Einfluß von salzgehalt und temperatur auf entwicklung,wachstum, fortpflanzung und energiebilanz von Artemia salina

The influence of salinity and temperature on various life processes of Artemia salina (L.) from the Great Salt Lake, Utah, USA, was investigated. Hatching rate, hatching success, energetics and metabolism of hatching, growth rate, maturation rate and reproductive rate were measured at all combinations of 4 temperature levels (10°, 15°, 20°, 30°C) and 4 salinity levels (5, 15, 32, 70‰S). Optimal temperature-salinity combinations differ for different life cycle stages and parameters. The hatching rate rises with increased temperature and sinks with increased salinity. Hatching success is optimal at 20°C and 32‰S. Larval growth is best at 30°C and 15‰S; however, the maximum growth is attained at 20°C and 32‰S. Maturation rate, onset of reproduction, interval between clutches as well as the total number of offspring are primarily influenced by temperature, whereas the clutch size is a function of salinity. As the temperature is lowered, the capacity to survive low salinities is decreased. At low temperature, reproduction is only possible at high salinity. The energy consumption of the hatching embryo is primarily determined by the salinity level of the medium and is directly proportional to it. Carbohydrate consumption is under all conditions greatest by weight, but measured by its caloric contribution the relative importance decreases with increased energy drain. Additional energy requirements, particularly during the later stages of hatching, are met by raising fat and protein metabolism, fat being the main energy reserve.     

Der einfluß von temperaturänderungen auf den Ionen- und Wassergehalt in blutplasma und geweben von Tinca tinca

Two-year old Tinca tinca L. (previously acclimated for at least 3 weeks to defined temperatures) were subjected to slow (24 h) and fast (2 h) temperature changes from 13.5° to 26°C (observational period 504 h) and from 6° to 16°C and vice versa (observational period 288 h). Effects on coefficient of condition, Na, K, Ca and Cl content of plasma, H₂O, Na and K content of muscle and liver, and rates of movements of gill-covers, when the temperature rose to 26°C, were recorded. After temperature change from 13.5° to 26°C, sharp increases occur in the amount of K and Cl in the blood plasma, of H₂O in the liver and, if the temperature rise is effected quickly, of muscle H₂O content. Substantial reductions were recorded in coefficient of condition and K content of the liver. With a fast rise in temperature, liver Na content decreases sharply at first, but rises again later. After temperature change from 6° to 16°C, Ca increase in blood plasma and (if the temperature is raised slowly), decline in muscle Na content are considerable; drop of liver H₂O content is less marked. If the temperature change is effected rapidly, then liver Na content and plasma K diminish initially and, thereafter, rise sharply. In the case of quick temperature change from 16° to 6°C, particularly frequent and marked changes in ion and water contents occur; in most cases adjustment is not complete after 288 h, and the observed variations are often clearly different from those observed in the case of slow temperature change. If temperature is lowered rapidly, the amounts of Na and K in muscle and liver fall and the amount of H₂O increases. There is a considerable loss of Na and Cl contents and, after rapid temperature change, also in plasmatic K and Ca contents. The responses of fishes acclimated to 6° and 16°C are compared; at 16°C the coefficient of condition and plasmatic Na, K and Cl contents decrease, and H₂O, Na and K contents of the liver increase. The amount of K in the plasma and of H₂O, Na and K in the muscle remains unchanged. The stress effect upon ion and water contents during transfer to 6°C is significantly greater during fast than during slow temperature change. The problem of proper differentiation between biological consequences of stress and adaptation phenomena is discussed. Complete adaptation was frequently not attained during the course of our experiments, especially not at low temperatures.     

Wirkung von Isoproturon auf Laich und Larven zweier Unkenarten (Bombina spec.)

