Seasonal Periodicity of Diatoms, and Silicon Limitation in Offshore Lake Michigan, 1975

1977 ◽  
Vol 34 (4) ◽  
pp. 552-558 ◽  
Author(s):  
J. I. Parker ◽  
H. L. Conway ◽  
E. M. Yaguchi
Keyword(s):  
Key Words ◽  
Primary Productivity ◽  
Rapid Growth ◽  
Lake Michigan ◽  
Spring Bloom ◽  
Accumulation Rate ◽  
Biomass Accumulation ◽  
Seasonal Periodicity ◽  
Silicon Uptake ◽  
Bloom Diatom

Diatom biomass maxima occurred in spring and fall and produced a bimodal bloom sequence at an offshore Lake Michigan station. The maximum in May was preceded by rapid growth as indicated by increased values of primary productivity and pigment concentration. As the spring bloom progressed, decreasing nutrient levels apparently slowed diatom growth. The diatom-biomass accumulation rate declined, assimilation quotients were minimal, and soluble reactive silicon was reduced from 13 to 6.8 μmol/ℓ. In summer, after the bloom, diatom biomass and silicon reached seasonal minima of < 250 mg C/m2 and ~ 1.0 μmol/ℓ, respectively. Diatom biomass increased again in October when silicon supplies were replenished and the concentration exceeded 6.6 μmol/ℓ. A critical silicon concentration of ~ 6.5 μmol/ℓ, may control the development and timing of offshore diatom populations in Lake Michigan. Key words: Lake Michigan, diatoms, growth, biomass, periodicity, silicon, uptake, limitation

Observations on the seasonal occurrence of marine endophytic and parasitic fungi

1992 ◽  
Vol 70 (10) ◽  
pp. 2089-2096 ◽  
Author(s):  
Susan J. Stanley
Keyword(s):  
Key Words ◽  
Marine Algae ◽  
Ascophyllum Nodosum ◽  
Life Cycles ◽  
Chondrus Crispus ◽  
Seasonal Periodicity ◽  
Parasitic Fungi ◽  
Algal Associations ◽  
Systemic Nature ◽  
Reproductive Cycles

Information is presented on three fungal–algal associations on intertidal marine algae. They comprise two members of the Ascomycotina, Lautitia danica parasitic on Chondrus crispus, and Mycosphaerella ascophylli, an obligate endophyte of Ascophyllum nodosum, and a member of the Basidiomycotina, Mycaureola dilseae, that is parasitic on Dilsea carnosa. Details are given of life cycles and seasonal periodicity. The reproductive cycles of Mycosphaerella ascophylli and Ascophyllum nodosum are synchronised, with the fungal sporocarps being confined to the algal receptacles. Lautitia danica occurs on cystocarpic Chondrus crispus throughout the year, with older fronds being more likely to have fungal sporocarps on them. Mycaureola dilseae infecting Dilsea carnosa was only found during September and October. The systemic nature of the association between Mycosphaerella ascophylli and Ascophyllum nodosum is compared with the apparently localized occurrence of Lautitia danica and Mycaureola dilseae. Key words: marine algicolous fungi, seasonality, Ascomycetes, Basidiomycetes.

scholarly journals Planting Density Induced Changes in Cotton Biomass Yield, Fiber Quality, and Phosphorus Distribution under Beta Growth Model

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 500 ◽  
Author(s):  
Aziz Khan ◽  
Xiangjun Kong ◽  
Ullah Najeeb ◽  
Jie Zheng ◽  
Daniel Kean Yuen Tan ◽  
...  
Keyword(s):  
Field Experiments ◽  
Biomass Yield ◽  
Accumulation Rate ◽  
Fiber Quality ◽  
Phosphorus Uptake ◽  
Biomass Accumulation ◽  
Planting Density ◽  
Maximum Height ◽  
Low Density ◽  
Moderate Density

