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Cross-ecosystem subsidies are critical to ecosystem structure and function, especially in recipient ecosystems where they are the primary source of organic matter to the food web. Subsidies are indicative of processes connecting ecosystems and can couple ecological dynamics across system boundaries. However, the degree to which such flows can induce cross-ecosystem cascades of spatial synchrony, the tendency for system fluctuations to be correlated across locations, is not well understood. Synchrony has destabilizing effects on ecosystems, adding to the importance of understanding spatiotemporal patterns of synchrony transmission. In order to understand whether and how spatial synchrony cascades across the marine-terrestrial boundary via resource subsidies, we studied the relationship between giant kelp forests on rocky nearshore reefs and sandy beach ecosystems that receive resource subsidies in the form of kelp wrack (detritus). We found that synchrony cascades from rocky reefs to sandy beaches, with spatiotemporal patterns mediated by fluctuations in live kelp biomass, wave action, and beach width. Moreover, wrack deposition synchronized local abundances of shorebirds that move among beaches seeking to forage on wrack-associated invertebrates, demonstrating that synchrony due to subsidies propagates across trophic levels in the recipient ecosystem. Synchronizing resource subsidies likely play an underappreciated role in the spatiotemporal structure, functioning, and stability of ecosystems.

While there is a global trend in kelp forests decline, sub-Antarctic Beagle Channel kelp ecosystems are among the most stable and extensive in the world, acting as a climatic refuge, indicating its high conservation value. Nevertheless, these coastal ecosystems are increasingly exposed to anthropogenic drivers that can affect kelp strategies and promote their replacement by turf. This study evaluated the urban impact of a coastal city in the Beagle Channel (Ushuaia, 54° S 68° W) on giant kelp (Macrocystis pyrifera) population dynamics. Seasonal samplings were conducted between 2020 and 2023 in two contrasting sites: an urban site directly exposed to Ushuaia pressures and a non-urban site. Our results indicate a reduction in both kelp adult density and kelp recruitment at the urban site. Here, high sediment inputs were the main factor affecting kelp recruitment, but higher density of potential grazers, and changes in the understory macroalgae assemblage were further observed. Morpho-functional composition and sediment trapped within the macroalgae suggest the prevalence of turf-forming algae dominating the urban site's understory assemblage. If neglected, the decline in kelp recruitment rates and the replacement of the forest by turf could eventually lead to a local loss of this urban-influenced sub-Antarctic kelp forest. [ABSTRACT FROM AUTHOR]

The global food production system is increasingly strained by abrupt and unpredictable weather events, which hinder communities' ability to adapt to climate variations. Despite advances in meteorological predictions, many communities lack the academic knowledge or infrastructure to interpret these complex models. This gap highlights the need for solutions that make climate forecasts more accessible and actionable, especially for communities reliant on natural resources. This study explores the potential of enhancing seasonal climate forecasts by integrating local ecological knowledge (LEK) with scientific data. Specifically, we combined ethnobiological information gathered between 2022 and 2024 with existing oceanographic and ecological data to create an ethnobiological calendar for four fishing cooperatives. An ethnographic approach was used to understand the population's ethnobiological knowledge and their perceptions of marine heatwaves and climate change impacts. Coastal monitoring data was collected using moorings that recorded temperature over a 14-year period (2010–2024). To characterize giant kelp dynamics, we used an existing dataset of multispectral Landsat images, which estimates the surface canopy biomass of giant kelp forests. Ecological monitoring was conducted annually every summer from 2006 to 2023 to record the in situ abundance of ecologically and economically important invertebrate and fish species. Combining oceanographic, ecological, and ethnographic data, allowed for alligning fishers' observations with recorded marine heatwave events and ecological shifts. Our findings revealed that these observations closely matched documented marine heatwave data and corresponding ecological changes. The integration of LEK with scientific oceanographic data can significantly improved our understanding of dynamic climate regimes, offering contextually relevant information that enhances the reliability and utility of seasonal climate forecasts. By incorporating yearly data into an ethnobiological calendar, we promote more inclusive, community-based approaches to environmental management, advocating for the integration of LEK in climate adaptation efforts, emphasizing its crucial role in strengthening resilience strategies against climatic shocks. [ABSTRACT FROM AUTHOR]

Aim: Dispersal and connectivity play important roles in shaping the population structure of giant kelp, Macrocystis pyrifera, across the western coast of South America. Its high potential dispersal capacity suggests the existence of metapopulations, where discrete habitat patches or groups of patches form subpopulations that interact at some level. However, the dispersal patterns of giant kelp in this region have not been quantified. This study assesses the dispersal and settlement of Macrocystis pyrifera in the southeast Pacific, specifically focusing on the impact of environmental variables and ocean currents within the Humboldt Current System. Location: Southeast Pacific (coast of Chile and Peru). Time Period: 1997–2008. Major Taxa Studied: Macrocystis pyrifera (giant kelp). Methods: Using a combination of hydrodynamic and individual‐based models, we analysed kelp fragment movements over 12 years, with a particular emphasis on the effects of the El Niño‐Southern Oscillation (ENSO) and seasonal changes. Results: Our results highlight a key settlement area in the southern Chilean region. We found that shorter travel distances of kelp fragments increased the likelihood of reaching a suitable habitat, underscoring the importance of local environmental conditions. We delineated intricate northward dispersal paths for kelp fragments, which appear to be governed by the interplay of wind and ocean current dynamics. Seasonal variations, notably in autumn and winter, favour the likelihood of reaching a settlement area due to favourable winds. Furthermore, ENSO events appear to influence dispersal distances, with fragments travelling the longest distances during El Niño phases. Main Conclusion: These findings are essential for informing kelp conservation strategies in the context of climate change, emphasizing the necessity of considering local and seasonal environmental factors alongside ENSO impacts. [ABSTRACT FROM AUTHOR]

The success and cost‐effectiveness of kelp forest restoration hinges on understanding the colonization ecology of kelps, particularly with respect to dispersal potential, recruitment success, and subsequent establishment. To gain needed insight into these processes we examined spatial patterns and temporal trajectories of the colonization of a large artificial reef by the giant kelp Macrocystis pyrifera. The 151 ha artificial reef complex was constructed in three phases over 21 years, enabling dispersal, recruitment, and subsequent establishment to be examined for a wide range of environmental conditions, dispersal distances, and source population sizes. Natural colonization of all phases of the artificial reef by giant kelp was rapid (within 1 year) and extended across the entire 7‐km‐long reef complex. Colonization density declined with distance from the nearest source population, but only during the first phase when the distance from the nearest source population was ≤3.5 km. Despite this decline, recruitment on artificial reef modules farthest from the source population was sufficient to produce dense stands of kelp within a couple of years. Experimental outplanting of the artificial reef with laboratory‐reared kelp embryos was largely successful but proved unnecessary, as the standing biomass of kelp resulting from natural recruitment exceeded that observed on nearby natural reefs within 2–3 years of artificial reef construction for all three phases. Such high potential for natural colonization following disturbance has important implications for kelp forest restoration efforts that employ costly and logistically difficult methods to mimic this process by active seeding and transplanting. [ABSTRACT FROM AUTHOR]