In intensively used arable areas, a contamination of the reproduction ponds with pesticides probably impairs the development of spawn and tadpoles of amphibians, based on the coincidental space and time. Therefore, the effects of the herbicide isoproturon (IPU) on the early life stages of the firebellied toad (Bombina bombina) and the closely related yellowbellied toad (Bombina variegata) were investigated. The results of the exposure with¹⁴C-labelled IPU (1 μg/L) indicated an uptake into the spawn and tadpoles of bothBombina species. The jelly capsules could not protect the embryo from effects of the herbicide. Tadpoles with complete opercula and without external gills were most sensitive to contamination by IPU. Physical and behavioral abnormalities of the tadpoles developed at concentrations, of 0.1 μg/L after 24 h exposure. At increasing IPU-concentrations the number of impaired and dead tadpoles increased significantly compared to the control. The enzymatic system of the Glutathion S-Transferase (GST) of theBombina tadpoles were influenced significantly by the duration and concentration of IPU exposure. Compared to the pure active ingredient IPU, the commercial herbicide TOLKAN FLO^® provoked a stronger enzymatic response in the tadpoles. This could be caused by the presence of an emulsifier used in the TOLKAN FLO^® formulation which enhanced the availability of IPU and/or the interaction between IPU and the emulsifier.     

Mathematische Analyse der kombinierten Wirkung von Temperatur und Salzgehalt auf den Stoffwechsel von Tilapia mossambica (Teleostei)

Job (1969 a, b) has presented experimental results on the influence of temperature and salinity on the rate of oxygen consumption in Tilapia mossambica. He evaluated his results on the basis of the allometric function. The present paper analyses, in addition, the data obtained on the basis of the temperature function proposed by the present author. The parameters of this formula reveal that, in 50 and 100% sea water, the curves for the logarithmic values for the given body weights are parallel to each other; only the slope is different for the two salinities. In fresh water, the logarithmic temperature curves diverge. Job's results clearly demonstrate that it is not possible to explain the differences in the respiratory metabolism of this fish on the grounds of the energy expenditure for osmoregulation. The present author supposes that the differences found in the rate of respiration are caused by differences in the ionic composition of the internal milieu in the different salinities.     

Wirkungen von 2,4- und 2,5-Dinitrophenol auf die Embryonalentwicklung des Herings Clupea harengus

The biological effects of dinitrophenol (DNP) were tested on Clupea harengus eggs of Baltic spring and autumn spawners. Experimental water temperature was maintained at 10.8°C±0.2C° (experiment 1) and 11.8°C±0.2C° (experiments 2 and 3); salinity ranged between 14 and 16‰. Eggs were artificially fertilized 1 to 4 h after catching the parent individuals; they were attached to glass plates and incubated in 1 l aerated containers. Thirty, 48 and 55 h after fertilization, eggs were transferred to various test concentrations of DNP (dilutions of 2,4- and 2,5-DNP used are listed in Table 1). 2,4-Dinitrophenol is known as a true uncoupling reagent, which inhibits the phosphorylation of ADP. The effects of DNP on embryo activity, heart rate, rates of body malformations and mortality are studied. Embryo activity rose above control values between the 6th and 7th days of the incubation period in low DNP concentrations (0.01 to 0.05 mM/l), and heart activity deviated after 5 to 7 days from that of the controls. Mortality rate depended on inhibitor concentration and time of poisoning (Table 4). Various malformations of embryos were observed (anophthalmy, symmetrical and unilateral microphthalmy, curled bodies, de-differentiations, Fig. 7).     

Der einfluß einer Vorbehandlung mit konstanten und wechselnden Temperaturen auf die Hitzeresistenz von Gammarus salinus und Idotea balthica

The crustaceans Gammarus salinus Spooner and Idotea balthica Pallas live in brackish waters and are capable of tolerating a variety of temperature and salinity conditions. Thus far, the capacity for non-genetic adaptation of such euryplastic animals has only been tested at different levels of constant temperatures. If exposed to both constant (8°, 14° or 20°C) and fluctuating (daily fluctuation: 8°?20°C) temperatures, the tested individuals reveal significant differences in heat resistance which become apparent within 12 h. G. salinus and I. balthica exhibit reasonable (meaningful) heat resistance, i.e., a positive correlation between the degree of heat resistance and the level of adaptation temperature (AT). Following a shift in AT (8° → 20°C or 20° → 8°C) the degree of resistance changes rather fast. This leads, under fluctuating temperature conditions, to diurnal changes in the degree of heat resistance. I. balthica also shows an endogenous diurnal periodicity of its heat resistance. In G. salinus, long-term exposure (2 to 4 weeks) to fluctuating temperatures [duration of temperature change: 2 h (Δ/2 h)] produces, during the day, a mean resistance value which coincides with the value obtained for AT 14°C-controls. This fact results from temperature-independent adaptation speeds (same after decrease and increase of AT). However, fast temperature change (ΔT/1 h) during exposure to fluctuating temperatures leads to a significant augmentation of heat resistance, presumably due to additional stress; such fast temperature changes are less well tolerated than slow fluctuations (ΔT/2 h). In I. balthica, low ATs are less efficient in terms of heat resistance than high ATs (great difference between AT=14° and 20 °C; small difference between AT=8° and 14 °C). In males, lowering of AT from 20° to 8 °C results, within the first 12 h, to faster loss of heat resistance than is the case for gain in heat resistance after AT increase from 8° to 20 °C. However, after prolonged exposure to the new ATs, completion of readaptation is temperature-independent. Under conditions of fluctuating temperatures (ΔT/2 h) resistance increases beyond the mean value (AT=14 °C). Further increase in resistance can be obtained through fast temperature changes (ΔT/1 h). In G. salinus, which occupies habitats with more extensive temperature fluctuations, the responses studied are less pronounced than in I. balthica.     

