Seasonal variations of some metals in bivalve mollusc Sunetta scripta from the Cochin coastal waters

Bivalve mollusc Sunetla scripta is abundant in the inshore waters of Co chin and is a suitable indicator species of metal pollution. The metal load in the bivalve showed an increase during the monsoon season indicating the apparent influence of river run off and reduction in salinity in the seasonality of metal uptake. In the case of copper, the smaller individuals recorded relatively higher load than that of larger ones

Water quality and metal uptake by Cabomba caroliniana in the lower reaches of Periyar River

Zinc cadmium copper and lead concentration as well as water quality parameters from Periyar river adjoining Adayar Industrial area and the bio accumulation of these metals by the submerged aquatic plant CCabomba carolinian

Physico chemical parameters: Water

The measured parameters can be stored and recorded through a printer in the laboratory . The portable instruments ensure speedy, in situ and accurate measurement of different parameters of water and sediment The instruments eliminate the risk of storage , transportation and preservation of large number of samples These instruments can save the recurring expenditure needed for chemicals, costly reagents and sample containers

Early-stage photodegradation of aromatic poly(urethane-urea) elastomers

The photooxidative stability of an aromatic segmented poly(urethane-urea) (PUU) elastomer, stabilised with a range of carbon black fillers, was assessed after very low UVA doses as a means to identify components that are highly susceptible to UV degradation, and suggest better design of such materials. Fourier-transform infrared (FTIR) analysis indicated rapid degradation of the urea bonds in the hard segments, followed by chain scission and photo-Fries reaction of the urethane linkages. In the soft segments, the oxidation of the original ether groups resulted in the formation of large amounts of ester groups, while some crosslinking of the ether groups was also evident. Carbon black provided moderate protection against degradation, with the smallest-sized particles being the most effective. Protection was evidenced by reduced surface cracking as well as an increased resistance to chemical changes in both the soft segments and hard segments. Even so, significant degradation was still evident at low UV doses suggesting that further stabilisation is required to increase the UV durability of these elastomers and improve their long-term performance

Data-based estimates of the ocean carbon sink variability – First results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM)

Using measurements of the surface-ocean CO2 partial pressure (pCO2) and 14 different pCO2 mapping methods recently collated by the Surface Ocean pCO2 Mapping intercomparison (SOCOM) initiative, variations in regional and global sea–air CO2 fluxes are investigated. Though the available mapping methods use widely different approaches, we find relatively consistent estimates of regional pCO2 seasonality, in line with previous estimates. In terms of interannual variability (IAV), all mapping methods estimate the largest variations to occur in the eastern equatorial Pacific. Despite considerable spread in the detailed variations, mapping methods that fit the data more closely also tend to agree more closely with each other in regional averages. Encouragingly, this includes mapping methods belonging to complementary types – taking variability either directly from the pCO2 data or indirectly from driver data via regression. From a weighted ensemble average, we find an IAV amplitude of the global sea–air CO2 flux of 0.31 PgC yr−1 (standard deviation over 1992–2009), which is larger than simulated by biogeochemical process models. From a decadal perspective, the global ocean CO2 uptake is estimated to have gradually increased since about 2000, with little decadal change prior to that. The weighted mean net global ocean CO2 sink estimated by the SOCOM ensemble is −1.75 PgC yr−1 (1992–2009), consistent within uncertainties with estimates from ocean-interior carbon data or atmospheric oxygen trend

Critical marine habitat restoration programme - initiative on mangrove restoration in Kerala, India

Mangroves are unique habitats which function as nursery ground for several valuable species of finfishes and shellfishes and they play a vital role in supporting marine food chains, protecting coastal areas and in improving water quality. Mangroves in general have relatively high productivity and tend to create highly organic soil and also export organic matter to nearby marine environments. They are effective in stabilizing soils in intertidal areas. Some species of mangroves have been planted in the coastal areas as bio-protection shields to guard coastal households from wind and wave action. They provide shelter to several avian fauna which feed on its fruits and nest in the branches. Rare or endangered species of birds have also been documented in the mangroves

Assimilative capacity of Cochin inshore waters with reference to contaminants received from the backwaters and the upstream areas

Assimilative capacity of inshore waters off Cochin was assessed using data on hydrography, photosynthetic pigments, primary productivity, dissolved nutrients and trace metals collected over a period of three years (April 2003 - October 2006) from selected stations spreading over the source to the sink. Assimilative indices for Cochin estuary and inshore waters off Cochin were worked out and a scale of safe, desirable, caution or critical was attributed with regard to different parameters based on the score. The results revealed that in the estuary, total suspnded solids (TSS) and cadmium have reached critical levels and lead have attained levels of cautiion. Similarly, in the Cochin inshore waters, cadmium have reached critical levels while copper and lead have attained levels of caution

