Diel patterns of carbon incorporation into biochemical constituents of Synechococcus spp. and larger algae in the Northwest Atlantic Ocean

Diel patterns of ¹⁴C-bicarbonate incorporation in>5 m algal communities were compared with those in cyanobacterial populations of Synechococcus spp. (0.6 to 1.0 m), collected from the surface and/or chlorophyll maximum at three stations in the Northwest Atlantic Ocean (a neritic front; in Warm-Core Eddy 84-E; and Wilkinson's Basin) from 21 July to 8 August, 1984. Cell constituents were chemically separated into four fractions: lipids, low molecular weight (LMW) metabolites, polysaccharides/nucleic acids, and proteins. The in situ diel pattern of ¹⁴C assimilation was virtually the same for >5 m algal communities adapted to different environments. Protein synthesis appeared to continue at a reduced rate at night using energy derived from the catabolism of polysaccharides and the mobilization of LMW compounds. Synechococcus spp. populations exhibited inherent physiological differences in their in situ diel pattern of carbon fixation from that in>5 m algal communities taken from the same water mass. There was no nighttime protein-synthesis in Synechococcus spp. The relative proportion of ¹⁴C-protein remained constant over night, while that of ¹⁴C-polysaccharides/nucleic acids declined and that of labelled LMW metabolites increased. Daytime light-intensity manipulations did not alter the diel pattern of carbon fixation in any of the>5 m algal assemblages, while changes in the carbon metabolism of surface and shadeadapted Synechococcus spp. populations could be rapidly induced by altering the light intensity.Bigelow Laboratory Contribution No. 86004     

On the life history of Centropages typicus: Responses to a fall diatom bloom in the New York Bight

Laboratory studies and field collections show that egg production by Centropages typicus (Krøyer) in New York shelf waters in autumn 1984 responded to both food and temperature. Rates of egg production were high (43 to 76 eggs female^-1 d^-1) in October, early in the fall diatom bloom. Later, although food concentrations remained high and female size actually increased, egg production declined, presumably in response to seasonally decreasing temperatures. Carnivorous diets did not support egg production. Development time for autumn-hatched C. typicus was 33 d at 15°C, a rate that gives a Q₁₀ of 2.21 when compared with the spring development rate of 49 d at 10°C. We could find no evidence of physiological adjustments being made by this copepod for overwintering. Development was not arrested at any subadult stage and resting eggs were not produced. Trends in body size of copepodid stage V, however, suggest that an overwintering strategy may be invoked by this copepod in Junuary or February.     

Optical characterization of primary productivity across a coastal front

Methods for the remote estimation of phytoplankton biomass and production rates using multiplatform sampling strategies are essential for the better understanding of oceanic bio-geochemical cycles. Recent advances in remote sensing of ocean color have made synoptic estimation of phytoplankton biomass attainable. While considerable success has been achieved in the estimation of plant biomass, the synoptic estimation of phytoplankton rates of production has been inadequate. Rapid shipboard estimates of the vertical distribution of primary productivity, on mesoscale spatial scales and event-time scales, are needed to provide both surface validation and data for the development of bio-optical models linking production to the optical characteristics of the water column. This study details the primary productivity and optical properties of a frontal region in July 1985 along 35°50N in the Southern California Bight which is shown to be consistent with the concurrent high-performance liquid-chromatography pigment-analysis. We describe here a quasi-synoptic shipboard bio-optical sampling strategy across a frontal region as an example of time-corrected data for assessing phytoplankton production in highly variable ocean regions.     

Provisioning rules and chick competition in asynchronously hatching common terns (Sterna hirundo)

Interactions between nestling birds and their parents are models for examining parent–offspring communication and sibling competition. Most studies have focused on species where young are restricted to a nest. However, offspring of many species are mobile and fed by parents for an extended period post-hatch. These chicks mobility may provide an opportunity to examine the role of signalling and physical competition on parental feeding decisions. We examined parental provisioning rules in relation to offspring behaviour and hatching order (i.e., competitive ability) in a species with mobile young, the common tern. We determined that about 95% of feedings were directed to the first chick to reach the parent when it landed with food. We developed a probabilistic model to predict the likelihood of a chick reaching the parent first, and thus receiving food. Our model showed that begging intensity, feeding history, and the interaction between begging intensity and relative proximity to the parent best predicted which chick would arrive first. Increased begging was associated with arriving first significantly more when a chick was relatively further from the parent than when it was closer than its siblings. Independently of these factors, larger, earlier-hatched chicks were more likely to be fed than smaller, later-hatched chicks. Additional analyses showed that parents landed closer to more intensively begging chicks, however, increased begging did not explain the advantage of earlier-hatched chicks because begging intensity did not vary with hatching order. Instead, earlier-hatched chicks were more likely to outrun later-hatched siblings and reach the parent first.     

Reproductive effort in relation to maternal social rank in reindeer (<Emphasis Type="Italic">Rangifer tarandus</Emphasis>)

In polygynous mammals, high-quality females may increase their fitness by providing superior care to their offspring. Based on the agonistic interactions of female reindeer in an experimental herd during two consecutive years (1997 and 1998), we tested whether maternal social rank influenced: (1) winter body-mass change of females, (2) preparturition reproductive effort (measured as fecundity, the birth mass and the birth date of their calves), (3) preweaning maternal effort (measured as calves preweaning mortality, early preweaning and late preweaning growth rate and September body mass of calves), and (4) postweaning maternal effort (measured as calves body-mass change during their first winter). In the models, we included September females body mass as a covariate to separate the effects of maternal rank and body mass. We also tested whether the effect of social rank on maternal efforts was dependent on offspring sex. High-ranked females gained body mass whereas low-ranked females lost weight during the winter. Fecundity was higher and date of birth was earlier in high-ranked females than in subordinates, whereas no effect of females rank on birth mass of calves was found. Early preweaning growth rate and September body mass of calves increased with increasing females social rank, whereas late preweaning daily growth rate of calves was not influenced by females rank. Calves preweaning mortality was only influenced by year, which also explained most of the variance in the winter body-mass change of calves. The effects of females rank on the reproductive-efforts parameters studied were not specific to offspring sex. These findings suggest that females rank influences reproductive effort during the preparturition, as well as the preweaning, period, the effect being sex independent.Communicated by R. Gibson     

Liver lesions produced by hydatid-like cysts in an elasmobranch,the electric ray (Torpedo californica)

Large masses composed of multiple sand-filled cysts were present in the liver of an electric ray, Torpedo californica. There was much inflammation and necrosis of pericystic parenchyma, but remarkably little fibrosis. Other organs were not involved. No evidence of microorganisms or neoplastic transformation was observed. The cysts are hydatid-like and are the first to be reported in a lower vertebrate. They possibly represent larval cestodes, for which elasmobranchs have not been known to be hosts.     

Coastal zone management in wales: The information gaps

In 1994 the Countryside Council for Wales, the government nature conservation and countryside advisor in Wales, published a consultation document on marine and coastal policy, and also commissioned research into the status of coastal zone management (CZM) in the Principality. The research, undertaken by the University of Wales Cardiff, investigated CZM from an international, national (U.K.) and Welsh perspective, concentrating on detailed case studies of three areas (including both urban and rural coasts). Policy makers, managers, practitioners and users from all sectors were included in the study which established current activity, identified problems and reviewe future plans. Interviews and questionnaire returns highlighted vital information gaps at all levels. These ranged fom a lack of basic data (including scientific and technical), to a breakdown in communication both within and between organisations, as well as a policy vacuum in both regional and central government.