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.