Lake Superior moored temperature and currents, Sep 2005-May 2015

Austin, Jay A.; Elmer, Cassandra

doi:10.13020/zqw9-mk81

Cited by 2 publications

(2 citation statements)

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“…Dreissena in water samples had a consistent gradient from the SLRE to APIS in weeks 1 and 3, but no such gradient in week 5, presumably connected to these changes in currents. Although the general trend of Lake Superior currents is from the west to the east direction along the south shore, there is natural variability due to water temperature, air temperature, and wind patterns ( Sun et al, 2020 ; Austin and Elmer, 2021 ). This variability is expected to increase due to climate change ( Lam and Schertzer, 1999 ).…”

Section: Discussionmentioning

confidence: 99%

Invasive Dreissena Mussel Coastal Transport From an Already Invaded Estuary to a Nearby Archipelago Detected in DNA and Zooplankton Surveys

et al. 2022

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Coastal waters of Lake Superior are generally inhospitable to the establishment of invasive Dreissena spp. mussels (both Dreissena polymorpha and Dreissena bugensis). Dreissena have inhabited the Saint Louis River estuary (SLRE; largest commercial port in the Laurentian Great Lakes) for over three decades, but only in the last few years have small colonies been found in the Apostle Islands National Lakeshore (APIS, an archipelago situated 85 km to the east of SLRE) A 2017 survey determined a low abundance Dreissena spatial distribution in APIS, with the largest colonies on the north and west islands which suggested potential veliger transport from the SLRE via longshore currents. Our objective in this study was to determine if Dreissena veligers are transported by currents at low densities along the south shore of Lake Superior from the SLRE to APIS. To do so, we used both eDNA (water and passive substrate samples) and zooplankton collection methods at eight sites evenly spaced between the SLRE and APIS with three sampling times over five weeks. Dreissena veligers were consistently detected along the south shore, although at low abundances (veligers per m3 range = 0–690, median = 8), and for every 1 km increase in distance from the SLRE, both veliger counts and water eDNA copy numbers decreased on average by 5 and 7%, respectively. D. polymorpha (suited to estuary habitats) was detected two times more than D. bugensis (better suited to deep-lake habitats). There was not a trend in the veliger size distribution along the south shore, and temperature and calcium concentrations fluctuated around the threshold for Dreissena veliger and adult development, averaging 11.0°C and 14.8 ppm, respectively. Three zooplankton taxa representative of the estuary community–Daphnia retrocurva, Diaphanosoma birgei, and Mesocyclops copepodites–decreased as the distance from the SLRE increased mirroring Dreissena veliger abundance patterns. Findings represent multiple sources of evidence of a propagule “conveyor belt” for Dreissena along the south shore of Lake Superior. We conclude that veligers are functioning as a propagule, using coastal currents to spread from the point of invasion, thereby traversing coastal habitat previously reported as inhospitable to distant habitats suitable for colonization.

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Section: Discussionmentioning

confidence: 99%

Invasive Dreissena Mussel Coastal Transport From an Already Invaded Estuary to a Nearby Archipelago Detected in DNA and Zooplankton Surveys

et al. 2022

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“…The region chosen is near the long-term NDBC buoy site 45006 (Fig. 1a,b), where the University of Minnesota Duluth's Large Lakes Observatory has occupied the site with subsurface moorings since 2005 (Austin and Elmer 2021), providing long-term thermal context for the region. The water depth was approximately 180 m, and the bathymetry relatively featureless.…”

Section: Methodsmentioning

confidence: 99%

Characterizing temporal and spatial scales of radiatively driven convection in a deep, ice‐free lake

Austin

Hill

Fredrickson

et al. 2022

Limnology & Oceanography

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From May to July 2019, an array of moored equipment was deployed in Lake Superior to characterize the spatial and temporal scales of radiatively driven convection (RDC). Previous work suggested that convective plumes have horizontal scales on the order of tens of meters, posing a significant observational challenge. The centerpiece of the deployment was a large, two‐dimensional (2D) array of thermistors that provided resolution on the order of 10 meters in both the vertical and a single horizontal dimension. This was augmented by an acoustic Doppler current meter mooring and a meteorology buoy capable of estimating surface heat and momentum fluxes. Instantaneous temperature variability at a given location is dominated by a lateral background flow advecting strong horizontal temperature gradients. By combining velocity data with temperature data, this fact can be used to examine horizontal structure at centimeter scales, and can produce 2D images of instantaneous temperature distribution on a horizontal surface, revealing multiple patterns of temperature anomaly distribution. The walls of convective structures are very sharp, with horizontal gradients on the order of 1°C m−1; horizontal scales of convective structures themselves are on the order of many tens of meters. Finally, convection is shown to strongly control the vertical distribution of water quality parameters.

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Lake Superior moored temperature and currents, Sep 2005-May 2015

Cited by 2 publications

References 0 publications

Invasive Dreissena Mussel Coastal Transport From an Already Invaded Estuary to a Nearby Archipelago Detected in DNA and Zooplankton Surveys

Invasive Dreissena Mussel Coastal Transport From an Already Invaded Estuary to a Nearby Archipelago Detected in DNA and Zooplankton Surveys

Characterizing temporal and spatial scales of radiatively driven convection in a deep, ice‐free lake

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