An investigation into iron-stimulated phytoplankton productivity in epipelagic Lake Erie during thermal stratification using trace metal clean techniques

2000 ◽  
Vol 57 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Michael R Twiss ◽  
Jean-Christian Auclair ◽  
Murray N Charlton
Keyword(s):  
Thermal Stratification ◽  
Lake Erie ◽  
Low Frequency ◽  
Phytoplankton Productivity ◽  
Eastern Basin ◽  
Basin Surface ◽  
Enrichment Experiments ◽  
Heat Budgets ◽  
Periodogram Analysis ◽  
Height Data

We tested the hypothesis that phytoplankton productivity in pelagic Lake Erie is limited by low Fe bioavailability during the period of thermal stratification. Iron enrichment (20 and 200 nM Fe) of water sampled from the eastern basin surface water (5 m depth) in July 1996 revealed a dramatic 180 and 30% increase in the standing crop of the picoplankton (0.2-2 µm) and nanoplankton (2-20 µm) size fractions, respectively. Light-saturated rates of photosynthesis for picoplankton increased 2.8 times that of the controls within 24 h. In contrast, simultaneous P and Fe enrichment experiments carried out in July 1997 and August 1998 with water samples from three pelagic stations revealed that P enrichment alone stimulated phytoplankton growth, although at several stations, phytoplankton yield was greater in combined P- and Fe-amended experiments relative to P-enriched treatments. Periodogram analysis of meteorological buoy wave height data and heat budgets calculated from thermal profiles in the eastern basin revealed important interyear differences in precruise conditioning of the epilimnion. Low-frequency, turbulent mixing events that characterized the 30-day precruise period in the years 1997 and 1998 relative to 1996 may have prevented Fe-stressed conditions in the phytoplankton community studied in 1997 and 1998.

Iron plays a role in nitrate drawdown by phytoplankton in Lake Erie surface waters as observed in lake-wide assessments

2012 ◽  
Vol 69 (2) ◽  
pp. 369-381 ◽  
Author(s):  
Sonya M. Havens ◽  
Christel S. Hassler ◽  
Rebecca L. North ◽  
Stephanie J. Guildford ◽  
Greg Silsbe ◽  
...  
Keyword(s):  
Surface Waters ◽  
Thermal Stratification ◽  
Lake Erie ◽  
Phytoplankton Community ◽  
Sampling Depth ◽  
Phytoplankton Pigment ◽  
Chl A ◽  
Dissolved Iron ◽  
Continuous Surface

Phytoplankton interactions with iron (Fe) were examined in surface waters of Lake Erie during summer thermal stratification. Lake-wide sampling in June and September 2005 was conducted using a continuous surface water sampler (1 m sampling depth) and in July at 18 hydrographic stations (5 m sampling depth). In situ measurements of photosynthetic efficiency (maximum quantum yield of photosystem II) and phytoplankton community composition were measured using fast repetition rate fluorometry and a phytoplankton pigment-specific fluorometer, respectively, during June and September. High ratios (73%–85%) of intracellular Fe to particulate Fe coincident with increases in chlorophyll a (Chl a) concentrations in the western and central basins in June and July imply that the majority of Fe in these regions was associated with intracellular pools. Correlations between intracellular Fe and Chl a were frequently observed when Heterokontophyta and Pyrrophyta dominated the phytoplankton community. Assimilation of Fe by the phytoplankton strongly influenced its partitioning between the dissolved and particulate phase. Dissolved iron (<0.45 µm) concentrations were proportional to Chl a concentrations and both dissolved iron and Chl a were inversely proportional to nitrate concentrations in July and September, suggesting that dissolved iron influenced both nitrate drawdown and Chl a concentrations in Lake Erie surface waters in summer.

Invasion of Lake Erie Offshore Sediments by Dreissena, and Its Ecological Implications

1993 ◽  
Vol 50 (11) ◽  
pp. 2298-2304 ◽  
Author(s):  
R. Dermott ◽  
M. Munawar
Keyword(s):  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Lake Erie ◽  
Quagga Mussel ◽  
Central Basin ◽  
Eastern Basin ◽  
Fine Sediments ◽  
Ecological Implications ◽  
Large Populations ◽  
Hard Substrates

Large populations of the exotic rounded (noncarinate) shelled mussel of the genus Dreissena were found to exist on soft sediments collected throughout the central and eastern basins of Lake Erie during July and August 1992. Two different phenotypes were present on fine sediments (<150 μm) in the eastern basin. An elongated white morph was common on the profundal sediments beyond 40 m depth, while the "quagga" mussel was common on sand and sandy silt at depths between 10 and 30 m. Together with the carinated zebra mussel Dreissena polymorpha, which is very abundant on hard substrates in the sublittoral region, at least 80% of Lake Erie's bottom sediments have been invaded by Dreissena. Only that region of the central basin (near Cleveland) which undergoes periodic summer anoxia was not inhabited by this genus.

scholarly journals Does behavioural thermoregulation underlie seasonal movements in Lake Erie walleye?

