Showing papers on "Water column published in 1972"

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.

Microcrystalline sphalerite in resin globules suspended in Lake Kivu, East Africa

Abstract: The origin and chemical nature of micron-sized spheres found as suspended particles in Lake Kivu are examined. It can be shown that the hollow spheres, with a wall thickness of 500 A, consist of a complex polymeric resinous material which has little functionality, except for hydroxyl groups. The spheres arise in the process of degassing of water samples at depth. Tiny gas bubbles, about 1 micron in size, act as scavengers of dissolved resinous material. The newly created resinous membrane promotes the selective coordination of zinc dissolved in the water column. In the prevailing H2S regime, formation of sphalerite crystals in induced. The size range of the crystals, 5 to 50 A, corresponds to 1 to 10 unit cells and suggests that the resinous membrane also acts as a template in sphalerite growth processes. The sources of the zinc and dissolved gases (CO2, CH4, H2S) are hydrothermal springs seeping from the lake bottom into the basin. Water discharge is substantial; about 100 years are required to fill the lake to its present level (ca. 550 km3 water). The average Kivu water contains 2 ppm zinc. Thus, 1 million tons of zinc are contained in Lake Kivu in the form of sphalerite.

The flux of particulate carbon in an estuary

Abstract: The major sources and sinks of suspended particulate carbon are identified for northern Chesapeake Bay, Maryland, USA. The area of the bay under consideration was divided into two sections. The northernmost section (upper bay), from the head of the bay to the vicinity of Baltimore, was characterized by a high input of particulate carbon from upland drainage. The section from Baltimore to the mouth of the Potomac River (middle bay) was dominated by an internal supply of particulate carbon from primary production. The northernmost section was characterized by major particulate carbon losses to the bottom and to benthic respiration, with slightly less than half (43%) of the particulate carbon respired in the water column or converted to dissolved organic matter. In contrast, respiration in the water column or conversion to dissolved organic matter was responsible for the loss of about 65% of the particulate carbon in the middle section of the bay, while losses to the bottom and to benthic respiration totaled only 12%. Even though the supply of particulate carbon to the upper bay was about 1.5 times the supply to the middle bay, the loss of carbon due to biological activity (biological efficiency) in each area was similar, and amounted to about 70% of the supply of particulate carbon.

The spatial structure of interzonal copepod populations in the Southern Ocean

Abstract: The vertical distributions of Calanoides acutus, Calanus propinquus and Rhinicalanus gigas have been studied during Cruises I and II of the R.V. “Ob” in the Indian sector of the Southern Ocean. During the spawning period, all 3 species reveal the highest concentrations, and occupy the highest positions in the water column. During the period of feeding and growth, they begin slowly to disperse and to descend to greater depths. In spring, the populations ascend again to the water surface. In both seasons, later stages migrate first. Pronounced temperature gradients may prevent the ascent, and result in the breeding and subsequent growth of the new generation occurring in subsurface waters. Details of the vertical distributions of populations depend on their seasonal state and the local hydrology.

Some Chemical and Microbiological Observations in the Pacific Ocean off the Hawaiian ISLANDS1

Abstract: Simultaneous chemical and microbial analyses of the water column were made at 33 stations off the leeward Hawaiian Islands. The overall distribution of oxygen, nitrate, and pH was similar at all stations located more than 5 km offshore. These parameters were closely correlated and also correlated with nitrifying and nitrate-reducing activity in the water column. The distribution of nitrite and ammonium did not correlate with the oxygen distribution. A nitrite band was consistently found in the lower portion of the photic zone and appeared to have originated from reduction of nitrate rather than from oxidation of ammonium. The distribution of aerobic and anaerobic bacteria was regulated by the amount of available organic nutrients and not by the oxygen concentration.

Fremont lake, wyoming-preliminary survey of a large mountain lake

Abstract: Fremont Lake, at' an altitude of 2,261 m, has an area of 20.61 kin2 and a volunte of 1.69 km3. The maximurn depth is 185 m, which makes it the sevcrith deepest natural lakr in the conterminous IJnited States. Theoretical renewal tirnc is I 1. I years. Temperature data for 1971 indicate that vernal circulation extcnded to a depth of less thau 90 m. l'hv summer heat income was 19,450 c:al/crn2. The dissolved-oxygcn curve is orthograd<:, with a slight mc:talirnnctic maximum, arid a tetidcticy toward decreasing concentrations at dcpth. At 180 in, oxygen was ;it 80 percent 01 saturation in late July 1970. Thc lake has ii rcniark:tbly low dissolved-solids content of 12.8 mgb, making it one ol the most dilute medium-sized lakes iii the world. Detailed c:heniical data arc given for the water column at three sites in the lake and lor the influent and t:ffluent streams. Net plankton included representativcs of sevm geiiera of phytoplankters and three gcncra ol zooplankters. A recoiiiiiiiss:Itic(: indicatrd substantially no bacteriologic:al contarniiiatioli in thc lakr. but there was an appreciable amount iir two minor strrams in the vicinity of a summer-home colony. atid on thc Continental Divide is Frernont