High input costs combined with multiple management and material inputs have threatened cotton productivity. We hypothesize that this problem can be addressed by a single fertilization at flowering with late sowing in a moderately populated plant stand. Field experiments were conducted to evaluate the cotton biomass accumulation, phosphorus dynamics, and fiber quality under three planting densities (low, 3 × 104; moderate, 6 × 104; and dense, 9 × 104 ha−1) and two cultivars (Zhongmian-16 and J-4B). High planting density had 6.2 and 12.6% larger stems and fruiting nodes m−2, while low density produced a 37.5 and 59.4% maximum height node ratio. Moderate density produced 26.4–15.5%, 24.7–12.6%, and 10.5–13.6% higher biomass accumulation rate at the peak bloom, boll set, and plant removal stages over low and high density in both years, respectively. J-4B produced a higher reproductive organs biomass yield when compared with Zhongmian-16 in both years. This higher biomass formation was due to both the higher average (0.8 VT kg·ha−1·d−1) and maximum (1.0 VM kg·ha−1·d−1) reproductive organ phosphorus uptake, respectively. Plants with low density had 5.3–18.5%, 9.5–15%, and 7.8–12.8% greater length, strength, and micronaire values over moderate and dense plants, respectively. Conclusively, moderate density with J-4B is a promising option for improved biomass, phosphorus acquisition, and fiber quality under a short season.

scholarly journals Sedimentary changes on the Southeastern Brazilian upper slope during the last 35,000 years

2007 ◽  
Vol 79 (1) ◽  
pp. 171-181 ◽  
Author(s):  
Michel M. Mahiques ◽  
Marina M. Fukumoto ◽  
Ilson C.A. Silveira ◽  
Rubens C.L. Figueira ◽  
Marcia C. Bícego ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Productivity ◽  
Accumulation Rate ◽  
Climatic Conditions ◽  
Southeastern Brazil ◽  
Sedimentation Rates ◽  
Sedimentary Characteristics ◽  
Brazil Current ◽  
Sedimentary Core ◽  
Upper Slope

A first evaluation of the sedimentary changes, including accumulation of inorganic and organic carbon on the upper slope off Southeastern Brazil under different climatic conditions, based on the analysis of a sedimentary core, is here presented. Results indicate that sedimentation rate as well sedimentary characteristics, including the nature of the organic carbon deposited during the LGM (Last Glacial Maximum), were different from the present deposition, indicating higher primary productivity during the LGM, to be accounted for by the higher values of marine organic carbon. Nevertheless, the higher values of Accumulation Rate of calcium carbonate and organic carbon can be credited to the higher values of the sedimentation rates. Conditions prevailing during Isotope Stage 3 may be considered intermediate as between the LGM and the present day. The conditions for a higher primary productivity associated with the deposition of finer terrigenous sediments may be explained as a response to the off shoreward displacement of the main flow of the Brazil Current.

AEC Glacier alpine bluegrass

2002 ◽  
Vol 82 (1) ◽  
pp. 95-98 ◽  
Author(s):  
B. A. Darroch ◽  
S. N. Acharya ◽  
J. Woosaree
Keyword(s):  
Key Words ◽  
Seed Production ◽  
Rapid Growth ◽  
Cultivar Description ◽  
High Elevations ◽  
Key Words Alpine

AEC Glacier alpine bluegrass, Poa alpina L., is a reclamation cultivar developed for use in reclaiming and revegetating disturbed sites at high elevations. It is the second alpine bluegrass cultivar released by the Alberta Environmental Centre, Vegreville, AB. This cultivar is expected to complement a prior release, AEC Blueridge alpine bluegrass. AEC Glacier is adapted to high elevations where it is capable of rapid growth and seed production. Key words: Alpine bluegrass, Poa alpina, cultivar description, reclamation

Changes in the Apparent Temperature Optima of the Plankton of Lake Michigan at Chicago, Illinois

