A day in the life of winter plankton: under-ice community dynamics during 24 h in a eutrophic lake

2021 ◽  
Author(s):  
Ariana M Chiapella ◽  
Haley Grigel ◽  
Hannah Lister ◽  
Allison Hrycik ◽  
Brian P O’Malley ◽  
...  
Keyword(s):  
Surface Waters ◽  
Community Dynamics ◽  
Sampling Period ◽  
Eutrophic Lake ◽  
Ice Cover ◽  
Lake Ice ◽  
Ice Dynamics ◽  
Upward Migration ◽  
And Function ◽  
Lipid Stores

Abstract Although diel vertical migration (DVM) in aquatic systems may account for the largest daily migration of biomass globally, our understanding of this process under ice cover is limited, particularly in fresh water. The date of lake ice onset and duration of ice cover is declining globally, therefore determining the extent of plankton migrations under ice is imperative to inform our baseline understanding of seasonal differences in community structure and function, and how conditions may change over time. We investigated whether plankton exhibit DVM under ice and explored interactions between phytoplankton and zooplankton at highly resolved space–time scales across 24 h in a eutrophic system. Despite the dominance of motile taxa, phytoplankton remained vertically segregated based on morpho-functional groups throughout the sampling period. Daphnia mendotae exhibited size-structured DVM with an upward migration at sunset and sunrise, and midnight sinking, presumably to avoid the rise of predatory Chaoborus. We hypothesize that because overwintering daphnids require rich lipid stores, D. mendotae migrated to access small, lipid-rich phytoplankton that were limited to surface waters. Given our study took place during an unusually warm winter in a eutrophic system, our results may represent future under-ice dynamics under increasing eutrophication pressure and climate warming in shallow lakes.

scholarly journals Analysis of local AWS and NCEP/NCAR reanalysis data at Lake El'gygtytgyn, and its implications for maintaining multi-year lake-ice covers

2012 ◽  
Vol 8 (2) ◽  
pp. 1443-1483 ◽  
Author(s):  
M. Nolan
Keyword(s):  
Full Range ◽  
Summer Rainfall ◽  
Barometric Pressure ◽  
Ice Cover ◽  
Warming Trend ◽  
Reanalysis Data ◽  
Lake Ice ◽  
Ice Dynamics ◽  
Air Temperatures ◽  
Perennial Ice

Abstract. We compared 7 years of local automated weather station (AWS) data to NCEP/NCAR reanalysis data to characterize the modern environment of Lake El'gygytgyn, in Chukotka Russia. We then used this comparison to estimate the air temperatures required to initiate and maintain multi-year lake-ice covers to aid in paleoclimate reconstructions of the 3.6 M years sediment record recovered from there. We present and describe data from our AWS from 2002–2008, which recorded air temperatures, relative humidity, precipitation, barometric pressure, and wind speed/direction, as well as subsurface soil moisture and temperature. Measured mean annual air temperature (MAAT) over this period was −10.4 °C with a slight warming trend during the measurement period. NCEP/NCAR reanalysis air temperatures compared well to this, with annual means within 0.1 to 2.0 °C of the AWS, with an overall mean 1.1 °C higher than the AWS, and daily temperature trends having a correlation of over 96% and capturing the full range of variation. After correcting for elevation differences, barometric pressure discrepancies occasionally reached as high as 20 mbar higher than the AWS particularly in winter, but the correlation in trends was high at 92%, indicating that synoptic-scale weather patterns driving local weather likely are being captured by the reanalysis data. AWS cumulative summer rainfall measurements ranged between 70–200 mm during the record. NCEP/NCAR reanalysis precipitation failed to predict daily events measured by the AWS, but largely captured the annual trends, though higher by a factor of 2–4. NCEP air temperatures showed a strong trend in MAAT over the 1961–2009 record, rising from a pre-1995 mean of −12.0 °C to a post-1994 mean of −9.8 °C. We found that nearly all of this change could be explained by changes in winter temperatures, with mean winter degree days (DD) rising from −5043 to −4340 after 1994 and a much smaller change in summer DD from +666 to +700. Thus, the NCEP record indicates that nearly all modern change in MAAT is driven by changes in winter (which promotes lake-ice growth) not summer (which promotes lake-ice melt). Whether this sensitivity is representative of paleo-conditions is unclear, but it is clear that the lake was unlikely to have initiated a multi-year ice cover since 1961 based on simple DD models of ice dynamics. Using these models we found that the NCEP/NCAR reanalysis mean MAAT over 1961–2009 would have to be at least 4 °C colder to initiate a multi-year ice cover, but more importantly that multi-year ice covers are largely controlled by summer melt rates at this location. Specifically we found that summer DD would have to drop by more than half the modern mean, from +640 to +280. Given that the reanalysis temperatures appears about 1 °C higher than reality, a MAAT cooling of 3 °C may be sufficient in the real world, but as described in the text we consider a cooling of −4°C ± 0.5 °C a reasonable requirement for multi-year ice covers. Also perhaps relevant to paleo-climate proxy interpretation, at temperatures cold enough to maintain a multi-year ice cover, the summer temperatures could still be sufficient for a two-month long thawing period, including a month at about +5 °C Thus it is likely that many summer biological processes and some lake-water warming and mixing may still have been occurring beneath perennial ice-covers; core proxies have already indicated that such perennial ice-covers may have persisted for tens of thousands of years at various times within the 3.6 M years record.

