Ecology and production of Nebalia sp. (Crustacea : Leptostraca) in a shallow-water seagrass community.

1991 ◽  
Vol 42 (1) ◽  
pp. 53 ◽  
Author(s):  
SF Rainer ◽  
P Unsworth
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Secondary Production ◽  
Dry Weight ◽  
Seagrass Beds ◽  
Seagrass Meadows ◽  
Seagrass Community ◽  
Field Samples ◽  
Fish Predators ◽  
Nocturnal Fish

Nebalia sp. is an abundant epifaunal crustacean in seagrass meadows at Seven Mile Beach, Western Australia, in water temperatures of 16-27�C. Its maximum length is 6.0-6.4 mm; females generally reach maturity when 4 mm long and males when 5 mm long. They breed throughout the year, and juveniles comprised 94% of animals sampled (n = 880). Males comprised only 11% of mature animals in field samples, compared with 40% in field chambers and 67% in the stomachs of nocturnal fish predators. Abundance during the year reflected changes in growth rate (0.050-0.088 mm day-1), mortality rate (0.020-0.069 day-1) and life span (49-102 days). The annual production of Nebalia sp. in seagrass meadows was estimated at 5.8 g ash-free dry weight (AFDW) m-2, with a corresponding P :B (production:biomass) ratio of 22.5. Predation is probably the main source of mortality at times of high density of Nebalia sp., and at least three significant fish predators on Nebalia sp. were found. Together with Nebalia sp., small crustaceans with high P:B ratios may have a significant role in secondary production in the seagrass beds at Seven Mile Beach.

Rates of Mortality, Growth, and Biomass Production of Lymnaea palustris During Chronic Exposure to Lead

1978 ◽  
Vol 35 (8) ◽  
pp. 1109-1115 ◽  
Author(s):  
U. Borgmann ◽  
O. Kramar ◽  
C. Loveridge
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Biomass Production ◽  
Lead Concentration ◽  
Lead Toxicity ◽  
Dry Weight ◽  
Freshwater Snail ◽  
Rate Function ◽  
Lead Uptake ◽  
Percent Mortality

Lymnaea palustris, a freshwater snail, was exposed to lead in a continuous-flow system from newly laid eggs until reproductive maturity. Lead, at concentrations as low as 19 μg∙L−1, caused a significant increase in the mortality rate, although the growth rate was not affected. The lead-induced mortality was proportional to the lead concentration raised to the exponent 2.5. The analysis of mortality as a rate function was found superior to the use of the more conventional LC50 (concentration resulting in 50% mortality). A plot of the logarithm of the lead-induced mortality against log lead concentration is linear and has the same slope as plots of double logarithms of the inverse survival at any one time versus log lead concentration or log time versus log LC50 or log LT50 (time to 50% mortality) versus log lead concentration. The mortality rate, unlike the percent mortality, is independent of time and can be combined directly with the growth rate to estimate the biomass production rate. A 50% drop in the rate of biomass production was observed at 36 μg∙L−1 and a drop to 0 production at 48 μg∙L−1. Lead uptake in whole snails was found to be proportional to the lead concentration in the water, giving a concentration factor of 8500 on a dry weight basis. Key words: snails, lead, toxicity, biomass production, bioaccumulation

Effects of feeding ration on larval swimming speed and responsiveness to predator attacks: implications for cohort survival

2000 ◽  
Vol 57 (1) ◽  
pp. 106-115 ◽  
Author(s):  
John H Chick ◽  
Michael J Van Den Avyle
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Striped Bass ◽  
Swimming Speed ◽  
Larval Growth ◽  
Simulation Models ◽  
Pomoxis Nigromaculatus ◽  
Alosa Aestivalis ◽  
Fish Predators ◽  
Larval Condition

We conducted laboratory experiments to examine the effects of feeding ration on the routine swimming speed of larval striped bass (Morone saxatilis) and their responsiveness to simulated-predator attacks. Striped bass were reared in low (7 prey·L-1), medium (354 prey·L-1), or high (740 prey·L-1) prey treatments from age 4 to 14 days posthatch. Larvae reared in the low-prey treatment had slower routine swimming speeds and shorter reactive distances and were less responsive to simulated-predator attacks. These differences were most pronounced after age 10 and appeared to be an effect of deteriorating larval condition rather than an effect of size. Simulation models were constructed for two potential fish predators, Alosa aestivalis and Pomoxis nigromaculatus, to examine how variation in growth rate, swimming speed, and responsiveness to predator attacks might influence mortality rate. Our simulations predicted that cohort mortality rate would decrease with increasing larval growth rates, even though faster routine swimming speed and growth rate increased encounter rates with predators. The influence of larval growth rate and responsiveness on mortality rate varied between the two predators, but cohorts experiencing no growth always had the greatest mortality rate.

