Causes of Daphnia midsummer decline in two deep meromictic subalpine lakes

2019 ◽  
Vol 65 (4) ◽  
pp. 731-744
Author(s):  
Martina Patelli ◽  
Barbara Leoni ◽  
Fabio Lepori
Keyword(s):  
Subalpine Lakes ◽  
Midsummer Decline

scholarly journals Detecting Climate Driven Changes in Chlorophyll-a in Deep Subalpine Lakes Using Long Term Satellite Data

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 866
Author(s):  
Gary Free ◽  
Mariano Bresciani ◽  
Monica Pinardi ◽  
Nicola Ghirardi ◽  
Giulia Luciani ◽  
...  
Keyword(s):  
Climate Change ◽  
Chlorophyll A ◽  
Nutrient Dynamics ◽  
Cascading Effects ◽  
The North ◽  
Subalpine Lakes ◽  
Winter Temperatures ◽  
Decadal Climate ◽  
The North Atlantic Oscillation ◽  
Traditional Pattern

Climate change has increased the temperature and altered the mixing regime of high-value lakes in the subalpine region of Northern Italy. Remote sensing of chlorophyll-a can help provide a time series to allow an assessment of the ecological implications of this. Non-parametric multiplicative regression (NPMR) was used to visualize and understand the changes that have occurred between 2003–2018 in Lakes Garda, Como, Iseo, and Maggiore. In all four deep subalpine lakes, there has been a disruption from a traditional pattern of a significant spring chlorophyll-a peak followed by a clear water phase and summer/autumn peaks. This was replaced after 2010–2012, with lower spring peaks and a tendency for annual maxima to occur in summer. There was a tendency for this switch to be interspersed by a two-year period of low chlorophyll-a. Variables that were significant in NPMR included time, air temperature, total phosphorus, winter temperature, and winter values for the North Atlantic Oscillation. The change from spring to summer chlorophyll-a maxima, relatively sudden in an ecological context, could be interpreted as a regime shift. The cause was probably cascading effects from increased winter temperatures, reduced winter mixing, and altered nutrient dynamics. Future trends will depend on climate change and inter-decadal climate drivers.

Geochemical Trends in Sediments From 13 Italian Subalpine Lakes

1986 ◽  
pp. 157-165 ◽  
Author(s):  
G. Premazzi ◽  
A. Provini ◽  
G. F. Gaggino ◽  
G. Parise
Keyword(s):  
Subalpine Lakes

Midge-inferred Holocene climate history of two subalpine lakes in southern British Columbia, Canada

The Holocene ◽  
2004 ◽  
Vol 14 (2) ◽  
pp. 258-271 ◽  
Author(s):  
Sandra M. Rosenberg ◽  
Ian R. Walker ◽  
Rolf W. Mathewes ◽  
Douglas J. Hallett
Keyword(s):  
British Columbia ◽  
Holocene Climate ◽  
Climate History ◽  
Subalpine Lakes ◽  
History Of

scholarly journals Measurements and significance of bio-optical parameters for remote sensing in two subalpine lakes of different trophic state

1994 ◽  
Vol 56 (3) ◽  
pp. 263-303 ◽  
Author(s):  
J. M. Jaquet ◽  
F. Schanz ◽  
P. Bossard ◽  
K. Hanselmann ◽  
F. Gendre
Keyword(s):  
Remote Sensing ◽  
Trophic State ◽  
Optical Parameters ◽  
Subalpine Lakes

scholarly journals Organic Contaminants in Zooplankton of Italian Subalpine Lakes: Patterns of Distribution and Seasonal Variations

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1901 ◽  
Author(s):  
Simona Pascariello ◽  
Michela Mazzoni ◽  
Roberta Bettinetti ◽  
Marina Manca ◽  
Martina Patelli ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Principal Component ◽  
Trophic Levels ◽  
Mean Values ◽  
Lake Maggiore ◽  
Subalpine Lakes ◽  
Main Driver ◽  
Trophic Webs ◽  
Persistent Organic Contaminants ◽  
Composition Pattern

Zooplankton is a key node in many trophic webs, both for food that for persistent organic contaminants that can accumulate in biota. Zooplankton of different size was seasonally sampled for two years in three deep Italian subalpine lakes (Maggiore, Como, Iseo) with the aim of determining the concentrations of perfluoroalkyl substances (PFAS), DDT, and PCB, and assessing the seasonality impacts on contaminants concentrations. In general, Lake Maggiore showed the highest concentrations for each group of contaminants, with mean values of 7.6 ng g−1 ww for PFAS, 65.0 ng g−1 dw for DDT, and 65.5 ng g−1 dw for PCB. When considering the composition pattern, perfluorooctane sulfonate (PFOS) was detected in 96% of the samples and it was the predominant PFAS compound in all of the lakes. pp’ DDE was the most detected congener among DDTs and their metabolites, while for PCBs, the prevalent group was hexa-CB that constituted 35.4% of the total PCB contamination. A seasonal trend was highlighted for all contaminant groups with concentrations in colder months greater than in spring and summer; it was evident that the contaminant concentrations were more dependent from seasonality than from size, trophic levels, and taxa composition of zooplankton. Principal component analysis showed that one of the main driver for the accumulation of most of the studied contaminants is their lipophilicity, except for perfluorooctanoic acid (PFOA) and octachlorobiphenyl.

Phytoplankton assemblage at equilibrium in large and deep subalpine lakes: a case study from Lago Maggiore (N. Italy)

Hydrobiologia ◽  
2003 ◽  
Vol 502 (1-3) ◽  
pp. 37-48 ◽  
Author(s):  
Giuseppe Morabito ◽  
Alessandro Oggioni ◽  
Pierisa Panzani
Keyword(s):  
Phytoplankton Assemblage ◽  
Subalpine Lakes

Dynamics of Unexploited and Lightly Exploited Populations of Rainbow Trout (Salmo gairdneri) from Coastal, Montane, and Subalpine Lakes in Western Canada

1986 ◽  
Vol 43 (9) ◽  
pp. 1733-1741 ◽  
Author(s):  
D. B. Donald ◽  
D. J. Alger
Keyword(s):  
Rainbow Trout ◽  
Age Structure ◽  
Growth Patterns ◽  
Summer Temperature ◽  
Salmo Gairdneri ◽  
Maximum Longevity ◽  
Subalpine Lake ◽  
Subalpine Lakes ◽  
Class Strength ◽  
Annual Mortality

Populations of rainbow trout (Salmo gairdneri) in one coastal and two montane lakes were characterized by a relatively stable age structure, approximately 50% annual mortality, maximum longevity of 7 yr, and close to linear growth beginning at age 1 or age 2. In contrast, populations in subalpine lakes were characterized by an unstable age structure, large annual variation in recruitment, maximum longevity of 13 yr or more, and growth patterns that were either asymptotic, complex, or linear. Age structure and thus year-class strength was directly related to cumulative summer temperature in one subalpine lake (r = 0.71, N = 11), and in others, strong year-classes were often associated with warm summers. These analyses indicate that the magnitude of recruitment in subalpine lakes was either primarily or at least partly due to annual differences in summer temperature. Longevity was inversely related to midsummer water temperature.

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