scholarly journals Biomass allocation to anchoring structures in the aquatic macrophytes from the subcontinental and Atlantic climates in Europe

2011 ◽  
Vol 77 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Józef Szmeja ◽  
Bernard Clement ◽  
Katarzyna Bociąg ◽  
Agnieszka Gałka ◽  
Piotr Skurzyński
Keyword(s):  
Biomass Allocation ◽  
Aquatic Macrophytes ◽  
Temperate Climate ◽  
Potamogeton Pectinatus ◽  
Mechanical Forces ◽  
Littorella Uniflora ◽  
Ground Structures ◽  
Juncus Bulbosus ◽  
A Current ◽  
Nw Poland

Biomass allocation to anchoring structures in 10 species of aquatic macrophytes in two types of the cool and humid temperate climate in Europe, subcontionental (NW Poland) and Atlantic (W France), was examined. The study focused on the weight of anchoring organs in <em>Chara delicatula</em> Ag., <em>Ch. fragilis</em> Desv., <em>Juncus bulbosus</em> L., <em>Littorella uniflora</em> (L.) Asch., <em>Luronium natans</em> (L.) Raf., <em>Potamogeton pectinatus</em> L., <em>P. perfoliatus </em>L., <em>P. natans</em> L. and <em>Ranunculus fluitans</em> (Lam.) Wimm., as well as submerged structures in <em>Hydrocharis morsus-ranae</em> L. The plants were collected from 10 geographically distant lakes and 2 rivers with a current velocity of 0.3-0.5 m s<sup>-1</sup>. It was assumed that biomass allocation to anchoring structures in rooting macrophytes depends on the time that mechanical forces, which can remove the plants from the occupied area, exert their effect. It was found that, in the Atlantic and subcontinental climates, the ratio between the biomass of underground (or submerged) and above-ground structures (U/A index), calculated for the ramets of <em>Chara fragilis</em>, <em>Hydrocharis morsus-ranae</em> and <em>Ranunculus fluitans</em>, has similar values (p&gt;0.05). Nevertheless, among seven species of <em>Cormophyta</em>, which were anchored in the lake or pond littoral, six (<em>Juncus bulbosus</em>, <em>Littorella uniflora</em>, <em>Luronium natans</em>, <em>Potamogeton pectinatus</em>, <em>P. perfoliatus</em> and <em>P. natans</em>) had higher values of the U/A index in the Atlantic climate than in the subcontinental type (p &lt; 0.05). This can be explained by the lack of ice cover and, consequently, a longer time of wave action than in the subcontinental climate.

Emergence of seedlings of aquatic macrophytes from lake sediments

1983 ◽  
Vol 61 (1) ◽  
pp. 148-156 ◽  
Author(s):  
Richard W. Haag
Keyword(s):  
Lake Sediments ◽  
Initial Treatment ◽  
Aquatic Macrophytes ◽  
Potamogeton Pectinatus ◽  
Sediment Texture ◽  
Substantial Variation ◽  
Initial Exposure ◽  
Sediment Samples ◽  
Thermal Effluent ◽  
Myriophyllum Exalbescens

Sediment samples were collected in May 1980 from 11 stations at five sites in Lake Wabamun. Emergence of seedlings was recorded in a greenhouse at 19 °C for 120 days. The sediments were then chilled at 4 °C for 120 days and reexposed to greenhouse conditions for a further 90 days. Total seedling densities varied from 0 to 2335 m−2. Depth and sediment texture each accounted for 20% of the variance in seedling numbers. Discharge of thermal effluent from the Wabamun generating station also caused substantial variation in seedling number; seedling numbers at the shallowest Wabamun Outlet station were over four times those at any other site. Chilling of the sediment samples in the laboratory caused further emergence of seedlings from the four sites with the highest seedling densities in the initial treatment. Total numbers were up to 50% of those for seedlings that emerged during the initial exposure to greenhouse conditions. Potamogeton pectinatus and P. pusillus were most common among the seedlings of six species. Two of the three most common macrophytes in the lake were rare as seedlings, while no seedlings were recorded for the most common angiosperm, Myriophyllum exalbescens. Reproduction by seed makes a secondary contribution to the dynamics of the vegetation of Lake Wabamun.

