Showing papers on "Productivity (ecology) published in 1972"

Trophic structure of deep-sea macrobenthos

Abstract: The effect of the trophic factor on large-scale distributional patterns of deep-sea macrobenthos inhabiting the floor of the World Ocean has been studied. Two hundred and twenty-eight bottom trawl samples collected by Soviet research vessels in the Pacific and Indian Oceans at depths ranging from 3000 to 6000 m were analyzed. For each sample, the weight of animals with a similar mode of feeding was determined to find the weight ratio of representatives of three main trophic groups, i.e., deposit-feeders, suspension-feeders and carnivores. These data, indicating predominance of alternate groups as well as data on their geographic distribution, were related to feeding conditions which depend on: (1) rates of sedimentation, (2) nature of sediments, (3) content of organic carbon, (4) degree of transformation of organic matter on and within sediments, and, when available, (5) data on redox potential, biochemical oxygen consumption, and state of heterotrophic microflora in the sediments. In dealing with the feeding conditions of deep-sea macrobenthos in the Atlantic Ocean, biological characteristics were deduced from literature data on the composition of sediments, their redox potential and organic carbon content. As a result of this research, eutrophic and oligotrophic regions on the floor of the World Ocean have been distinguished and their boundaries defined. Eutrophic regions lie within areas with high biological productivity of surface-water layers, and cover the peripheral and equatorial parts of the oceans; they are characterized by quantities of labile (digestible) organic matter within sediments which are sufficient for deposit-feeders to predominate in eutrophic regions everywhere, except on considerable bottom elevations. Oligotrophic regions are confined to open areas of the oceans lying beyond the equatorial belt; they are characterized by very low rates of sedimentation and, consequently, by scarce quantities of deposited organic matter. Here, suspension-feeders predominate, although their population density is very low.

On the quantitative characteristics of the pelagic ecosystem of Dalnee lake (Kamchatka)

Abstract: The parameters of biomass and productivity of the main components of the pelagic ecosystem have been estimated in lake Dalnee (Kamchatka) during the first phase of the period of vegetation in July 1969. The water column in the lake during this period was stratified. The layer-character of vertical distribution of bacteria, phytoplankton, protozoa, rotifers and young stages of crustaceans was elucidated. The adult copepods migrate during the day. The nutrition of the mass species of zooplankton was studied using the C14-method. The data on the spectrum of feeding, on rations and on optimal food concentrations were ascertained. All these data, together with the observations in the lake, were used for the construction of a scheme of energy flow. The scheme shows that the ecosystem of the lake receives the third part of its energy from the land as allochtonous organic matter via microbial biosynthesis. The main part of energy accessible to the animals of the second trophical level is used by protozoa, and of a third part by the predatory rotiferAsplanchna.

Chlorination at Power Plants: Impact on Phytoplankton Productivity

Abstract: Studies of the eflects of passage through a power plant on river phytoplankton have shown that chlorination depresses rates of photosynthesis and respiration to a much greater extent than does heating.

Productivity of Glossina morsitans morsitans Westwood maintained in the laboratory, with particular reference to the sterile-insect release method.

Abstract: Glossina morsitans is of great economic importance in Africa and if a mass-rearing project were to be undertaken with a view to control by the release of sterilized males it would be necessary to know the productivity that could be obtained from this species in the laboratory Data for life tables and age-specific fecundity schedules of G m morsitans fed on goats or lop-eared rabbits are used to calculate outputs of viable pupae or of young adult males that would be available for disposal For control by the sterile-male method, it is likely that pupae bred in captivity would be the organisms of choice for field release The weekly output of viable males could be 18-25% of the total adult stock Some implications of these findings are discussed

Primary productivity and related data from tropical and subtropical marine sediments

Abstract: Measurements in situ were made of oxygen exchange and 14C fixation in calcareous sediments off the coast of Florida, USA, and at various sites in the Caribbean Sea at depths to 60 m. Sediment samples were analyzed for total organic carbon, nitrogen and photosynthetic pigments. In some cases, measurements were made of the pH of sediment interstitial water and its concentration of total CO2. In the Caribbean Sea, routine hydrological sampiing was undertaken and in situ plankton productivity determined.

Temperature, transparency, and phytoplankton productivity in crater lake, oregon1

Abstract: Maximum productivity and the largest concentration of chlorophyll a in Crater Lake during summer 1968 and 1969 occurred at depths where temperatures were near 4C and measurable light <4% of surface illumination. It is suggested that the phytoplankton in the lake consists mostly of oligothermal-oligophotic populations that are limited to depths greater than 70 m in summer, but occupy the 0-70-m stratum in winter, so that a rather constant rate of production per unit arca is maintained throughout the year.

