Some problems related to the measurements of primary production using radiocarbon technique

The SCOR/IBP Working Group-24 held its first meeting in Southampton (U.K.) from 30 July to 1 August 1968 under the chairmanship of Dr. T. R. PARSON(Canada). The members of this Working Group were : Dr. O. I. KOBLENTZ- MISHK(EU .S.S.R.), Prof. S. ICHIMURA(Japan), Dr. P. D. V. SAVAGE (U.K.) and Dr. S. Z. QASIM (India). The terms of reference of the Working Group were: "To review and suggest the best methods for estimating primary production under special conditions, such as those found beneath polar ice, and the turbid conditions found in estuaries, heavily polluted waters and exceptionally eutrophic or oligotrophic waters"

Effect of intensity and quality of illumination on the photosynthesis of some tropical marine phytoplankton

Using solar energy as a source of illumination, photosynthesis in 11 species of marine plankton algae was studied as a function of light intensity. From the photosynthesis-light curve for each organism, the saturation points (Is) in different organisms were determine

Primary production of an atoll in the Laccadives

According to YONGE (1960) "an atoll raised to the surface in the midst of oceanic waters may be described as a large scale experiment in nature". Earlier studies have contributed to an understanding of primary production of atolls and coral reefs of the Pacific and Atlantic Oceans (SARGENTan d AUSTIN, 1949, 1954; ODUMa nd ODUM1, 955; KOHNa nd HELBRICH1, 957; ODUMB, URKHOLDER and RIVERO1, 959 ; GORDOaNn d KELLY1, 962). Comparable information on the atolls of the Indian Ocean has been completely lacking. Since GARDINER (1903-1906) published his classical work on the Maldive and Laccadive Archipelagoes, practically no knowledge has been added to the atolls of the Laccadive

Variation in postoperative outcomes of patients with intracranial tumors: insights from a prospective international cohort study during the COVID-19 pandemic

Background: This study assessed the international variation in surgical neuro-oncology practice and 30-day outcomes of patients who had surgery for an intracranial tumor during the COVID-19 pandemic. Methods: We prospectively included adults aged ≥18 years who underwent surgery for a malignant or benign intracranial tumor across 55 international hospitals from 26 countries. Each participating hospital recorded cases for 3 consecutive months from the start of the pandemic. We categorized patients’ location by World Bank income groups (high [HIC], upper-middle [UMIC], and low- and lower-middle [LLMIC]). Main outcomes were a change from routine management, SARS-CoV-2 infection, and 30-day mortality. We used a Bayesian multilevel logistic regression stratified by hospitals and adjusted for key confounders to estimate the association between income groups and mortality. Results: Among 1016 patients, the number of patients in each income group was 765 (75.3%) in HIC, 142 (14.0%) in UMIC, and 109 (10.7%) in LLMIC. The management of 200 (19.8%) patients changed from usual care, most commonly delayed surgery. Within 30 days after surgery, 14 (1.4%) patients had a COVID-19 diagnosis and 39 (3.8%) patients died. In the multivariable model, LLMIC was associated with increased mortality (odds ratio 2.83, 95% credible interval 1.37–5.74) compared to HIC. Conclusions: The first wave of the pandemic had a significant impact on surgical decision-making. While the incidence of SARS-CoV-2 infection within 30 days after surgery was low, there was a disparity in mortality between countries and this warrants further examination to identify any modifiable factors

Primary productivity of the Andaman Sea

243-247The average surface and column primary productivity, chl a and particulate organic carbon, estimated at 24 stations during Feb. 1979, were respectively 5.3 mg C/m3/d and 273 mg C/m2 /d; 0.03 mg/m3 and 3.64 mg/m2; and 132mg/m3 and 4.59 g/m2. The corresponding values during Jan. 1980 were 12.4 mgC/m3/d and 431mgC/m2/d;0.02mg/m3 and 2.33mg/m2; and 306 mg/m3 and 16.4g/m2. Chlorophyll a alone was greater in Feb. 1979 than in Jan. 1980. Navicula spp, Peridinium spp, Trichodesmium thiebautii and flagellates were abundant. Turnover rates of phytoplankton were estimated. Variationsin the phytoplankton carbon, zooplankton carbon and detrital carbon were discussed

Diel variation in phytoplankton pigments and primary production off Bombay

96-99Variations in biological parameters over 24 hr at 4 stations off Bombay indicated that chlorophyll a concentration, organic carbon production and particulate organic carbon (POC) were generally maximum during the day. Concentrations of pigments at any depth ranged from 0.09 to 1.74 (mg m-3). Similarly the production and POC varied from 1.15 to 86.12 (mgC m-3 d-1) and 107.6 to 585.4 (mgC m-3). 'Smaller phytoplankton' contributed 50 to 100% to the pigment of the total phytoplankton. The maximum in assimilation number was found when NH4-N and NO3-N were maximum

Distribution of Phytoplankton & Chlorophyll <i>a</i> around Little Andaman Island

248-252Surface chl a and phaeopigments of the whole phytoplankton varied from 0.02 to 0.085 mg/m3 (av. 0.043) and 0.017 to 0.068 mg/m3 (av. 0.039)respectively; chl a of the nannoplankton fluctuated from 0.013 to 0.085 mg/m3 (av.0.034) and phaeopigments from 0.014 to 0.064 (av.0.029). Depthwise distribution of phytoplankton chl a and phaeo-pigments showed an increasing trend up to 1% light in the 2 coral banks. Phytoplankton population ranged from 1400 to 4900 cells/litre. Dinoflagellates formed an important constituent unlike those of the Arabian Sea and coastal waters of Bay of Bengal. Comparison of environmental data from the shallow coral banks with those from similar locations in the Arabian Sea was made

Phytoplankton ecology of the cochin backwaters

46-50Average concentration of phytoplankton in the Cochin backwaters varied from 22200 to 299700 cells/litre. The minimum and maximum numbers were observed during September and November. Diatoms, dinoflagellates and other algae had their maximum concentration during postmonsoon, premonsoon periods respectively. On few occasions diatoms and dinoflagellates were found to bloom. The maximum concentration observed during a bloom was 2 million cells/litre. A negative correlation was found between cell concentration and salinity. Variation of phytoplankton was directly related to that of phosphate and nitrite. Cell numbers and organic carbon production showed a positive relation. Species diversity index varied from 1.59 to 4.50 and the lowest was observed during a phytoplankton bloom

Not Available

Not AvailableAlong the intertidal zone of Kavaratti Lagoon, a seagrass bed, consisting largely of Thalassia and Cymodocea, grows on a substratum of loose coral sand and coral debris. Primary production of this grass bed was estimated from a study of diurnal changes in dissolved oxygen over the bed and experiments were conducted on some isolated plants to determine their rates of oxygen production and consumption. Both these studies showed that photosynthesis of the community during daylight is greater than its respiration during day and night combined.Not Availabl