Niedere pilze als testorganismen für schadstoffe in meer- und brackwasser die wirkung von schwermetallverbindungen und phenol auf Thraustochytrium striatum

Three test-series were applied, which differed in regard to the basal medium (natural or artificial sea water, salinity level, addition of detergent); the culture conditions (primary cultures, subcultures, back-inoculations into basal medium without toxic metals); the criterion employed (zoospore activity, sporangia development, or dry weight of Thraustochytrium striatum Schneider). The temperature applied was 18° to 20°C. The sea water-pollen-method (MWP) proved to be the most suitable: it is simple and more sensitive than the other tests; subcultures and back-inoculations are possible without much additional work; conditions simulate nature; first results are available after 3 to 4 days. The SMS-method (enriched natural sea water of different salinities) provides additional information on salinity effects. Nine substances have been tested: (CH₃COO)₃Hg, HgCl₂, CdCl₂·H₂O, ZnSO₄ ·7H₂O, NiSO₄·7H₂O, CuSO₄·5H₂O, CoCl₂·6H₂O, MnCl₂ ·4H₂O, and phenol. In regard to their toxicity these substances can be divided into 2 groups: Hg- and Cd-salts inhibit development down to greater dilutions than the remainder; Zn and Ni seem to yield intermediate effects. Salinity modifies the toxic effects of the test substances. In higher salinities, comparable concentrations of test substances reveal stronger inhibitory effects than in lower salinities. Detergents may augment the toxic effects, at least of CuSO₄. The marine lower fungus T. striatum is a useful organism for testing biological consequences of water pollutants.     

Einfluß von Benetzungsspannung und lonen auf die Substratbesiedlung und das Einsetzen der Metamorphose bei Bryozoenlarven (Bowerbankia gracilis)

Settlement and metamorphosis in larvae of Bowerbankia gracilis depend on the wettability of the substratum. The wettability of a solid can be characterized by it's specific contact angle, . Larvae settle on solids with angles >17°, but not on surfaces with high wettability properties. In an attempt to explain this phenomenon, we consider the larvae as a second liquid and their attachment as a second wetting. In such case, water and larvae would compete in wetting the substratum. Adhesion can be accounted for by assuming the wetting tension of solid to water to be lower than that of the larval surface (|_solid/water| < |_solid/larvae|). Adhesion would thus be favoured energetically. The rate of settlement and that of metamorphosis are demonstrated as depending on the degree of contact angle, , in an all-or-none fashion. Settlement of larvae on high-wetting solids is prevented by high capillary pressure accruing at the point of contact. Metamorphosis is initiated by contractions occurring after adhesion. Application of CsCl or KCl induces such contractions and metamorphosis in free-swimming larvae. MgCl₂ prevents the onset of metamorphosis but not adhesion. Two mechanisms are considered as possibly accounting for induction of metamorphosis: (1) mechanical stimulation by shearing the cilia at the point of contact, and (2) a chemical stimulation of the cell membrane after application of K⁺ or Cs⁺.     

