Metadata for KELPEX

WP3 

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WP1 - PRODUCTION, EXPORT AND TURN-OVER OF KELP DETRITUS ALONG A WAVE EXPOSURE GRADIENT

Lead: Morten Pedersen, Roskilde University (Denmark)

 

Objective 1.1. Spatio-temporal quantification of production, turnover and export of kelp detritus. The objective of this WP is to quantify the annual detritus budget associated with Laminaria hyperborea under different wave regimes. Detrital production varies substantially between species (Krumhansl & Scheibling 2012), yet no data exist for L. hyperborea, the dominant kelp in Norway and most of Europe. A key unanswered question concerns the magnitude and relative contribution to detritus production from blade erosion and dislodgement. These processes have different underlying drivers (e.g., phenology, temperature or fouling induced necrocis, water movement) with important implications for the delivery (seasonal timing, predictability, magnitude, export distances) and their sensitivity to environmental change (de Bettignies et al., 2015). This, in turn, has important consequences for the communities which rely on kelp detritus as a resource. Meeting this objective necessitates an intensive field study over 1.5 years, to be conducted in the study area (mouth of Malangen Fjord) and supplemented with laboratory studies on decomposition characteristics (rates and changes in chemical composition of kelp detritus).

Task 1.1. Quantifying the annual kelp detritus budget under different wave regimes

Task 1.2. Determination of decay rate and changes in nutritional value of kelp detritus under various environmental constraints (i.e. temperature, aerobic/anaerobic conditions)

Task 1.3. Quantifying detritus turnover and export from kelp across wave exposure and season.

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WP2 - EFFECTS OF KELP DETRITUS ON SHALLOW-WATER COMMUNITIES

Lead: Stein Fredriksen, UiO (Norway)

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Objective 2.1. Is kelp detritus important for microbial diversity in sandy beaches? Kelp detritus often accumulates in shallow water areas like seagrass beds and sandy beaches (Krumhansl & Scheibling 2012), which constitute a wealth of life in the form of photosynthetic and heterotrophic microorganisms (Eikrem & Throndsen 2010). Here, we will investigate the ecological role kelp detritus in shaping the structure (abundance and biodiversity) of microbial communities to assess the importance of sandy beaches as retention areas for kelp-derived detritus. The results will be linked to the export data quantified in WP1.

Task 2.1. To determine and quantify the effect of kelp detritus on the abundance and diversity of microorganisms on sandy beaches.

Objective 2.2. Does kelp detritus affect the growth of key filter-feeder species? On littoral rocky shores, filter feeders may benefit from kelp detritus (Renaud et al., 2015). The blue mussel (Mytilus edulis) and common barnacle (Semibalanus balanoides) are common species along the entire Norwegian shore, in particular in exposed areas dominated by the kelp L. hyperborea. Here, we will address the potential for increased growth and survival of filter feeders fuelled by kelp detritus. Such benefit, if observed, could have important implications in the trophic chain, including top predators such as large crustaceans, birds and humans, particularly under the scenario of an expected recovery of kelp forests in the Arctic. The results will be analysed in the context of the data obtained by WP1 and will provide valuable data to WP4 (stable isotopes and biomass).

Task 2.2. Determine the effect of kelp detritus on growth of blue mussels and barnacles.

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WP3 - EFFECTS OF KELP DETRITUS ON DEEP-SEA COMMUNITIES

Lead: Eva Ramirez-Llodra, NIVA (Norway)

