skip to main content

Attention:

The NSF Public Access Repository (NSF-PAR) system and access will be unavailable from 11:00 PM ET on Friday, April 12 until 2:00 AM ET on Saturday, April 13 due to maintenance. We apologize for the inconvenience.


Title: Reduced snow and increased nutrients show enhanced ice‐associated photoautotrophic growth using a modified experimental under‐ice design
Abstract

Under‐ice photoautotrophs in lakes are generally considered to be limited by light rather than nutrients. Despite reduced light intensity under the ice, there is increasing evidence that suggests some lakes support high levels of photoautotrophs. We explored how snow cover (i.e., light) and nutrients (i.e., nitrogen and phosphorus) influence ice‐associated photoautotroph growth in a Minnesota, USA lake. Using a novel under‐ice approach, we deployed nutrient diffusing substrates (single or combined nutrient amendments) under two different light scenarios (snow covered, reduced light; snow removed, increased light) near the water‐ice interface to mimic a range of conditions ice‐associated photoautotrophs may be exposed to. Natural snow cover reduced light compared with snow removal, particularly early in the experiment before snow began to melt. When comparing photoautotroph chlorophylla(Chla) between snow treatments, we found a significant snow effect with higher concentrations in the snow removed treatment. We also found a significant nutrient effect, for all nutrient treatments, on Chlaconcentrations in both snow conditions. The effect of any nutrient treatment on Chlaconcentrations was similar. Our results suggest that ice‐associated photoautotrophs were able to grow in all snow conditions, but snow removal resulted in higher growth and nutrient availability also mediated responses. Thus, both light and nutrient conditions in the winter may strongly affect ice‐associated photoautotroph dynamics.

 
more » « less
NSF-PAR ID:
10476052
Author(s) / Creator(s):
 ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Limnology and Oceanography
Volume:
69
Issue:
1
ISSN:
0024-3590
Format(s):
Medium: X Size: p. 203-216
Size(s):
["p. 203-216"]
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    At broad spatial scales, primary productivity in lakes is known to increase in concert with nutrients, and variables that may disrupt or modify the tight coupling of nutrients and algae are of increasing interest, particularly for those shifting with climate change. Storms may disrupt algae–nutrient relationships, but the expected effects differ between winter and summer seasons, particularly for seasonally ice‐covered lakes. In winter, storms can dramatically change the under‐ice light environment, creating light limitation that disrupts algae–nutrient relationships. Further, storms can bring both snow that blocks light and also wind that blows snow off of ice. In open water conditions, storms may promote turbulence and external nutrient loading. Here, we test the hypotheses that winter and summer storms differentially affect algae–nutrient relationships across 84 seasonally ice‐covered lakes included in the Ecology Under Lake Ice dataset. While nutrients explained most of the variation in chlorophyll across these lakes, we found that secondary drivers differed between seasons. Under‐ice chlorophyll was higher under a variety of precipitation and wind conditions that tend to promote snow‐free clear ice, highlighting the importance of light as a limiting factor for algal growth during winter. In summer, higher water temperatures and storms corresponded with higher chlorophyll. Our study suggests that examining ice‐covered lakes in a gradient from the perennial ice cover of the poles to the intermittent ice cover of lower latitudes would yield key information on the shifts in light and nutrient limitation that control algal biomass.

     
    more » « less
  2. Although it is a historically understudied season, winter is now recognized as a time of biological activity and relevant to the annual cycle of north-temperate lakes. Emerging research points to a future of reduced ice cover duration and changing snow conditions that will impact aquatic ecosystems. The aim of the study was to explore how altered snow and ice conditions, and subsequent changes to under-ice light environment, might impact ecosystem dynamics in a north, temperate bog lake in northern Wisconsin, USA. This dataset resulted from a snow removal experiment that spanned the periods of ice cover on South Sparkling Bog during the winters of 2019, 2020, and 2021. During the winters 2020 and 2021, snow was removed from the surface of South Sparkling Bog using an ARGO ATV with a snow plow attached. The 2019 season served as a reference year, and snow was not removed from the lake. This dataset represents the snow depths, black and white ice thickness, and Secchi depths during the period of ice cover each winter. 
    more » « less
  3. Although it is a historically understudied season, winter is now recognized as a time of biological activity and relevant to the annual cycle of north-temperate lakes. Emerging research points to a future of reduced ice cover duration and changing snow conditions that will impact aquatic ecosystems. The aim of the study was to explore how altered snow and ice conditions, and subsequent changes to under-ice light environment, might impact ecosystem dynamics in a north, temperate bog lake in northern Wisconsin, USA. This dataset resulted from a snow removal experiment that spanned the periods of ice cover on South Sparkling Bog during the winters of 2019, 2020, and 2021. During the winters 2020 and 2021, snow was removed from the surface of South Sparkling Bog using an ARGO ATV with a snow plow attached. The 2019 season served as a reference year, and snow was not removed from the lake. This dataset represents under ice zooplankton community samples (integrated tows at depths of 7 m) and some shoulder-season (open water) zooplankton community samples. Zooplankton samples were preserved in 90% ethanol and later processed to determine taxonomic classification at the species-level, density (individuals / L), and average length (mm). 
    more » « less
  4. Although it is a historically understudied season, winter is now recognized as a time of biological activity and relevant to the annual cycle of north-temperate lakes. Emerging research points to a future of reduced ice cover duration and changing snow conditions that will impact aquatic ecosystems. The aim of the study was to explore how altered snow and ice conditions, and subsequent changes to under-ice light environment, might impact ecosystem dynamics in a north, temperate bog lake in northern Wisconsin, USA. This dataset resulted from a snow removal experiment that spanned the periods of ice cover on South Sparkling Bog during the winters of 2019, 2020, and 2021. During the winters 2020 and 2021, snow was removed from the surface of South Sparkling Bog using an ARGO ATV with a snow plow attached. The 2019 season served as a reference year, and snow was not removed from the lake. This dataset represents under ice zooplankton community samples (integrated tows at depths of 7 m) and some shoulder-season (open water) zooplankton community samples. Zooplankton samples were preserved in 90% ethanol and later processed to determine taxonomic classification at the species-level, density (individuals / L), and average length (mm). 
    more » « less
  5. Although it is a historically understudied season, winter is now recognized as a time of biological activity and relevant to the annual cycle of north-temperate lakes. Emerging research points to a future of reduced ice cover duration and changing snow conditions that will impact aquatic ecosystems. The aim of the study was to explore how altered snow and ice conditions, and subsequent changes to under-ice light environment, might impact ecosystem dynamics in a north, temperate bog lake in northern Wisconsin, USA. This dataset resulted from a snow removal experiment that spanned the periods of ice cover on South Sparkling Bog during the winters of 2019, 2020, and 2021. During the winters 2020 and 2021, snow was removed from the surface of South Sparkling Bog using an ARGO ATV with a snow plow attached. The 2019 season served as a reference year, and snow was not removed from the lake. This dataset represents phytoplankton community samples (pooled epilimnion and hypolimnion samples representative of 7 m water column) both under-ice and during some shoulder-season (open water) dates. Samples were collected into amber bottles and preserved with Lugol's solution before they were sent to Phycotech Inc. (St. Joseph MI, USA) for phytoplankton taxonomic identification and quantification. 
    more » « less