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

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

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Preliminary observations of the effects of rainwater addition on Lake Michigan phytoplankton primary productivity

10.2172/8505457 ◽

1979 ◽

Author(s):

J. I. Parker

Keyword(s):

Primary Productivity ◽

Lake Michigan

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Ultrastructure of Melosira resting cell rejuvenation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011355x ◽

1984 ◽

Vol 42 ◽

pp. 734-735

Author(s):

C. E. M. Bourne ◽

L. Sicko-Goad

Keyword(s):

Electron Microscopy ◽

Lake Michigan ◽

Light And Electron Microscopy ◽

Resting Cells ◽

Planktonic Diatoms ◽

Resting Cell ◽

Vegetative Survival ◽

Cytological Changes ◽

Recent Attention ◽

Freshwater Diatom

Much recent attention has been focused on vegetative survival forms of planktonic diatoms and other algae. There are several reports of extended vegetative survival of the freshwater diatom Melosira in lake sediments. In contrast to those diatoms which form a morphologically distinct resistant spore, Melosira is known to produce physiological resting cells that are indistinguishable in outward morphology from actively growing cells.We used both light and electron microscopy to document and elucidate the sequence of cytological changes during the transition from resting cells to actively growing cells in a population of Melosira granulata from Douglas Lake, Michigan sediments collected in mid-July of 1983.

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Limnological characteristics, community metabolism and management strategies of a coastal sinkhole in Cuba (Cenote Jennifer)

Annales de Limnologie - International Journal of Limnology ◽

10.1051/limn/2020022 ◽

2020 ◽

Vol 56 ◽

pp. 24

Author(s):

Roberto González-De Zayas ◽

Liosban Lantigua Ponce de León ◽

Liezel Guerra Rodríguez ◽

Felipe Matos Pupo ◽

Leslie Hernández-Fernández

Keyword(s):

Hydrogen Sulfide ◽

Primary Productivity ◽

Major Ions ◽

Saline Water ◽

Management Strategies ◽

Tourist Destination ◽

Community Metabolism ◽

Morphological Studies ◽

Made In ◽

Limnological Parameters

The Cenote Jennifer is an important and unique aquatic sinkhole in Cayo Coco (Jardines del Rey Tourist Destination) that has brackish to saline water. Two samplings were made in 1998 and 2009, and 4 metabolism community experiments in 2009. Some limnological parameters were measured in both samplings (temperature, salinity, pH, dissolved oxygen major ions, hydrogen sulfide, nutrients and others). Community metabolism was measured through incubated oxygen concentration in clear and dark oxygen bottles. Results showed that the sinkhole limnology depends on rainfall and light incidence year, with some stratification episodes, due to halocline or oxycline presence, rather than thermocline. The sinkhole water was oligotrophic (total nitrogen of 41.5 ± 22.2 μmol l−1 and total phosphorus of 0.3 ± 0.2 μmol l−1) and with low productivity (gross primary productivity of 63.0 mg C m−2 d−1). Anoxia and hypoxia were present at the bottom with higher levels of hydrogen sulfide, lower pH and restricted influence of the adjacent sea (2 km away). To protect the Cenote Jennifer, tourist exploitation should be avoided and more resources to ecological and morphological studies should be allocated, and eventually use this aquatic system only for specialized diving. For conservation purposes, illegal garbage disposal in the surrounding forest should end.

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