Range Extension of Mesophotic Kelps (Ochrophyta: Laminariales and Tilopteridales) in the Central North Atlantic: Opportunities for Marine Forest Research and Conservation

Abstract

Kelp was first recorded for the remote warm‐temperate Azores archipelago (central North Atlantic) in 1971, when a few Laminaria specimens were collected on the Formigas Bank at depths beyond conventional SCUBA diving reach. A shortage of technical means and projects targeting mesophotic environments has since kept this offshore marine protected area as the single known kelp occurrence site. Here, we present new kelp records collected on previously unexplored mesophotic reefs using remote imaging systems, open‐ and closed‐circuit SCUBA diving, and fisheries bycatch information. The new data extend the known distribution range of kelp in the Azores 350 km to the west and 25 km to the southwest, henceforth including several island shelves in the eastern and central Azores. In addition to the previously recorded Laminaria ochroleuca, kelp specimens with a morphology akin to Phyllariopsis brevipes subsp. brevipes are also reported. For the first time, seabed imagery is used to document the depth‐wise diversity of the Azores kelp beds and their associated biota. Our findings emphasize the poor knowledge that persists in regard to Macaronesia’s mesophotic environments located beyond conventional SCUBA diving limits. The new on‐shelf kelp occurrences add conservation value to coastal areas and should facilitate island‐based research. However, their greater proximity to land‐based impacts and exposure to climate change also raise management needs.

Contribution of Speciated Monoterpenes to Secondary Aerosol in the Eastern North Atlantic

“…Here we evaluate how ocean biological and meteorological variables and atmospheric oxidation chemistry might have impacted the speciation and concentration of MT during marine periods at this site. The phytoplankton community in the Azores-region of the Eastern North Atlantic is dominated by coccolithophores, diatoms, and dinoflagellates in spring and summer months. − These phytoplankton species are known MT-producers with unique emission rates dependent on type and environmental stressors. , Additionally, the surrounding shore of Graciosa Island has documented occurrences of kelp species, which can be monoterpene producers and provide a near-shore source in line with our observations. , During summer months, the water is often oligotrophic, in line with MODIS-derived chlorophyll- a during this study, and nutrient-limited dependent on mixed layer depth . Without additional measurements of phytoplankton or macroalgal speciation and information about the stage of a potential bloom, we use the bulk MODIS-derived chlorophyll- a to hypothesize that there was a relatively low dissolved MT concentration and stable speciation during the first two marine periods.…”

“…26,28 Additionally, the surrounding shore of Graciosa Island has documented occurrences of kelp species, which can be monoterpene producers and provide a near-shore source in line with our observations. 38,64 During summer months, the water is often oligotrophic, 56 in line with MODIS-derived chlorophyll-a during this study, and nutrient-limited dependent on mixed layer depth. 62 Without additional measurements of phytoplankton or macroalgal speciation and information about the stage of a potential bloom, we use the bulk MODIS-derived chlorophyll-a to hypothesize that there was a relatively low dissolved MT concentration and stable speciation during the first two marine periods.…”

Temperate Kelp Forest Collapse by Fish Herbivory: A Detailed Demographic Study

“…For example, the golden kelp Laminaria ochroleuca is a perennial seaweed that ranges from Morocco to Great Britain, being the northwest coast of the Iberian Peninsula its range-center (Birkett et al, 1998). Occasional small deep waters populations have also been found in the southwest Mediterranean (Algeria, Sea of Alboran), of the Straits of Messina and Azores (Drew, 1974;Tittley and Neto, 2000;Flores-Moya, 2012;Tempera et al, 2021). Like other Laminariales, its life cycle alternates between a haploid microscopic stage (gametophyte), and a diploid macroscopic one (sporophyte).…”

A quantitative synthesis of approaches, biases, successes, and failures in marine forest restoration, with considerations for future work

“…‘Marine forest’ is a broad term increasingly used to describe coastal marine habitats dominated by stands of large brown macroalgae, most commonly of kelp and fucoids (Küpper et al, 2019; Wernberg et al, 2019; Tempera et al, 2021). Coupled with a high diversity of associated organisms, marine forests represent highly productive ecosystems that support a range of ecologically and socio‐economically important ecosystem services (Smale et al, 2013; Bennett et al, 2016; Wernberg et al, 2019).…”