2018 ◽  
Vol 75 (3) ◽  
pp. 488-496 ◽  
Author(s):  
Graham D. Raby ◽  
Christopher S. Vandergoot ◽  
Todd A. Hayden ◽  
Matthew D. Faust ◽  
Richard T. Kraus ◽  
...  
Keyword(s):  
Lake Erie ◽  
Seasonal Migration ◽  
Central Basin ◽  
Behavioural Thermoregulation ◽  
Long Distance ◽  
Western Basin ◽  
Eastern Basin ◽  
Temperature Records ◽  
Thermal Preferences

Thermoregulation is presumed to be a widespread determinant of behaviour in fishes, but has not often been investigated as a mechanism shaping long-distance migrations. We used acoustic telemetry and animal-borne thermal loggers to test the hypothesis that seasonal migration in adult walleye (Sander vitreus) in Lake Erie is size- and (or) sex-specific and related to behavioural thermoregulation. Female walleye migrated out of the warm, shallow western basin earlier than did males and were 1.8 times more likely to be detected on acoustic receivers in the deeper and cooler eastern basin. The few fish that remained in the western basin were restricted to a smaller range of higher temperatures (≥20 °C) than those that migrated to the central and eastern basins (∼16–21 °C). However, temperature records from walleye in the central basin were nearly indistinguishable from those in the eastern basin, suggesting thermal preferences alone could not explain migration to the eastern basin. As such, our effort to understand the mechanisms that cause migratory behaviours has generated mixed evidence on the role of temperature and that factors like foraging opportunities may have synergistic roles in the migration.

Spatial Distribution of Nearshore Fish in the Vicinity of Two Thermal Generating Stations, Nanticoke and Douglas Point, on the Great Lakes

1978 ◽  
Vol 35 (6) ◽  
pp. 885-892 ◽  
Author(s):  
C. K. Minns ◽  
J. R. M. Kelso ◽  
W. Hyatt
Keyword(s):  
Spatial Distribution ◽  
Thermal Stratification ◽  
Lake Erie ◽  
Temperature Response ◽  
Incident Radiation ◽  
Fish Distribution ◽  
Lake Huron ◽  
Vertical Variation ◽  
Pelagic Communities ◽  
Key Words Temperature

At Nanticoke, Lake Erie, 1974, mean fish density varied considerably, range 162–14 204/10 000 m3, as estimated by digital acoustic fish enumeration. At Douglas Point, Lake Huron, 1975, mean density varied less, range 108–671/10 000 m3. At both sites fish densities were generally greatest in the shallowest, 3–5 m, depths. At Nanticoke, where the nearshore has low relief, there were no distinguishable communities. At Douglas Point, where depth increases rapidly offshore, there was evidence of benthic and pelagic communities. There was no evidence of altered fish distribution in relation to temperature. At Nanticoke there was no vertical variation in temperature and no vertical response was to be expected. At Douglas Point there was thermal stratification present in the summer and there was no apparent response. The influence of incident radiation was uncertain because of the effects of diurnal migrations. At both locations fish were clustered horizontally to varying degrees in the spring and fall, while in the summer fish were distributed more evenly. Densest clusters were usually in the vicinity of the turbulent discharge at both locations. The lack of temperature response and the similarity of Nanticoke with situations at nearby streams on Lake Erie suggest that the fish are responding to currents and perhaps topography. Key words: temperature, acoustic enumeration, topography, light

Stratification in a small lagoon in the Great Barrier Reef

1984 ◽  
Vol 35 (3) ◽  
pp. 273 ◽  
Author(s):  
JC Andrews ◽  
WC Dunlap ◽  
NF Bellamy
Keyword(s):  
Great Barrier Reef ◽  
Time Scales ◽  
Wind Stress ◽  
Thermal Stratification ◽  
Bottom Water ◽  
Reef Flat ◽  
Low Frequency ◽  
Wind Vector ◽  
Barrier Reef ◽  
Lunar Synchronization

Temperatures were measured in a small lagoon in the windward reef flat of Davies Reef in the central Great Barrier Reef and examined on three time scales to gain three perspectives on thermal stratification and the trapping of bottom water. Profiling for stratification and dye revealed layering where bottom water was trapped and released by the successive capping and uncapping of the lagoon by a diurnal thermocline. A 1-month monitoring array revealed a solar synchronization, with the temperature of reef-flat water exceeding temperatures of lagoon water by up to 1 5�C within 1 h of midday, and lagoon stratification lagging this by 1 h. There was also a lunar synchronization with mixing proceeding during nocturnal rising tides. Lagoon surface and bottom temperatures were also monitored for 11 months. The amplitude of the diurnal stratification showed no coherence either with the amplitude of the tide (marked spring-neap tides) or with scalar wind stress. The low frequency amplitude of the diurnal oscillation was coherent with the longshore wind vector at periods near 3 6 days and in a band approximately from 10 to 40 days. Daily stratification increased when winds were poleward and decreased when winds were equatonvard. Events of flushing were separated on average by 9 h, but the most frequently observed separation was 5 h and only 10% of separations exceeded 18 h during the 11 months.