Bank filtration: a suitable process for the removal of iodinated X-ray contrast media?

2004 ◽  
Vol 50 (5) ◽  
pp. 261-268 ◽  
Author(s):  
S. Schittko ◽  
A. Putschew ◽  
M. Jekel
Keyword(s):  
Drinking Water ◽  
Contrast Media ◽  
Surface Waters ◽  
Sampling Period ◽  
Transformation Products ◽  
Bank Filtration ◽  
Anoxic Conditions ◽  
X Ray ◽  
High Concentrations ◽  
Media Concentration

After bank filtration, effluent influenced surface waters are often used as raw drinking water. It is known that high concentrations of iodinated X-ray contrast media are detectable in such surface waters and thus, more knowledge about the behaviour of the contrast media during bank filtration is necessary and the subject of investigations in this study. The adsorbable organic iodine (AOI), four widely used iodinated X-ray contrast media and four possible transformation products were quantified in an influenced lake, five groundwater wells and a drinking water well. Under anoxic conditions the AOI as well as the concentration of the contrast media are decreased by bank filtration, whereby the AOI is decreased by 64% and the contrast media concentration can be reduced up to 95%, depending on the compound. In the raw drinking water the following average concentrations were determined: Iopromid <20 ng/L, Diatrizote 166 ng/L, Iopamidol 166 ng/L and Iohexol 34 ng/L. Instationary conditions during the sampling period indicate that, at least under anoxic conditions, a large part of the contrast media and transformation products, which are still iodinated, may be associated to colloids and/or humic material.

Antioxidant enzymes in sea cucumber Apostichopus japonicus (Selenka) during aestivation

2010 ◽  
Vol 91 (1) ◽  
pp. 209-214 ◽  
Author(s):  
Wang Fangyu ◽  
Yang Hongsheng Yang ◽  
Wang Xiaoyu ◽  
Xing Kun ◽  
Gao Fei
Keyword(s):  
Oxygen Consumption ◽  
Glutathione Peroxidase ◽  
Sea Cucumber ◽  
Apostichopus Japonicus ◽  
Sampling Period ◽  
Coelomic Fluid ◽  
Sharp Change ◽  
Antioxidant Defence ◽  
Antioxidant Defences ◽  
And Function