Chemical studies on carbon cycle in lake suwa by determining ph and total carbon dioxide

Abstract: Carbon cycle in Lake Suwa (maximum depth : 6.7 m;area : 14.5 km2) which is a highly polluted and eutrophic lake in Nagano Prefecture, Japan, was studied by determining pH and total carbon dioxide as follows :(1) Total carbon dioxide (Total CO2) of the lake water was determined by KOYAMA's method. The same water sample was aerated in order to be equilibrated with air. Total CO2 of the aerated water sample was determined as an original total carbon dioxide (Orig. CO2).In the stably stratified lake waters, the difference (ΔCO2) between Orig. CO2 and Total CO2 corresponds to the net fixation of CO2 (N. Fix. CO2) in a case of positive value and the net formation of CO2 (N. Form. CO2) in a case of negative value.In the case of Lake Suwa, however, it should be suitable to call the former as the preserved amount of net fixation of CO2 (P. A. N. Fix. CO2) and the latter as the preserved amount of net formation of CO2 (P. A. N. Form. CO2), because the lake water layers are easily mixed and some of the dissolved CO2 may be exchanged for the atmospheric CO2 through all seasons.From a vertical distribution of ΔCO2, P. A. N. Fix. CO2 or P. A. N. Form. CO2 in a water column was calculated on the basis of (g C/m2).(2) Relation curves between pH and Total CO2 of the lake water were constructed from pH and Total CO2 values obtained from the water samples collected in different months.(3) Greater part of the numerous data of Total CO2 values used in this study were estimated from a large number of vertical distributions of pH values obtained at different times in different days while comparing with the relation curves between pH and Total CO2.(4) Average P. A. N. Fix. CO2 (A. P. A. N. Fix. CO2) and average P. A. N. Form. CO2 (A. P. A. N. Form. CO2) in a whole day were estimated from the values of P. A. N. Fix. CO2 and P. A. N. Form. CO2 in a water column, which were estimated at different times in the day.(5) Numerous data of these A. P. A. N. Fix. CO2 or A. P. A. N. Form. CO2 in the water column were estimated on different days in different months.(6) A histogram of A. P. A. N. Fix. CO2 and A. P. A. N. Form. CO2 was then constructed against months.(7) This histogram shows the following facts : (a) A. P. A. N. Fix. CO2 ranged between 3.8 and 6.6 g C/m2 from April through August. (b) A. P. A. N. Form. CO2 ranged between -8.2 and -12.9 g C/m2 from September through December. (c) On the assumption that the average exchangeability of CO2 between air and lake water in a month is similar to those of the adjacent months, the difference between A. P. A. N. Fix. CO2 or A. P. A. N. Form. CO2 of a month and that of an adjacent month corresponds to the average net fixation rate of CO2 during the two months in a case of positive value and to the average net formation rate of CO2 in a case of negative value. (d) The average net fixation rate of CO2 and the average net formation rate of CO2 correspond to the average net production rate and the average net decomposition rate of organic matter respectively.(8) The maximum net production rate which was found between March and April amounted up to 4.5 g C/m2. day and the maximum net decomposition rate which was found between August and September amounted up to-13.5 g C/m2. day.

Dynamic status of primary production in lake yunoko, a small eutrophic subalpine lake in central Japan

Abstract: Investigation was made of the primary productivity of Lake Yunoko. The concentrations of PO4-P and NH3-N were highest in summer. The total amount of chlorophylla in the entire water column varied from 45 mg/m2 to 405 mg/m2 during the year with the maximum values occurring in late spring and in December. These values are very high compared with those reported for other lakes in the same district. The standing crop of phytoplankton as organic carbon was approximately 50∼70% of the total particulate organic carbon in the lake with values as high as 80∼90% being obtained in the spring and autumn. The rate of phytosynthesis under saturated light conditions was 3.7 mg C/mg chla/hr in the case of phytoplankton of the sun type and 1.2∼1.6 mg C/mg chla/hr in those of the shade type. The daily gross primary production in the lake varied from a low of 134 mg C/m2 to a high of 1,003 mg C/m2 during the year, the mean value being 372 mg C/m2. The total amount of daily microbial respiration varied from 177 mg C/m2 in winter to 1,476 mg C/m2 in summer. Thus, the daily balance of production and consumption of organic matter in the lake itself was concluded to be negative. The main factor contributing to the rectification of this imbalance of material budget seems to be the leaf litter coming from the forest surrounding the lake. In conclusion, Lake Yunoko is a very productive and at the same time, fairly heterotrophic lake.

