Vertical and Seasonal Distribution of Chlorophyll a in Lake Michigan

1977 ◽  
Vol 34 (12) ◽  
pp. 2280-2287 ◽  
Author(s):  
Arthur S. Brooks ◽  
Byron G. Torke
Keyword(s):  
Great Lakes ◽  
Chlorophyll A ◽  
Thermal Stratification ◽  
Lake Michigan ◽  
Seasonal Distribution ◽  
Laurentian Great Lakes ◽  
Deep Chlorophyll Maximum ◽  
Phytoplankton Dynamics ◽  
Chain Dynamics ◽  
Offshore Station

Vertical and seasonal distribution of chlorophyll a was observed for 2 yr at an offshore station in Lake Michigan. Chlorophyll a concentrations increased uniformly at all depths during spring reaching 3–4 mg/m3 by late May. Thermal stratification was followed by development of a subthermocline chlorophyll peak between 10 and 30 m that reached 8.5 mg/m3 by late July. The major subthermocline peak collapsed in mid-August but was followed by two lesser peaks at depths of 10 and 30 m. Autumn mixing dispersed these peaks in the mixed layer, increasing the chlorophyll content of the epilimnion at a time when integral chlorophyll levels were declining. At fall overturn chlorophyll concentrations were uniformly distributed at approximately 1 mg/m3, where they remained throughout the winter. The presence of a deep chlorophyll maximum in Lake Michigan adds a new dimension to limnological studies of the Great Lakes. The influence of this peak must be considered in future investigations of food chain dynamics and eutrophication processes in the Great Lakes system. Key words: Laurentian Great Lakes, limnology, chlorophyll a, spatial distribution, phytoplankton dynamics

Phosphorus Enrichment, Silica Utilization, and Biogeochemical Silica Depletion in the Great Lakes

1986 ◽  
Vol 43 (2) ◽  
pp. 407-415 ◽  
Author(s):  
Claire L. Schelske ◽  
Eugene F. Stoermer ◽  
Gary L. Fahnenstiel ◽  
Mark Haibach
Keyword(s):  
Steady State ◽  
Great Lakes ◽  
Urban Population ◽  
Thermal Stratification ◽  
Lake Erie ◽  
Lake Michigan ◽  
Lake Ontario ◽  
Lake Huron ◽  
Phosphorus Enrichment

Our hypothesis that silica (Si) depletion in Lake Michigan and the severe Si depletion that characterizes the lower Great Lakes were induced by increased phosphorus (P) inputs was supported by bioassay experiments showing increased Si uptake by diatoms with relatively small P enrichments. We propose that severe Si depletion (Si concentrations being reduced to ≤0.39 mg SiO2∙L−1 prior to thermal stratification) results when P levels are increased to the extent that increased diatom production reduces Si concentrations to limiting levels during the thermally mixed period. Large P enrichments such as those that characterized the eastern and central basis of Lake Erie and Lake Ontario in the early 1970s are necessary to produce severe Si depletion. It is clear that severe Si depletion in the lower lakes was produced by P enrichment because inflowing waters from Lake Huron have smaller P concentrations and larger Si concentrations than the outflowing waters of either Lake Erie or Lake Ontario. Severe Si depletion probably began in the 1940s or 1950s as the result of increased P loads from expanded sewering of an increasing urban population and the introduction of phosphate detergents. The model proposed for biogeochemical Si depletion is consistent with previous findings of high rates of internal recycling because, under steady-state conditions for Si inputs, any increase in diatom production will produce an increase in permanent sedimentation of biogenic Si provided some fraction of the increased biogenic Si production is not recycled or unless there is a compensating increase in dissolution of diatoms.

scholarly journals Gene expression of benthic amphipods (genus: Diporeia) in relation to a circular ssDNA virus across two Laurentian Great Lakes

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3810 ◽  
Author(s):  
Kalia S.I. Bistolas ◽  
Lars G. Rudstam ◽  
Ian Hewson
Keyword(s):  
Gene Expression ◽  
Viral Load ◽  
Great Lakes ◽  
Lake Michigan ◽  
De Novo ◽  
Cell Structure ◽  
Transcriptional Profile ◽  
Laurentian Great Lakes ◽  
Post Translational Modification ◽  
Dna Viruses

