7 research outputs found
Modeling impact of blue mussel mitigation farms in coastal ecosystems. Skive Fjord, Denmark, an example
Mussels are an important component of many coastal ecosystems and estuaries and mussel beds can mediate the benthic-pelagic coupling via among others filter-feeding activities. In recent years, mussel aquaculture productions for human consumption have been increasing in Denmark. In addition, it has been proposed that mussel aquacultures can serve as a tool to mitigate eutrophication effects by removing nutrients from the system through mussel harvesting. To evaluate the effects of blue mussel mitigation cultures on the water quality in Skive Fjord and neighboring water bodies, an individual-level mechanistic model for blue mussel growth was scaled to farm-level and implemented in a coupled hydrodynamic-biogeochemical coastal model setup for the estuary Limfjord. This presentation provides model results on the effects of blue mussel mitigation cultures on water quality and the light environment, both at a farm and basin scale. The validity and certainty of the model results are discussed and compared to previous model and observational studies, with a focus on their relevance for management and policy analysis
WET: Water Ecosystems Tool
<p>WET is being released in its second stable version – v2.0</p>
<p>The release follows the submission of the paper by Schnedler-Meyer and Andersen fish optimal foraging behavior.</p>
<p>WET v2.0 builds upon previous versions with the largest development being the implementation of the fish optimal foraging behavior and optimal diet breadth (documented in detail in Schnedler-Meyer and Andersen (submitted)). A test case specific for exploring the optimal foraging behavior has been included. Previous fish module (from FABM-PCLake and WET v1.0) remains as a module option as fish_pclake.F90. Additional development includes inclusion of potential oxygen stress in zoobenthos and fixed bug in burial functions.</p>
<p>For this and newer versions of the source code see also <a href="https://gitlab.com/wateritech-public/waterecosystemstool/wet">https://gitlab.com/wateritech-public/waterecosystemstool/wet</a></p>
Modeling the Ecological Response of a Temporarily Summer-Stratified Lake to Extreme Heatwaves
Climate extremes, which are steadily increasing in frequency, can have detrimental consequences for lake ecosystems. We used a state-of-the-art, one-dimensional, hydrodynamic-ecosystem model [General Ocean Turbulence Model (GOTM)-framework for aquatic biogeochemical models (FABM)-PCLake] to determine the influence of extreme climate events on a temperate and temporarily summer stratified lake (Lake Bryrup, Denmark). The model was calibrated (eight years data) and validated (two years data), and the modeled variables generally showed good agreement with observations. Then, a span of extreme warming scenarios was designed based on weather data from the heatwave seen over northern Europe in May-July 2018, mimicking situations of extreme warming returning every year, every three years, and every five years in summer and all year round, respectively. We found only modest impacts of the extreme climate events on nutrient levels, which in some scenarios decreased slightly when looking at the annual mean. The most significant impacts were found for phytoplankton, where summer average chlorophyll a concentrations and cyanobacteria biomass peaks were up to 39% and 58% higher than during baseline, respectively. As a result, the phytoplankton to nutrient ratios increased during the heat wave experiments, reflecting an increased productivity and an increased cycling of nutrients in the pelagic. The phytoplankton blooms occurred up to 15 days earlier and lasted for up to half a month longer during heat wave years relative to the baseline. Our extreme scenarios illustrated and quantified the large impacts of a past heat wave (observed 2018) and may be indicative of the future for many temperate lakes