Longitudinal patterns and response lengths of algae in riverine ecosystems: A model analysis emphasising...

Area of Science:

• Riverine ecology
• Aquatic primary production
• Algal dynamics

Background:

• Primary production in rivers occurs in benthic (sessile algae) and pelagic (planktonic algae) habitats.
• The relative importance of these habitats shifts along river gradients.
• Interactions between benthic and planktonic algae and their controlling factors are understudied.

Purpose of the Study:

• To analyze the interaction between benthic and planktonic algae in riverine ecosystems.
• To investigate the impact of river depth on these algal dynamics.
• To model nutrient and algal interactions across various river scales.

Main Methods:

• Utilized a simplified advection-diffusion model with ecological process kinetics.
• Focused on the influence of river depth on algal interactions.
• Analyzed spatial equilibria using an ordinary differential equation (ODE) model variant.

Main Results:

• River depth dictates algal habitat reliance: shallow rivers need detaching benthic algae for phytoplankton, while deep rivers require sinking plankton for benthic algae.
• Spatial equilibria are reached independently of upstream boundary conditions.
• Shallow river systems demonstrate significantly faster recovery from disturbances compared to deep systems.

Conclusions:

• River depth is a key factor structuring primary production in riverine ecosystems.
• Algal communities exhibit depth-dependent dependencies, with distinct subsidies between benthic and planktonic forms.
• Shallow rivers possess greater resilience and faster recovery rates from disturbances.