Circular rep-encoding ssDNA (CRESS-DNA) viruses are common constituents of invertebrate viral consortia. Despite their ubiquity and sequence diversity, the effects of CRESS-DNA viruses on invertebrate biology and ecology remain largely unknown. This study assessed the relationship between the transcriptional profile of benthic amphipods of genus Diporeia and the presence of the CRESS-DNA virus, LM29173, in the Laurentian Great Lakes to provide potential insight into the influence of these viruses on invertebrate gene expression. Twelve transcriptomes derived from Diporeia were compared, representing organisms from two amphipod haplotype clades (Great Lakes Michigan and Superior, defined by COI barcode sequencing) with varying viral loads (up to 3 × 106 genome copies organism−1). Read recruitment to de novo assembled transcripts revealed 2,208 significantly over or underexpressed contigs in transcriptomes with above average LM29173 load. Of these contigs, 31.5% were assigned a putative function. The greatest proportion of annotated, differentially expressed transcripts were associated with functions including: (1) replication, recombination, and repair, (2) cell structure/biogenesis, and (3) post-translational modification, protein turnover, and chaperones. Contigs putatively associated with innate immunity displayed no consistent pattern of expression, though several transcripts were significantly overexpressed in amphipods with high viral load. Quantitation (RT-qPCR) of target transcripts, non-muscular myosin heavy chain, β-actin, and ubiquitin-conjugating enzyme E2, corroborated transcriptome analysis and indicated that Lake Michigan and Lake Superior amphipods with high LM29173 load exhibit lake-specific trends in gene expression. While this investigation provides the first comparative survey of the transcriptional profile of invertebrates of variable CRESS-DNA viral load, additional inquiry is required to define the scope of host-specific responses to potential infection.

scholarly journals Are the Laurentian Great Lakes great enough for Hjort?

2014 ◽  
Vol 71 (8) ◽  
pp. 2242-2251 ◽  
Author(s):  
John Janssen ◽  
J. Ellen Marsden ◽  
Thomas R. Hrabik ◽  
Jason D. Stockwell
Keyword(s):  
Great Lakes ◽  
Spatial Scale ◽  
Critical Period ◽  
Yellow Perch ◽  
Lake Michigan ◽  
Larval Fish ◽  
Biotic Interactions ◽  
Laurentian Great Lakes ◽  
Freshwater Lakes ◽  
Fish Predator

Abstract Hjort's insights on marine fish recruitment and larval fish advection are presumed not applicable to freshwater lakes because most freshwater lakes are small. The Laurentian Great Lakes (LGL), however, are large enough for certain oceanic-type hydrodynamics, such as strong currents and upwelling, to affect the distribution and survival of larval fish and thus fall under Hjort's purview. However, there are evolutionary constraints because LGL species underwent an evolutionary bottleneck during glaciation, ∼10 000 years BP. We consider three narratives pertinent to both the spatial scale and the evolutionary time-scale of the LGL. The first reviews recent evidence of offshore advection and subsequent cross-lake dispersal of larval and juvenile yellow perch, a coastal demersal species in Lake Michigan. The second narrative suggests that biotic interactions, rather than spatial scale itself, could account for the transition in the critical period of Lake Michigan yellow perch period from a juvenile to a larval critical period. In the third narrative, we consider whether the deep LGL lack a significant native pelagic larval fish predator. We propose that the LGL, in combination with the older World's Great Lakes, present an opportunity to explore evolution and adaptation of fish to oceanic type physical conditions.

scholarly journals How Many Ciscoes are Needed for Stocking in the Laurentian Great Lakes?

2021 ◽  
Author(s):  
Benjamin Rook ◽  
Michael J. Hansen ◽  
Charles R. Bronte
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Lake Superior ◽  
Production Capacity ◽  
Lake Huron ◽  
Laurentian Great Lakes ◽  
Saginaw Bay ◽  
Thunder Bay ◽  
Western Lake ◽  
Coregonus Artedi

