Annual cycles of nutrients and chlorophyll in Narragansett Bay, Rhode Island.

The nutrient cycles in the bay can be driven largely by activities internal to the bay, especially sediment-water exchanges.-from Author Graduate School of Oceanography, Univ of Rhode Island, Narragansett, RI 02882, USA

The Nansen bottle-A major contributor to reported concentrations of particulate iron in sea water

Concentrations of particulate iron in sea water samples collected in Teflon® coated Nansen bottles were 15-86 times as high as those collected in 30-1. Niskin bottles at the same time, depth and station. It is concluded that the results of any studies of particulate iron sea water which made use of the Nansen bottle may have been affected by contamination. © 1970

Experimental ecology of the temperate scleractinian coral Astrangia danae I. Partition of respiration, photosynthesis and calcification between host and symbionts

Calcification, photosynthesis and respiration of the scleractinian coral Astrangia danae were calculated from the changes in total alkalinity, pH, calculated total CO2, and oxygen concentration produced by colonies incubated in glass jars. A correction for changes in ammonia, nitrate and nitrite was taken into account and the method evaluated. The fluxes of oxygen and CO2 were highly correlated (r=0.99). The statistical error of alkalinity determinations was less than 10% of the changes observed in the slowest calcifying samples. Metabolism of polyparium alone was estimated by difference after removal of tissue and reincubation of bare corallum. Zooxanthellae concentration in the polyps was obtained from cell counts made on homogenates of polyp tissue. The calculated photosynthetic rate of the zooxanthellae in vivo was 25 μmol O2 (108 cell)-1 h-1 at a light intensity of 120 μEin m-2 s-1. In corals having 0.5x109 zooxanthellae/dm2 of colony area up to 8% of the total photosynthesis was attributed to the corallum microcosm. Polyp respiration, photosynthesis, and CaCO3 uptake rates were all much higher than rates previously reported from A. danae, apparently because in these experiments the organisms were better fed. This increased photosynthesis in turn enhanced calcification still further. The symbiosis therefore appears to provide a growth advantage even to fed corals, under the conditions of these experiments. © 1980 Springer-Verlag

The Oxidation of Arsenite in Seawater

The oxidation rate of arsenite in seawater is very slow. Of the parameters investigated which might affect this rate the most important were temperature, initial arsenite concentration, salinity and pH. An empirical rate expression was developed from experimental data which led to a prediction that the natural rate of oxidation in the ocean is about 0.023 micromoles of As(III) per liter each year. This value is about twice the natural concentration of arsenite; the only mechanism which seems able to account for the continued presence of arsenite is biological reduction of arsenate. © 1975, Taylor & Francis Group, LLC. All rights reserved

Effects of feeding frequency and symbiosis with zooxanthellae on nitrogen metabolism and respiration of the coral Astrangia danae

Colonies of the temperate coral Astrangia danae occur naturally with and without zooxanthellae. Basal nitrogen excretion rates of nonsymbiotic colonies increased with increasing feeding frequency [average excretion rate was 635 ng-at N (mg-at tissue-N)-1 h-1]. Reduced excretion rates of symbiotic colonies were attributed to N uptake by the zooxanthellae. Nitrogen uptake rates of the zooxanthellae averaged 8 ng-at N (106 cells)-1 h-1 in the dark and 21 ng-at N (106 cells)-1 h-1 at 200 μEin m-2 s-1. At these rates the zooxanthellae could provide 54% of the daily basal N requirement of the coral if all of the recycled N was translocated. Basal respiration rates were 172 nmol O2 cm-2 h-1 for starved colonies and 447 nmol O2 cm-2 h-1 for colonies fed three times per week. There were no significant differences between respiration rates of symbiotic and nonsymbiotic colonies. N excretion and respiration rates of fed (symbiotic and nonsymbiotic) colonies increased greatly soon after feeding. N absorption efficiencies decreased with increasing feeding frequency. A N mass balance, constructed for hypothetical situations of nonsymbiotic and symbiotic (3×106 zooxanthellae cm-2) colonies, starved and fed 15 μg-at N cm-2wk-1, showed that the presence of symbionts could double the N growth rate of feeding colonies, and reduce the turnover-time of starved ones, but could not provide all of the N requirements of starved colonies. Rates of secondary production, estimated from rates of photosynthesis and respiration were similar to those estimated for reef corals. © 1984 Springer-Verlag