Über den Einfluß des hydrostatischen Druckes auf die Ultrastrukturen von Zellen und Geweben. II. Untersuchungen an membransystemen von Kiemenepithelien mariner Muscheln und dem Kiemendarm von Branchiostoma lanceolatum

Employing the technique of pressure fixation, high hydrostatic pressure effects on ultrastructures of membrane systems and cell organelles have been investigated, using as material the gill epithelium of marine bivalves and the pharynx epithelium of Branchiostoma lanceolatum (Pallas). Pressure was increased stepwise between 1 and 800 atm. Pressure sensivity of the tissues varies as a function of their structure and function. The degree of disorganization of cell structures increases with increasing pressure. At 300 to 500 atm, the microvilli tend to form small vsicles, which are connected with each other by thin filaments. Especially the basic vesicles become enlarged to oedematous expansions. A variety of membrane disintegrations can be observed on cell organelles, which are connected by membrane-flow. This supports the thesis of the heterogeneity of membranes. Mitochondria reveal destruction of the cristae to an electron-dense material. Membrane lysis can be demonstrated in the endoplasmic reticulum and the plasmalemma of spezialized pharynx cells of B. lanceolatum. The Golgi-apparatus is the only organelle which remains almost unaffected by hystrostatic pressure. There are probably interactions between pressure sensivity of membrane structures and their enzymatic activities.     

Die von REACH ausgelösten Veränderungen im Hinblick auf die neu definierte Verantwortung von Herstellern und industriellen Nutzern

The changes initiated by REACH towards the newly defined responsibility of producers and industrial users are presented. The data acquisition for ‘old chemicals’, and hereby the improvement of risk assessment, will start in 2007, though will take more than ten years. The data material shows gaps in the area of occupational health and safety. The protection of consumers from substances in products remains insufficient. Nevertheless, for chemicals policy, REACH is a big step forward.     

Über den einfluß des hydrostatischen druckes auf die ultrastrukturen von zellen und geweben. IV. Der effekt der temperatur auf die druckresistenz der membran-, filament- und mikrotubulisysteme verschiedener gewebe mariner muscheln und Branchiostoma lanceolatum

Temperature-pressure experiments have been carried out on gill epithelium of Modiolus modiolus and Mytilus edulis (Baltic and North Seas), as well as on the skin, pharynx, and trunk muscles of Branchiostoma lanceolatum (Pallas), employing the technique of pressure fixation. Temperatures of 0°, 5° and 15°C have been combined with pressures up to 800 atm. Low temperature (0°C) intensifies disintegration of ultrastructures by pressure in comparison to 5°C. The highest degree of structural disorganization can be observed at 600 atm and 0°C. Increased temperature (15°C) increases pressure resistance, but the structural difference is more quantitative than qualitative. In pressure experiments, temperature probably affects cell organelles at the molecular level.     

Einfluß von 2,4-dinitrophenol auf die atmung und die Konzentration einiger metabolite bei embryonen des herings Clupea harengus

In rearing experiments with herring eggs (temperature=14.0°±0.1°C; salinity=15‰), oxygen consumption under normal conditions and after addition of 2,4-DNP (concentration=0.1 mM/l; pH=8.1) was measured over the period of embryonic development by means of the Wabburg-technique. Additionally, the concentration of low molecular sugars, polysaccharides, free amino-acids, and adenosintriphosphate (ATP) was determined. The oxygen consumption increases during embryonic development; this increase is not linear. Periods of high intensity of oxygen consumption are followed by others with only slight increase. Immediately before hatching, the respiration curve distincly declines (Fig. 1). Under the influence of 2,4-DNP (dinitrophenol), the embryos increase their respiration intensity after a short period of incubation. The maximum rise in percentage over the normal values reaches up to 400% at the beginning of gastrulation, falls to 50% even before the locking of the blastopore, and decreases slightly to about 30% until hatching. The immense decline in the percentage increase in respiration following the addition of 2,4-DNP at the end of the first day of development is caused by the rapid increase in normal respiration. After poisoning with DNP at different stages of development, the uncoupled respiration curves are normally almost equal. This holds both for the temporal position of the respiration maxima (about 12 to 24 h after poisoning), and for the absolute amounts of the increased respiration over the normal values (5 to 7 μl/h/100 embryos). Excluded from these regularly repeated findings are two stages of development: (1) the stage of epiboly after exceeding the yolk equator until shortly before locking of the blastopore (26 to 32 h after fertilization at 14°C); (2) the period at the end of the 4th day of development when the eyes become pigmented (100 to 120 h after fertilization). These two stages are characterized by the fact that, at the moment of poisoning, the normal respiration shows retarded activity. On the other hand, these two stages are well able to undergo periods of development in which long-living embryonic deformations can occur after uncoupling of respiration with 2,4-DNP. The content in low molecular sugars and polysaccharides decreases slightly in the course of embryonic development and, following the addition of 2,4-DNP, decreases considerably during the first 24 h. After 48 h, accelerated decomposition of carbohydrates continues. Under the influence of 2,4-DNP, the embryos metabolize more carbohydrates in 1 day than during the whole normal development period. The changeover of the metabolism to increased decomposition of carbohydrates can be explained as a dislocation of the energetic sources from the respiration chain to glycolytic phosphorylation. In accordance with these facts, the concentration of free amino-acids, almost equal during normal embryonic development, remains unchanged under the influence of 2,4-DNP.     

