Making realistic wave climates in low‐cost wave mesocosms: A new tool for experimental ecology and biogeomorphology

Abstract

Wave flume facilities that are primarily designed for engineering studies are often complex and expensive to operate, and hence not ideal for long-term replicated experiments as commonly used in biology. This study describes a low-cost small wave flume that can be used for biological purposes using fresh-or seawater with or without sediment. The wave flume can be used as a mesocosm to study interactions between wave hydrodynamics and benthic organisms in aquatic ecosystems. The low-costs wave maker (< 2000 USD) allows for experimental setups which can be easily replicated and used for longer term studies; hence the term wave mesocosm. Waves were generated with a pneumatic piston and wave heights ranged between 3 and 6 cm. Maximum orbital flow velocities ranged between 10 and 50 cm s −1 representing shallow coastal areas with a short fetch. The system can generate both regular waves (i.e., the wave period and orbital velocity remains constant), using a wave absorber, and irregular waves (i.e., varying wave period and orbital velocity) using a fast push and slow pull motion of the wave paddle. This wave mesocosm system is particularly useful in biogeomorphology to quantify interactions between organisms, sediment, and hydrodynamics and for aquatic ecologist aiming to simulate realistic bed shear stress where short-and long-term experiments (weeks-months) can be replicated.

Coastal ecosystem engineers and their impact on sediment dynamics: Eelgrass–bivalve interactions under wave exposure

“…We used four identical hydraulic wave mesocosms of 3 m length, 0.5 m width, and 0.8 m height (for detailed description, see Infantes et al 2021). Waves were generated with a moving paddle driven by a pneumatic piston.…”

“…Each of the wave tanks was calibrated to a set wave regime (approximate mean orbital velocities U rms ½ = 10, 15, 20, and 25 cm s À1 with a constant wave period [T p ] of $ 3.6 s), simulating a hydrodynamic gradient with maximum bottom shear velocities (U Ã ) between 1 and 3 cm s À1 . These shear velocities represent moderate to severe storm events in Baltic Sea shallow coastal areas with short fetch (Jönsson et al 2005;Infantes et al 2021). Individual treatments were replicated three times, resulting in 48 trials in total.…”

Identifying trait‐based tolerance to sediment dynamics during seedling establishment across eight mangrove species

“…We measured two types: toppling and dislodgement, as these might have different consequences for a seedling's survival (e.g., if a seedling is toppled its roots still have access to nutrients in the soil and may re‐erect). Critical erosion depth (CED) was measured as follows: first, we subjected each seedling to a wave treatment by placing it in a flume with a water depth of 15 cm and generating waves with a wave height of 7–8 cm for approximately 1 min or 7 waves, such that the maximum wave orbital velocity was 0.26 m s −1 and the bed shear stress 0.26 Pa (Infantes et al 2021; Supplementary Information 1.2). If the seedling did not topple, we removed a 0.5‐cm layer of sediment and subjected the seedling to another wave treatment, until a seedling was toppled, upon which the erosion depth CED topple was noted.…”

Assessing Tolerance to the Hydrodynamic Exposure of Posidonia oceanica Seedlings Anchored to Rocky Substrates

“…The wave flume was 3.5 m long, 0.6 m wide, and 0.8 m deep, with PVC modules placed in the bottom with a 35 × 35 cm box for holding the tiles with the seedlings anchored on them. The flume was driven by a pneumatic pedal that generated waves by adjusting the piston stroke and speed (see flume details in Infantes et al, 2021). A wave absorber made of synthetic fibers with a slope of 20 • was placed at the end of the flume to reduce wave reflections.…”