Resource quality controls detritivore consumption, growth, survival and body condition recovery of reproducing females

2014 ◽  
Vol 65 (10) ◽  
pp. 910 ◽  
Author(s):  
Aitor Larrañaga ◽  
Ana Basaguren ◽  
Jesús Pozo

Although the effect of resource quality on density, biomass, growth rate and secondary production of consumers has been frequently documented, the direct repercussion of resource quality on reproduction has been less investigated. Here we tested the hypothesis that resource quality can limit body-condition recovery of reproducing individuals. For this, we reared ovigerous females of the freshwater amphipod Echinogammarus berilloni in the laboratory and fed them with leaves differing in quality (native Alnus, Quercus, or the exotic Eucalyptus) conditioned in three streams differing in the concentration of dissolved nutrients. Both consumption and growth rate, as well as the length-corrected mass and protein content of females after the release of the eggs, were negatively related to the C : N and C : P ratios of the resource. Survival was significantly lower with the exotic eucalypt leaf litter compared to native alder and oak, a result likely explained by the toxicity of the leaves. The conditioning of the leaves in the different streams did not affect the measured variables, although it interacted with survival. The present study suggests that resource quality can affect the recovery of body condition of reproducing females and shape the population structure of iteroparous species.

Author(s):  
J.P. Martin ◽  
R. Bastida

A benthic survey was carried out from November 1998 to December 1999 in the tidal flats of Bahía Samborombón (Río de la Plata estuary, Argentina), in order to study the population structure, growth and secondary production of Laeonereis culveri. The samples were collected monthly in two intertidal areas with different environmental characteristics (San Clemente Creek and Punta Rasa). Growth was analysed using computer-based methods of length–frequency data (ELEFAN), and the secondary production was estimated by Crisp's and Hynes & Coleman's methods. Laeonereis culveri were recruited throughout the year, with two main peaks during spring and autumn. The autumn cohort showed growth rate (K) of 2 in San Clemente Creek and 1.8 in Punta Rasa. The seasonal oscillation of growth pointed out that worms grow very slowly during winter months. The life span of this cohort ranged from 15 to 17 months. The spring cohort showed higher growth rates in both sampled areas (K=3.3 in Punta Rasa and 3.1 in San Clemente Creek), whereas the growth oscillation showed similar values to those of the autumn cohort. The lowest growth rate was found in January and the life span was 9.5 months. The annual mean biomass in San Clemente Creek was 5.44 g m−2, with a mean production of 40.8 and 43.8 g m−2 y−1, according to the method used, and a production/biomass (P/B) ratio of 7.5 and 8 y−1 respectively. In Punta Rasa, the annual mean biomass (2.69 g m−2) and mean secondary production (19.44 and 23.61 g m−2 y−1, according to the method used) were lower than in San Clemente Creek, nevertheless the P/B ratio (7.2 and 8.7 y−1) was similar. The high secondary production and P/B ratio observed suggest that L. culveri transfer an important biomass to higher trophic levels, pointing out the very important role that this polychaete plays in the energy flux of this coastal estuarine ecosystem.


1983 ◽  
Vol 61 (11) ◽  
pp. 2417-2423 ◽  
Author(s):  
B. Vincent ◽  
M. Gaucher

In 1982, we studied three populations of the snail Bithynia tentaculata living in a cold environment in the upper estuary of the St. Lawrence River (Quebec), with particular emphasis on the population structure and the fecundity of the different generations. This and other studies show that large variations can occur in the age of sexual maturity from year to year; these are caused by variations in the growth rate and could cause important changes in the growth rate of the populations. Also, there does not appear to be an adequate mechanism to compensate poor recruitment in one year and thus an unbalance in the population structure can be seen for at least 7 years. Fecundity varies from one population to another and from one year to the next. Differences are greater between populations, but both phenomena often interact. These results show the relevance of long-term observations, still quite rare, in order to interpret spatial and temporal variations in the bionomics of iteroparous species.[Journal translation]