EFFECTS OF TEMPERATURE ON RATE AND DURATION OF KERNEL DRY MATTER ACCUMULATION OF MAIZE

1988 ◽  
Vol 68 (4) ◽  
pp. 935-940 ◽  
Author(s):  
M. TOLLENAAR ◽  
T. W. BRUULSEMA
Keyword(s):  
Growth Rate ◽  
Zea Mays ◽  
Dry Matter ◽  
Zea Mays L ◽  
Dry Weight ◽  
Controlled Environment ◽  
Dry Matter Accumulation ◽  
Linear Kernel ◽  
Effects Of Temperature ◽  
Kernel Growth

The response of rate and duration of kernel dry matter accumulation to temperatures in the range 10–25 °C was studied for two maize (Zea mays L.) hybrids grown under controlled-environment conditions. Kernel growth rates during the period of linear kernel growth increased linearly with temperature (b = 0.3 mg kernel−1 d−1 °C−1). Kernel dry weight at physiological maturity varied little among temperature treatments because the increase in kernel growth rate with increase in temperature was associated with a decline in the duration of kernel growth proportional to the increase in kernel growth rate.Key words: Zea mays L, period of linear kernel dry matter accumulation, controlled-environment conditions, kernel growth rate

The Energy-Sources in Ontogenesis

1927 ◽  
Vol 5 (1) ◽  
pp. 27-42
Author(s):  
JOSEPH NEEDHAM
Keyword(s):  
Growth Rate ◽  
Oxygen Consumption ◽  
Building Materials ◽  
Calorific Value ◽  
Dry Weight ◽  
Energy Sources ◽  
Chemical Analyses ◽  
Inorganic Substance ◽  
Absorption Intensity ◽  
Dry Substance

1. The percentage growth-rate curves for carbohydrate and protein in the chick enbryo have been determined and compared with those already in the literature for the percentage growth-rates of the whole embryo, the dry substance, the fat, and the calorific value. 2. The composition of the embryo in gm. per cent, of dry weight has been calculated and an ontogenetic succession of carbohydrate, protein, and fat, has been brought to light. These three cell-constituents are at their highest levels in the embryo at 4, 11 and 20 days of incubation respectively. This may be correlated with the succession of maximum intensities of combustion, which have the same order (about 5,8.5 and about 18 days). 3. By comparing the curves for absorption-intensity with those representing the constitution of the embryo, it has been possible to trace the passage of building-materials from the yolk and white into the embryo and to analyse still further the movements of the fat and carbohydrate fractions. 4. The concentration of the carbohydrate and protein in the water of the embryonic body has been calculated and compared with a curve already in existence for fat. 5. The curve for intensity of absorption of total foodstuff has been calculated from the results of chemical analyses. It agrees as well as can be expected at present with that calculated from the oxygen consumption and the increase of dry substance in the embryo. 6. The ratio Carbohydrate : Protein decreases during development, thus falling into line with the ratios Water : Solid, Inorganic Substance : Organic Substance, and Protein : Fat. Certain speculations arising out of these facts are discussed. 7. There is a relation of simultaneity between the combustion of carbohydrate, protein, and fat, and the part these types of molecule play in the constitution of the whole embryo.

Seagrass Ecosystems of Andaman and Nicobar Islands: Status and Future Perspective

2020 ◽  
Vol 7 (4) ◽  
pp. 169-174
Author(s):  
Chatragadda Ramesh ◽  
Raju Mohanraju
Keyword(s):  
Water Quality ◽  
Primary Production ◽  
Environmental Changes ◽  
Future Perspective ◽  
Marine Biodiversity ◽  
Seagrass Beds ◽  
Seagrass Meadows ◽  
Seagrass Ecosystem ◽  
Seagrass Ecosystems ◽  
Nicobar Islands

Seagrasses are unique marine flowering plants that play an important ecological role by yielding primary production and carbon sequestration to the marine environment. Seagrass ecosystems are rich in organic matter, supporting the growth of bio-medically important epi and endophytic microorganisms and harbor rich marine biodiversity. They are an essential food source for endangered Andaman state animal Dugongs. Seagrasses are very sensitive to water quality changes, and therefore they serve as ecological bio-indicators for environmental changes. The benthic components in and around the seagrass beds support a significant food chain for other Micro and organisms apart from fishery resources. The epiphytic bacterial communities of the leaf blades support the sustenance against the diseases. Recent reports have shown that the loss of seagrass beds in tropical and temperate regions emphasizes the depletion of these resources, and proper management of seagrass is urgent. The decline of seagrass will impact primary production, biodiversity, and adjacent ecosystems, such as reefs. Therefore, restoring the seagrass meadows could be possible with effective implementing management programs, including seagrass meadows in marine protected areas, restoration projects, seagrass transplantation, implementation of legislative rules, monitoring coastal water quality and human activities in the coastal zone. Lacunas on the seagrass ecosystem management in Andaman & Nicobar Islands are addressed.

