This relatively invariant isotopic signature contrasts with that of the atmosphere, which has NN proportions in excess of the random distribution by 19.

Nitrous oxide from chemodenitrification: A possible missing link in the Proterozoic greenhouse and the evolution of aerobic respiration.

The potent greenhouse gas nitrous oxide (N O) may have been an important constituent of Earth's atmosphere during Proterozoic (~2.5-0.5 Ga).

Extreme enrichment in atmospheric NN.

Molecular nitrogen (N) comprises three-quarters of Earth's atmosphere and significant portions of other planetary atmospheres. We report a 19 per mil (‰) excess of NN in air relative to a random distribution of nitrogen isotopes, an enrichment that is 10 times larger than what isotopic equilibration in the atmosphere allows. Biological experiments show that the main sources and sinks of N yield much smaller proportions of NN in N.

Site-specific variation in gene expression from Symbiodinium spp. associated with offshore and inshore Porites astreoides in the lower Florida Keys is lost with bleaching and disease stress.

Scleractinian coral are experiencing unprecedented rates of mortality due to increases in sea surface temperatures in response to global climate change. Some coral species however, survive high temperature events due to a reduced susceptibility to bleaching. We investigated the relationship between bleaching susceptibility and expression of five metabolically related genes of Symbiodinium spp.

Genetically divergent Symbiodinium sp. display distinct molecular responses to pathogenic Vibrio and thermal stress.

Global climate change and anthropogenic activities are threatening the future survival of coral reef ecosystems. The ability of reef-building zooxanthellate coral to survive these stressors may be determined through fundamental differences within their symbiotic dinoflagellates (Symbiodinium sp.).

Ulcerated yellow spot syndrome: implications of aquaculture-related pathogens associated with soft coral Sarcophyton ehrenbergi tissue lesions.

We introduce a new marine syndrome called ulcerated yellow spot, affecting the soft coral Sarcophyton ehrenbergi. To identify bacteria associated with tissue lesions, tissue and mucus samples were taken during a 2009 Indo-Pacific research expedition near the Wakatobi Island chain, Indonesia. Polymerase chain reaction targeting the 16S rDNA gene indicated associations with the known fish-disease-causing bacterium Photobacterium damselae, as well as multiple Vibrio species.