[Display omitted] • Toxoplasma gondii DNA was detected in bivalves from the Kerguelen and Galapagos archipelagos. • Its occurrence differed between sampling sites in Kerguelen but not in Galapagos. • In both archipelagos, quantitative PCR-positive bivalves were found on islands without cats. • Our finding demonstrated the waterborne transport of oocysts over at least 20 km. • Exposure to currents and giant kelp density affect T. gondii detection in bivalves. Oocysts of the protozoan Toxoplasma gondii are found in felid feces and can be washed into coastal waters, where they persist for months, attaching to algae and accumulating in invertebrates. We used wild bivalves to assess contamination of coastal waters of the Kerguelen and Galapagos archipelagos by this zoonotic parasite. Additionally, we leveraged the contrasting situations of these archipelagos to identify some potential drivers of contamination. In the Galapagos, with a cat density reaching 142 per km2, 15.38% of the sampled oysters (Saccostrea palmula) tested positive for T. gondii by quantitative real-time PCR (qPCR) (n = 260), and positive samples were found in all eight sampling sites. In Kerguelen, with 1-3 cats per km2, 40.83% of 120 tested mussels (Mytilus edulis platensis) were positive, and positive samples were found in four out of the five sampling sites. These findings provide evidence of T. gondii contamination in the coastal waters of these archipelagos. Furthermore, T. gondii -positive bivalves were found on islands located 20 km away (Galapagos) and 5 km away (Kerguelen) from the nearest cat population, indicating that T. gondii oocysts can disperse through waterborne mechanisms over several kilometers from their initial deposition site. In the Galapagos, where runoff is infrequent and all sites are exposed to currents, the prevalence of qPCR-positive bivalves did not show significant variations between sites (p = 0.107). In Kerguelen where runoff is frequent and site exposure variable, the prevalence varied significantly (p < 0.001). The detection of T. gondii in Kerguelen mussels was significantly correlated with the site exposure to currents (odds ratio (OR) 60.2, p < 0.001) and the on-site density of giant kelp forests (OR 2.624, p < 0.001). This suggests that bivalves can be contaminated not only by oocysts transported by currents but also by consuming marine aggregates containing oocysts that tend to form in kelp forests. [ABSTRACT FROM AUTHOR]

The commercial use of kelp continues to gain interest worldwide. While in some East Asian countries kelp farming has a long history, the kelp industry in South Africa is based on harvesting of kelp from natural kelp forests or by beach-cast collection. This study examined the potential for kelp aquaculture on South Africa's west coast, focusing on the three indigenous species of kelp, Ecklonia maxima, Laminaria pallida and Macrocystis pyrifera. Geospatial analysis was used to identify and assess nine potentially suitable areas for kelp farming, based on natural habitat conditions, and examination of potential conflicts with other users and enabling land-use factors. An assessment of the market, technical and financial aspects of a kelp farming opportunity indicated that a 4 ha kelp farm, with longlines producing 750 to 1,000 t of fresh kelp per annum, could be viable as an integrated aquaculture activity adjacent to an existing mussel or oyster farm. We recommend a detailed feasibility study for kelp aquaculture in South Africa, with market and technical research, and financial modelling. Current seaweed industry legislation is mostly concerned with the wild resource, and there is a need for specific policies relating to seaweed aquaculture to facilitate growth of the industry. [ABSTRACT FROM AUTHOR]

The Benguela upwelling region on the west coast of South Africa/Namibia has the only major kelp forests on the African continent. South Africa has four species of laminarian kelps; Ecklonia maxima, Laminaria pallida dominate kelp forests in the west coast Benguela upwelling system, with Macrocystis pyrifera occurring rarely in this region and Ecklonia radiata largely confined to the more nutrient-poor south and east coasts. Growth studies on these species have been limited to laboratory experiments and very few initial, small-scale coastal studies. As in other Atlantic regions, there is growing interest in the potential for kelp aquaculture in Southern Africa, and recent pilot initiatives. A comprehensive summary of available literature on South African kelps, their biology and ecology, distribution and growth parameters, is presented, and the potential for kelp aquaculture discussed in relation to recent developments elsewhere on Atlantic and Eastern Pacific coastlines. Recommendations are made with respect to the choice of potential species and sites. [ABSTRACT FROM AUTHOR]

Kelp forests are productive and biodiverse ecosystems with high ecological, cultural, and economic importance. However, the high sensitivity of kelp to water temperature means that these ecosystems are vulnerable to marine heatwaves (MHWs), especially at the equatorward edge of their range. To date, few laboratory studies have compared the effects of MHWs of different durations or intensities on kelp, and it is difficult to determine these effects from naturally occurring MHWs in the field. We exposed juvenile sporophytes of the giant kelp Macrocystis pyrifera from Wellington, Aotearoa New Zealand to simulated MHWs three or six weeks in duration, at temperatures of 18°C, 20°C, and 22°C, corresponding to 2, 4, and 6°C above local mean summer temperatures. While all MHW treatments reduced mean kelp growth rates by over 30% relative to 16°C controls, the 22°C treatments had much more severe and wide-ranging effects, including rapid blade erosion, reduced chlorophyll fluorescence, tissue bleaching, increased δ13C values, andmortality. Nonetheless, sporophytes had some ability to recover from heat stress; within the 18°C treatment, mean relative growth rates neared or exceeded those within the control treatment within three weeks after MHWs concluded. These results support the findings of previous studies which indicate that M. pyrifera sporophytes experience a key physiological tipping point around 20°C. Additionally, our findings suggest that juvenile M. pyrifera from the Wellington population could be relatively resilient toMHWs if temperatures remain at sub-lethal levels. However, if averageMHWintensities and durations continue to increase over time, survival and recruitment of juvenile kelp could be adversely affected, thus threatening the long-term persistence of giant kelp forests near the warm edge of their range in New Zealand. [ABSTRACT FROM AUTHOR]

The two most common ecomorphs of giant kelp, Macrocystis pyrifera and Macrocystis integrifolia, exhibit almost no geographic overlap across their range in the temperate waters of North and South America, with few exceptions such as Stillwater Cove, CA, USA. However, in laboratory settings they are able to interbreed. The mechanism for the morphological variation is unknown, and whether these features are genetically fixed or malleable under different environmental conditions is unclear. Our study, for the first time, directly compared the growth, development, and morphological transformations of the two Macrocystis ecomorphs in a common garden experiment. We experimentally tested the influence of local environment on giant kelp morphology by rearing lab‐cultured embryonic sporophytes from spores released by M. pyrifera and M. integrifolia sporophylls collected from multiple individuals at Stillwater Cove, CA. The spores were cultured in three treatments: "pyrifera‐morph" only, "integrifolia‐morph" only, and mixed (50:50 "pyrifera‐morph":"integrifolia‐morph" spores). We outplanted the resultant embryonic sporophytes to concrete blocks installed at 7.5–9 m depth in the ocean and monitored the development of the sporophytes over 5 months. Our findings of distinct differences in morphology between the pyrifera‐treatment and integrifolia‐treatment individuals at multiple stages of development including reproductive adults indicates that the morphological differences between the two ecomorphs are genetically determined rather than environmentally induced. We found that primary stipe length and number of branches can be used as diagnostic traits for distinguishing the ecomorphs prior to the stage when adult sporophyte morphology can be definitively characterized. Additionally, no morphological hybrids were observed in the mixed‐treatment, and ultimately the mixed‐treatment individuals were more often categorized as "integrifolia‐morph"‐like than "pyrifera‐morph"‐like. [ABSTRACT FROM AUTHOR]