1979 ◽  
Vol 36 (10) ◽  
pp. 1169-1173 ◽  
Author(s):  
J. C. Makarewicz ◽  
R. I. Baybutt ◽  
K. Damann
Keyword(s):  
Lake Michigan ◽  
Cold Water ◽  
Plankton Community ◽  
Apparent Temperature ◽  
Optimum Temperature ◽  
Seasonal Periodicity ◽  
Blue Green Algae ◽  
Plankton Distribution ◽  
Temperature Optima ◽  
Water Species

Forty years (1937–76) of data from Lake Michigan water intakes at Chicago, Illinois, were examined to explain reported differences in the apparent temperature optima of phytoplankton. The bimodal seasonal plankton distribution, typical at Chicago, still occurs. However, there has been a shift in seasonal periodicity with spring peaks occurring in March from 1957 to 1976 instead of May–June as previously reported for 1937–56. An optimum temperature of 10 °C for the plankton community was observed between 1936 and 1956, while for the last 20 yr an optimum temperature range from 0 to 4 °C was observed. This change in optimum temperature of the plankton community is related to a change in the abundance of the genera Asterionella, Fragilaria, Stephanodiscus, and Tabellaria. Asterionella and Fragilaria were the dominant spring plankton with maximum standing crops observed around 10 °C prior to 1956. Stephanodiscus first increased significantly in 1957 and was the dominant spring plankter through 1976. More recently (1972–76), blue-green algae have increased in numbers. Differences in apparent temperature optima reported are real and are caused by the emergence of cold water species of Stephanodiscus as the dominant spring plankter from 1957 to 1976. Key words: plankton, temperature optima, Lake Michigan

Density Estimates of Mysis relicta in Lake Michigan

1979 ◽  
Vol 36 (6) ◽  
pp. 694-698 ◽  
Author(s):  
Nevin E. Grossnickle ◽  
Mark D. Morgan
Keyword(s):  
Key Words ◽  
Lake Michigan ◽  
Density Estimates ◽  
Mysis Relicta ◽  
Deep Station ◽  
Late Instar ◽  
Order Of Magnitude

Density estimates of Mysis relicta based on night vertical net tows at stations of 30–50 m in Lake Michigan were about an order of magnitude larger than previous estimates based on sled tows. Significantly greater density estimates were obtained in night vertical net tows than those collected before sunset at these shallow stations. However, density estimates based on sled tows during daylight were not significantly different from those based on night vertical net tows at a 115-m station in Lake Michigan. At this deep station, a substantially larger percentage of late instar mysids was collected in sled tows than in night vertical net tows. Key words: Mysis relicta, Lake Michigan, density estimates, vertical net tows, epibenthic sled tows

Seasonal biomass accumulation and nutrient uptake of wheat, barley and oat on a Black Chernozem Soil in Saskatchewan

2006 ◽  
Vol 86 (4) ◽  
pp. 1005-1014 ◽  
Author(s):  
S. S. Malhi ◽  
A. M. Johnston ◽  
J. J. Schoenau ◽  
Z. L. Wang ◽  
C. L. Vera
Keyword(s):  
Nutrient Uptake ◽  
Uptake Rate ◽  
Accumulation Rate ◽  
Biomass Accumulation ◽  
Growing Season ◽  
Early Growth ◽  
Growth Stages ◽  
Nutrient Accumulation ◽  
Maximum Biomass ◽  
Cereal Species