Objective 3.1. Compare community structure and diversity of microbes, meio-, macro and megafauna in deep areas with and without kelp debris accumulation. Food quantity and quality is the most important factor shaping the structure and function of deep-sea heterotrophic ecosystems (Levin et al., 2001). Particle transport, including macorphyte detritus, can be enhanced by modified hydrography in canyons and fjords (Vetter et al. 2010). As such, these systems are often areas of enhanced β-diversity, can support important fisheries and can act as nursery grounds (Würtz et al., 2012.). Even though deep fjords and kelp forests are characteristic and ecologically significant habitats along the northern Norwegian coast, the trophic coupling of these two bathymetrically distant ecosystems is mostly unknown. Here, we propose to investigate the role of kelp debris in shaping the structure and function of benthic communities, from microbes to meio- to megafauna, in a deep Northern Norwegian fjord. All samples for WP3 will be collected in the Malangen fjord at 425 m depth during a 2-week cruise on board UiT’s R/V Johan Ruud in 2017 (shiptime application in August 2016). The cruise will alternate 6 YoYo Camera (YYC) seabed surveys of 1h each (Task 3.1), benthic sampling with 6 multicores, 10 boxcores and 10 benthic trawls (Tasks 3.1 and 3.3) and 6 Time-Lapse Camera (TLC) deployments (Task 3.2). The YYC surveys and benthic sampling will be conducted while the TLC is on the bottom (30 h per deployment). One day will be allowed for transit and two days for contingency to account for weather or technical issues.

Task 3.1. Structure and biodiversity of deep-sea microbes and fauna.

Objective 3.2. To assess the trophic relationship between kelp debris and benthic megafauna. A recent pilot study in the deep Oslo fjord showed the attraction of the arctic prawn Pandalus borealis and amphipods to experimentally deployed kelp, suggesting a trophic relationship yet to be confirmed (Ramirez-Llodra et al., pers. obs.). In KELPEX, we propose to undertake a significant step forward using state-of-the-art technology to assess this hypothetical trophic relationship between kelp debris and arctic deep benthic species, including ecologically and commercially important species such as P. borealis. 

Task 3.2. In situ investigations of the response of benthic fauna to kelp falls.

Task 3.3. To determine the contribution of kelp to the diet of ecologically- and commercially-important species.

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WP4 - ECOTROPHIC MODELLING

Lead: Marta Coll, ICM-CSIC (Spain)

Objective 4.1. Quantify main structural and functional features of shallow and deep ecosystems associated with kelp export. Ecological modelling has emerged as a highly suitable tool to integrate available biological data with the final objective to obtain an overall picture of how ecosystems are structured and how they function (Link 2011). This overall picture is the first step to move towards the development of future scenarios for natural ecosystems. In KELPEX we will use a combination of two modelling techniques (one from the qualitative and another from the quantitative realm) to advance on the knowledge on how the shallow and deep ecosystems associated with kelp exports are structured and how the function under present conditions and future change. Previous studies using EwE in Jurien Bay Marine Park (Australia) demonstrated a clear influence of kelp on food web dynamics (Lozano-Montes et al. 2011) although the role of kelp production export to adjacent ecosystems is unknown to a larger extent. To develop the ecological models we will integrate data and results obtained during WP1-2 and 3, in addition to other information available from the literature and previous monitoring and sampling campaigns. Experts on the ecosystems will be consulted to retrieve their knowledge on main species occurring in the ecosystems, main drivers and main historical changes (following Coll et al. 2014).

Task 4.1. To qualitatively describe the structure of shallow and deep ecosystems associated with kelp export.

Task 4.2. To quantitatively describe the structure of shallow and deep ecosystems associated with kelp export.

Objective 4.2. Assess how changes in kelp export translate into changes in structure and functioning of adjacent shallow and deep ecosystems. After proper validation, ecological models are useful tools to develop future simulations of change (Christensen 2013). In KELPEX, ecological models developed under Objective 4.1 will be used to develop simulations of kelp export change associated with climate change scenarios. The impact of these changes will be assessed by analysing the robustness of shallow and deep ecosystems food web components and properties to simulated changes in kelp production and export. Finally, potential changes in ecosystem services will be quantified (such as changes in food provisioning and ecosystem stability).

Task 4.3. To temporally quantify the impact of kelp export changes on ecosystem structure and functioning due to climate change.

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