Studies of the hydrobiology of a tropical lake in north-western Queensland. III. Growth, chemical composition and potential for harvesting of the aquatic vegetation

1984 ◽  
Vol 35 (5) ◽  
pp. 525 ◽  
Author(s):  
CM Finlayson ◽  
TP Farrell ◽  
DJ Griffiths
Keyword(s):  
Aquatic Plants ◽  
Aquatic Vegetation ◽  
Hydrilla Verticillata ◽  
Limiting Factor ◽  
Potamogeton Crispus ◽  
Low Light ◽  
Mean Values ◽  
Nitrogen Concentrations ◽  
North Western ◽  
Nitrogen Phosphorus

The biomass of aquatic plant species and the standing crop of submerged species were estimated in Lake Moondarra from 1977 to 1979. In July 1978, the biomass of Salvinia molesta exceeded 53 000 t fresh weight, with a density of 167 t ha-1 (0.81 kg dry wt m-2). Hydrilla verticillata reached a maximum density of almost 3 kg dry wt m-2 and Potamogeton crispus more than double that density. Photosynthetic activity of a range of species was high, and was still detectable at water depths allowing only very low light penetration. Organic nitrogen concentrations were high (0.91-4.37% dry wt), and phosphorus (0.07-0.47% dry wt) appeared to be a limiting factor for growth of the aquatic plants. Heavy metal concentrations varied with species, location and season but, although generally higher than world-wide 'mean' values (48 �g g-1 copper, 11 �g g-1 lead, 14.3 �g g-1 zinc), were significantly less than those of aquatic macrophytes in heavily polluted environments. H. verticillata was more efficient than S. molesta in removal of nitrogen, phosphorus and zinc, whereas for copper and lead the reverse was true. The potential for using this property of the aquatic plants and subsequent harvesting in order to remove nutrients and metals from the lake is also discussed.

scholarly journals Viability of Aquatic Plant Fragments following Desiccation

2013 ◽  
Vol 6 (2) ◽  
pp. 320-325 ◽  
Author(s):  
Matthew A. Barnes ◽  
Christopher L. Jerde ◽  
Doug Keller ◽  
W. Lindsay Chadderton ◽  
Jennifer G. Howeth ◽  
...  
Keyword(s):  
Mass Loss ◽  
Aquatic Plants ◽  
Aquatic Plant ◽  
Myriophyllum Spicatum ◽  
Hydrilla Verticillata ◽  
Ceratophyllum Demersum ◽  
Myriophyllum Aquaticum ◽  
Potamogeton Crispus ◽  
Air Exposure ◽  
Desiccation Rate

AbstractDesiccation following prolonged air exposure challenges survival of aquatic plants during droughts, water drawdowns, and overland dispersal. To improve predictions of plant response to air exposure, we observed the viability of vegetative fragments of 10 aquatic plant species (Cabomba caroliniana, Ceratophyllum demersum, Elodea canadensis, Egeria densa, Myriophyllum aquaticum, Myriophyllum heterophyllum, Myriophyllum spicatum, Potamogeton crispus, Potamogeton richardsonii, and Hydrilla verticillata) following desiccation. We recorded mass loss, desiccation rate, and plant fragment survival across a range of air exposures. Mass loss accurately predicted viability of aquatic plant fragments upon reintroduction to water. However, similar periods of air exposure differentially affected viability between species. Understanding viability following desiccation can contribute to predicting dispersal, improving eradication protocols, and disposing of aquatic plants following removal from invaded lakes or contaminated equipment.

Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy

Science ◽  
2021 ◽  
Vol 371 (6536) ◽  
pp. eaax9050
Author(s):  
Steffen Breinlinger ◽  
Tabitha J. Phillips ◽  
Brigette N. Haram ◽  
Jan Mareš ◽  
José A. Martínez Yerena ◽  
...  
Keyword(s):  
United States ◽  
Aquatic Vegetation ◽  
Southeastern United States ◽  
Hydrilla Verticillata ◽  
Toxin Production ◽  
The United States ◽  
Biosynthetic Gene Cluster ◽  
Biosynthetic Gene ◽  
Bald Eagles ◽  
Cyanobacterial Species

Vacuolar myelinopathy is a fatal neurological disease that was initially discovered during a mysterious mass mortality of bald eagles in Arkansas in the United States. The cause of this wildlife disease has eluded scientists for decades while its occurrence has continued to spread throughout freshwater reservoirs in the southeastern United States. Recent studies have demonstrated that vacuolar myelinopathy is induced by consumption of the epiphytic cyanobacterial species Aetokthonos hydrillicola growing on aquatic vegetation, primarily the invasive Hydrilla verticillata. Here, we describe the identification, biosynthetic gene cluster, and biological activity of aetokthonotoxin, a pentabrominated biindole alkaloid that is produced by the cyanobacterium A. hydrillicola. We identify this cyanobacterial neurotoxin as the causal agent of vacuolar myelinopathy and discuss environmental factors—especially bromide availability—that promote toxin production.

Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

2017 ◽  
Keyword(s):  
Aquatic Vegetation ◽  
Lake Michigan ◽  
Radio Telemetry ◽  
Habitat Preferences ◽  
Vegetation Coverage ◽  
Limiting Factor ◽  
Suitable Habitat ◽  
Spawning Habitat ◽  
Green Bay ◽  
Natural Reproduction

<em>Abstract</em>.—The identification, protection, and restoration of spawning habitat for Muskellunge <em>Esox masquinongy </em>in Green Bay, Lake Michigan are vital steps for re-establishing a self-sustaining population. This study was designed to locate spawning areas, document and model spawning habitat preferences, assess natural recruitment, and determine if suitable habitat was found throughout Green Bay (Fox River, lower Green Bay, Menominee River, and Little Sturgeon Bay). Radio transmitters were inserted into the oviduct of mature female Muskellunge prior to spawning and expelled transmitters were later located using radio telemetry to identify spawning locations. Between 2009 and 2010, 26 of 37 (70%) implanted transmitters were located as deposited at spawning locations. Using identified spawning locations, habitat selection was estimated for key environmental variables, and MaxEnt (maximum entropy) was utilized to model Muskellunge spawning habitat in the Menominee River, as it was the only study area where natural reproduction was documented. Menominee River Muskellunge showed significant preferences for spawning in areas with shallow bottom slopes (5%), with medium-to-high submerged aquatic vegetation coverage (>33%), where coarse woody debris was present, and where dominant substrates were sand or cobble. MaxEnt modeling predicted a ~2.5 magnitude greater likelihood of spawning at an average spawning location compared to an average background location. Comparisons of available habitat among study areas showed the Menominee River contained more spawning habitat with preferred characteristics. Results from this study are important steps in identifying spawning habitat as a potential limiting factor to successful Muskellunge reintroduction and models could be used to locate suitable areas to stock and guide delineation of critical spawning habitat to designate for protection.

Biological and physicochemical characteristics of the Ross River Dam, Townsville

1982 ◽  
Vol 33 (5) ◽  
pp. 811 ◽  
Author(s):  
CM Finlayson ◽  
JC Gillies
Keyword(s):  
Water Quality ◽  
Water Level ◽  
Chlorophyll A ◽  
Aquatic Vegetation ◽  
Physicochemical Characteristics ◽  
Artificial Lake ◽  
Management Planning ◽  
Nitrogen Concentrations ◽  
Low Nitrogen ◽  
Future Management

The biological and physicochemical characteristics of the Ross River Dam, an artificial lake near Townsville in northern Queensland, are described. The lake is characterized by a sodium and chloride ionic dominance, may be polymictic, and contains a relatively low ratio of total phosphorus to total nitrogen due to the low nitrogen concentrations. The aquatic vegetation is widespread and dominated by the submerged Hydrilla verricillata and Potamogeton javanicus. Both species are plentiful in the lake but are not, at present, major weeds. The phytoplankton were not found in bloom conditions despite chlorophyll a concentrations near 10 mg m-3. The main fish species of 11 recorded was Glossamia gilli. The results from this survey will provide a useful basis for future management planning, especially if the water level or water-quality conditions were to vary.

OBSERVATIONS ON THE STUDY OF VARIETAL DIFFERENCES IN THE MALTING QUALITY OF BARLEY. PART IV

1939 ◽  
Vol 17c (3) ◽  
pp. 57-71 ◽  
Author(s):  
Henry R. Sallans ◽  
J. Ansel Anderson
Keyword(s):  
Differential Effect ◽  
Malting Quality ◽  
Limiting Factor ◽  
Standard Variety ◽  
Real Difference ◽  
Mean Values ◽  
Reasonable Range ◽  
Diastatic Activity ◽  
The Mean

An investigation was undertaken to compare the relative magnitudes of the differential effects of environment (i.e., stations) and of malting methods on the malting quality of barley varieties. Samples of Olli, O.A.C. 21, Hannchen, and Regal from four stations were malted by eight methods representing the combinations of germinating at 50° and 56° F., at 42 and 46% moisture, and for six and nine days.Statistical analyses showed that, with respect to diastatic activity, wort nitrogen, and extract yield, the variations due to the differential effect of environment on varieties were greater than the variations due to the differential effect of malting methods on varieties. As a result of this study and earlier ones, it appears that the former effect is the limiting factor in studies of the comparative malting qualities of varieties. The latter effect is of less importance but must be kept in mind if errors in the interpretation of the results of routine tests are to be avoided. In general, it appears that if routine tests show that the mean values for any variety, when grown at 12 stations representing a reasonable range of environment, differ from the values for the standard variety by more than 1% in extract, or 10% in diastatic activity or wort nitrogen, a real difference exists between the varieties, which cannot be overcome by any reasonable change in malting conditions.