Ökologie und Postlarvalentwicklung von Scottomyzon gibberum,eines auf Asterias rubens parasitisch lebenden Copepoden (Cyclopoida siphonostoma)

Scottomyzon gibberum (copepodid stages, males and females) lives ectoparasitically on the sea star Asterias rubens. The female digests the skin of Asterias extra-intestinally, and sucks up the food by means of the sipho-shaped mouth, the structure of which is described. The skin of Asterias rubens, chiefly the tissue of the pedicellariens, forms gall-like structures overgrowing feeding females of S. gibberum. The mature females grow by extension of the chitincuticula and by moulting from a slender, cyclopslike shape to balloon-formed, swollen-up individuals. On the abdomen, simultaneous reductions take place which, in a certain period of life are retrogressive and, after this, start anew. the number of eggs depends on season and the post-larval developmental stage of the female. It varies between 1 and 24 eggs for each eggsack, averaging about 8. Old females are no longer able to swim, they become progressively sessile as their body volume increases, and can no longer leave the sea star. At the beginning of May, the population of S. gibberum on the Helgoländer Austernbank (Southern North Sea) reaches the maximum rate of egg production. At the beginning of June, large numbers of copepodid stages attack the Asterias rubens population. Four weeks later the bulk of them metamorphose into males and females. The males die in August after mating-time. The females develop during autumn and winter. By January of the next year they have attained the size of old females. In spring they procreate the nauplii of the following generation, finally dying in summer or autumn. The cycle of development of populations of S. gibberum of other localities around Helgoland and in the Kattegat, varies from that of the population of the Helgoländer Austernbank. The parasite S. gibberum has so far been found in the area between the Irish Sea in the West, the Big Belt (Baltic Sea) in the East, and the Oslofjord (Norway) in the North. It demands a higher and more constant salinity than its host Asterius rubens and does not, therefore, follow Asterias into the more brackish parts of the Baltic Sea.     

Bioakkumulation von Metallen und Stickstoff zwischen 1990 und 2005 in Niedersachsen

