KOB (Kiel-Outdoor-Benthocosms)

The long-term effect of warming on benthic communities (performances, interaction shifts, selection, bioinvasion, parasitism).

Project lead: Martin Wahl. 01 April – 31 July 2021.

The BENTHOCOSMS are open for user approved for AQUACOSM Transnational Access to participate in running experiment from April through July 2021.

KOB project in 2021:

Rationale: The fate of native Baltic communities in response to global change is determined by the shifts in specific performance of interacting species. Existing interaction webs may be modified by the arrival or spread of invasive species. We will assess performance and interaction shifts of and among native (Fucus vesiculosus) and invasive(Agarophyton vermiculophylla) macroalgae, their epiphytes (filamentous algae, bacteria), their grazers (amphipods, snails) and the parasites of the latter.

This is a collaborative project with the IOLR (Haifa) and The University Duisburg-Essen.

Research Topic: We will examine the impact of moderate warming (delta 3°C over ambient) on species – specific performance and their competitiveness. One particular focus nested within the overall experiment is the interaction among native and invasive macroalgae, grazers, epiphytes and parasites. This topic will be examined in various smaller experiments nested in the KOB.

Approach: The outdoor benthocosms KOB are run in a flow-through mode allowing recruitment from the in-situ species pool and access to all natural fluctuations. 6 tanks are run at ambient conditions, 6 tanks are dynamically warmed to 3°C above ambient. Sub-experiments are run in sub-units of various size introduced into the KOB.

Given the flexible nature of KOB own project ideas of the visiting researchers may be incorporated as long as they are compatible with the 2 temperature levels.

Any expertise of users is welcome. We specifically encourage experts in stress physiology of algae or parasitism in marine invertebrates to join the experiment. We welcome the input of visiting researchers for the customization and optimization of the experimental design.

For additional information contact Martin Wahl (mwahl@geomar.de). Here you learn more about the KOB in a (German) movie.

We can accommodate up to 5 external users at a time.

Procedural information at (https://www.aquacosm.eu/transnational-access/)

The long term effect of warming on benthic communities (performances, interaction shifts, selection, bioinvasion).

Project lead: Martin Wahl. 01 April – 15 September 2020.

The BENTHOCOSMS are open for user approve to AQUACOSM Transnational Access to participate in running experiment from April through October.

Rationale: The fate of native Baltic communities in response to global change is determined by the shifts in specific performance of interacting species. Existing interaction webs may be modified by the arrival or spread of invasive species. In this long term experiments (just entering its second year) we assess performance and interaction shifts of and among native (e.g. Fucus vesiculosus, Zostera marina, Mytilus edulis Asteria rubens, Gammarus spp.etc) and invasive (e.g. Fucus evanescens, Agarophyton vermiculophylla) components of benthic communities and the ensuing shifts in community functioning.

Research Topic: We will examine the impact of moderate warming (delta 3°C over ambient) on species – specific performance and their competitiveness. Given the long run of the experiment and the nature of this flow-through set-up, we will also examine selection under warming of some species. One particular focus nested within the overall experiment is the interaction among native and invasive macroalgae, grazers, epiphytes and parasites. This topic will be examined in various smaller experiments nested in the KOB and also KIB (the indoor benthocosms of GEOMAR).

Approach: The outdoor benthocosms KOB are run in a flow-through mode allowing recruitment from the in-situ species pool and access to all natural fluctuations. 6 tanks are run at ambient conditions, 6 tanks are dynamically warmed to 3°C above ambient. Sub-experiments are run in sub-units of various size introduced into the KOB or, where appropriate, the KIB.

Given the flexible nature of KOB and KIB, own ideas of the visiting researchers may be incorporated as long as they are compatible with the 2 temperature levels.

Any expertise of users is welcome. We specifically encourage experts in stress physiology of algae to join the experiment. We welcome the input of visiting researchers for the customization and optimization of the experimental design.

For additional information contact Martin Wahl (mwahl@geomar.de). Here you learn more about the KOB in a (German) movie , the KIB or our department as text.

We can accommodate up to 5 external users at a time.

Procedural information at (https://www.aquacosm.eu/transnational-access/)

The effect of warming on macroalgae-consumer-parasite interactions. Project lead: Martin Wahl. 01 April – 30 October 2019.