Inshore–Offshore Sedimentation Differences Resulting from Resuspension in the Eastern Basin of Lake Erie

1982 ◽  
Vol 39 (5) ◽  
pp. 748-759 ◽  
Author(s):  
J. Bloesch
Keyword(s):  
Lake Erie ◽  
Sediment Cores ◽  
Dry Weight ◽  
Sediment Traps ◽  
Particulate Phosphorus ◽  
Particulate Nitrogen ◽  
Eastern Basin ◽  
Fine Grained ◽  
Lake Bottom ◽  
Offshore Station

From June through October 1978 sediment traps were moored at three stations in an inshore–offshore transect in the Eastern Basin of Lake Erie. Settling fluxes measured with the traps exposed close to lake bottom were rather similar at all three stations during summer stratification, averaging 6.1 g∙m−2∙d−1 for dry weight, 293 mg∙m−2∙d−1 for particulate organic carbon (POC), 38 mg∙m−2∙d−1 for particulate nitrogen (PN), and 5.44 mg∙m−2∙d−1 for particulate phosphorus (PP). A comparison of the hypolimnetic traps with the epilimnetic traps at the offshore station indicated that considerable resuspension takes place even in summer. During fall, however, the nearshore sedimentation rates were markedly increased because of storm-induced bottom resuspension. By comparing the trap catches with sediment cores taken at all three stations, a resuspension model for dry weight, POC, and PN was developed. The calculations showed that newly formed organic material is resuspended and redeposited more frequently at nearshore locations than offshore. This repeated nearshore resuspension enhances decomposition of detritus, as shown by low relative phytoplankton activity in the hypolimnetic traps, and results in horizontal transport of fine-grained organic matter in the offshore direction. The significant POC and PN concentration differences found in the inshore–offshore transect of the bottom sediments can be explained by these two processes.Key words: sedimentation, sediment traps, sediment cores, resuspension, inshore–offshore differences

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.

Heat uptake and resistance to mixing in small humic forest lakes in Southern Finland

1990 ◽  
Vol 41 (6) ◽  
pp. 747 ◽  
Author(s):  
LC Bowling ◽  
K Salonen
Keyword(s):  
Thermal Stratification ◽  
Heat Of Fusion ◽  
Short Term ◽  
Thermal Stabilities ◽  
Maximum Heat ◽  
Lake Volume ◽  
Heat Uptake ◽  
Forest Lakes ◽  
Heat Budgets ◽  
Term Fluctuation

The annual heat budgets and maximum thermal stabilities achieved by small Finnish forest lakes are considerable for lakes of their size. Heat uptake is rapid during the brief period of vernal circulation, with the latent heat of fusion of ice contributing substantially to this. Heating then slows, with maximum heat contents and thermal stabilities occurring around early August. Absorption of solar radiation by the dystrophic waters, effective shelter from wind-induced turbulence, and considerable relative depths all combine to prevent mixing of heat much below the surface 2 m of most study lakes. Birgean wind-work values therefore remain low, and cold hypolimnetic waters occupy much of the lake volume. The lakes also respond quickly to meteorological change, which causes considerable year-to-year variation, and some short-term fluctuation, in their heat budgets and maximum stabilities. The lakes' small size and shallow thermal stratification may contribute to this.

Nutrient Budgets for Lake Erie, 1970

1976 ◽  
Vol 33 (3) ◽  
pp. 520-536 ◽  
Author(s):  
N. M. Burns
Keyword(s):  
Lake Erie ◽  
Loss Rate ◽  
Inorganic Nitrogen ◽  
Phytoplankton Growth ◽  
Phosphorus Concentration ◽  
Nutrient Budgets ◽  
Eastern Basin ◽  
Phosphorus Budget ◽  
Upward Transport ◽  
Reactive Silica

Budgets for the quantities of water, chloride, and phosphorus entering and leaving Lake Erie during the year of 1970 have been developed. The phosphorus budget was broken down into basin budgets which were further subdivided into epilimnion budgets for the Central and Eastern basins. Epilimnion budgets for soluble inorganic nitrogen (SIN) and soluble reactive silica (SRS) were also developed. The average coefficients of elimination by sedimentation of the phosphorus within each basin were 4.0, 0.38, and 0.18%/day for the Western, Central, and Eastern basins, respectively. The phosphorus elimination was found to be inversely related to mean basin depth but directly related to the phosphorus concentration of the water. The epilimnion budgets showed that during the summer the internal loading of SRS to the epilimnion was greater than the uptake of SRS by phytoplankton growth. The epilimnion budget of SIN demonstrated a massive uptake of the material during the summer, which was only partially replenished. The loss rate of phosphorus from the Central and Eastern basin epilimnia decreased as the summer progressed, to the extent that there was a net gain of phosphorus in the Eastern basin epilimnion toward the end of the summer. It is believed that this resulted from significant upward transport of phosphorus from the hypolimnion to the epilimnion by flagellate species of phytoplankton.

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