Productivity of an arid zone shrub (Eremophila gilesii) community in south-western Queensland

Abstract: The above-ground biomass of a monospecific Eremophila gilesii shrub community (69,200 bushes/ha including seedlings) had a mean value of 2106 kg/ha (range 1502-2402 kg/ha) over a year of measurement. Above-ground primary production (biomass increment and litter fall) averaged 0.23 g/m2/day. Rainfall utilization represented 3700 g water/g above-ground dry matter produced. The proportion of the total nitrogen and phosphorus pool incorporated in the organic matter is high when compared with other Australian arid zone shrub vegetation of similar biomass. Litter production varied markedly throughout the period of measurement, and was greatest following falls of rain. Average litter breakdown time was estimated to be 20 months. Litter production and decomposition account for the release of up to 0.33 kg organic phosphorus per hectare each year. About 53% of the phosphorus content in green leaves is extracted before abscission for redistribution within the plant. The intrinsic and extrinsic sources of organic phosphorus provide well over half the phosphorus required for the above-ground production each year. The results are discussed in relation to the possible centre of origin of Eremophila and the adaptation of E. gilesii to its harsh abiotic environment.

Laboratory studies of assemblages of attached estuarine diatoms1

Abstract: EFfects of light intensity, exposure to desiccation, salinity, and heated water on the vertical distribution and growth of populations of attached estuarine diatoms were studied in a laboratory model ecosystem. Of the 35 most abundant diatom taxa found in 36 samples from the laboratory system, all but 8 were also abundant in s‘amples obtained from Yaquina Bay and estuary. Vertical distribution of diatoms was more closely related to light intensity and period of exposure to desiccation in the summer experiments than in the winter experiments. A sudden, unseasonable decre,ase in salinity or increase in water temperature had a much greater effect on diatom assemblages exposed to 12,270 lux than on those that developed at either 1,030 or 4,710 lux; the most noticeable changes in community structure included a decrease in species diversity and a rapid growth of a population of Mebosiru nummuloides, a filamentous species. Primary productivity in diatom assemblages exposed to periods of desiccation was less under winter conditions than under corresponding conditions in summer. Prim,ary productivity in assemblages not exposed to desiccation was strongly affected by light intensity during both summer and winter experiments, and the ratio primary productivity : chlorophyll a was greater during winter than summer.

An estimate of carbonate production by macrobenthos in some tropical, soft-bottom communities

Abstract: Productivity figures are available for most of the species comprising a few soft-bottom communities in the Miami area, USA. These are in the form of the ratio of annual somatic production to standing crop, both being measured as drytissue weight. These values have been converted to carbonate productivity ratios, and from these the carbonate production per square metre per year calculated. The values range from less than 1 g to nearly 400 g for sublittoral communities, and about 1 kg for one intertidal area.

Photosynthetic production and its regulating factors in the Baltic Sea

Abstract: Measurements of primary production in the Baltic Sea over a period of 2 years (1969/1971) by the 14C method are reported. The rate of total annual production for the Baltic Sea proper and the Gulf of Finland including coastal areas appears to lie between 35 and 40 gC·m2, a rate which can be assumed as characteristic for oligotrophic waters with a low production rate. An apparent increase in productivity between the 2 years could be noted. Calculations for the water mass below the halocline show that between 0.7 and 0.8 ml/l oxygen is used up during a period of 3 months required for the development of anoxic conditions. The major portion of the organic matter in the Baltic Sea undergoes decomposition in the sub-photic zone above the halocline. The ratio of organic material in deep water to the total available oxidizable matter appears to remain constant with time; therefore, the apparent increase in productivity in the photic layer does not affect apprecibly the development of anoxic conditions in deep water. Of the different areas investigated, the Gulf of Finland seems to be the most productive. In the southern Baltic Sea, the rate of production over 5 years between 1966 and 1971 has not changed appreciably. In fact, it shows a trend toward a slight decrease, whereas, in other areas of the Baltic Sea, the rate of production indicates an apparent increase. Comparison with oceanic coastal areas of the west coast of Sweden shows that the rate of production there is higher than in the Baltic Sea. Of the micronutrients controlling productivity in the photic layer of the Baltic Sea, nitrate has a stronger limiting effect on plant growth than phosphate, a fact which is in agreement with existing conceptions on the subject. Dissolved iron does not seem to exert any appreciable influence on the productivity.

