Aspects of the physiology and ecology of Corophium volutator (pallas) in relation to salinity

The effects of salinity on the physiology and ecology of the mud-dwelling estuarine animal Corophium volutator (Pallas), a crustacean amphipod, have been investigated. A study of the effects ot salinity on the distribution and abundance of C. volutator on the estuary of the River Ythan, Aberdeenshire, indicates that 2‰ is a critical minimum salinity controlling its distribution. In areas with salinities between 2 and 5‰ C. volutator was present, but in reduced numbers. In areas with salinity greater than 5‰ , the distribution and abundance of C. volutator were controlled by the nature of the substrate; however, in areas with suitable substrates, but where the salinity was below 5‰ , the effects of salinity override the effects of the substrate. Experimental studies indicated that, if supplied with mud, it will survive the salinity range of 2 - 50‰, and without mud, the range 7.5 - 47.5‰. Moulting occurred in salinities of 2.6 - 46‰ , but most frequently in tho range 5 - 20‰ . Growth occurred at a maximum rate in 15.4 o/oo and only slightly slower at 4.4 and 30.6‰ ; but below 4.4‰ the growth rate was progressively reduced. The effects of salinity on the various stages in the life cycle are discussed. Freezing point studies show C. volutator to be a hyperosmotic regulator, having a tissue tolerance range of 13 - 50‰ . The effect of size, sex, feeding and moulting on the freezing point have been investigated. C. volutator was found to produce urine hypoosmotic to the blood when acclimated to low salinities, and isosmotic urine at salinities above 20‰ . Over a range of salinities from 1 - 35‰ , C. volutator was found to maintain Na+, K+,Ca ++,Cl-, more concentrated than the medium, and Mg++ less concentrated. The restricted permeable areas of the cuticle have been localised by silver staining. The oxygen consumption of animals of the same size, at the same level of activity, and at the same temperature, did not differ significantly between animals in different salinities. A salinity preference range of 10 - 30‰ has been demonstrated. Relevant literature on estuarine life, and osmoregulation of crustacea is reviewed. The adaptations of C. volutator to an environment with varying salinity are discussed

Modelling the Eddy Pattern in the harbour of Zeebrugge

Hydrodynamic

An ecological study of Diatomovora amoena, an interstitial acoel flatworm, in an estuarine mudflat on the central coast of Oregon

The distribution and abundance of the interstitial acoel turbellarian, Diatomovora amoena Kozloff, 1965 was studied in an estuarine intertidal sand flat in Yaquina Bay, Oregon, from May 1970 through May 1971. Monthly measurements of biological (organics, sulfides, chlorophyll, and carotenoids), pore water (salinity, pH,oxygen, and temperature), and sediment (fine sediment percentage, grain size, sorting, skewness, and kurtosis) factors were made along a transect at four intertidal stations with elevations of -2.0, 0.0, 1. 6, and 3.0 feet, stratified by selection from a curve for tidal exposure, and at two depths (0, 0 cm to 0. 5 cm and 0. 5 cm to 1. 0 cm) of the sediment. Estuarine factors that were monitored continuously included temperature, salinity, tide elevation, and insolation. The interrelationships among these environmental parameters, their roles in the interstitial sediment system, and the hydrology of the groundwater in the beach, were investigated in order to characterize the interstitial environment of the sand flat and to determine the environmental factors limiting the distribution and abundance of D. amoena. Seasonality was indicated in most of the factors measured. The sediment system was strongly reducing during summer and fall as organic production increased. Particle size analyses showed that transport and deposition of fine sediments contributed to the development of reducing conditions. The properties of the interstitial environment of D. amoena were found to be controlled by the level of groundwater, rate of percolation, and degree of mixing within the beach. Density of D. amoena was highest during the fall and early winter, and lowest throughout the winter. Summer production of plant material in the lower intertidal lead to reducing conditions at the sediment surface. Reduction in animal density at the lower two stations was attributed to these reducing conditions, and to the rafting of animals away from the intertidal with the algal mat. Decrease in animal density in the upper two stations was attributed to lethal low temperatures and salinities that occurred during heavy precipitation in the winter and coincided with low tidal exposure. Exclusion of animals from depths greater than 0. 5 cm in the sediment was attributed to lethal levels of sulfide. Tolerance of D. amoena to temperature, salinity, and sulfide was determined experimentally. The 25 combinations of temperature and salinity, and the 12 combinations of temperature and sulfide that were employed were selected on the basis of actual levels measured in the study area. The temperature and salinity survival results were fitted to a response surface which was used to evaluate these factors in limiting animal distribution. Survival of acoels was independent of temperature up to 6 hours of exposure, and strongly temperature-dependent after 24 hours of exposure. Initial mortality was attributed to osmotic stress. Upon exposure to sulfide at 50 μgm S/ml, these animals did not survive beyond 6 hours, demonstrating that sulfide in high concentrations is toxic to D. amoena. At lower concentrations of sulfide (10 μgm S/ml), the acoels were able to live for over 20 hours. Lowering the temperature at both concentrations helped to prolong the lives of the animals. Levels of sulfide similar to those used in the experiment Levels of sulfide similar to those used in the experiment (10 μgm S/0.5 cm³ = 50 μgm S/ml.) were found at the sediment surface in the lower two stations during September, at which time animal density was found to be decreasing. At the upper two stations in September, where the level of sulfide was 3 μgm S/0.5 cm³, the acoel population was found to be increasing, thus bearing out the assumption that population density is, indeed, affected by sulfide. The nature of the interstitial sediment system as a habitat for meiofaunal organisms was explored and the role of the groundwater hydrology, as a buffer against seasonal variation in the estuary, in maintaining this system was examined. A portion of the littoral shore considered in this investigation was conceptualized as a factor model, the principal parts of which were selected for study. The seasonal cycles of the major input factors were found to be relatively stable from year to year, while the timing of these cycles varied. The numerous positive and negative correlations that were found within and between the biological, pore water, and sediment groups of factors indicated the multiplicity of direct and indirect interactions and supported the contention that the tidal flat is a complex interrelated system. Change in one or more of the major factors, such as precipitation, river runoff, sedimentation, or tidal prism, can be expected to have diverse effects on the littoral sediment environment