Dry matter and nutrient accumulation in the growing season are the main factors in the determination of seed yield and nutrient use efficiency. Field experiments were conducted with spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and oat (Avena sativa L.) in 1998 and 1999 at Melfort, Saskatchewan, Canada, to determine the biomass accumulation and plant nutrient uptake at different growth stages, and their relationship with days after emergence (DAE) and growing degree days (GDD). All crops generally followed a similar pattern of biomass and nutrient accumulation in the growing season, which increased continuously with growing time, with much faster increase at early growth stages than at late growth stages. Maximum biomass accumulation rate and amount usually occurred at late boot stage (46–47 DAE or 443–460 GDD) and ripening stage (89–90 DAE or 948–1050 GDD), respectively. Maximum rate of nutrient uptake occurred at tillering to stem elongation stages (22–36 DAE or 149–318 GDD). Maximum amount of nutrient uptake generally occurred at the beginning of flowering to medium milk stages (61–75 DAE or 612–831 GDD), except for P in 1998 when it occurred at late milk to ripening stages (80–90 DAE or 922–1050 GDD). In general, the maximum nutrient uptake rate and amount, respectively, occurred earlier than maximum biomass accumulation rate and amount. For various cereal species/cultivars, maximum biomass accumulation rate was 204–232 kg ha-1 d-1, and maximum uptake rate of N, P, K and S, respectively, was 3.2–5.7, 0.30–0.60, 3.85–7.05 and 0.45–0.60 kg ha-1 d-1. The findings suggest that a sufficient supply of nutrients from soil and fertilizers at early growth stages is of great importance for optimum crop yield. Key words: Barley, biomass accumulation, cereals, growth stages, nutrient uptake, oat, wheat

Penicillium kananaskense, a new species from Alberta soil

1994 ◽  
Vol 72 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Keith A. Seifert ◽  
J. C. Frisvad ◽  
Mary Ann McLean
Keyword(s):  
New Species ◽  
Secondary Metabolites ◽  
Key Words ◽  
Rapid Growth ◽  
Preliminary Data ◽  
Pinus Contorta ◽  
The Many ◽  
A New Species

The new species Penicillium kananaskense is described based on an isolate from soil in a Pinus contorta forest from Alberta, Canada. Colonies are characterized by their relatively rapid growth, velutinous texture, white to slightly pink conidial masses, growth at 5 °C, and absence of growth at 37 °C. The conidiophores are monoverticillate or have one metula, are up to 300 μm tall, smooth walled or with slightly roughened walls, vesiculate, and bear ampulliform phialides, 8–11.5(−14.5) × 2.5–4 μm, that produce disordered chains of ellipsoidal conidia, 3–5 × 2.5–4 μm, with smooth or finely roughened walls. The species is compared with previously described taxa and its subgeneric affinities are discussed. Preliminary data on the many secondary metabolites produced by the ex-type culture are presented. Key words: Penicillium kananaskense, soil, Pinus contorta var. latifolia, mycotoxins.

Life History and Abundance of Mysis relicta in Lake Michigan

1978 ◽  
Vol 35 (9) ◽  
pp. 1165-1170 ◽  
Author(s):  
Mark D. Morgan ◽  
Alfred M. Beeton
Keyword(s):  
Life History ◽  
Key Words ◽  
Lake Michigan ◽  
Fourth Instar ◽  
Mysis Relicta ◽  
First Instar ◽  
Males And Females

Mysis relicta was sampled in Lake Michigan approximately monthly with an epibenthic sled, August 1975–July 1976. Total numbers ranged from a low of 23 m−2 in February to a high of 337 m−2 in May and averaged 188 m−2. It was possible to partition the population into five instars. Major peaks in proportions of first instar individuals occurred in March, July, and November. It took about 1 yr for first instar individuals to reach the fourth instar. Growth averaged a little less than 1 mm/mo. Males and females reached maturity and bred in the fourth instar, so females produced their first brood at 1 yr of age. Males died at this time, but females were found to molt to the fifth instar, mate, and produce a second brood approximately 4 mo later. Key words: Mysis relicta, Lake Michigan, life history, abundance

A model for determining satellite-derived primary productivity estimates for Lake Michigan

2013 ◽  
Vol 39 ◽  
pp. 46-54 ◽  
Author(s):  
Robert A. Shuchman ◽  
Michael Sayers ◽  
Gary L. Fahnenstiel ◽  
George Leshkevich
Keyword(s):  
Primary Productivity ◽  
Lake Michigan
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