Bacterial productivity of a high-mountain lake: With 5 figures in the text

Abstract: In the Vorderer Finstertaler See bacterial cell numbers as determined by direct counts on membrane filters are unexpectedly high (220–800 · 103 cells cm−3). As a consequence of the high turbulence ...

Role of Benthic Plants in Fertilized Estuary

Abstract: A study to elucidate the productivity contribution of benthic macrophytes in a fertile estuary was undertaken Methods for utilizing C\U14\N uptake as a productivity monitor of benthic plants are described Both phytoplankton and macrophyte productivity determinations were made at various distances from a small sewage outfall, and the effect of nutrients on the phytoplankton and seaweeds was observed It was also observed that the benthic flora was a better indicator of nutrient enrichment, because there was a uniform gradient of productivity stimulation away from the outfall The phytoplankton showed erratic values at various distances from the outfall due to mixing in and out of the fertilized zone It is proposed that a productivity model such as the Baule-Mitscherlich relationship can be used to predict the photosynthetic response of algae due to a combination of nutrients This model will allow for the concept of multiple limiting nutrients in nature

Phytoplankton productivity and response to altered nutrient content in lakes of contrasting trophic state

Abstract: Lakes Findley, Chester Morse and Sammamish, Washington, are characterized by one major outburst of phytoplankton productivity and biomass (mainly diatoms) with usually no or low fall activity Vernal outbursts were often delayed in some lakes and years probably by unfavorable climate (snow cover and cloudy rainy conditions) Mean spring-summer productivity ranged from 270 mgC/m day in the most oligotrophic lake, Findley, to nearly 1000 mgC/m2 day in mesotrophic-eutrophic Lake Sammamish The range in mean Chlorophyll a content was 08 to 10 ug/l for the same lakes respectively Mean biomass within and between the lakes was related to winter phosphorus content but not to nitrogen However, nitrogen (N) and phosphorus (P) were simultaneously limiting productivity increase in the three lakes in summer Carbon assimilation in response to added P showed increasing half-saturation constants for the natural phytoplankton progressing from oligotrophy to eutrophy While diversion of over 1/2 the phosphorus from nearby Lake Washington during 1963-1967 was followed by reduction in winter mean P content and a rapid shift from eutrophy to mesotrophy (Edmondson 1970), mean winter P content and measured characteristics of plankton response have not changed significantly in Lake Sammamish following a diversion of similar magnitude P availability in the water column (winter mean content) appears to be controlled by precipitation with Fe to a greater extent than in Lake Washington INTRODUCTION The need to understand aquatic ecological processes in order to predict the impact of man's activity is rapidly increasing To a large extent, this is a result of accelerated regional planning for water resource use An area of major concern in this planning is the impact of man's activity through the cultural eutrophication of aquatic ecosystems, particularly lakes since standing water usually responds slower to corrective action than does running water The eutrophication process, to be sure, is poorly understood in general quantitative sense Some lakes seem to respond to nutrient manipulation as expected while othersshow little or no response To be useful for management and water resource planning, predictive models of nutrient cycling and biomass change must meet the criteria of generality by containing the modifications that account for the important differing characteristics among lakes and consequently their different behavior

Productivity estimates from alpine tundra in british columbia

Abstract: Estimates of net primary productivity and combined nitrogen content are given for exclosures on three alpine sites in British Columbia. The estimates are useful for determining carrying capacity of alpine ranges for domestic and native ungulates, for comparative studies in biological zonation, and for environmental sensitivity decisions.

Role of benthic and littoral fish in the productivity and ecology of the Lake Washington drainage

Abstract: The primary objective of the Western Forest Biome Studies is a multidisciplinary approach to develop a mathematical model of the ecosystem which will aid in understanding the mechanisms of productivity. To determine productivity in terms of fish, an estimate of their relative abundance is required that can be expanded later into estimates of biomass or energy. The early work of the Washington Cooperative Fishery Unit on Lake Washington revealed that certain non-salmonid and non-game species, such as peamouth and northern squawfish, were numerous and that we should determine their importance in the overall ecology and productivity of the drainage. To form a base from which we could develop our program, we prepared two reports. First, we developed a checklist of fishes for the drainage that summarizes our current knowledge of their occurrence in streams or lakes and their relative abundance (Wydoski 1972a). This list will be revised as we gain additional information on the drainage from current and future research on the aquatic environment. In addition, we compiled an annotated bibliography that provides a ready reference source of the published and unpublished information for use by our students and others who are studying the drainage (Wydoski 1972b).

