Winter dynamics in mountain lakes and impacts of an introduced species to the endangered Devils Hole pupfish
type: CreativeWork
description: Having intrinsic knowledge of our aquatic ecosystems lets us predict how they will respond to change and allows us to make better management decisions. Changes in climate and introduced species are two major threats to aquatic ecosystems. This research explores inherent characteristics of two aquatic ecosystems facing different threats; mountains lakes facing the threat of climate change and an endangered pupfish species in a limnocrene spring, facing the threat of a new colonizing species. Climate change is causing ice-periods on lakes to shorten globally and elevation-dependent warming means mountain lakes may be at a higher risk of warming and ice loss. Winter, under-ice studies of mountain lakes are limited and in order to understand the potential impacts of shorter ice periods, we must first understand the differences in basic ecological attributes of ice-cover and ice-free seasons in mountain lakes. Chapter 1 analyzed primary productivity rate, phytoplankton biovolume and composition, zooplankton biomass and composition, nutrient concentrations, and hypolimnetic dissolved oxygen of 10 global mountain lakes in ice-covered (winter) and ice-free (summer) seasons. Productivity was 44% lower in winter compared to summer but varied in magnitude by lake. Winter phytoplankton biovolume and zooplankton abundance were 35% (p=0.01) and 25% (p= 0.01) of the summer values, respectively. Phytoplankton and zooplankton compositions were not significantly different between seasons at the class level of taxonomic analysis. Total dissolved nitrogen was 78% higher in winter compared to summer (p= 0.001) indicating nitrogen build-up during the winter months. Hypolimnetic dissolved oxygen concentrations were variable across lakes, indicating that lake thermal stratification may play a role in governing concentrations. This study shows winter is not the dormant season of which it has been historically characterized and incites the need for additional winter limnological sampling to …
abstract: Having intrinsic knowledge of our aquatic ecosystems lets us predict how they will respond to change and allows us to make better management decisions. Changes in climate and introduced species are two major threats to aquatic ecosystems. This research explores inherent characteristics of two aquatic ecosystems facing different threats; mountains lakes facing the threat of climate change and an endangered pupfish species in a limnocrene spring, facing the threat of a new colonizing species. Climate change is causing ice-periods on lakes to shorten globally and elevation-dependent warming means mountain lakes may be at a higher risk of warming and ice loss. Winter, under-ice studies of mountain lakes are limited and in order to understand the potential impacts of shorter ice periods, we must first understand the differences in basic ecological attributes of ice-cover and ice-free seasons in mountain lakes. Chapter 1 analyzed primary productivity rate, phytoplankton biovolume and composition, zooplankton biomass and composition, nutrient concentrations, and hypolimnetic dissolved oxygen of 10 global mountain lakes in ice-covered (winter) and ice-free (summer) seasons. Productivity was 44% lower in winter compared to summer but varied in magnitude by lake. Winter phytoplankton biovolume and zooplankton abundance were 35% (p=0.01) and 25% (p= 0.01) of the summer values, respectively. Phytoplankton and zooplankton compositions were not significantly different between seasons at the class level of taxonomic analysis. Total dissolved nitrogen was 78% higher in winter compared to summer (p= 0.001) indicating nitrogen build-up during the winter months. Hypolimnetic dissolved oxygen concentrations were variable across lakes, indicating that lake thermal stratification may play a role in governing concentrations. This study shows winter is not the dormant season of which it has been historically characterized and incites the need for additional winter limnological sampling to …
author: Feher, Karly
keywords: Devils Hole, ice-cover, mountain lake, neoclypeodytes cinctellus, pupfish, winter
date published: 2019
date modified: 2026-07-27T21:46:19Z
provider: University of Nevada - Reno
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Nevada - Reno

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11714/6038