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

On the Food and Feeding Habits of Lepidomysis longipes (Pillai & Mariamma) (Crustacea Mysidacea)

Abstract: Lepidomysis longipes is a subterranean mysid inhabiting the freshwater wells at Kottayam, Kerala, S. India. The wells are rather deep pits excavated to obtain regular supplies of drinking water. As such, they are protected by a circular embankment about a meter high from the ground level. This embankment prevents the entry of extraneous matter into the well. Therefore, the well water is practically devoid of food materials for the mysids. This apparent paucity of food in the habitat prompted us to make a detailed study of the food and feeding habits of the animal. HABITAT A short description of these wells is necessary here. The well from which L. longipes were collected for study is an open pit, about 12 m deep. The maximum depth of the water column in the well during the monsoons is about 3 m, while the minimum during summer is I ~ m. During the last fifty years, there is no record of the water in the well having completely dried up. The well is emptied annually for cleaning purposes, but water flowing in through the subterranean springs fills up the well in a short time. These underground springs thus provide a perennial supply of water which is always clear and devoid of suspended particles. The well has a thin layer of bottom deposit of fine mud mixed with decaying organic ma tter. The sediment layer is generally 7 to 15 cm thick. The upper parts of the side walls of the well from the ground level to a depth of I to 1.3 m always show a profuse growth of vegetation composed of ferns, mosses and a few flowering plants. The dead leaves from these fall into the water below, undergo decay and add to the organic content of the sediment. Even in wells cleaned annually, there is generally a growth of these plants providing organic substance to the bottom sediment. The water also harbours algal forms like Spirogyra, Mucor and Oscillatoria. During summer, every year. when the level of the water is low, the wells at Kottayam are emptied and thoroughly cleaned. The cleaning operations are so thorough that all the animals and vegetable matter in the well is completely removed. Yet within a few days the mysids reappear in the well, indicating that they gain entry into the wells through the underground channels.

An annual cycle of phytoplankton, with special reference to the diatoms and armored dioflagellates at Logy and Robin Hood Bays, Avalon Peninsula, Newfoundland, February, 1970-January, 1971

Abstract: During the period of February 1970 to January 1971, a qualitative and quantitative investigation of the phytoplankton population, with particular reference to the diatoms and armored dinoflagellates, was carried out at Logy and Robin Hood Bays on the east coast of the Avalon Peninsula of Newfoundland. -- Samples were collected at three depths in the bays and from the pumphouse of the Marine Sciences Research Laboratory. Related physical factors: water temperatures, Secchi disc readings, weather conditions, sea states and monthly total hours of bright sunshine, were simultaneously determined. -- Water samples preserved in Lugol's solution were examined by the sedimentation method using an inverted microscope. Net samples were examined for forms which might be missing from the water samples. -- The annual cycle of phytoplankton pattern found was as follows: a very low winter population of diatoms, dino flagellates, and other flagellates was replaced by a large population of diatoms (mainly species of Chaetoceros and Thalassiosira) during the spring bloom. With a reduction in numbers and species of diatoms in the late spring, the phytoplankton population became low and irregular during the summer and autumn and consisted mainly of naked dinoflagellates and Cryptomonas sp. -- Generally speaking, the vertical distribution of diatoms was variable at the three depths sampled, while largest numbers of dinoflagellates and other flagellates were found mainly in the upper water layers. -- The seasonal and vertical distribution of phytoplankton abundance was related to such physical factors as water temperature, solar radiation and stability of the water column. -- During the warm season the alternate increase and decrease of the phytoplankton population appeared to be due to the material examined, the methods employed and such local factors as water movements and run-off which might bring about varying growth conditions of these organisms. The phytoplankton was found to differ in numbers and species between bay and pumphouse waters because these sampling locations represented different ecological conditions of water movements and algal flora.

The physical matrix of Castle Lake

Abstract: The physical framework or matrix in which the biological processes of aquatic ecosystems occur is currently under investigation at the Castle Lake Research Station. Special attention has been given these physical parameters in view of their close interrelationship with important biological properties within the lake (as exemplified by the rate of change of phytoplankton biomass). A series of prognostic submodels is being developed and tested using equations that describe the energy flow, eddy diffusivities, water and elemental cycling, and the heat budget of the lake. The weather station and varied instrumentation that have been established at Castle Lake to measure these parameters are also described. -2In discussing and modeling the varied biological processes of lakes, it is important to consider the physical environment that provides the framework, or matrix, for these processes. For example, the rate of change of phytoplankton biomass in Castle Lake is given by the equation (Jassby and Goldman 1972): dB/dt P(G+F+S+B+D) (1) where Pt net productivity, G herbivore grazing rate, F vertical turbulent diffusion, S passive sinking due to gravity, B horizontal transport, and D death. The interrelationship between the biological and physical properties of an ecosystem is apparent in equation (1) since: (1) metabolism, of which Pn is the result, is an increasing function of temperature (according to the Qgp rule), (2) G is temperature-dependent in Castle Lake (unpublished data), (3) B is dependent upon heat content of the water column and wind, and (4) P (thus the entire ecosystem) is driven by solar energy. Implicit in equation (1) are measurements of evaporation and inflows needed for calculations of water and nutrient budget.