Sea-air CO2 fluxes in the Indian Ocean between 1990 and 2009

The Indian Ocean (44 S-30 N) plays an important role in the global carbon cycle, yet it remains one of the most poorly sampled ocean regions. Several approaches have been used to estimate net sea-air CO2 fluxes in this region: interpolated observations, ocean biogeochemical models, atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Indian Ocean sea-air CO2 fluxes between 1990 and 2009. Using all of the models and inversions, the median annual mean sea-air CO2 uptake of −0.37 ± 0.06 PgC yr -1 is consistent with the −0.24 ± 0.12 PgC yr -1 calculated from observations. The fluxes from the southern Indian Ocean (18-44 S; -0.43 ± 0.07 PgC yr-1 are similar in magnitude to the annual uptake for the entire Indian Ocean. All models capture the observed pattern of fluxes in the Indian Ocean with the following exceptions: underestimation of upwelling fluxes in the northwestern region (off Oman and Somalia), overestimation in the northeastern region (Bay of Bengal) and underestimation of the CO2 sink in the subtropical convergence zone. These differences were mainly driven by lack of atmospheric CO2 data in atmospheric inversions, and poor simulation of monsoonal currents and freshwater discharge in ocean biogeochemical models. Overall, the models and inversions do capture the phase of the observed seasonality for the entire Indian Ocean but overestimate the magnitude. The predicted sea-air CO 2 fluxes by ocean biogeochemical models (OBGMs) respond to seasonal variability with strong phase lags with reference to climatological CO 2 flux, whereas the atmospheric inversions predicted an order of magnitude higher seasonal flux than OBGMs. The simulated interannual variability by the OBGMs is weaker than that found by atmospheric inversions. Prediction of such weak interannual variability in CO2 fluxes by atmospheric inversions was mainly caused by a lack of atmospheric data in the Indian Ocean. The OBGM models suggest a small strengthening of the sink over the period 1990-2009 of -0.01 PgC decade-1. This is inconsistent with the observations in the southwestern Indian Ocean that shows the growth rate of oceanic pCO 2 was faster than the observed atmospheric CO2 growth, a finding attributed to the trend of the Southern Annular Mode (SAM) during the 1990s

Regional CO2 flux estimates for 2009-2010 based on GOSAT and ground-based CO2 observations

We present the application of a global carbon cycle modeling system to the estimation of monthly regional CO2 fluxes from the column-averaged mole fractions of CO2 (XCO2) retrieved from spectral observations made by the Greenhouse gases Observing SATellite (GOSAT). The regional flux estimates are to be publicly disseminated as the GOSAT Level 4 data product. The forward modeling components of the system include an atmospheric tracer transport model, an anthropogenic emissions inventory, a terrestrial biosphere exchange model, and an oceanic flux model. The atmospheric tracer transport was simulated using isentropic coordinates in the stratosphere and was tuned to reproduce the age of air. We used a fossil fuel emission inventory based on large point source data and observations of nighttime lights. The terrestrial biospheric model was optimized by fitting model parameters to observed atmospheric CO2 seasonal cycle, net primary production data, and a biomass distribution map. The oceanic surface pCO2 distribution was estimated with a 4-D variational data assimilation system based on reanalyzed ocean currents. Monthly CO2 fluxes of 64 sub-continental regions, between June 2009 and May 2010, were estimated from GOSAT FTS SWIR Level 2 XCO2 retrievals (ver. 02.00) gridded to 5° � 5° cells and averaged on a monthly basis and monthly-mean GLOBALVIEW-CO2 data. Our result indicated that adding the GOSAT XCO2 retrievals to the GLOBALVIEW data in the flux estimation brings changes to fluxes of tropics and other remote regions where the surface-based data are sparse. The uncertainties of these remote fluxes were reduced by as much as 60 through such addition. Optimized fluxes estimated for many of these regions, were brought closer to the prior fluxes by the addition of the GOSAT retrievals. In most of the regions and seasons considered here, the estimated fluxes fell within the range of natural flux variabilities estimated with the component models

Heavy metal concentration in sea water, sediment and bivalves off Tuticorin

Concentration of heavy metals Cd, Cu, Fe, Mn, Ni, Pb and Zn in sea water, sediment and bivalve samples from three stations was studied for one year along Tuticorin coast. The concentration was in the order of Fe>Mn>Zn>Cu>Pb>Cd>Ni. Generally the concentration of Fe was very high in the sediment and bivalves when compared to earlier studies from other areas along the Indian coast. High concentration of Fe, Mn, Cu, Pb and Zn was observed during monsoon season. One way ANOVA indicated statistically significant differences (p<0.01) among the samples in the concentration of Cu, Fe, Mn, Pb and Zn. Except for Cd and Cu, no significant difference was noticed in the seasonal variation of other metals