This study set out to provide a preliminary assessment of nutritional profiles of five selected New Zealand macroalgae to investigate the potential of landcultivated Ulva spp. The New Zealand seaweeds species, selected from a limited range, were either collected from the wild (Pyropia plicata from Tauranga and Kaikōura), or were sourced from commercial wild harvest suppliers (Macrocystis pyrifera and Undaria pinnatifida), and were compared to land-based cultivated Ulva species (Ulva ralfsii and Ulva stenophylloides). Species were assessed for their content of crude protein, total lipids, carbohydrates, fibers, amino acids, mineral profiles, heavy metals and antioxidant capacity (Oxygen Radical Absorbance Capacity, ORAC). The two cultivated Ulva spp. had the highest crude protein content of the six seaweeds analyzed (approximately 21% dw, N×6.25), as expected with nutrient supplemented cultivation. They also had the highest total, essential and branched chain amino acid quantities (151, 70, and 29 mg/g for U. stenophylloides and 138, 62, and 27 mg/g for U. ralfsii). Though the two Ulva spp. were grown to the same cultivation specifications, they varied in carbohydrate and total fiber content (U. stenophylloides: 63% and 62%; U. ralfsii: 39% and 40%, respectively). Pyropia plicata collected in Kaikōura had the highest carbohydrate levels (65%) though not the highest total fiber. Both P. plicata had the highest trace minerals (417 mg/kg and 720 mg/kg for Kaikōura and Tauranga P. plicata respectively). All seaweeds analyzed showed no lipophilic antioxidants, though the two Phaeophyceae had the highest hydrophilic antioxidant content at 115 TE and 168 TE for Macrocystis pyrifera and Undaria pinnatifida, respectively. This paper provides a preliminary indication of the relative nutritional attributes of a range of potential New Zealand seaweed aquaculture targets benchmarked against sealettuce (Ulva spp.). [ABSTRACT FROM AUTHOR]

Macrocystis pyrifera (Linnaeus) C. Agardh 1820 is a type of algae widely located along the Chilean coastline with extensive biological value. Mitochondrial genome is 37 289 bp in length and consists of a circular DNA molecule. The circular genome is composed of 66 genes, including 38 protein coding genes, 25 tRNA genes, and 3 rRNA genes. The total content of G+C is 31.80%, lower than that of A+T. M. pyrifera formed a monophyletic clade together with Macrocystis integrifolia, which offer valuable insights into the phylogeny and gene functions within the family Laminariaceae andpromote novel references for the genetic and phylogenetic research of M. pyrifera through the provision of these data. [ABSTRACT FROM AUTHOR]

Giant kelp (Macrocystis pyrifera) forests are common along the California coast. Attached on the rocky bottom at depths of approximately 5–25 m, the kelp, when mature, spans the water column and develops dense, buoyant canopies that interact with waves and currents. We present two novel results based on observations of surface gravity waves in a kelp forest in Point Loma, California. First, we report short wave (1–3 s) attenuation in kelp, quantified by an exponential decay coefficient α∼O10−3m−1—comparable to the dampening effect of sea ice. Second, we identify seasonal and tidal changes in attenuation, peaking mid‐summer with maximum kelp cover, and during low tide when a greater proportion of the fronds are at the surface. Thus, the naturally occurring surface canopies of kelp forests can act as temporally varying, high‐frequency filters of wave energy. [ABSTRACT FROM AUTHOR]

Background: Specialized aesthetic skincare treatments are an important part of helping reduce facial signs of aging. Aims: This article highlights real‐world experience with a Macrocystis pyrifera ferment‐containing skincare regimen comprising a cleansing foam, a serum, and a moisturizer with anti‐aging, anti‐inflammatory, anti‐erythema, and healing properties for facial skin condition improvement. Patients/Methods: The real‐world case (RWC) series presented highlights and the expert panel's clinical experience with the M. pyrifera ferment‐containing skincare regimen used for 12 weeks to improve facial skin conditions. The panelists convened a meeting to discuss and select RWCs from their practice using the M. pyrifera ferment‐containing skincare regimen. Results: The RWC series showed that erythema and inflamed, easily irritated skin bother patients, even when it is mild. Reducing inflammation, erythema, and visible signs of facial aging and improving skin health contributed to patient satisfaction. Conclusion: The M. pyrifera ferment‐containing skincare regimen comprising a cleansing foam, a serum, and a moisturizer is effective in decreasing the visible effects of inflammation and signs of aging while promoting healing by enhancing barrier resilience and recovery. [ABSTRACT FROM AUTHOR]

Macrocystis sp. isolate 501 is a brown algae in the family Laminariaceae. Here, we sequenced, assembled, and annotated the complete chloroplast (cp) genome of Macrocystis sp. isolate 501. The cp genome of Macrocystis sp. isolate 501 is 130 103 bp in length with a GC content of 30.86%. The assembled genome has a typical cyclic structure, containing a large single-copy (LSC) region of 76 397 bp, a small single-copy (SSC) region of 42 856 bp, and a pairof inverted repeatregions(IRs) of 10 850 bp. The cp genome contains 140 unique genes, including 105 protein-codinggenes, six rRNA genes, and 29 tRNA genes. Phylogenetic analysis showed that Macrocystis sp. isolate 501 was closely related to Phaeophyceae. The chloroplast sequence of this species was aligned on NCBI, and the highest coverage was Macrocystis pyrifera (99.18%). Macrocystis pyrifera, also known as the giant brown algae, was first described by the French naturalist Nicolas Duclos in 1750. However, the first detailed description and name of the species was given by the French naturalist Adolphe-Francois Le Jolis in 1863, an article entitled "Étude des Algues littorales de la Manche." We named the algae we get "Macrocystis sp. isolate 501," which is the first time that this species has been mentioned. Herein we present the first report on Macrocystis sp. isolate 501 with published genomic information. [ABSTRACT FROM AUTHOR]

Sea urchins can strongly reduce their mobility, exposure to predation, and feeding rates upon detection of chemical cues produced by predators, driving behavioral effects on grazing activity that may contribute to macroalgal community dynamics. However, the extent of chemically induced antipredator behaviors in urchins can vary by predator–prey species pair and ecological context and is therefore important to characterize in novel settings. Additionally, the effect of predator and prey size on urchin reactions to predator cues has rarely been considered, with the few existing examples yielding mixed conclusions. Here, we used a replicated split‐plot experiment to measure the effects of red rock lobsters (Jasus edwardsii) on consumption of macroalgae by the New Zealand sea urchin (Evechinus chloroticus) across a range of predator and prey body sizes. Overall, per‐capita consumption rates of kelp by urchins declined by 30% in the presence of lobsters, though feeding activity varied widely among individuals. Based on mass‐specific measurements of feeding rates, responses to predator cues appeared similar across all urchin sizes but only yielded distinguishable differences in the amount of kelp consumed in trials with larger urchins due to their considerably higher feeding capacity. Conversely, consumption rates of kelp by urchins had no apparent relationship with lobster size, likely due to chemical cue saturation in our experimental setting or a risk gradient that was insufficient to elicit a graded behavioral response. Our findings provide new evidence for a nonconsumptive effect of lobsters on feeding rates of an important grazer that can potentially reinforce the ecological role of this key predator in New Zealand kelp beds. [ABSTRACT FROM AUTHOR]

