Limnological Review

232 KiB

Open AccessArticle

Fifty Years of Limnology (1969–2019) at Mahoney Lake, British Columbia, Canada

by Markus L. Heinrichs, Ian R. Walker, Ken J. Hall, Jörg Overmann and Molly D. O’Beirne

Limnol. Rev. 2020, 20(4), 219-227; https://doi.org/10.2478/limre-2020-0021 - 31 Dec 2020

Cited by 2 | Viewed by 412

Mahoney Lake is a small, meromictic saline lake in south-central British Columbia noted for its unique layer of purple sulfur bacteria. First examined in 1969, this lake has undergone physical, chemical, biological, and pre-historical research to generate an understanding of how the lake and its biota function have developed through time. Advances in understanding the sulfur transformations and bacterial nutrient cycling over the last fifty years have been prolific, resulting in the description of several new taxa. Mahoney Lake is exceptional in its limnological characteristics and is an ideal site for training future limnologists. Full article

2079 KiB

Open AccessArticle

Evolution of Primary Production and Its Drivers on the Lebanese Coast between 1986 and 2013

by Ali Fadel, Lama Salameh, Malak Kanj and Ahmad Kobaissi

Limnol. Rev. 2020, 20(4), 207-217; https://doi.org/10.2478/limre-2020-0020 - 31 Dec 2020

Viewed by 490

Abstract

Physical-biogeochemical models help us to understand the dynamics and the controlling factors of primary production. In this study, the outputs of a validated hydrodynamic and biogeochemical model were used to elucidate the primary production dynamics between 1992 and 2012 for three studied sites on the Lebanese coast: Naqoura, Beirut, and Tripoli. The results showed that primary production presents a homogeneous spatial distribution along the Lebanese coastline. The phytoplankton community has a low optimal temperature. The thermocline develops in March, with maximum stratification in August and fades in October. Chlorophyll, dissolved oxygen and salinity were positively correlated throughout the water column. A significant increasing trend of sea surface temperature was found on the Lebanese coast over 27 years, between 1986 and 2013. Annual averages increased from 22 °C in 1986 to 23.1 °C in 2013 with the highest recorded average temperature of 23.7 °C in 2010. Full article

1264 KiB

Open AccessArticle

Formulas for Calculating Ice Cover Thickness on Selected Spring Lakes on the Upper Radunia (Kashubian Lakeland, Northern Poland)

by Katarzyna Barańczu and Jacek Barańczuk

Limnol. Rev. 2020, 20(4), 199-205; https://doi.org/10.2478/limre-2020-0019 - 31 Dec 2020

Cited by 2 | Viewed by 406

Abstract

This publication is to confirm the existence of a correlation between lakes under hydrometric supervision and unmonitored lakes using formulas for calculating thickness of ice cover observed on lakes located within the same physico-geographical unit. The article presented herein covers lakes located on the upper Radunia River in the central part of the Kashubian Lakeland. Lake Raduńskie Górne has been under constant hydrometric supervision of the Limnological Station of Gdańsk University for over 60 years. The study covers three spring lakes: Stężyckie, Bukrzyno Małe and Lubowisko. The cover thickness was measured during the period of 2003–2006 and in 2016. Analysing the measurement data gathered during field research and the data obtained from the station allowed formulas for calculating ice cover thickness to be established. The formulas were tested in 2016 with the use of the fieldwork data. The result confirmed that the formulas can be used to calculate thickness of ice cover with considerable accuracy. Full article

1292 KiB

Open AccessArticle

Importance of Environmental Flows in the Wimmera Catchment, Southeast Australia

by Ehsan Atazadeh, Andrew Barton and Jafar Razeghi

Limnol. Rev. 2020, 20(4), 185-198; https://doi.org/10.2478/limre-2020-0018 - 31 Dec 2020

Cited by 1 | Viewed by 707

Abstract

In this paper the environment, climate, vegetation, indigenous and European settlement history, stream flow patterns, water quality and water resources development in western Victoria, Australia are studied. The last part of the paper focuses on the MacKenzie River, a tributary of the Wimmera River located on the northern slopes of the Grampians Ranges in western Victoria, Australia. Water release along the MacKenzie River was regulated to improve water quality, stream condition and river health especially in the downstream reaches. The upstream section tends to receive water most days of the year due to releases to secure the requirements of water supply for the city of Horsham and its recreational and conservation values, which is diverted into Mt Zero Channel. Below this the middle and downstream sections receive a more intermittent supply. Annually, a total of 10,000 dam³ of water is released from Wartook Reservoir into the MacKenzie River. Of this volume, only about 4000 dam³ was released explicitly for environmental purposes. The remaining 6000 dam³ was released to meet consumptive demands and to transfer water to downstream reservoirs. The empirical data and models showed the lower reaches of the river to be in poor condition under low flows, but this condition improved under flows of 35 dam³ per day, as indicated. The results are presented to tailor discharge and duration of the river flows by amalgamation of consumptive and environmental flows to improve the condition of the stream, thereby supplementing the flows dedicated to environmental outcomes. Ultimately the findings can be used by management to configure consumptive flows that would enhance the ecological condition of the MacKenzie River. Full article

662 KiB

Open AccessArticle

Alternative Prey Influence the Predation of Mosquito Larvae by Three Water Bug Species (Heteroptera: Nepidae)

by Nabaneeta Saha, Malini Kundu, Goutam K. Saha and Gautam Aditya

Limnol. Rev. 2020, 20(4), 173-184; https://doi.org/10.2478/limre-2020-0017 - 31 Dec 2020

Cited by 5 | Viewed by 532

Abstract

The indirect interactions among multiple prey sharing a common predator characterize apparent competition. In conservation biological control involving mosquitoes and controphic prey against generalist insect predators, apparent competition may be a crucial factor determining the extent of success. The possible influence of apparent competition on mosquito prey consumption by three water bugs (Heteroptera: Nepidae): Ranatra elongata, Ranatra filiformis, and Laccotrephes griseus was assessed under laboratory conditions. Tadpoles (Duttaphrynus melanostictus), chironomid larvae, snails (Racesina luteola) and fish fingerlings (Labeo rohita) were considered as alternative prey under two prey or multi prey conditions against instar IV larvae of Culex quinquefasciatus as target prey. Under two prey conditions all the predators exhibited a preference (significant Manly’s α) for mosquito larvae, against fish fingerlings by R. filiformis. In the presence of multiple prey, mosquito larvae were selected by the predators. Using the ratio of mosquito selectivity in two prey and multi-prey conditions as a measure of apparent competition, chironomid larvae had greatest effect in suppressing mosquito selectivity for R. elongata, and fish fingerlings for R. filiformis and L. griseus. It seems that the prey preference of R. elongata, R. filiformis and L. griseus may differentially evoke apparent competition among the prey. In the aquatic community where these predators and prey coexist, mosquito larvae may benefit from apparent competition that reduces their vulnerability to predators. The identity of the alternative prey appears to be an important factor for shielding the vulnerability of mosquito prey to the generalist insect predators. Full article

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Limnol. Rev., Volume 20, Issue 4 (December 2020) – 5 articles , Pages 173-227

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