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In 2015, the largest recorded harmful algal bloom (HAB) occurred in the Northeast Pacific, causing nearly 100 million dollars in damages to fisheries and killing many protected marine mammals. Dominated by the toxic diatom Pseudo-nitzschia australis, this bloom produced high levels of the neurotoxin domoic acid (DA). Through molecular and transcriptional characterization of 52 near-weekly phytoplankton net-tow samples collected at a bloom hotspot in Monterey Bay, California, we identified active transcription of known DA biosynthesis (dab) genes from the three identified toxigenic species, including P. australis as the primary origin of toxicity. Elevated expression of silicon transporters (sit1) during the bloom supports the previously hypothesized role of dissolved silica (Si) exhaustion in contributing to bloom physiology and toxicity. We find that coexpression of the dabA and sit1 genes serves as a robust predictor of DA one week in advance, potentially enabling the forecasting of DA-producing HABs. We additionally present evidence that low levels of iron could have colimited the diatom population along with low Si. Iron limitation represents an overlooked driver of both toxin production and ecological success of the low-iron-adapted Pseudo-nitzschia genus during the 2015 bloom, and increasing pervasiveness of iron limitation may fuel the escalating magnitude and frequency of toxic Pseudo-nitzschia blooms globally. Our results advance understanding of bloom physiology underlying toxin production, bloom prediction, and the impact of global change on toxic blooms. [ABSTRACT FROM AUTHOR]

Climate change is an existential threat to the environmental and socioeconomic sustainability of the coastal zone and impacts will be complex and widespread. Evidence from California and across the United States shows that climate change is impacting coastal communities and challenging managers with a plethora of stressors already present. Widespread action could be taken that would sustain California's coastal ecosystems and communities. In this perspective, we highlight the main threat to coastal sustainability: the compound effects of episodic events amplified with ongoing climate change, which will present unprecedented challenges to the state. We present two key challenges for California's sustainability in the coastal zone: 1) accelerating sea-level rise combined with storm impacts, and 2) continued warming of the oceans and marine heatwaves. Cascading effects from these types of compounding events will occur within the context of an already stressed system that has experienced extensive alterations due to intensive development, resource extraction and harvesting, spatial containment, and other human use pressures. There are critical components that could be used to address these immediate concerns, including comanagement strategies that include diverse groups and organizations, strategic planning integrated across large areas, rapid implementation of solutions, and a cohesive and policy relevant research agenda for the California coast. Much of this has been started in the state, but the scale could be increased, and timelines accelerated. The ideas and information presented here are intended to help expand discussions to sharpen the focus on how to encourage sustainability of California's iconic coastal region. [ABSTRACT FROM AUTHOR]

Managing natural resources under large-scale environmental fluctuations like the El Nino Southern Oscillation (ENSO) is likely to become increasingly important under climate change. Forecasts of environmental conditions are improving, but the best response to an unfavorable forecast remains unclear; many practitioners advocate reducing harvest as a more precautionary approach, while prior economic theory favors increasing harvest. Using logistic and age-structured fisheries models, we show that informational constraints--uncertain stock estimates and restrictions on harvest policies--play a central role in choosing how to respond to a forecasted shock. With perfect knowledge and no policy constraints, risk-neutral managers should increase harvest when a negative shock is forecast. However, informational constraints may drive the optimal response to a forecast of a negative shock toward or away from precaution. Precautionary forecast responses arise when informational constraints make the harvest policy insufficiently sensitive to the true resource status. In contrast, uncertainty about the stock size can lead to more aggressive forecast responses when stock dynamics are nonlinear and not all fish are susceptible to fishing. La gestion des ressources naturelles en reponse a des fluctuations environnementales a grande echelle comme l'oscillation australe El Nino (ENSO) sera vraisemblablement de plus en plus importante dans un contexte de changements climatiques. Les predictions concernant les conditions environnementales s'ameliorent, mais la meilleure reaction a une prediction defavorable demeure incertaine; de nombreux specialistes recommandent la reduction des prises comme approche prudente, alors que la theorie economique existante favorise une hausse des prises. En utilisant des modeles logistiques et de peches structures par age, nous montrons que des contraintes associees a l'information, comme des estimations des stocks incertaines et des restrictions aux politiques de prises, jouent un role central dans la selection de la reaction a un choc predit. Avec des connaissances parfaites et aucune contrainte associee aux politiques, des gestionnaires ayant une approche neutre a l'egard du risque devraient accroitre les prises quand un choc negatif est predit. Cependant, des contraintes associees a l'information pourraient faire en sorte que la reaction optimale a une prediction d'un choc negatif tende vers l'approche prudente ou s'en eloigne. Des reactions prudentes aux predictions sont de mise quand des contraintes associees a l'information rendent les politiques en matiere de prises trop peu sensibles a l'etat reel des ressources. A l'inverse, l'incertitude associee a la taille des stocks peut mener a des reactions moins prudentes aux predictions quand la dynamique des stocks est non lineaire et que tous les poissons ne sont pas susceptibles d'etre peches. [Traduit par la Redaction], Introduction Fluctuations in the physical ocean environment can have major effects on fish and fisheries (Brander 2007; Holland and Herrera 2009; Pinsky and Byler 2015; Dee et al. 2016). Many [...]