Kelp forests provide habitat for many species, but it remains uncertain whether specific kelp forest types support distinct biodiversity. Surface canopy-forming giant kelp (Macrocystis pyrifera) forests in Tasmania, Australia, have declined significantly due to climate change, and have been widely replaced by forests dominated by smaller stipitate kelps like Ecklonia radiata. However, there is limited knowledge of the community composition of Macrocystis forests and how this may differ from the stipitate kelp forest community. Underwater visual census surveys were conducted of the fishes and macroinvertebrates (> 2.5 cm length) in remnant Macrocystis forests in south-eastern Tasmania, and in adjacent stipitate kelp forests. 18 sites (9 of each forest type) were surveyed across two regions during the period of peak growth and canopy cover (i.e. winter-spring). Faunal community composition varied little between forest types, although Macrocystis forests supported more than double the abundance and biomass of mobile fishes, while cryptic fishes differed by forest type depending on region. Macroinvertebrate assemblages did not differ between forest types nor regions. Thus, for the taxa and time period examined, Tasmanian Macrocystis and stipitate kelp forests supported mostly similar faunal communities. Kelp forest communities showed spatial variation and were also likely influenced by a variety of other habitat characteristics, such as the relatively small patch sizes and/or ephemeral state of the remnant Macrocystis forests. Quantifying the community structure of these endangered communities informs the ecological changes that have occurred and will serve as an important reference for ongoing conservation and restoration activities. [ABSTRACT FROM AUTHOR]

The giant kelp (Macrocystis pyrifera (Linnaeus) C. Agardh 1820) is a habitatforming brown seaweed in temperate systems with an unexplored potential as a source of seaweed bioproducts. This study used M. pyrifera sporophytes sourced in Tasmania, Australia, to investigate the effect of photoperiod and temperature on growth rates and the nutritional characteristics of the resulting juvenile biomass. Four cultivation treatments combined growth temperatures of 12 °C, 15 °C, 18 °C with light:dark (L:D) of 12:12 and 16:8 (L:D) photoperiods, (12 °C – (12:12); 12 °C – (16:8); 15 °C – (12:12); 18 °C – (12:12) to investigate their effect on the number and size of sporophytes, biomass accumulation and nutritional composition. After 60 days of cultivation the 12 °C – (12:12) treatment had the greatest number of juvenile sporophytes, and the greatest biomass of 14 ± 1.3 g dry weight (DW). The lowest biomass of 1 g DW, was obtained from the 18 °C – (12:12) treatment. The protein content across all treatments ranged from 16- 22.48% DW, with the 12 °C (12:12) treatment having largest range, then the 12°C (16:18) treatment was next with 18.48-22.48% DW, and the 15°C (12:12) treatment had the lowest protein range with 16.48-18% DW. These results are in the range of protein content previously reported for brown seaweeds of 5- 20%. Total polysaccharide content ranged from 9.6-16.2% DW with the highest content of 16.2% DW obtained for the 15 °C – (12:12) treatment, and the lowest total polysaccharide content of 9.6% DW obtained for the 12 °C (16:18) treatment. After 66 days of cultivation, the highest yield of sulphated polysaccharides of 0.4% DW was obtained for the 12 °C (12:12) treatment. Total fatty acids were analysed, with the highest polyunsaturated fatty acid content of 60.4% detected in the 12 °C (12:12) treatment. This study demonstrates that temperature and photoperiod are factors impacting juvenile sporophyte growth, biomass accumulation and biochemical composition. The study showed the least stressed sporophytes produced the most potentially beneficial nutritional or bioactive profile. [ABSTRACT FROM AUTHOR]

Nitrate, the form of nitrogen often associated with kelp growth, is typically low in summer during periods of high macroalgal growth. More ephemeral, regenerated forms of nitrogen, such as ammonium and urea, are much less studied as sources of nitrogen for kelps, despite the relatively high concentrations of regenerated nitrogen found in the Southern California Bight, where kelps are common. To assess how nitrogen uptake by kelps varies by species and nitrogen form in southern California, USA, we measured uptake rates of nitrate, ammonium, and urea by Macrocystis pyrifera and Eisenia arborea individuals from four regions characterized by differences in nitrogen availability—Orange County, San Pedro, eastern Santa Catalina Island, and western Santa Catalina Island—during the summers of 2021 and 2022. Seawater samples collected at each location showed that overall nitrogen availability was low, but ammonium and urea were often more abundant than nitrate. We also quantified the internal %nitrogen of each kelp blade collected, which was positively associated with ambient environmental nitrogen concentrations at the time of collection. We observed that both kelp species readily took up nitrate, ammonium, and urea, with M. pyrifera taking up nitrate and ammonium more efficiently than E. arborea. Urea uptake efficiency for both species increased as internal percent nitrogen decreased. Our results indicate that lesser‐studied, more ephemeral forms of nitrogen can readily be taken up by these kelps, with possible upregulation of urea uptake as nitrogen availability declines. [ABSTRACT FROM AUTHOR]

The recent surge in interest for restoring kelp forests in California has created a confusing and crowded landscape to navigate. Additionally, most existing resources are in the form of formal reports or journal articles, both of which rely heavily on specific terminology and can be physically locked behind a paywall. It is therefore unreasonable to assume interested members of the public and policy makers can reliably access or understand the intricacies of the kelp restoration landscape. To address these gaps, this project develops a multimedia web-based resource that provides unique access to kelp restoration projects happening in California. Through photos, videos, audio and maps, users can interact with the StoryMap and learn directly from stakeholders and learn how they are using various methodologies to restore kelp in California.See media created for this project here: https://storymaps.arcgis.com/stories/d35a011b5dd747b89d4d94d324e62693

This document is an editorial from the journal Frontiers in Marine Science, discussing the Marine Biotechnology and Bioproducts session of the 13th Asia-Pacific Marine Biotechnology Conference and the 5th Australia New Zealand Marine Biotechnology Society Conference. The joint conference aimed to bring together academic and industry participants to promote collaborations and research in marine biotechnology. The editorial also highlights specific research topics discussed at the conference, including the identification of coloration traits in marine macroalgae, new approaches for isolating marine bacteria, seaweed drying techniques, and the nutritional profiles of various seaweed species. [Extracted from the article]

Macrocystis pyrifera (giant kelp), is a brown macroalga of great ecological importance as a primary producer and structure-forming foundational species that provides habitat for hundreds of species. It has many commercial uses (e.g. source of alginate, fertilizer, cosmetics, feedstock). One of the limitations to exploiting giant kelp's economic potential and assisting in giant kelp conservation efforts is a lack of genomic tools like a high quality, contiguous reference genome with accurate gene annotations. Reference genomes attempt to capture the complete genomic sequence of an individual or species, and importantly provide a universal structure for comparison across a multitude of genetic experiments, both within and between species. We assembled the giant kelp genome of a haploid female gametophyte de novo using PacBio reads, then ordered contigs into chromosome level scaffolds using Hi-C. We found the giant kelp genome to be 537 MB, with a total of 35 scaffolds and 188 contigs. The assembly N50 is 13,669,674 with GC content of 50.37%. We assessed the genome completeness using BUSCO, and found giant kelp contained 94% of the BUSCO genes from the stramenopile clade. Annotation of the giant kelp genome revealed 25,919 genes. Additionally, we present genetic variation data based on 48 diploid giant kelp sporophytes from three different Southern California populations that confirms the population structure found in other studies of these populations. This work resulted in a high-quality giant kelp genome that greatly increases the genetic knowledge of this ecologically and economically vital species.