The half-life of the cytochrome bf complex in leaves of pea plants after transfer from moderately-high growth light to low light

2017 ◽  
Vol 44 (3) ◽  
pp. 351 ◽  
Author(s):  
Hui Zhu ◽  
Ling-Da Zeng ◽  
Xiao-Ping Yi ◽  
Chang-Lian Peng ◽  
Wang-Feng Zhang ◽  
...  
Keyword(s):  
Half Life ◽  
Time Course ◽  
Photosynthetic Capacity ◽  
High Growth ◽  
Limiting Factor ◽  
Low Light ◽  
High Photosynthetic Capacity ◽  
Growth Irradiance ◽  
The Difference ◽  
Time Courses

The content of cytochrome (cyt) bf complex is the main rate-limiting factor that determines light- and CO2-saturated photosynthetic capacity. A study of the half-life of the cyt f content in leaves was conducted whereby Pisum sativum L. plants, grown in moderately high light (HL), were transferred to low light (LL). The cyt f content in fully-expanded leaves decreased steadily over the 2 weeks after the HL-to-LL transfer, whereas control leaves in HL retained their high contents. The difference between the time courses of HL-to-LL plants and control HL plants represents the time course of loss of cyt f content, with a half-life of 1.7 days, which is >3-fold shorter than that reported for tobacco leaves at constant growth irradiance using an RNA interference approach (Hojka et al. 2014). After transfer to LL (16 h photoperiod), pea plants were re-exposed to HL for 0, 1.5 h or 5 h during the otherwise LL photoperiod, but the cyt f content of fully-expanded leaves declined practically at the same rate regardless of whether HL was re-introduced for 0, 1.5 h or 5 h during each 16 h LL photoperiod. It appears that fully-expanded leaves, having matured under HL, were unable to increase their cyt f content when re-introduced to HL. These findings are relevant to any attempts to maintain a high photosynthetic capacity when the growth irradiance is temporarily decreased by shading or overcast weather.

scholarly journals Arsenic, Zinc, and Aluminium Removal from Gold Mine Wastewater Effluents and Accumulation by Submerged Aquatic Plants (Cabomba piauhyensis,Egeria densa, andHydrilla verticillata)

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ahmad Farid Abu Bakar ◽  
Ismail Yusoff ◽  
Ng Tham Fatt ◽  
Faridah Othman ◽  
Muhammad Aqeel Ashraf
Keyword(s):  
Waste Water ◽  
Plant Species ◽  
Aquatic Plants ◽  
Mine Drainage ◽  
Plant Biomass ◽  
Mine Waste ◽  
Hydrilla Verticillata ◽  
The Other ◽  
Egeria Densa ◽  
Submerged Aquatic Plant

The potential of three submerged aquatic plant species (Cabomba piauhyensis, Egeria densa, andHydrilla verticillata) to be used for As, Al, and Zn phytoremediation was tested. The plants were exposed for 14 days under hydroponic conditions to mine waste water effluents in order to assess the suitability of the aquatic plants to remediate elevated multi-metals concentrations in mine waste water. The results show that theE. densaandH. verticillataare able to accumulate high amount of arsenic (95.2%) and zinc (93.7%) and resulted in a decrease of arsenic and zinc in the ambient water. On the other hand,C. piauhyensisshows remarkable aluminium accumulation in plant biomass (83.8%) compared to the other tested plants. The ability of these plants to accumulate the studied metals and survive throughout the experiment demonstrates the potential of these plants to remediate metal enriched water especially for mine drainage effluent. Among the three tested aquatic plants,H. verticillatawas found to be the most applicable (84.5%) and suitable plant species to phytoremediate elevated metals and metalloid in mine related waste water.

The effect of season on the composition of the blood of lactating and non-lactating cows as revealed from repeated metabolic profile tests on 24 dairy herds

1974 ◽  
Vol 83 (1) ◽  
pp. 27-35 ◽  
Author(s):  
G. J. Rowlands ◽  
W. Little ◽  
R. Manston ◽  
Sally M. Dew
Keyword(s):  
Cell Volume ◽  
Packed Cell Volume ◽  
Dairy Herds ◽  
Urea Nitrogen ◽  
Blood Samples ◽  
Mean Values ◽  
Lactating Cows ◽  
Nitrogen Concentrations ◽  
Volume Blood ◽  
Autumn And Winter

SUMMARYBlood samples were taken from groups of lactating and non-lactating cows on three occasions from each of 24 commercial dairy herds sampled eight herds at a time at 6-weekly intervals throughout 1972. The blood samples were analysed for packed cell volume, blood glucose and haemoglobin, and for the serum concentrations of albumin, total protein, urea nitrogen, Ca, inorganic phosphate, Mg, K, Na, Cu, and Fe.Clear seasonal patterns were evident for packed cell volume and the mean concentrations of urea nitrogen and haemoglobin each of which were highest during the summer months. The effect of season on the concentrations of the other constituents was smaller. Mean values of packed cell volume, haemoglobin and Fe were consistently higher in the non-lactating cows than in the lactating cows. Mean concentrations of Mg were lower in the blood of non-lactating cows throughout the year; Cu concentrations followed a similar trend in the autumn and winter.There was evidence of overall herd differences regardless of season, in particular for Cu, globulin, Fe and urea nitrogen concentrations.

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