05 Oct 2023
 | 05 Oct 2023
Status: this preprint is open for discussion.

Phytoplankton Retention Mechanisms in Estuaries: A Case Study of the Elbe Estuary

Laurin Steidle and Ross Vennell


Due to their role as primary producers, phytoplankton are essential to the productivity of estuarine ecosystems. However, it is important to understand how these nearly passive organisms are able to persist within estuaries, when river inflow results in a net outflow to the ocean. Estuaries are also representing challenging habitats due to a strong salinity gradient. So far, little is known about how phytoplankton are able to be retained within estuaries. We present a new individual-based Lagrangian model of the Elbe estuary which examines possible retention mechanisms for phytoplankton. Specifically, we investigated how reproduction, sinking and rising, as well as diel vertical migration may allow for populations to persist within the estuary. We find that vertical migration especially rising favors the retention, fast sinking does not. We further provide first estimates on outwashing losses. Our simulations illustrate that riverbanks and tidal flats are essential for the long-term survival of phytoplankton populations, providing refuges from strong downstream currents. These results contribute to the understanding needed to advance ecosystem-based management of estuaries.

Laurin Steidle and Ross Vennell

Status: open (until 30 Nov 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2231', Anonymous Referee #1, 02 Nov 2023 reply
  • RC2: 'Comment on egusphere-2023-2231', Anonymous Referee #2, 03 Nov 2023 reply

Laurin Steidle and Ross Vennell

Laurin Steidle and Ross Vennell


Total article views: 193 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
118 63 12 193 6 6
  • HTML: 118
  • PDF: 63
  • XML: 12
  • Total: 193
  • BibTeX: 6
  • EndNote: 6
Views and downloads (calculated since 05 Oct 2023)
Cumulative views and downloads (calculated since 05 Oct 2023)

Viewed (geographical distribution)

Total article views: 188 (including HTML, PDF, and XML) Thereof 188 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 29 Nov 2023
Short summary
Phytoplankton are key in estuaries, forming the ecosystem's base. Despite being washed out by river flow and facing a large range of different salinity, they persist. Our simulation of the Elbe estuary shows growth rates and buoyancy help them retain. Riverbanks and tidal flats offer refuge from strong currents. Our findings emphasize the need for careful ecosystem management in estuaries.