Species range shifts due to changing ocean conditions are occurring around the world. As species move, they build new interaction networks as they shift from or into new ecological communities. Typically, species ranges are modeled individually, but biotic interactions have been shown to be important to creating more realistic modeling outputs for species. To understand the importance of consumer interactions in Eastern Pacific kelp forest species distributions, we used a Maxent framework to model a key foundation species, giant kelp (Macrocystis pyrifera), and a dominant herbivore, purple sea urchins (Strongylocentrotus purpuratus). With neither species having previously been modeled in the Eastern Pacific, we found evidence for M. pyrifera expansion in the northern section of its range, with no projected contraction at the southern range edge. Despite its known co-occurrence with M. pyrifera, models of S. purpuratus showed a non-concurrent southern range contraction and a co-occurring northern range expansion. While the co-occurring shifts may lead to increased spatial competition for suitable substrate, this non-concurrent contraction could result in community wide impacts such as herbivore release, tropicalization, or ecosystem restructuring. [ABSTRACT FROM AUTHOR]

Sexual dimorphism and the reproductive strategy of the isopod Amphoroidea typa were examined and compared with other species from the isopod family Sphaeromatidae. We analyzed populations of A. typa occurring on the kelps Lessonia spp. and Macrocystis pyrifera at six locations on the coast of northern-central Chile. Males could be clearly distinguished from females starting at total body lengths (TL) ⩾ 14 mm, taking as criteria the presence of reproductive appendages and the development of gonopods in males. Females reached substantially larger sizes (up to 22.20 mm) than males (up to 18.25 mm), confirming the existence of sexual size dimorphism in A. typa. Although females had developed oostegites at lengths ⩾ 14 mm TL, only the largest females (⩾17 mm TL) were ovigerous. This suggests that female A. typa reproduce once before dying. At most study sites there were more adult females than males occurring on Lessonia spp., while males dominated on M. pyrifera. Some A. typa individuals had white stripes present on the dorsal part of the pereon, a colour polymorphism apparently independent of the sex of the isopods but becoming more frequent in large individuals, suggesting high predation pressure and that individuals with these stripes have higher survival rates. The results of this study confirm sexual size dimorphism in A. typa , which appears to be a semelparous species. A comparison with other sphaeromatid species indicates that the evolution of semelparity is unrelated to body size, but might be more common in species from habitats with high predation pressure. [ABSTRACT FROM AUTHOR]

The giant kelp Macrocystis pyrifera is in global decline as a result of numerous stressors operating on both local and global scales. It is a species that holds significant value in terms of the ecosystem services that it provides and its application in aquaculture. In order to safeguard, restore and utilize this species, it is essential that a sound understanding of genetic structure and diversity is established at scales relevant to local management. Seven microsatellite markers were used to analyze 389 individuals from sites across eight geographical regions in New Zealand. While samples of M. pyrifera from the west coast of the South Island (Fiordland), were genetically isolated, the biogeographic separation of sites along the east coast of New Zealand, between Wellington and Stewart Island, remained unclear due to low genetic differentiation between regions. The greatest genetic diversity was seen in the southeast sites, whereas the northeast had the lowest diversity. This pattern is likely driven by the effects of stressors such as high sea surface temperature in these areas as well as oceanic circulation patterns. A key finding from this work was the significant genetic isolation, and therefore vulnerability of M. pyrifera in the Fiordland population, an area that is being subjected to more intense and longer lasting heatwave events. [ABSTRACT FROM AUTHOR]

Spatial synchrony is the tendency for population fluctuations to be correlated among different locations. This phenomenon is a ubiquitous feature of population dynamics and is important for ecosystem stability, but several aspects of synchrony remain unresolved. In particular, the extent to which any particular mechanism, such as dispersal, contributes to observed synchrony in natural populations has been difficult to determine. To address this gap, we leveraged recent methodological improvements to determine how dispersal structures synchrony in giant kelp (Macrocystis pyrifera), a global marine foundation species that has served as a useful system for understanding synchrony. We quantified population synchrony and fecundity with satellite imagery across 11 years and 880 km of coastline in southern California, USA, and estimated propagule dispersal probabilities using a high‐resolution ocean circulation model. Using matrix regression models that control for the influence of geographic distance, resources (seawater nitrate), and disturbance (destructive waves), we discovered that dispersal was an important driver of synchrony. Our findings were robust to assumptions about propagule mortality during dispersal and consistent between two metrics of dispersal: (1) the individual probability of dispersal and (2) estimates of demographic connectivity that incorporate fecundity (the number of propagules dispersing). We also found that dispersal and environmental conditions resulted in geographic clusters with distinct patterns of synchrony. This study is among the few to statistically associate synchrony with dispersal in a natural population and the first to do so in a marine organism. The synchronizing effects of dispersal and environmental conditions on foundation species, such as giant kelp, likely have cascading effects on the spatial stability of biodiversity and ecosystem function. [ABSTRACT FROM AUTHOR]

Microbial inoculants can increase the yield of cultivated crops and are successful in independent trials; however, efficacy drops in large-scale applications due to insufficient consideration of microbial community dynamics. The structure of microbiomes, in addition to the impact of individual taxa, is an important factor to consider when designing growth-promoting inoculants. Here, we investigate the microbial network and community assembly patterns of Macrocystis pyrifera gametophyte germplasm cultures (collectively referred to as a "seedbank") used to cultivate an offshore farm in Santa Barbara, California, and identify network features associated with increased biomass of mature sporophytes. We found that [1] several network features, such as clustering coefficient and edge ratios, significantly vary with biomass outcomes; [2] gametophytes that become low- or high-biomass sporophytes have different hub taxa; and [3] microbial community assembly of gametophyte germplasm cultures is niche-driven. Overall, this study describes microbial community dynamics in M. pyrifera germplasm cultures and ultimately supports the development of early life stage inoculants that can be used on seaweed cultivars to increase biomass yield. [ABSTRACT FROM AUTHOR]