Author(s):  
Libe Solagaistua ◽  
Arturo Elosegi ◽  
Aitor Larrañaga

Microcosms try to mimic the behaviour of natural ecosystems; however, differences in experimental conditions reduce comparability among studies. A standard incubation duration may increase comparability between experiments without losing realism in the response. Some response variables can respond fast, acting as early warning signals of other, more important oncoming changes. In this experiment, we test the effects of resource quality and incubation duration on the performance of the amphipod Echinogammarus berilloni. Individuals were fed on five leaf species of contrasting quality and we measured their consumption rate, death rate, RNA:body mass (RNA:BM), growth rate, mass body condition and lipid body condition over time. We predicted that (i) resource quality would affect the response variables, (ii) consumption rate and RNA:BM ratio would act as early warning signals of oncoming changes in growth or death rates, and (iii) the inter-individual variation would gradually decrease with time. Resource quality was positively related to consumption rates, although it did not correlate to nutrient concentration and toughness of the materials. Amphipod body mass condition changed with diet, animals feeding on oak and beech showing the lowest values. Death rate, growth rate, RNA:BM, and lipid mass condition did not change with food resources. Consumption, growth rate and mass body condition changed with time. Moreover, consumption, mass body condition and RNA:BM significantly interacted with incubation duration. Variability among individuals in consumption and growth rate decreased with time, as predicted. Our results pointed that special care should be taken when comparing microcosm experiments with different incubation duration.


2016 ◽  
Vol 23 (1) ◽  
pp. 89
Author(s):  
A. Padmanabha ◽  
H. R. V. Reddy ◽  
N. B. Shridhar ◽  
Muttappa Khavi ◽  
B. T. Naveen Kumar

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 695
Author(s):  
Sara Farhadi ◽  
Behrooz Atashbar Kangarloei ◽  
Ahmad Imani ◽  
Kourosh Sarvi Moghanlou

B. orientalis, fairy shrimp, is often among the most conspicuous invertebrates inhabiting temporary aquatic habitats with a typical variation in environmental conditions. Its life history characteristics and biochemical composition were studied under four different photoperiodic regimes (24L:0D, 0L:24D, 16L:8D, and 12L:12D). The significantly highest cumulative and initial hatching rates (48 h) were obtained at 24L:0D (p < 0.05). Cultivating the larvae under different photoperiods did not significantly affect specific growth rate (SGR) (p > 0.05). However, higher final total body length and daily growth rate were recorded under constant darkness. Higher lipid content was found at 24L:0D to the extent that it was more than two times higher than that at 16L:8D and 12L:12D (p < 0.05). There was also a remarkable increase in body crude protein content at 24L:0D (p < 0.05). Body fatty-acid profiles of the fairy shrimps were also affected by culture condition (p < 0.05). Extension of lighting period resulted in a subtle increase in body contents of arginine, lysine, histidine, isoleucine, leucine, valine, methionine, and phenylalanine, especially in the group kept under a 16L:8D regime. The highest and lowest digestive enzyme activity was observed at 0L:24D and 24L:0D, respectively (p < 0.05). In contrast, the highest and lowest soluble protein content was recorded at 24L:0D and 0L:24D, respectively (p < 0.05). Similarly, antioxidant status was significantly higher at 0L:24D (p < 0.05). In conclusion, a 16L:8D light–dark cycle might be an optimal condition in terms of growth performance and physio-biochemical characteristics. These findings could be helpful in optimizing the rearing conditions for upscaling B. orientalis production.


2015 ◽  
Vol 95 (1) ◽  
pp. 20-26 ◽  
Author(s):  
E.M. Mostafa ◽  
A.M.A. Hassan

Exposure ofAzollaplants to UV-B radiation for 6 h resulted in a decrease in biomass and relative growth rate (RGR), which coincided with an increase in doubling time (DT) as compared with the control. Also, the protein content decreased. On the other hand, hydrogen peroxyde (H2O2) and malondialdehyde (MDA) accumulated significantly in UV-treatedAzollaplants. Conversely, the addition of selenium (Se) at 1 ppm resulted in a significant increase in biomass and protein content of untreated and UV-treatedAzollaplants, and a significant reduction in both H2O2and MDA. Moreover, the addition of Se to UV-treated and untreatedAzollaplants resulted in a significant increase in total ascorbate and total glutathione (GSH) contents compared with the control and UV-stressedAzollaplants. Also, glutathione redox potential (GSH/TG) increased significantly in UV-treatedAzollaplants in the presence of Se. There also was a significant increase (38%) in ascorbate peroxidase (APX) activity in UV-treated plants compared with the control. APX activity in the presence of Se did not change significantly compared with the control. Glutathione reductase (GR) activity increased significantly in UV-treatedAzolla, while glutathione peroxidase (GSH-PX) activity did not. On the other hand, both GSH-PX and GR activity in untreated and UV-treatedAzollaplants were significantly enhanced by the application of Se to the nutrient media at a concentration of 1 ppm. Therefore, we can conclude that Se protectsAzollaplants from UV-B stress.