Background, aim, and scope Since 1990 the UN ECE Heavy Metals in Mosses Surveys provide data inventories of the atmospheric heavy metal bioaccumulation across Europe. In the survey 2005 the nitrogen accumulation was measured for the first time in most of the participating countries. In Germany, the surveys were conducted in close cooperation of the relevant authorities of both the Federal Republic and the sixteen states. Therefore, statistical evaluations of the moss survey data with regard to the whole German territory and single federal states are of interest. This article concentrates on Lower Saxony, dealing with the mapping of the spatiotemporal trends of metal accumulation from 1990 to 2005, the spatial patterns of nitrogen accumulation in 2005, and the spatial variability of bioaccumulation due to characteristics of the sampling sites and their surroundings. Materials and methods The bioaccumulation of up to 40 trace elements and nitrogen in mosses was determined according to a Europe-wide harmonised methodology. The according experimental protocol regulates the selection of sampling sites and moss species, the chemical analysis and quality control and the classification of the measured values for mapping spatial patterns. In Lower Saxony all sampling sites were described with regard to topographical and ecological characteristics and several criteria to be fulfilled according to the guideline. Together with the measurements this metadata was combined with other information regarding land use in the surroundings of the sampling sites in the WebGIS MossMet. The spatial structure of the metal bioaccumulation was analysed and modelled by variogram analyses and then mapped by applying different Kriging techniques. Furthermore, multi metal indices (MMI) were derived for both the sampling sites and raster maps with help of percentile statistics: The MMI_1990–2005 was calculated for As, Cd, Cr, Cu, Fe, Ni, Pb, Ti, V and Zn. The statistical association of the metal and nitrogen bioaccumulation, site specific characteristics as well as information on land use and emissions was analysed by bivariate nonparametric correlation analysis, contingency tables and Classification and Regression Trees (CART). Results The results of the quality controlled chemical analyses shows a significant decrease of the metal bioaccumulation in Germany from 1990 to 2000 for all elements but Zn. From 2000 to 2005 a further significant decrease can be stated for Cd, Hg and Pb, to most parts non significant increases can be observed for Cr, Cu, Fe, Sb and Zn. Cr thereby exhibits the highest accumulation in 2005 when compared to the results of 1990, 1995 and 2000. The MMI illustrates the temporal trend of the metal bioaccumulation as a whole: From 1990 to 2000 a continuous significant decrease can be observed. From 2000 to 2005 the median of the MMI increases, again significantly, from 3.4 to 4. The N concentration in mosses in Lower Saxony reaches from 1.1 to 1.9?% in dry mass. High N concentrations were detected in agriculturally intensively used areas. Highly significant bivariate correlations between the metal bioaccumulation and land use in the surroundings of the sampling sites were found reaching from 0.3 to 0.5. Other location criteria with similar correlation coefficients/Cramér’s V are moss species, altitude, distance to the North and Baltic Sea and the distance of the sampling site to the nearest tree crown. N only shows negative correlations to urban land use and the distance to the nearest tree. Exemplified for Sb multivariate correlations were furthermore detected by CART. It could be shown that the Sb bioaccumulation interacts with the moss species and the ratio of agriculture, forests and urban areas around the sampling site. Discussion The decrease of the continuously decrease of heavy metals reflects the improving air quality in the past 15 years. Compared to other environmental monitoring and modelling programmes the moss surveys registered increasing concentrations of toxic metal elements between 1990 and 2005, e.?g. Cr. High Cr loads in mosses were also registered in other European countries like in Switzerland. Further investigations are therefore necessary to investigate whether this is due to different emission conditions or biogenic effects (e.?g. as a result of increasing nitrogen depositions). Contrary to deposition measurements that exhibit a higher temporal resolution the moss surveys provide measurement data on a wide range of elements. Some of these elements are important with regard to human-toxicological aspects (e.?g. As, Al, Hg, Sb, V). Due to its ecotoxicological relevance nitrogen was monitored in the European moss survey 2005 for the first time. Compared to the metals regionally high emissions of nitrogen compounds into the atmosphere can be detected in Lower Saxony. The standardised biomonitoring of atmospheric pollution with mosses is an important link between the technical acquisition of depositions and the accumulation in biological material. To claim that the element concentrations in mosses should correlate to a high degree with measured or modelled depositions is not appropriate since these approaches are considering different biological or physical receptors. Nevertheless, the accumulation of air pollutants in terricolous mosses reflects the degree of air pollution which is permanently deposited and affects the system of plants and soils. The degree of correlation thereby depends on the boundary conditions of the physical processes, like regional and site-specific meteorological conditions within the accumulation period, the vertical and horizontal vegetation structure or land use conditions. Conclusions The moss surveys contribute to the heavy metal and the multi-component-model of CLRTAP because they prove on different spatial scales how air pollution control influences the accumulation of emitted substances in environmental subjects of protection like vegetation incl. arable crops. If environmental monitoring is seen as a continuous task and the applied methodology works well as an early warning system then environmental policy is enabled to act in preventative sense and to pursue unexpected developments. No other environmental monitoring programme provides such a wide range of ecotoxicologically relevant elements measured as spatially dense as the case for the moss surveys. The spatial distribution of environmental information is an essential criterion for their usability in terms of political measures for the federal states and the federation. Recommendations and perspectives Heavy Metals in Mosses Surveys are a positive example for environmental monitoring activities reaching across three spatial and administrative levels: regional (e.?g. federal state or natural landscape), nation wide (e.?g. Germany) and continental (e.?g. Europe). In Germany the harmonised and quality controlled moss data are made available via a WebGIS portal. Therefore the moss data may easily be accessed for environmental monitoring purposes and the control of environmental political actions. Hence, the continuous task of environmental monitoring can be met and carried on in the future.