Worldwide climate‐driven shifts in the distribution of species is of special concern when it involves habitat‐forming species. In the coastal environment, large Laminarian algae—kelps—form key coastal ecosystems that support complex and diverse food webs. Among kelps, Macrocystis pyrifera is the most widely distributed habitat‐forming species and provides essential ecosystem services. This study aimed to establish the main drivers of future distributional changes on a global scale and use them to predict future habitat suitability. Using species distribution models (SDM), we examined the changes in global distribution of M. pyrifera under different emission scenarios with a focus on the Southeast Pacific shores. To constrain the drivers of our simulations to the most important factors controlling kelp forest distribution across spatial scales, we explored a suite of environmental variables and validated the predictions derived from the SDMs. Minimum sea surface temperature was the single most important variable explaining the global distribution of suitable habitat for M. pyrifera. Under different climate change scenarios, we always observed a decrease of suitable habitat at low latitudes, while an increase was detected in other regions, mostly at high latitudes. Along the Southeast Pacific, we observed an upper range contraction of −17.08° S of latitude for 2090–2100 under the RCP8.5 scenario, implying a loss of habitat suitability throughout the coast of Peru and poleward to −27.83° S in Chile. Along the area of Northern Chile where a complete habitat loss is predicted by our model, natural stands are under heavy exploitation. The loss of habitat suitability will take place worldwide: Significant impacts on marine biodiversity and ecosystem functioning are likely. Furthermore, changes in habitat suitability are a harbinger of massive impacts in the socio‐ecological systems of the Southeast Pacific. [ABSTRACT FROM AUTHOR]

ABSTRACTKelp aquaculture is typically a two-stage process, with an indoor nursery phase and a grow-out phase at sea. For the successful development and implementation of commercial kelp aquaculture, production of viable seeded lines in the nursery is essential. This study investigated optimal nursery conditions of three kelp species native to Tasmania, Australia: Ecklonia radiata, Lessonia corrugata, and Macrocystis pyrifera. The interactive effects of temperature (12°C, 15°C, and 18°C) and light level (~30 µmol photons s−1 m−2, and ~ 60 µmol photons s−1 m−2) on sporophyte length, sporophyte density, and contamination of spools were examined over a 34-day period. The optimal temperature and light levels were 15°C and 30 µmol photons m−2 s−1 for E. radiata, 12°C and 60 µmol photons m−2 s−1 for L. corrugata, and 12°C and 30 or 60 µmol photons m−2 s−1 for M. pyrifera. Under these optimal conditions, the mean ± SEM sporophyte lengths after 34 days were 0.60 ± 0.02 mm, 1.04 ± 0.04 mm, and 0.60 ± 0.01 mm for E. radiata, L. corrugata, and M. pyrifera, respectively. The mean ± SEM sporophyte densities for each of these three species were 15.5 ± 6.2 sporophytes cm−1 of line, 10.8 ± 5.9 sporophytes cm−1 of line, and 19.3 ± 8.1 sporophytes cm−1 of line, respectively. Contamination increased with increasing temperature and was not significantly affected by light level. This work highlights the need for a species- and ecotype-specific approach in the nursery phase to ensure successful seaweed aquaculture outcomes in new regions of cultivation.

Macroalgae, commonly known as seaweed, are foundational species in coastal ecosystems and contribute significantly to coastal primary production globally. However, the impact of macroalgal decomposition on benthic biological nitrogen fixation (BNF) after deposition to the seafloor remains largely unexplored. In this study, we measure BNF rates at three different sites at the Big Fisherman's Cove on Santa Catalina Island, CA, USA, which is representative of globally distributed rocky bottom macroalgal habitats. Unamended BNF rates varied among sites (0.001-0.05 nmol N g-1 h-1) and were generally within the lower end of previously reported ranges. We hypothesized that the differences in BNF between sites were linked to the availability of organic matter. Indeed, additions of glucose, a labile carbon source, resulted in 2-3 orders of magnitude stimulation of BNF rates in bottle incubations of sediment from all sites. To assess the impact of complex, autochthonous organic matter, we simulated macroalgal deposition and remineralization with additions of brown (i.e., Macrocystis pyrifera and Dictyopteris), green (i.e., Codium fragile), and red (i.e., Asparagopsis taxiformis) macroalgae. While brown and green macroalgal amendments resulted in 53- to 520-fold stimulation of BNF rates--comparable to the labile carbon addition--red alga was found to significantly inhibit BNF rates. Finally, we employed nifHsequencing to characterize the diazotrophic community associated with macroalgal decomposition. We observed a distinct community shift in potential diazotrophs from primarily Gammaproteobacteria in the early stages of remineralization to a community dominated by Deltaproteobacteria (e.g., sulfate reducers), Bacteroidia, and Spirochaeta toward the latter phase of decomposition of brown, green, and redmacroalgae. Notably, the nifH-containing community associated with red macroalgal detritus was distinct from that of brown and green macroalgae. Our study suggests coastal benthic diazotrophs are limited by organic carbon and demonstrates a significant and phylum-specific effect of macroalgal loading on benthic microbial communities. [ABSTRACT FROM AUTHOR]

Sub-Antarctic giant kelp (Macrocystis pyrifera) forests have remained relatively wild and far from anthropogenic pressures. However, they are increasingly exposed to multiple stressors that might affect kelp forest persistence. The urban impact of a coastal city, Ushuaia (54° S 68° W), in the Beagle Channel, Argentina, on giant kelp forest environments was evaluated in this study and implications on morphological variability were explored. Seasonal samplings were conducted from 2019 to 2021 in two contrasting sites: an urban site directly exposed to coastal discharges, and a non-urban site. Our results indicate that the combination of coastal discharges, kelp canopy and low wave exposure increases light attenuation inside kelp forests, promoting coastal darkening. Additionally, and based on the present results, we present the first record of algal turf in the Beagle Channel. We further propose the Kelp Structure Index to describe the effect of environmental conditions on kelp structure, which highlights an increased blade surface in sites with urban impacts. These results suggest that giant kelp shows high plasticity in morphological traits under varying environmental conditions, particularly in environments exposed to coastal darkening effects. However, the presence of turf indicates that urban pressures might be severely limiting kelp forest health. [ABSTRACT FROM AUTHOR]

Background and Aims Coastal Alaska contains vast kelp habitat that supports diverse marine and human communities. Over the past century, the North Pacific Ocean has undergone oceanographic and ecological regime shifts that have the potential to influence the structure and function of kelp ecosystems strongly. However, the remoteness and complexity of the glacially carved region precludes the regular monitoring efforts that would be necessary to detect such changes. Methods To begin to fill this critical knowledge gap, we drew upon historical and modern surveys to analyse the change in spatial coverage and species composition of canopy kelp between two time points (1913 and the early 2000s to 2010s). We also incorporated decadal surveys on sea otter range expansion following complete extirpation and reintroduction to assess the influence of sea otter recovery on the spatial extent of canopy kelp. Key Results We found increases in the spatial extent of canopy kelp throughout the Gulf of Alaska where there was coverage from both surveys. Kelp in Southcentral Alaska showed extensive recovery after the catastrophic Novarupta volcano. Kelp in Southeast Alaska showed persistence and spatial increase that closely matched increases in the range of sea otters. Observations of thermally tolerant kelp species increased more than observations of cold-adapted species between the two surveys. Conclusions Contrary to trends observed at lower latitudes, the kelp forests that ring the Gulf of Alaska have been remarkably stable and even increased in the past century, despite oceanographic and ecosystem changes. To improve monitoring, we propose identification of sentinel kelp beds for regular monitoring to detect changes to these iconic and foundational canopy kelp species more readily. [ABSTRACT FROM AUTHOR]