Grazing and production by zooplankton in lakes of contrasting trophic status : a progress report

Abstract: Grazing rates and density of the crustacean zooplankton were measured in Findley and Chester Morse Lakes and Lake Sammamish, Washington. Sample analysis is incomplete at reporting time, thus estimates of production from examination of life stage biomass changes was not possible. Maximum density of crustacean zooplankton was about 10/1 in the water column of oligotrophic Findley and Chester Morse Lakes and 70/1 in mesotrophic-eutrophic Lake Sammamish during 1972. Densities averaged about 10 times greater in Lake Sammamish than in the other lakes. Copepods comprised most of the numbers in all three lakes. Grazing apparently represents a sizable loss to phytoplankton in the three lakes feeding rates experimentally determined in situ from changes in 14C tagged phytoplankton ranged from nearly one half to over six times the algal biomass per day. However, feeding rate was always less than phytoplankton productivity

Primary production of lake tatsu-numa in the goshiki-numa lake group at volcano bandai, north-east japan

Abstract: The Urabandai Lake Group consisting of about 80 lakes and ponds was formed by the eruption of the Volcano Bandai in 1888. The waters of these lakes are similar in nature in having sulphuric or hydrochloric acid in high concentrations. Lake Tatsu-numa is one of such lakes. Lake Tatsu-numa was selected as the IBP water area for two reasons : (1) all trophic levels from primary producers to higher consumers are present, and (2) the lake is comparatively small and is convenient for censuring by a few researchers.As a part of the studies on the biological productivity in the disharmonic waters in the JIBP-PF The Urabandai Lake Group consisting of about 80 lakes and ponds was formed by the eruption of the Volcano Bandai in 1888. The waters of these lakes are similar in nature in having sulphuric or hydrochloric acid in high concentrations. Lake Tatsu-numa is one of such lakes. Lake Tatsu-numa was selected as the IBP water area for two reasons : (1) all trophic levels from primary producers to higher consumers are present, and (2) the lake is comparatively small and is convenient for censuring by a few researchers.As a part of the studies on the biological productivity in the disharmonic waters in the JIBP-PF section, the author has engaged in research on the primary production since 1967, especially the plankton production in Lake Tatsu-numa.(1) Lake Tatsu-numa is situated at the central portion of the Goshiki-numa Lake Group (Fig. 1). Its water contains such ions in high concentrations as SO4-- (237mg/l), Ca++ (61.6mg/l), and Na+ (67.5mg/l), and has a pH of 6.4 (5.9-6.9) (KATO & AITA, 1970) (Fig. 2). Under such environmental conditions, there were found in this lake about 43 species of phytoplankton, among which, the following 9 species were selected by ADACHI (1970) as the important phytoplanktonic species in Lake Tatsu-numa. They are : Oscillatoria pseudogeminata, Melosira granulata, M. italica, Nitzschia obtusa var. scalpeiiiformis, Surireiia sp., Gymnodinium ordinatum, Peridinium inconspicuum, Scourfieldia cordiformis, and Tracheiomonas volvocina.(2) The standing crop of the phytoplankton in Lake Tatsu-numa varied from 40.5 to 557.4 in the number of cells per 1 millilitre during these five years. The chlorophyll-a content showed the value from 0.136 to 2.5mg/m3 and from 0.5 to 9.1 mg/m2, and the energy efficiency in the gross production ranged from 0.0042 to 0.036% throughout the year. The carbon uptake obtained by 14C-experiments was 19.97 mg/m2/day in November, 1971. On the basis of these results, Lake Tatsu-numa is classified into an oligotrophic type (Figs. 4-6, Table 1).(3) In the marginal shrub zone of Lake Tatsu-numa, there were found abundantly Oedogonium sp. and diatoms (Fig.8), which grew to a large biomass by autumn. The standing crop of these littoral sessile algae was estimated to be 10.77 kg in dry weight in November, 1971 for the lake as a whole. Moreover, the algal mat consisting of Vaucheria hamata, Niteiia sp., and diatoms developed over the bottom surface of the lake (Fig. 9). The standing crop of such benthic algae was estimated by SHOJI and SHISHIDO (1972) to be 65 kg in dry weight and about 500 kg in fresh weight in November, 1971.The standing crops of phytoplankton, sessile algae in the marginal shrub zone, and of benthic algae on the lake bottom were estimated to be 4.2kg, 10.77kg, and 65kg in dry weight, respectively in the late autumn. Their percentages to the whole were 5.25%, 13.5%, and 81.3%, respectively, their ratios to the phytoplankton being 1 : 2.6 : 15.5, respectively.