Studies on the intertidal sandy-beach fauna of the Cape Peninsula

The thesis comprises six published papers and two papers in mnuscript. Five of the publications and the second of the manuscripts deal with the sandy-beach snail, Bullia, while the sixth published paper is a brief account of food-relationships on the Cape Peninsula's sandy beaches. The first manuscript is an introduction to the ecology of the sandy beaches of the Cape Peninsula, the first of a series of papers to be published on this topic. The manuscript on Bullia forms the second part of this series

Proceedings of a Summer Institute in Water Resources: Volume 3 - Water Quality Control and Management

Foreward: Recognizing the need for training of individuals to meet the rapidly rising problems connected with water resources development, Utah State University, with National Science Foundation support, organized a Summer Institute in Water Resources for college teachers. it was hoped that participants carefully selected from all regions of the country would receive additional insight and stimulation to improve and enlarge water resources training programs at their own institutions. Thus, the accelerated dissemination of such knowledge on a national scale could be facilitated. Realizing further that the key to a successful institute of this nature lay in the excellence of its staff, efforts were made to obtain instructors with intimate knowledge and broad experience int he subject matter area they were asked to rpesent. In nearly every case those selected willingly accepted the invitation to participate, although this meant considerable monetary sacrifice and major adjustment of busy schedules. The subject matter treated paralleled regular offerings listed in the University catalog and is considered to be central or core to a water resources planning and management training program. one course treated the philosophical, historical, institutional, political, and legal aspects of water development. The responsibility for this course was shared jointly with Cleve H. Milligan, Charles E. Corker, and Wayne D. Criddle. The second course considered the principles of water resources economics and was presented by B. Delworth Gardner. The third course dealt with concepts of water quality management and was under the direction of P. H. McGauhey. The final course was on principles and procedures of regional resources planning and was presented jointly by Aaron Wiener, W. R. Derrick Sewell, and Harvey O. Banks. Having assembled a distinguished and diversified staff to present some of the best current professional thinking in the topics suggested in the preceding paragraph, it was felt most appropriate to attempt to put their lectures into writing. A proceedings of the Institute would have considerable utility beyong the Institute itself. Hence, the instructors were encouraged to prepare written material for the proceedings and were given secretarial and other assistance to aid them. This material has been organized according to the four major courses and is issued in four comanion volumes. Clearly, this has been a prodigious effort which required Institute staff and others to go the extra mile. Special thanks and recognition are due Mrs. Dorothy Riley who not only typed the entire proceedings but also attended to many details necessary for the successfult operations of the Institute. Jay M. Bagley served as director of the Institute and assumed a general coordinating and editing role in the development of these proceedings

Urban Areas in Coastal Zones

[First Paragraph] Coastal cities have been subjected to extreme weather events since the onset of urbanization. Climatic change, in particular sea level rise, coupled with rapid urban development are amplifying the challenge of managing risks to coastal cities. Moreover, urban expansion and changes and intensification in land use further pressure sensitive coastal environments through pollution and habitat loss

Maine Ecosystems

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