To evaluate the effect of antioxidant defence in coelomic fluid of sea cucumber, Apostichopus japonicus in aestivation was studied in the field from July to November 2006 in Qingdao. During the sampling period, activities of superoxide dismutase and catalase increased significantly in August and November. Activities of glutathione reductase and glutathione decreased significantly in August and increased significantly in November and activities of Se-glutathione peroxidase increased significantly in August. There were no significant differences in total glutathione peroxidase. In relation to the water temperature in the field, it is known that the oxygen consumption rate dropped and antioxidant defence was enhanced in August. The structure and function of respiratory trees of A. japonicus were completely vivified as normal in November, and it is suggested that antioxidant defence was enhanced because of the sharp change of oxygen consumption. Data indicate that both enzymatic and metabolite antioxidant defences in sea cucumber are adaptable systems that are modulated during pre-aestivating stage and arousing stage.

scholarly journals Terms and conditions of high-mountain lake ice-cover chemistry (Carpathians, Poland)

2015 ◽  
Vol 61 (230) ◽  
pp. 1207-1212 ◽  
Author(s):  
Iwona Kurzyca ◽  
Adam Choiński ◽  
Joanna Pociask-Karteczka ◽  
Agnieszka Lawniczak ◽  
Marcin Frankowski
Keyword(s):  
Water Body ◽  
Ice Cover ◽  
Multilayered Structure ◽  
Mountain Lake ◽  
High Mountain ◽  
Lake Ice ◽  
High Mountain Lake ◽  
Spatial Diversification ◽  
The Tatra Mountains

AbstractWe discuss the results of an investigation of the chemical composition of the ice cover on the high-mountain lake Morskie Oko in the Tatra Mountains, Carpathians, Poland. In the years 2007–13, the ice cover was characterized by an average duration of 6 months, a thickness range of 0.40–1.14 m, and a multilayered structure with water or slush inclusion. In water from the melted ice cover, chloride (max. 69%) and sulphate (max. 51%) anions and ammonium (max. 66%) and calcium (max. 78%) cations predominated. Different concentrations of ions (F−, Cl−, NO3−, SO42−, Na+, K+, Mg2+, Ca2+, NH4+) in the upper, middle and bottom layers of ice were observed, along with long-term variability and spatial diversification within the ice layer over the lake. Snowpack lying on the ice and the water body under the ice were also investigated, and the influence on the ice cover of certain ions in elevated concentrations was observed (e.g. Cl− in the upper ice cover and the snowpack, and Ca2+ in the bottom ice cover and water body).

Comparison of field data with theories on ice cover progression in large rivers

1984 ◽  
Vol 11 (4) ◽  
pp. 798-814 ◽  
Author(s):  
Bernard Michel
Keyword(s):  
Quantitative Determination ◽  
Key Words ◽  
Field Data ◽  
Ice Cover ◽  
Large Rivers ◽  
Ice Dynamics ◽  
Physical Mechanisms ◽  
Flow Parameters ◽  
Existing Data ◽  
St Lawrence River

There are many theories pertaining to the progression of ice covers in rivers fed by frazil slush and floes but very few have been examined critically by comparing them with field data. In this paper the existing theories on dynamic ice cover progression are reviewed, an additional one is proposed, and they are classified according to the physical mechanisms that are involved. Finally, they are compared with some existing field data for large rivers. The data are extremely scarce and difficult to obtain because of the costs involved and the dangers in traveling over thin ice when the ice cover is being formed.It is usually easier to get only the critical values of parameters giving the limits of ice cover progression. In this paper, complete data were taken from the St. Lawrence River, the Beauharnois Canal, and the La Grande Rivière where the ice thicknesses along with the flow parameters have been measured.In these cases the existing data are adequate, so they could be grouped to explain the various mechanisms involved and to obtain numerical values for their quantitative determination. Key words: glaciology, river ice, ice dynamics, fluvial processes, ice hydraulics.

scholarly journals Quantitative and qualitative constraints on hind-casting the formation of multiyear lake-ice covers at Lake El'gygytgyn

2013 ◽  
Vol 9 (3) ◽  
pp. 1253-1269 ◽  
Author(s):  
M. Nolan
Keyword(s):  
Water Exchange ◽  
Sediment Cores ◽  
Ice Cover ◽  
Lake Ice ◽  
Ice Growth ◽  
Temperature Reduction ◽  
Air Temperatures ◽  
Lake El’Gygytgyn ◽  
Oxygen Conditions ◽  
Multiyear Ice