1986 ◽  
Vol 1 (3) ◽  
Author(s):  
Daura Regina de Brito Eiras ◽  
Rudival Ribeiro Stofella

EFFECT OF SALINITY ON THE DEVELOPMENT OF JUVENILES OF Eugerres brasilianus (Cuvier, 1830) (PISCES-GERREIDAE). Juveniles of Eugerres brasilianus (L< = 8,9 — 9,1cm) were used in bio-assays in order to assess the effect of different salinities (0, 10, 20, 26, 30 and 40%c) upon their development. The rate of food consumption, growth rate and weight increase were analyzed during 6 months. Preferential salinities were, in increasing order: 0, 30, 26, 20 and 10%e>. All individuals died within 48 hours when exposed to a salinity of 40%e.Foram realizados bio-ensaios com exemplares da caratinga Eugerres brasilianus em fase juvenil (L* = 8,9 — 9,1cm), visando determinar os padrões preferenciais de salinidade da espécie neste estádio de desenvolvimento. Utilizou-se como meio de determinação, a taxa de consumo de alimento ao longo dos 6 meses de experimento e as diferenças de comprimento e peso médios totais dos exemplares de cada aquário, entre as fases inicial e final do trabalho. Dentre as salinidades testadas, apenas 40%c é letal e as salinidades preferenciais são, em ordem crescente de aceitação, 0, 30, 26, 20 e 10%o.


2020 ◽  
Vol 17 (34) ◽  
pp. 667-677
Author(s):  
Hiba Khaleel Saeed AL-SHAKARCHI ◽  
Yousef Jabbar AL-SHAHERY

rthrospira sp. is an aquatic and photosynthetic microorganism that is extensively employed as a food supplement due to its rich contents of nutrients, proteins, and carbohydrates. In this study, a local strain of cyanobacterium of the genus Arthrospira was isolated from the Iraqi soil, in the region of Mosul city, using the Chu’s Medium No. 10. The growth rate, as well as the effects on biomass and cellular component contents of proteins, carbohydrates, and chlorophyll of this strain, were evaluated on the molasses medium alone or supplemented with iron, copper, nickel, cadmium and cobalt salts after fifteen days of incubation. The results showed that the best growth rate (1.09 OD), the highest value of biomass (120.0 mg/l), proteins content (297.2 mg/l), chlorophyll content (14.9 mg/l) and carbohydrates content (400.0 mg/l) of Arthrospira sp. was achieved after fifteen days of incubation. Generally, it was observed that adding iron, copper, nickel, cadmium, and cobalt salts into the molasses medium increased the contents of biomass, proteins, and carbohydrates of Arthrospira sp.. It was noticed that the highest biomass concentration (1960 mg/l) was obtained when Arthrospira sp. grown on molasses medium supplemented with nickel. Also, none of the metal salts added to the molasses medium increased the protein content of Arthrospira sp.. Conversely, adding copper, nickel, and cobalt to the medium showed an adverse effect on the protein content. It was shown that adding iron metal salts into the molasses medium increased the carbohydrates and the chlorophyll contents of Arthrospira sp.. These results suggest that Arthrospira sp. can be utilized for the bioremediation of heavy metals pollution in the environment and industrial sites.


2020 ◽  
Vol 24 (04) ◽  
pp. 819-833
Author(s):  
Luciana Sanches Dourado Leão ◽  
◽  
Abílio Soares-Gomes ◽  
José Roberto Botelho de Souza ◽  
Cinthya Simone Gomes Santos ◽  
...  

The secondary production is the result of the functional response of populations subject to various environmental factors. Marine habitats vary in terms of quantity and quality of food supply, and the use of secondary production values, as well as renewal rates (P/B), may be used as estimates for understanding the incorporation of organic matter and energy per unit, population or community in each area. This estimative was performed for the population of Scolelepis goodbodyi in a tropical beach in the Southwestern Atlantic, located in an upwelling area. A comparison of Spionidae and non-spionid populations from different latitudes was also done. The Mass Specific Growth Rate method (MSGR) and the Production/Biomass ratio (P/B) were used to estimate the somatic annual production and average annual biomass. The mean density and biomass were 16.38 ind. m-2 and 2.78 g AFDW m-2,respectively. The secondary production and P/B were 8.3 g AFDW m-2 y-1 and 2.98 y1, respectively. The growth rate in weight was greater for the small size than the large size classes. The largest individuals (W3C = 1.0 mm) showed the lowest biomass and secondary production values. The observed high rates of secondary production and P/B suggest that this S. goodbodyi population can transfer large amounts of biomass to higher trophic levels of the local food web. Studies of the secondary production of spionidae populations in different latitudes, including the population of S. goodbodyi in the beach of Manguinhos, showed variability in their rates probably due to the differences of several factors such as life history and environmental variability


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