Importance Of Chlorophyll Research Articles

Cyclopoid copepods as indicators of trophic level in South American reservoirs: A new perspective at species level based on a wide spatial-temporal scale

Aiming to identify efficient indicators for reservoir water quality, the abundance of cyclopoid copepods, 11 limnological variables, and a modified trophic state index (TSI) for tropical/subtropical reservoir systems were studied in 30 different reservoirs in South America. A total of 331 fieldwork campaigns, originated from six different studies on a wide spatial–temporal scale were analyzed. Samplings included small to large reservoirs (varying between 6 and 2250 km2 area) with oligo, meso and eutrophic conditions, and places with punctual eutrophication from fish cage farms. Spatial scale ordination was relevant for variables and reservoirs, but the temporal scale was also important in all analyses, positioning the same reservoir sampled in different years contrasting correlations in terms of species and variables. Principal component analysis consistently indicated the importance of chlorophyll, nutrients (phosphorus and nitrogen), turbidity, transparency, and depth for proper ordination of reservoirs according to their trophy. Of all the 13 cyclopoid species identified, ten were planktonic and at the end, after conclusive statistical correlation analysis, five species were selected as efficient water quality indicators. Redundancy analysis related different species with different trophic aspects: Acanthocyclops robustus, Microcyclops anceps and Tropocyclops prasinus were positively associated with chlorophyll and inversely associated with water transparency, Thermocyclops decipiens and T. inversus with electrical conductivity, and slightly associated with chlorophyll and total nutrients (phosphorus and nitrogen), and finally Thermocyclops minutus was positively correlated with transparency. Spearman correlations indicated that only T. inversus abundance was correlated with water temperature, but T. decipiens was not correlated with TSI, which is intriguing because this species has been commonly associated with eutrophic waters. Despite tolerate a wide range of trophic conditions, as pointed in RDA, T. decipiens seems to be replaced by other more resistant species when trophic conditions become too high – hypereutrophic environments. Four other selected species were correlated with TSI, and T. minutus was negatively correlated, confirming its association with oligotrophic waters. From all species found, we conclude that A. robustus, M. anceps, T. prasinus, T. decipiens and T. minutus are good indicators of trophic state level in South American reservoirs.

Recent advances in chlorophyll biosynthesis

The importance of chlorophyll (Chl) to the process of photosynthesis is obvious, and there is clear evidence that the regulation of Chl biosynthesis has a significant role in the regulation of assembly of the photosynthetic apparatus. The understanding of Chl biosynthesis has rapidly advanced in recent years. The identification of genetic loci associated with each of the biochemical steps has been accompanied by a greater appreciation of the role of Chl biosynthesis intermediates in intracellular signaling. The purpose of this review is to provide a source of information for all the steps in Chl and bacteriochlorophyll a biosynthesis, with an emphasis on steps that are believed to be key regulation points.

Import of Coastally-Derived Chlorophyll a to South Slough, Oregon

Material transfer between estuaries and the nearshore zone has long been of interest, but information on the processes affecting Pacific Northwest estuaries has lagged behind other areas. The west coast of the U.S. is a region of seasonally variable upwelling that results in enhanced phytoplankton production in the nearshore zone. We examined estuarine-nearshore links over time by measuring physical oceanographic variables and chlorophylla concentration from an anchor station in South Slough, Oregon. Data was collected during 24-h cruises conducted at approximately weekly intervals during summer 1996 and spring 1997. The results demonstrate that the physical oceanography of this estuarine site was strongly influenced by the coastal ocean. Marine water reached the estuarine site on every sampled tide, and chlorophylla was clearly advected into the estuary with this ocean water. In contrast, phytoplankton concentrations were comparatively reduced in the estuarine water. There were, however, large fluctuations in the import of chlorophyll over the course of the summer. These variations likely reflect upwelling-generated phytoplankton production in the coastal ocean and subsequent cross-shelf transport to the estuary. Suspension feeding organisms in South Slough likely depend on the advection of this coastally-derived phytoplankton. The large allochthonous chlorophyll input measured for this system appears dissimilar from most estuaries studied to date. Previous investigations have focused on the outwelling and inwelling of materials in estuaries. We must now consider the influence of coastal upwelling and downwelling processes on estuarine material exchange.

Absorption of chlorophyll phytol in normal man and in patients with Refsum's disease

This study was made to determine the extent of absorption of chlorophyll phytol from the intestine of man, and the importance of chlorophyll as a source of the phytanic acid that accumulates in Refsum's disease. Uniformly (14)C-labeled pheophytin a (the Mg-free derivative of chlorophyll a) was fed to normal human subjects and to patients with Refsum's disease. Feces were collected and analyzed. In all subjects, 90-95% of the administered radioactivity was recovered in the feces, still largely in the form of pheophytin a. The phytol radioactivity recovered in the feces averaged about 95% of that in the administered material, which indicates that there had been little absorption of the phytol moiety. Similarly, after 250 g of cooked spinach had been fed to a normal subject, almost the entire phytol content was found in the feces. Less than 5% of the ingested spinach phytol was accounted for in the thoracic duct lymph of another subject. It was concluded that not more than about 5% of the ingested chlorophyll phytol is absorbed by man, whether normal or afflicted with Refsum's disease. On this basis we conclude that the major portion of the phytanic acid that accumulates in Refsum's disease could not be derived from dietary chlorophyll.