EFFECT OF SOLID AND LIQUID ORGANIC FERTILIZER ON GROWTH, YIELD AND YIELD COMPONENTS OF ROSSELLE (Hibiscus sabdariffa L.) IN THE NIGERIAN SAVANNAH

2021 ◽  
Vol 5 (2) ◽  
pp. 428-439
Author(s):  
K. M. Ladan ◽  
M. G. Abubakar ◽  
J. Suleiman
Keyword(s):  
Growth Rate ◽  
Plant Height ◽  
Seed Weight ◽  
Organic Fertilizer ◽  
Poultry Manure ◽  
Dry Weight ◽  
Assimilation Rate ◽  
Area Index ◽  
Net Assimilation ◽  
100 Seed Weight

The Study was conducted to evaluate the effect of solid and liquid organic fertilizer on growth and yield of rosselle in 2016 cropping season at Institute of Agricultural Reserve Zaria, Samaru (11011’N 07038E and 686m) and Institute of Horticultural Research Farm Bagauda (12000’N 8031”Em 488m) in Northern Guinea Savannah and Sudan Savannah Ecological Zones of above sea level Nigeria. Treatments consisted of four levels of solid poultry manure (0.0, 1.0, 2.0 and 3.0) tons/ha and five levels of liquid organic manure from Grand Total Organic Fertilizer Limited (0.0, 0.5, 1.0, 1.5 and 2.9) litres/ha, which were factorially combined in a randomized complete block design (RCBD) and replicated three times. Data on growth parameter were collected on plant height (cm), plant dry weight (g), leaf Area index crop growth rate (CGR) Relative Growth Rate (RGR) and Net assimilation rate (NAR) while data on yield parameters like number of calyx per pant, 100 seed weight (g) and  calyx yield per hectare kg/ha were collected. Results showed that plant height, plant dry weight(g), 100 seed weight(g) and calyx dry yield kg/ha had a significant increase with application of 2.0 litres/ha of liquid fertilizer than other rates. While application of solid poultry manure at 3.0ton/ha significantly increases plant height, net assimilation rate, leaf area index and calyx dry weight when compared with other rates. From the results obtained, the combination of 2.0 litres/ha liquid organic fertilizer and 3.0 ton/ha solid poultry manure produce the highest calyx yield at both location.

Movement, Growth and natural mortality rate of the Red Spot King Prawn, Penaeus longistylus Kubo, from the Great Barrier Reef Lagoon

1990 ◽  
Vol 41 (3) ◽  
pp. 399 ◽  
Author(s):  
MCL Dredge
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Great Barrier Reef ◽  
Annual Variation ◽  
Growth Parameters ◽  
Natural Mortality ◽  
Barrier Reef ◽  
Fishing Mortality ◽  
Nursery Areas ◽  
Reef Lagoon

Movement, growth and natural mortality rate of the red spot king prawn, Penaeus longistylus, occurring in waters of the Great Barrier Reef off Townsville, Queensland, were investigated in a series of tagging experiments. Adult P. longistylus did not migrate after leaving nursery areas. Their growth rate was slower than that of the conspecific species P. plebejus, and significant inter-annual variation in growth parameters was observed. The natural mortality rate, assessed by sequential tagging experiments that eliminated the possibility of confounding with the rate of fishing mortality, was estimated to be 0.072 (week-1).

scholarly journals Root Morphology of Eight Hybrid Oil Palms Under Iron (Fe) Toxicity

2016 ◽  
Vol 1 (1) ◽  
pp. 013
Author(s):  
Aprilia Ike Nurmalasari ◽  
Eka Tarwaca Susila Putra ◽  
Prapto Yudono
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Surface Area ◽  
Root Morphology ◽  
Block Design ◽  
Dry Weight ◽  
Root Volume ◽  
Oil Palms ◽  
Fe Toxicity ◽  
Root Growth Rate

The research aims to study the change of morphology root characters of eight hybrid oil palms under iron toxicity (Fe). Field experiment done in arranged in a Randomized Complete Block Design (RCBD) two factors and three blocks as replications. The first factor was Fe concentration. It consists of two levels which are concentration 0µ.g-1 and concentration 600 µg.g-1 Fe. The second factor is the hybrid of oil palms which consists of eight hybrid oil palms as Yangambi, Avros, Langkat, PPKS 239, Simalungun, PPKS 718, PPKS 540 and Dumpy. Fe was applied by pouring FeSO4 solvent for 600 µg.g-1 500 ml.-1plant.-1day-1 on two months of plants after transplanting in the main nursery. Data were collected on root morphology and plant dry weight The data were analysis of variance (ANOVA) at 5% significanly, followed by Duncan's multiple range test (DMRT). The relationships by among variables were determined by correlation analysis. The results showed that Fe concentration 600 µg.g-1 inhibits relatively root growth rate, narrows surface area, reduces the diameter, and shrinks root volume of all hybrid oil palms tested. The slowing relatively root growth rate, narrowing of root surface area and root diameter also root volume shrinkage due to Fe stress. It was also shown that the dry weight of plants was inhibit by existing of Fe toxicity.

scholarly journals SECONDARY PRODUCTION OF Scolelepis goodbodyi (POLYCHAETA: SPIONIDAE) IN A TROPICAL SANDY BEACH IN THE SOUTHWESTERN ATLANTIC, BRAZIL

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 ◽  
...  
Keyword(s):  
Growth Rate ◽  
Secondary Production ◽  
Environmental Variability ◽  
Trophic Levels ◽  
Southwestern Atlantic ◽  
Web Studies ◽  
Marine Habitats ◽  
Production Values ◽  
Annual Biomass ◽  
Density And Biomass

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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