Accumulation and effects of copper on aquatic macrophytes Potamogeton pectinatus L.: Potential application to environmental monitoring and phytoremediation

2018 ◽  
Vol 155 ◽  
pp. 117-124 ◽  
Author(s):  
Marcela Brandão Costa ◽  
Francesca Valêncio Tavares ◽  
Claudia Bueno Martinez ◽  
Ioni Gonçalves Colares ◽  
Camila de Martinez Gaspar Martins
Keyword(s):  
Environmental Monitoring ◽  
Potential Application ◽  
Aquatic Macrophytes ◽  
Potamogeton Pectinatus

Effect of altitude on resource allocation in the weed Achillea millefolium (yarrow, Asteraceae) in the Australian Alps

2004 ◽  
Vol 52 (5) ◽  
pp. 639 ◽  
Author(s):  
Frances Mary Johnston ◽  
Catherine Marina Pickering
Keyword(s):  
Biomass Allocation ◽  
Dry Weight ◽  
Achillea Millefolium ◽  
Reproductive Structures ◽  
Australian Alps ◽  
Allocation Patterns ◽  
Below Ground ◽  
Total Dry Weight ◽  
Environmental Weed ◽  
Ground Structures

Increasing severity of environment associated with increasing altitude in mountain ecosystems (decreasing temperature, increasing duration of snow cover) can affect relative and absolute biomass-allocation patterns in plants. Biomass allocation was examined along a 620-m altitudinal gradient in the Australian Alps for the important environmental weed Achillea millefolium (L., Asteraceae, yarrow). Relative and absolute biomass allocation (dry weight) to reproductive (capitula, flowering stems and associated leaves), vegetative (leaves not on the flowering stem) and below-ground structures (rhizome and roots) were measured at each of nine sites by using quadrats. Increasing altitude resulted in a decrease in relative and absolute allocation of biomass to reproductive structures. For example, the dry weight of inflorescences declined as altitude increased because of a decrease in the weight of the terminal and side branches of the inflorescences, but not the total number of capitula produced. There was also a trend for increased relative allocation to below-ground structures with increasing altitude, even though altitude did not affect absolute allocation to below-ground and vegetative structures, or the total dry weight of A. millefolium. These results are consistent with those for other species growing at high altitude. The management implications for the control of A. millefolium in the Australian Alps are discussed, including in relation to predicted climatic change.

Long-term response of periphyton and macrophytes to reduced municipal nutrient loading to the Bow River (Alberta, Canada)

2002 ◽  
Vol 59 (6) ◽  
pp. 987-1001 ◽  
Author(s):  
Al Sosiak
Keyword(s):  
Nutrient Removal ◽  
Aquatic Macrophytes ◽  
Municipal Wastewater ◽  
Nutrient Loading ◽  
Wastewater Treatment Plants ◽  
Phosphorus Loading ◽  
Potamogeton Pectinatus ◽  
Municipal Wastewater Treatment ◽  
Dissolved Phosphorus ◽  
Nitrite Nitrate

The biomass of periphyton and aquatic macrophytes (Potamogeton vaginatus and Potamogeton pectinatus) in the Bow River was sampled over 16 years to assess the response of these plants to improved phosphorus (1982–1983) and nitrogen removal (1987–1990) at Calgary's two municipal wastewater treatment plants. These improvements in treatment reduced total phosphorus loading to the Bow River by 80%, total ammonia loading by 53%, and nitrite + nitrate loading by 50%. No change in periphytic biomass was detected after enhanced phosphorus removal where total dissolved phosphorus (TDP) in river water remained relatively high (10–33 μg·L–1). However, periphytic biomass declined at sites further downstream with TDP < 10 μg·L–1. Regression analysis predicted that nuisance periphyton biomass (>150 mg·m–2) occurred at TDP > 6.4 μg·L–1 (95% confidence interval: 1.9–7.6 μg·L–1). Macrophyte biomass was inversely correlated with discharge and was lower during high-discharge years. Biomass also declined following enhanced nutrient removal, with the greatest decrease following reduced nitrogen discharge. These results provide the first evidence for a response of periphyton and aquatic macrophytes to enhanced nutrient removal from municipal wastewater.

Resolving Crystallites in Zirconium Oxide Films

1969 ◽  
Vol 27 ◽  
pp. 140-141
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscope ◽  
Inelastic Scattering ◽  
Zirconium Oxide ◽  
Oxide Films ◽  
Optic Axis ◽  
Objective Lens ◽  
Microscope Objective ◽  
Linear Optic ◽  
A Current ◽  
Microscope Objective Lens

The optic axis of an electron microscope objective lens is usually assumed to be straight and co-linear with the mechanical center. No reason exists to assume such perfection and, indeed, simple reasoning suggests that it is a complicated curve. A current centered objective lens with a non-linear optic axis when used in conjunction with other lenses, leads to serious image errors if the nature of the specimen is such as to produce intense inelastic scattering.

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