Fractionation of butyltin species during sample extraction and preparation for analysis

Solvent extraction and evaporative concentration steps are often used in procedures for the measurement of butyltins in environmental samples. As part of a larger study utilizing radiolabeled butyltins, the loss and fractionation of butyltins during sample preparation was investigated. TBT, DBT, and MBT were extracted from acidified seawater by hexane with efficiencies of about 95-99, 50-60 and 11% respectively. In addition, losses of about 70% of DBT were found during evaporative concentration of hexane. A variety of sediment extraction procedures were tested and none were found to be highly efficient for total butyltin extraction. © 1991 Kluwer Academic Publishers

RADIOLABELED BUTYL TIN STUDIES IN THE MERL ENCLOSED ECOSYSTEMS.

Radiolabeled tributyltin was introduced into an enclosed ecosystem in which most of the processes occurring in adjacent Narragansett Bay also can be found. The tributyl tin was initially removed from the water column with a half-life of 3. 5 days. A partitioning coefficient to suspended sediments of 4 multiplied by 10**4 was found for tributyl tin

Control of nutrient concentrations in the Seekonk-Providence River region of Narragansett Bay, Rhode Island

Six synoptic samplings of nutrient concentrations of the water column and point-source inputs (rivers, sewage treatment plants) were conducted in the Seekonk-Providence River region of Narragansett Bay. Concentrations of nutrients (NH4+, NO2-+NO3-, PO4-3, dissolved silicon, particulate N, particulate C) were predicted using a conservative, two-layer box model in order to assess the relative influence of external inputs and internal processes on observed concentrations. Although most nutrients were clearly affected by processes internal to the system, external input and mixing explained most of the variability in and absolute magnitude of observed concentrations, especially for dissolved constituents. In the bay as a whole, two functionally distinct regions can now be identified: the Seekonk-Providence River, where dissolved nutrient concentrations are externally controlled and lower Narragansett Bay where internal processes regulate the behavior of nutrients. A preliminary nitrogen budget suggests that the Seekonk-Providence River exports some 95% of the nitrogen entering the system via point sources and bottom water from upper Narragansett Bay. © 1990 Estuarine Research Federation

Surface-water acidification and extinction at the Cretaceous- Tertiary boundary

If published estimates of SO2 volatilization and NOx generation by the Cretaceous-Tertiary impact were atmospherically converted to sulfuric and nitric acid, globally dispersed, and rapidly rained out, the resulting acid concentrations would bracket a critical threshold in surface-ocean chemistry. Deposition of masses corresponding to the highest estimates would have provided enough acid to destroy the carbonate-buffering capacity of the upper 100 m of the world ocean and catastrophically reduce surface-ocean pH. Despite the possible effect of the highest estimated acid yields, scenarios that rely on acid rain as the primary explanation of global K-T extinctions are not readily compatible with K-T records of terrestrial and marine survival or culturing studies of modern marine plankton. -from Author

Whole truths vs. half truths - And a search for clarity in long-term water temperature records

There is widespread acceptance among the scientific community that human activities are the primary cause of present day climate change. But, how a changing climate impacts ecosystems is still a source of confusion to the public. Some of this confusion is associated with a lack of clear communication among journalists and scientists, particularly when it comes to addressing variability and uncertainty in ecological datasets. Here we use long-term surface water temperature data sets from Narragansett Bay and a recent misunderstanding of long-term temperature data that occurred on the national stage as a case study. Specifically, we re-evaluate and update the record and examine the variability inherent in long-term data sets. We found that despite high year to year variations the surface waters of Narragansett Bay have increased between 1.4°C to 1.6°C total rise over the last fifty years. Winter warming has been especially high over this time period, increasing between 1.6°C to 2.0°C. Finally, we identify the need for scientists, politicians, and journalists to appropriately address data variability and we argue for increased communication among these groups