Historically, Cisco Coregonus artedi and deepwater ciscoes Coregonus spp. were the most abundant and ecologically important fish species in the Laurentian Great Lakes, but anthropogenic influences caused nearly all populations to collapse by the 1970s. Fishery managers have begun exploring the feasibility of restoring populations throughout the basin, but questions regarding hatchery propagation and stocking remain. We used historical and contemporary stock-recruit parameters previously estimated for Ciscoes in Wisconsin waters of Lake Superior, with estimates of age-1 Cisco rearing habitat (broadly defined as total ha ≤ 80 m depth) and natural mortality, to estimate how many fry (5.5 months post-hatch), fall fingerling (7.5 months post-hatch), and age-1 (at least 12 months post-hatch) hatchery-reared Ciscoes are needed for stocking in the Great Lakes to mimic recruitment rates in Lake Superior, a lake that has undergone some recovery. Estimated stocking densities suggested that basin-wide stocking would require at least 0.641-billion fry, 0.469-billion fall fingerlings, or 0.343-billion age-1 fish for a simultaneous restoration effort targeting historically important Cisco spawning and rearing areas in Lakes Huron, Michigan, Erie, Ontario, and Saint Clair. Numbers required for basin-wide stocking were considerably greater than current or planned coregonine production capacity, thus simultaneous stocking in the Great Lakes is likely not feasible. Provided current habitat conditions do not preclude Cisco restoration, managers could maximize the effectiveness of available production capacity by concentrating stocking efforts in historically important spawning and rearing areas, similar to the current stocking effort in Saginaw Bay, Lake Huron. Other historically important Cisco spawning and rearing areas within each lake (listed in no particular order) include: (1) Thunder Bay in Lake Huron, (2) Green Bay in Lake Michigan, (3) the islands near Sandusky, Ohio, in western Lake Erie, and (4) the area near Hamilton, Ontario, and Bay of Quinte in Lake Ontario. Our study focused entirely on Ciscoes but may provide a framework for describing future stocking needs for deepwater ciscoes.

Regulation of phytoplankton dynamics in a Laurentian Great Lakes estuary

Hydrobiologia ◽  
1994 ◽  
Vol 286 (2) ◽  
pp. 97-108 ◽  
Author(s):  
David M. Klarer ◽  
David F. Millie
Keyword(s):  
Great Lakes ◽  
Laurentian Great Lakes ◽  
Phytoplankton Dynamics

Dynamics of Lake Michigan Phytoplankton: Recent Changes in Surface and Deep Communities

1987 ◽  
Vol 44 (3) ◽  
pp. 509-514 ◽  
Author(s):  
Gary L. Fahnenstiel ◽  
Donald Scavia
Keyword(s):  
Water Column ◽  
Green Algae ◽  
Thermal Stratification ◽  
Lake Michigan ◽  
Nutrient Supply ◽  
Grazing Pressure ◽  
Zooplankton Grazing ◽  
Phytoplankton Dynamics ◽  
Phytoplankton Composition ◽  
Isothermal Mixing

Lake Michigan phytoplankton dynamics were studied from the end of spring isothermal mixing (May) through midstratification (July–August) in 1982–84. Phytoplankton composition shifted from a diatom-dominated community (75% of phytoplankton carbon) during May to a phytoflagellate-dominated community (71% of phytoplankton carbon) during July–August. This summer phytoflagellate dominance in the 1980s is distinctly different from the summer blue-green and green algae dominance in the 1970s. Foodweb interactions caused by a changing zooplankton composition and nutrient supply changes were two possible causes. A deep chlorophyll layer (DCL) developed after the onset of thermal stratification. The DCL initially developed in the 15–30 m region and deepended to 25–50 m in July and the 40–70 m region in August. The DCL in 1982–84 was larger in size and located deeper in the water column than those reported from the 1970s. This difference was related to increases in light transparency found in the 1980s that were a result of increased zooplankton grazing pressure.

scholarly journals Present and future Laurentian Great Lakes hydroclimatic conditions as simulated by regional climate models with an emphasis on Lake Michigan-Huron

2015 ◽  
Vol 130 (4) ◽  
pp. 603-618 ◽  
Author(s):  
Biljana Music ◽  
Anne Frigon ◽  
Brent Lofgren ◽  
Richard Turcotte ◽  
Jean-François Cyr
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Laurentian Great Lakes

Measurement of spring thermal stratification in Lake Michigan with the GLUCOS observing system

OCEANS 2009 ◽  
2009 ◽  
Author(s):  
T. R. Consi ◽  
G. Anderson ◽  
G. Barske ◽  
H. Bootsma ◽  
T. Hansen ◽  
...  
Keyword(s):  
Thermal Stratification ◽  
Lake Michigan
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