Abstract. Analysis of the 3.6 Ma, 318 m long sediment core from Lake El'gygytgyn suggests that the lake was covered by ice for millennia at a time for much of its history and therefore this paper uses a suite of existing, simple, empirical degree-day models of lake-ice growth and decay to place quantitative constraints on air temperatures needed to maintain a permanent ice cover on the lake. We also provide an overview of the modern climatological and physical processes that relate to lake-ice growth and decay as a basis for evaluating past climate and environmental conditions. Our modeling results indicate that modern annual mean air temperature would only have to be reduced by 3.3 °C ± 0.9 °C to initiate a multiyear ice cover and a temperature reduction of at least 5.5 °C ± 1.0 °C is likely needed to completely eliminate direct air–water exchange of oxygen, conditions that have been inferred at Lake El'gygytgyn from the analysis of sediment cores. Once formed, a temperature reduction of only 1–3 °C relative to modern may be all that is required to maintain multiyear ice. We also found that formation of multiyear ice covers requires that positive degree days are reduced by about half the modern mean, from about +608 to +322. A multiyear ice cover can persist even with summer temperatures sufficient for a two-month long thawing period, including a month above +4 °C. Thus, it is likely that many summer biological processes and some lake-water warming and mixing may still occur beneath multiyear ice-covers even if air–water exchange of oxygen is severely restricted.

scholarly journals Big Questions, Few Answers About What Happens Under Lake Ice

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Stephanie Hampton ◽  
Stephen Powers ◽  
Shawn Devlin ◽  
Diane McKnight
Keyword(s):  
Ice Cover ◽  
Lake Ice ◽  
Cold Temperatures

Scientists long eschewed studying lakes in winter, expecting that cold temperatures and ice cover limited activity below the surface. Recent findings to the contrary are changing limnologists’ views.

scholarly journals QUALITY CHARACTERISTICS OF SURFACE WATERS AT ASPROLAKKAS RIVER BASIN, N.E. CHALKIDIKI, GREECE

2017 ◽  
Vol 43 (4) ◽  
pp. 1737
Author(s):  
E. Kelepertzis ◽  
A. Argyraki ◽  
E. Daftsis ◽  
D. Ballas
Keyword(s):  
Surface Waters ◽  
Water Samples ◽  
Major Ions ◽  
Stream Water ◽  
Water Discharge ◽  
Sampling Period ◽  
Quality Characteristics ◽  
Sampling Point ◽  
The Past ◽  
Surface Water Samples

The present study reports on a four sampling period (April 2008-July 2008-November 2008-February 2009) study of water quality in streams of NE Chalkidiki. A total of 80 surface water samples were collected and analysed for the major ions Ca2+, Mg2+, K+, Na+, Cl- , HCO3 - , SO4 2-, NO3 - and the trace elements Pb, Fe, Cd, Cu, Cr, Ni, Zn, Mn and As. Also pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Temperature, as well as the stream water discharge at each sampling point, were determined in the field. The treatment and the subsequent evaluation of the data showed that the water samples are divided into three separate groups, reflecting the chemistry of water in the three sub-basins of the area i.e., Kokkinolakkas, Kerasia and Piavitsa. The water of the first one is possibly affected by the past mining activities of the area, whereas samples from the other two reflect the influence of sulphide mineralization on the hydrogeochemistry of the corresponding streams. No effect of the seasonal differentiation of stream water discharge was observed.