Background and Aims The increased likelihood and severity of storm events has brought into focus the role of coastal ecosystems in provision of shoreline protection by attenuating wave energy. Canopy-forming kelps, including giant kelp (Macrocystis pyrifera), are thought to provide this ecosystem service, but supporting data are extremely limited. Previous in situ examinations relied mostly on comparisons between nominally similar sites with and without kelp. Given that other factors (especially seafloor bathymetry and topographic features) often differ across sites, efforts to isolate the effects of kelp on wave energy propagation confront challenges. In particular, it can be difficult to distinguish wave energy dissipation attributable to kelp from frictional processes at the seabed that often covary with the presence of kelp. Here, we use an ecological transition from no kelp to a full forest, at a single site with static bathymetry, to resolve unambiguously the capacity of giant kelp to damp waves. Methods We measured waves within and outside rocky reef habitat, in both the absence and the presence of giant kelp, at Marguerite Reef, Palos Verdes, CA, USA. Nested within a broader kelp restoration project, this site transitioned from a bare state to one supporting a fully formed forest (density of 8 stipes m−2). We quantified, as a function of incident wave conditions, the decline in wave energy flux attributable to the presence of kelp, as waves propagated from outside and into reef habitat. Key Results The kelp forest damped wave energy detectably, but to a modest extent. Interactions with the seabed alone reduced wave energy flux, on average, by 12 ± 1.4 % over 180 m of travel. The kelp forest induced an additional 7 ± 1.2 % decrease. Kelp-associated declines in wave energy flux were slightly greater for waves of longer periods and smaller wave heights. Conclusions Macrocystis pyrifera forests have a limited, albeit measurable, capacity to enhance shoreline protection from nearshore waves. Expectations that giant kelp forests, whether extant or enhanced through restoration, have substantial impacts on wave-induced coastal erosion might require re-evaluation. [ABSTRACT FROM AUTHOR]

The glycoside hydrolase 107 (GH107) family includes fucanase enzymes from only two bacterial phyla, Bacteroidota and Pseudomonadota. The goal of this work was to explore the diversity of putative fucanase enzymes related to this family in organisms of the PVC superphylum (Planctomycetota, Verrucomicrobiota, Chlamydiota), in order to expand our knowledge of the fucoidan-degrading potential in this ecologically and biotechnologically relevant group. Using hidden Markov model- and peptide-based annotation tools, 26 GH107 homolog sequences were identified in metagenome and genome datasets. The sequences formed two distinct clusters in a phylogenetic analysis, only one including members of the GH107 family. The endo-acting fucoidan degrading activity was confirmed in an enzyme included in the most divergent cluster. The fucanase, which probably originated in an uncultured planctomycete from the sampled subantarctic sediments, was cloned and expressed in Escherichia coli. The enzyme catalyzed the rapid hydrolysis of internal glycosidic bonds of fucoidan from Macrocystis pyrifera, a macroalgae species abundant at the site. It was active in a wide range of temperatures (5–45 °C), salinities (9.5–861 mM NaCl), and pH values (4.5–9), mainly producing sulfated α-(1,3)-linked fuco-oligosaccharides of various lengths. The PVC superphylum represents a promising source of fucanase enzymes with various biotechnological applications. [ABSTRACT FROM AUTHOR]

Variability in primary producers' responses to environmental change may buffer higher trophic levels against shifts in basal resource composition. Then again, in instances where there is a lack of functional redundancy because consumers rely on a few species to meet their energetic requirements at specific times of the year, altered community production dynamics may significantly impact food web resilience. In high‐latitude kelp forests, a complementary annual phenology of seaweed production supports coastal marine consumers' metabolic needs across large seasonal variations in their environment. Yet, marine consumers in these systems may face significant metabolic stress under the pronounced low pH conditions expected in future winters, particularly if they lack the resources to support their increased energetic demands. In this study, we investigate how the growth and nutritional value of three dominant, coexisting macroalgal species found in subpolar kelp forests will respond to ocean acidification and warming in future winter and summer seasons. We find that the three kelps Macrocystis pyrifera, Hedophyllum nigripes, and Neoagarum fimbriatum differ in their vulnerability to future environmental conditions, and that the seasonal environmental context of nutrient and light availability shapes these responses. Our results suggest that poleward fringe populations of M. pyrifera may be relatively resilient to anticipated ocean warming and acidification. In contrast, ocean warming conditions caused a decrease in the biomass and nutritional quality of both understory kelps. Considering the unique production phenology of H. nigripes, we emphasize that negative impacts on this species in future winters may be of consequence to consumer energetics in this system. This work highlights how interspecific variation in autotrophs' responses to global change can disrupt the diversity and phenological structure of energy supply available to higher trophic levels. [ABSTRACT FROM AUTHOR]

Because foundation species create structure in a community, understanding their ecological and evolutionary responses to global change is critical for predicting the ecological and economic management of species and communities that rely on them. Giant kelp (Macrocystis pyrifera) is a globally distributed foundation species with seasonal fluctuations in abundance in response to local nutrient levels, storm intensity, and ocean temperatures. Here we examine genetic variation in individual and population‐level responses of early life history stages (zoospore settlement, survival, and gametogenesis) to increased temperatures to determine the potential for natural selection on temperature‐tolerant individuals that would allow adaptation to a changing climate. We collected fertile M. pyrifera sporophyll blades from three sites along the California coast (Los Angeles, Santa Barbara, Monterey Bay) and induced zoospore release in the lab. Spores settled on microscope slides at three treatment temperatures (16, 20, and 22°C), matured for 21 days, and were imaged weekly to determine settlement, survival, and maturation success. On average, individuals from all sites showed lower rates of settlement and maturation in response to increasing temperature. However, the magnitude of the responses to temperature varied among populations. Survival tended to increase with temperature in Los Angeles and Santa Barbara populations but decreased with increasing temperature for the Monterey Bay population. We observed little genetic variation in temperature responses among individuals within sites, suggesting little scope for evolution within populations to increase the resilience of M. pyrifera populations to warming ocean temperatures and predicted declines in kelp abundance. Yet sufficient dispersal among populations could allow for adaptation of early life history traits among populations via evolutionary rescue of declining populations. [ABSTRACT FROM AUTHOR]

Background: There is an increasing demand for facial skin rejuvenation. Specialized aesthetic skincare treatments may be one of the first steps to help prevent or treat facial signs of aging. This article discusses aesthetic skin care for facial skin rejuvenation, particularly data on two creams containing Macrocystis pyrifera ferment. Methods: The authors convened a dermatology advisory board to discuss challenges and practices in using skincare for facial rejuvenation, combining their expert opinion and experience on facial rejuvenation with preclinical and clinical data on two creams containing Macrocystis pyrifera ferment and a review of the literature. Results: Preclinical and clinical studies on Macrocystis pyrifera ferment and two creams containing the ferment exhibit anti‐inflammatory, anti‐aging, and healing properties. In preclinical studies, the ferment demonstrated collagen type I enhancing properties in ex vivo skin models, and skin cells treated with the ferment migrated faster than untreated cells in the in vitro study. In clinical studies measuring visible anti‐inflammatory activity, the ferment alone and the ferment‐containing products significantly decreased erythema, and in anti‐aging studies, they improved visible skin aging parameters. Finally, in clinical studies on the stratum corneum, the two creams increased moisture levels and decreased transepidermal water loss (TEWL), reflecting healing by enhancing barrier strength and recovery. Conclusions: The Macrocystis pyrifera ferment and creams containing the ferment are effective skin care treatment products to decrease the visible effects of inflammation and signs of aging while promoting healing by enhancing barrier resilience and recovery. [ABSTRACT FROM AUTHOR]

