background: eutrophication is one of the detrimental environmental problems in water reservoirs dye to the irregular introducing nutrients (phosphorus and nitrogen). this study aimed to explore the eutrophication state of ekbatan reservoir, hamadan, western iran. methods: monthly sampling was conducted during april 2010 to march 2011. seven sampling stations were selected in the various locatio...

Chlorophyll b is found in photosynthetic prokaryotes and primary and secondary endosymbionts, although their light-harvesting systems are quite different. Chlorophyll b is synthesized from chlorophyll a by chlorophyllide a oxygenase (CAO), which is a Rieske-mononuclear iron oxygenase. Comparison of the amino acid sequences of CAO among photosynthetic organisms elucidated changes in the domain s...

this study investigated the effects of sewage discharge on nutrient concentrations and bod5 levels in the coastal waters and sediments ofthe city of mombasa. the results indicated that nutrient concentrations in tudor, mtwapa and makupa creeks were elevated as compared to concentrations in gazi creek (mean ranges of 0.022-0.039mg/l, 0.038-0.163mg/l and 0.034-0.118mg/lphosphates, nitrates and a...

Tlhe biosynthetic pathway to chlorophyll a (chl a) is now quite complete in terms of porphyrin intermediates (3, 8). The biosynthetic pathway to protochlorophyll a (Pchl a) is undoubtedly identical with that of chl a to the protochlorophyllide a (Pchlide a) step, however, the sequence of steps from Pchlide a to Pchl a still remains unknown (1, 9). The production of Pchl a by etiolated plants i(...

Chlorophyll a (Chl-a) is at the heart of solar energy capture and conversion in plants. Because of this, Chl-a has been the subject of innumerable studies. Recently, we have been able to use quantum mechanical methods to calculate the vibrational properties of neutral and oxidized Chl-a in the gas phase [Wang, R.; Parameswaran, S.; Hastings, G. Vib. Spectrosc. 2007, 44, 357-368]. The calculated...

The Sunda Banda Seascape (SBS), located in the center of the Coral Triangle, is a global center of marine biodiversity and a conservation priority. We proposed the first biophysical environmental delineation of the SBS using globally available satellite remote sensing and model-assimilated data to categorize this area into unique and meaningful biophysical classes. Specifically, the SBS was par...

Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the individual and combined effects of blue and red ligh...

Profiles of N(2) fixation, O(2) production (gross photosynthesis), O(2) concentration, chlorophyll a concentration, and photon fluence rates were measured with 50-mum resolution in colonies of the heterocyst-forming cyanobacterium Nostoc parmelioides. Microelectrode measurements were made after 20 h of incubation under N(2) gas. Colonies were frozen, and 50-mum sections were prepared by using a...

We use a 6.8-fs laser as the light source for broad-band femtosecond pump-probe real-time vibrational spectroscopy to investigate both electronic relaxation and vibrational dynamics of the Q(y)-band of Chl-a at 293 K. More than 25 vibrational modes coupled to the Q(y) transition are observed. Eleven of them have been clarified predominantly due to the excited state, and six of them are conclude...

Understanding the fate of enteric viruses in water is vital for protection of water quality. However, the decay of enteric viruses is not well characterized, and its uncertainty has not been examined yet. In this study, the decay of coliphages, an indicator for enteric viruses, was investigated in situ under both sunlit and shaded conditions as well as in summer and winter. The decay rates of c...