Lake ice phenology changes in the northern hemisphere

2021 ◽  
Author(s):  
Yubao Qiu ◽  
Xingxing Wang ◽  
Matti Leppäranta ◽  
Bin Cheng ◽  
Yixiao Zhang
Keyword(s):  
Remote Sensing ◽  
North America ◽  
Northern Hemisphere ◽  
Ice Cover ◽  
Passive Microwave ◽  
Lake Area ◽  
Lake Ice ◽  
Northern Tibetan Plateau ◽  
Break Up ◽  
Ice Phenology

<p>Lake-ice phenology is an essential indicator of climate change impact for different regions (Livingstone, 1997; Duguay, 2010), which helps understand the regional characters of synchrony and asynchrony. The observation of lake ice phenology includes ground observation and remote sensing inversion. Although some lakes have been observed for hundreds of years, due to the limitations of the observation station and the experience of the observers, ground observations cannot obtain the lake ice phenology of the entire lake. Remote sensing has been used for the past 40 years, in particular, has provided data covering the high mountain and high latitude regions, where the environment is harsh and ground observations are lacking. Remote sensing also provides a unified data source and monitoring standard, and the possibility of monitoring changes in lake ice in different regions and making comparisons between them. The existing remote sensing retrieval products mainly cover North America and Europe, and data for Eurasia is lacking (Crétaux et al., 2020).</p><p>Based on the passive microwave, the lake ice phenology of 522 lakes in the northern hemisphere during 1978-2020 was obtained, including Freeze-Up Start (FUS), Freeze-Up End (FUE), Break-Up Start (BUS), Break-Up End (BUE), and Ice Cover Duration (ICD). The ICD is the duration from the FUS to the BUE, which can directly reflect the ice cover condition. At latitudes north of 60°N, the average of ICD is approximately 8-9 months in North America and 5-6 months in Eurasia. Limited by the spatial resolution of the passive microwave, lake ice monitoring is mainly in Northern Europe. Therefore, the average of ICD over Eurasia is shorter, while the ICD is more than 6 months for most lakes in Russia. After 2000, the ICD has shown a shrinking trend, except northeastern North America (southeast of the Hudson Bay) and the northern Tibetan Plateau. The reasons for the extension of ice cover duration need to be analyzed with parameters, such as temperature, the lake area, and lake depth, in the two regions.</p>

Palynological evidence of sea-surface conditions in the Barents Sea off northeast Svalbard during the postglacial period

2020 ◽  
pp. 1-15
Author(s):  
Camille Brice ◽  
Anne de Vernal ◽  
Elena Ivanova ◽  
Simon van Bellen ◽  
Nicolas Van Nieuwenhove
Keyword(s):  
Sea Ice ◽  
Surface Waters ◽  
Barents Sea ◽  
Ice Cover ◽  
Atlantic Water ◽  
Transitional Period ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Conditions ◽  
The Barents Sea

Abstract Postglacial changes in sea-surface conditions, including sea-ice cover, summer temperature, salinity, and productivity were reconstructed from the analyses of dinocyst assemblages in core S2528 collected in the northwestern Barents Sea. The results show glaciomarine-type conditions until about 11,300 ± 300 cal yr BP and limited influence of Atlantic water at the surface into the Barents Sea possibly due to the proximity of the Svalbard-Barents Sea ice sheet. This was followed by a transitional period generally characterized by cold conditions with dense sea-ice cover and low-salinity pulses likely related to episodic freshwater or meltwater discharge, which lasted until 8700 ± 700 cal yr BP. The onset of “interglacial” conditions in surface waters was marked by a major change in dinocyst assemblages, from dominant heterotrophic to dominant phototrophic taxa. Until 4100 ± 150 cal yr BP, however, sea-surface conditions remained cold, while sea-surface salinity and sea-ice cover recorded large amplitude variations. By ~4000 cal yr BP optimum sea-surface temperature of up to 4°C in summer and maximum salinity of ~34 psu suggest enhanced influence of Atlantic water, and productivity reached up to 150 gC/m2/yr. After 2200 ± 1300 cal yr BP, a distinct cooling trend accompanied by sea-ice spreading characterized surface waters. Hence, during the Holocene, with exception of an interval spanning about 4000 to 2000 cal yr BP, the northern Barents Sea experienced harsh environments, relatively low productivity, and unstable conditions probably unsuitable for human settlements.

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