Abstract Macrocystis pyrifera (giant kelp), is a brown macroalga of great ecological importance as a primary producer and structure-forming foundational species that provides habitat for hundreds of species. It has many commercial uses (e.g. source of alginate, fertilizer, cosmetics, feedstock). One of the limitations to exploiting giant kelp’s economic potential and assisting in giant kelp conservation efforts is a lack of genomic tools like a high quality, contiguous reference genome with accurate gene annotations. Reference genomes attempt to capture the complete genomic sequence of an individual or species, and importantly provide a universal structure for comparison across a multitude of genetic experiments, both within and between species. We assembled the giant kelp genome of a haploid female gametophyte de novo using PacBio reads, then ordered contigs into chromosome level scaffolds using Hi-C. We found the giant kelp genome to be 537 MB, with a total of 35 scaffolds and 188 contigs. The assembly N50 is 13,669,674 with GC content of 50.37%. We assessed the genome completeness using BUSCO, and found giant kelp contained 94% of the BUSCO genes from the stramenopile clade. Annotation of the giant kelp genome revealed 25,919 genes. Additionally, we present genetic variation data based on 48 diploid giant kelp sporophytes from three different Southern California populations that confirms the population structure found in other studies of these populations. This work resulted in a high-quality giant kelp genome that greatly increases the genetic knowledge of this ecologically and economically vital species.

Atopic dermatitis is a chronic condition where epidermal barrier dysfunction and cytokine production by infiltrating immune cells exacerbate skin inflammation and damage. A total lipid extract from Macrocystis pyrifera, a brown seaweed, was previously reported to suppress inflammatory responses in monocytes. Here, treatment of human HaCaT keratinocytes with M. pyrifera lipids inhibited tumour necrosis factor (TNF)-α induced TNF receptor-associated factor 2 and monocyte chemoattractant protein (MCP)-1 protein production. HaCaT cells stimulated with TNF-α, interleukin (IL)-4, and IL-13 showed loss of claudin-1 tight junctions, but little improvement was observed following lipid pre-treatment. Three-dimensional cultures of HaCaT cells differentiated at the air–liquid interface showed increased MCP-1 production, loss of claudin-1 tight junctions, and trans-epidermal leakage with TNF-α, IL-4, and IL-13 stimulation, with all parameters reduced by lipid pre-treatment. These findings suggest that M. pyrifera lipids have anti-inflammatory and barrier-protective effects on keratinocytes, which may be beneficial for the treatment of atopic dermatitis or other skin conditions. [ABSTRACT FROM AUTHOR]

Kelp species provide many ecosystem services associated with their three‐dimensional structures. Among these, fast‐growth, canopy‐forming species, like giant kelp Macrocystis pyrifera, are the foundation of kelp forests across many temperate reefs. Giant kelp populations have experienced regional declines in different parts of the world. Giant kelp canopy is very dynamic and can take years to recover from disturbance, challenging comparisons of standing biomass with historical baselines. The Santa Barbara Coastal LTER (SBC LTER), curates a time series of Landsat sensed surface cover and biomass for giant kelp in the west coast of North America. In the last decade, this resource has been fundamental to understanding the species' population dynamics and drivers. However, simple ready‐to‐use summary statistics aimed at classifying regional kelp decline or recovery are not readily available to stakeholders and coastal managers. To this end, we describe here two simple metrics made available through the R package kelpdecline. First, the proportion of Landsat pixels in decline (PPD), in which current biomass is compared with a historical baseline, and second, a pixel occupancy trend (POT), in which current year pixel occupancy is compared to the time‐series long probability of occupancy. The package produces raster maps and output tables summarizing kelp decline and trends over a 0.25 × 0.25° scale. Using kelpdecline, we show how sensitivity analysis on PPD parameter variation can increase the confidence of kelp decline estimates. [ABSTRACT FROM AUTHOR]

Spatial synchrony, the tendency for populations across space to show correlated fluctuations, is a fundamental feature of population dynamics, linked to central topics of ecology such as population cycling, extinction risk, and ecosystem stability. A common mechanism of spatial synchrony is the Moran effect, whereby spatially synchronized environmental signals drive population dynamics and hence induce population synchrony. After reviewing recent progress in understanding Moran effects, we here elaborate a general theory of how Moran effects of different environmental drivers acting on the same populations can interact, either synergistically or destructively, to produce either substantially more or markedly less population synchrony than would otherwise occur. We provide intuition for how this newly recognized mechanism works through theoretical case studies and application of our theory to California populations of giant kelp. We argue that Moran interactions should be common. Our theory and analysis explain an important new aspect of a fundamental feature of spatiotemporal population dynamics. [ABSTRACT FROM AUTHOR]

The early life history of decapod species involves several stages and ontogeny-related shifts in habitat requirements and behaviour. Early publications have reported that, in the San Jorge Gulf (45–47°S), Argentina, juvenile southern king crab Lithodessantolla (Molina, 1782) (SKC) remain in rocky coastal habitats for at least three years, prior to their migration to soft bottoms. In this study, we analysed the gregarious behaviour of juvenile SKCs and its relation with moulting activity through the early ontogeny of the species. Different aggregation patterns were observed in SKC juveniles during sampling. These aggregation patterns were related to an increase in moulting activity. SKC 1+ and 2+ formed small groups of 7–31 juveniles in holes or cracks at shallower depths. A large aggregation was recorded in November 2014 associated with Macrocystis pyrifera forests. This aggregation involved advanced juveniles 3+, probably at the end of their stay in the coastal environment. Our results suggest that the aggregation of juvenile SKCs is related to high moulting activity and that differences in the aggregation patterns are related to ontogeny. The aggregation of advanced juveniles may reflect a (re)synchronous moult prior to a coordinated abandonment of the coastal environment. The aggregation behaviour of SKC juveniles is related to an increase in moulting activity. The aggregation pattern exhibits differences related to the size/age of SKC juveniles. SKCs form large aggregations at the end of their stay in coastal environments. [ABSTRACT FROM AUTHOR]

Disentangling the roles of the external environment and internal biotic drivers of plant population dynamics is challenging due to the absence of relevant physiological and abundance information over appropriate space and time scales. Remote observations of giant kelp biomass and photosynthetic pigment concentrations are used to show that spatiotemporal patterns of physiological condition, and thus growth and production, are regulated by different processes depending on the scale of observation. Nutrient supply was linked to regional scale (>1 km) physiological condition dynamics, and kelp forest stands were more persistent where nutrient levels were consistently high. However, on local scales (