Importance of refractory plant material to the carbon budget of the oyster Crassostrea virginica

1989 ◽  
Vol 100 (3) ◽  
pp. 343-352 ◽  
Author(s):  
M. P. Crosby ◽  
C. J. Langdon ◽  
R. I. E. Newell
Keyword(s):  
Crassostrea Virginica ◽  
Refractory Plant ◽  
Plant Material ◽  
Carbon Budget

Softening Refractory Plant Material Embedded in Paraffin

1950 ◽  
Vol 25 (3) ◽  
pp. 161-162 ◽  
Author(s):  
Ernest M. Gifford
Keyword(s):  
Refractory Plant ◽  
Plant Material

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

BIOEFFICACY OF PLANT EXTRACTS AGAINST MUSTARD APHID AND THEIR NATURAL ENEMIES

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
NARENDRA SINGH ◽  
N. S. BHADAURIA ◽  
PRADYUMN SINGH
Keyword(s):  
Plant Extracts ◽  
Natural Enemies ◽  
Untreated Control ◽  
Plant Material ◽  
Aphid Population ◽  
College Of Agriculture ◽  
Mustard Aphid ◽  
Plant Materials

The Bio-efficacy of eleven plant extracts namely viz.Neem Kernel; Rhizome of Ginger; Leaves of Datura, Gajarghas, Harsingar, Oak and Latjeera; Bulb of Garlic and Onion; Flowers of Chrysenthemum and Fruits of Chilli in the concentration of 5 percent and imidacloprid @ 40 g ai/ha was tested against mustard aphid, Lipaphiserysimi and their effect on D. rapae and Coccinellid beetle were tested in the Department of Entomology, College of Agriculture, Gwalior (M.P.). All the tested plant materials and imidacloprid @ 40 g ai/ha were effective significanty in reducing the aphid population over control.The aphid population in treated plots ranged from 7.2 to 40.0 as against 85.4 aphid/twig in untreated control. Among the plant material, three sprays of Neem Kernel were found most effective followed by three sprays of chilli fruits.All the plant extracts were found significantly safer to D. rapae and coccinellid bettle in comparision to insecticide (imidacloprid).

Effects of resuspension of eastern oyster Crassostrea virginica biodeposits on phytoplankton community structure

2020 ◽  
Vol 640 ◽  
pp. 79-105
Author(s):  
ET Porter ◽  
E Robins ◽  
S Davis ◽  
R Lacouture ◽  
JC Cornwell
Keyword(s):  
Water Quality ◽  
Community Structure ◽  
Crassostrea Virginica ◽  
Skeletonema Costatum ◽  
Eastern Oyster ◽  
Energy Dissipation Rate ◽  
Negative Effects ◽  
Cell Densities ◽  
Sediment Bottom ◽  
Nitrite Nitrate

Anthropogenic disturbances in the Chesapeake Bay (USA) have depleted eastern oyster Crassostrea virginica abundance and altered the estuary’s environment and water quality. Efforts to rehabilitate oyster populations are underway; however, the effect of oyster biodeposits on water quality and plankton community structure are not clear. In July 2017, we used 6 shear turbulence resuspension mesocosms (STURMs) to determine differences in plankton composition with and without the daily addition of oyster biodeposits to a muddy sediment bottom. STURM systems had a volume-weighted root mean square turbulent velocity of 1.08 cm s-1, energy dissipation rate of ~0.08 cm2 s-3, and bottom shear stress of ~0.36-0.51 Pa during mixing-on periods during 4 wk of tidal resuspension. Phytoplankton increased their chlorophyll a content in their cells in response to low light in tanks with biodeposits. The diatom Skeletonema costatum bloomed and had significantly longer chains in tanks without biodeposits. These tanks also had significantly lower concentrations of total suspended solids, zooplankton carbon, and nitrite +nitrate, and higher phytoplankton carbon concentrations. Results suggest that the absence of biodeposit resuspension initiates nitrogen uptake for diatom reproduction, increasing the cell densities of S. costatum. The low abundance of the zooplankton population in non-biodeposit tanks suggests an inability of zooplankton to graze on S. costatum and negative effects of S. costatum on zooplankton. A high abundance of the copepod Acartia tonsa in biodeposit tanks may have reduced S. costatum chain length. Oyster biodeposit addition and resuspension efficiently transferred phytoplankton carbon to zooplankton carbon, thus supporting the food web in the estuary.

EVALUATION OF CLOVERS ON SANDY COASTAL SOIL

1977 ◽  
pp. 130-138 ◽  
Author(s):  
W.M. Williams ◽  
L.B. Anderson ◽  
B.M. Cooper
Keyword(s):  
New Zealand ◽  
Drought Stress ◽  
Sandy Soil ◽  
White Clover ◽  
Plant Material ◽  
Red Clover ◽  
Early Spring ◽  
Commercial Cultivars ◽  
Mediterranean Origin ◽  
Winter Annual

In evaluations of clover performances on summer-dry Himatangi sandy soil, it was found that none could match lucerne over summer. Emphasis was therefore placed on production in autumn-winter- early spring when lucerne growth was slow. Evaluations of some winter annual clover species suggested that Trifolium spumosum, T. pallidum, T. resupinatum, and T. vesiculosum would justify further investigation, along with T. subterraneum which is already used in pastures on this soil type. Among the perennial clover species, Kenya white clover (7'. semipilosum) showed outstanding recovery from drought and was the only species to produce significantly in autumn. However, it failed to grow in winter-early spring. Within red clover, materials of New Zealand x Moroccan origin substantially outproduced the commercial cultivars. Within white clover, material from Israel, Italy and Lebanon, as well as progeny of a selected New Zealand plant, showed more rapid recovery from drought stress and subsequently better winter growth than New Zealand commercial material ('Grasslands Huia'). The wider use of plant material of Mediterranean origin and of plants collected in New Zealand dryland pastures is advocated in development of clover cultivars for New Zealand dryland situations.

Consumption of plant material by perch (Perca fluviatilis)

2016 ◽  
Vol 65 (2) ◽  
pp. 95-97 ◽  
Author(s):  
Tomáš Zapletal ◽  
Zdeněk Adámek ◽  
Pavel Jurajda ◽  
Kevin Roche ◽  
Lucie Všetičková ◽  
...  
Keyword(s):  
Plant Material ◽  
Perca Fluviatilis ◽  
Perch Perca Fluviatilis
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