The BENTHOCOSMS are open for user approve to AQUACOSM Transnational Access to participate in running experiment from April through October.

KOB project in 2019:

Rationale: The fate of Baltic macroalgal habitats in response to warming is determined by the shifts in specific performance of an algal species, shifting interactions among competing macroalgae or between macroalgae and their consumers, and finally shifting impact of parasites on consumers and epiphytes on macroalgae. Existing interaction webs may further be modified by the arrival or spread of invasive species. In this first of a series of experiments (2019, 2010, 2021) we will concentrate on competitiveness and palatability shifts of macroalgae.

Research Topic: We will examine the impact of warming on algal performance and their palatability for mesograzers. If manpower and time allows we will compare the responses between invasive and native representatives of the two functional groups, and changes in parasitism.

Approach: To this end the 12 KOB are subjected two levels of warming (ambient vs warmed) relative to the naturally fluctuating temperature of Kiel fjord. In each tank we will introduce an assortment of green, brown, red macroalgae and various mesograzer populations (e.g. isopods, gammarids, snails).

The treatment consists of 2 levels of warming (0, 3°C above fjord temperature).

Response variables assessed will be, inter alia, individual performance (e.g. growth, reproduction), shifts in competitive and trophic interactions, and – optionally – parasite/epiphyte load and parasite/epiphyte impacts.

Additionally, own ideas of the visiting researchers may be incorporated.

Any expertise of users is welcome. We specifically encourage experts in stress physiology of algae and invertebrates to join the experiment. We welcome the input of visiting researchers for the customization and optimization of the experimental design.

For additional information contact Martin Wahl (mwahl@geomar.de)

Application deadline is Nov 14, 2018.

Procedural information at (https://www.aquacosm.eu/transnational-access/)

A total of 135 person-days is allocated to external users through AQUACOSM Transnational Access provision in 2019. An average of 3 persons for 45 days is envisaged each year. We can accommodate up to 5 external users at a time.

Impact of sporadic upwelling on structure and functioning of benthic communities. Project lead: Martin Wahl. 01 April – 30 October 2018.

The BENTHOCOSMS are open for user approve to AQUACOSM Transnational Access to participate in running experiment from April through October.

KOB project in 2018:

Rationale: Wind and upwelling regimes will shift in the course of Global Change. In addition, in the wake of ongoing warming (intensifying stratification) and eutrophication the difference between surface water and upwelled bottom water will become more extreme with regard to temperature, nutrients, salinity, pH and oxygen.

Research Topic: We will examine the impact of sporadic upwelling on community structure, biotic interactions and ecosystem functioning.

Approach: To this end the 12 KOB are complemented with 12 pelagic mesocosms floating alongside the KOB and having a volume of ca 3 m³ each. Communities included will be a natural inoculum of spring plankton, sediment cores and a macrophyte community composed (initially) of Fucus vesiculosus, Fucus serratus and co-occurring species (snails, gammarids, isopods, mussels etc.) in natural proportions. The experimental unit composed of interconnected sediment community, macroalgal community and plankton community will be replicated six-fold.

The treatment consists of one triggered upwelling of bottom water per month via an existing deep water pipe of 2-3 days duration in half of the tanks. This bottom water will be similar to surface water in spring, have increased nutrients and salinity and lower temperature in summer and, additionally, reduced oxygen and pH in autumn.

Response variables assessed will be, inter alia, individual performance (e.g. growth reproduction), shifts in competitive and trophic interactions, changes in community composition and shifts in community services.

Additionally, own ideas of the visiting researchers may be incorporated.

Any expertise of users is welcome. We specifically encourage experts in stress physiology of algae, sea grass, and invertebrates to join the experiment. We welcome the input of visiting researchers for the customization and optimization of the experimental design.

For additional information contact Martin Wahl (Please login or register to view contact information.)

Application deadline is Oct 6, 2017.

Procedural information at (https://www.aquacosm.eu/transnational-access/)

A total of 135 person-days is allocated to external users through AQUACOSM Transnational Access provision in 2018. An average of 3 persons for 45 days is envisaged each year. We can accommodate up to 5 external users at a time.