Photosynthesis in the surface ocean converts atmospheric CO2 into organic particles, with the fraction sinking to depth representing a major part of the ocean's biological pump. Although sinking particles are known to be altered by attached‐bacteria during transit, most prior organic geochemical data indicated only minor replacement of plankton‐derived particles by bacterial material. We exploit bacteria‐specific biomarkers (d‐amino acids) in a multi‐year sediment trap in the Pacific Ocean (1,200 m) and suggest a different view. Major d‐amino acids were consistently measured at abundance demonstrating widespread accumulation of bacterial material in sinking particles. Bacterial detritus was estimated to account for up to 19% of particulate organic carbon and up to 36% of particulate nitrogen, much higher than cell count‐based values. The bacterial relative contribution increased with decreasing export production. Our results indicate that bacterial material constitutes an underappreciated component of the biological pump, a role expected to rise as the ocean warms. Plain Language Summary: Phytoplankton photosynthesis in the surface ocean plays a critical role in stabilizing atmospheric CO2. It converts CO2 into organic particles that sink and are reworked by colonizing bacteria. Bacteria respire most particles back to CO2 while also transforming some into their cell components. Although the involvement of bacteria can replace the plankton‐derived particles to bacterial material, most past organic geochemical data have suggested that the deep‐sea particles are still comprised mainly of plankton remnants. This renders the contribution of bacterial material to total particle export an unresolved and yet important question, because the source and composition of particles are important to their fate in the ocean. Here, we analyzed bacteria‐specific molecules in deep‐sea sinking particles and found that bacterial organic matter actually made up a large fraction of the particles. In addition, the relative contribution of bacterial material to the sinking particles increased as the total carbon export decreased. This has important implications for the future ocean carbon cycle, because modeling work predicts a scenario of lower carbon export to the deep sea as the ocean warms. In this context, our findings imply a greater importance of bacteria in marine organic matter export and sequestration in a warming ocean. Key Points: We exploit d‐amino acid biomarkers in multi‐year deep‐sea sediment trap time series to evaluate bacterial contribution to total exportBacterial detritus accounts for up to 19 ± 8% of sinking POC and up to 36 ± 14% of PN, making up a large unrecognized part of biological pumpThe relative contribution of bacterial detritus to sinking particles increases with decreased export production [ABSTRACT FROM AUTHOR]

Eastern boundary upwelling systems (EBUS) contribute a disproportionate fraction of the global fish catch relative to their size and are especially susceptible to global environmental change. Here we present the evolution of communities over 50 d in an in situ mesocosm 6 km offshore of Callao, Peru, and in the nearby unenclosed coastal Pacific Ocean. The communities were monitored using multi-marker environmental DNA (eDNA) metabarcoding and flow cytometry. DNA extracted from weekly water samples were subjected to amplicon sequencing for four genetic loci: (1) the V1–V2 region of the 16S rRNA gene for photosynthetic eukaryotes (via their chloroplasts) and bacteria; (2) the V9 region of the 18S rRNA gene for exploration of eukaryotes but targeting phytoplankton; (3) cytochrome oxidase I (COI) for exploration of eukaryotic taxa but targeting invertebrates; and (4) the 12S rRNA gene, targeting vertebrates. The multi-marker approach showed a divergence of communities (from microbes to fish) between the mesocosm and the unenclosed ocean. Together with the environmental information, the genetic data furthered our mechanistic understanding of the processes that are shaping EBUS communities in a changing ocean. The unenclosed ocean experienced significant variability over the course of the 50 d experiment, with temporal shifts in community composition, but remained dominated by organisms that are characteristic of high-nutrient upwelling conditions (e.g., diatoms, copepods, anchovies). A large directional change was found in the mesocosm community. The mesocosm community that developed was characteristic of upwelling regions when upwelling relaxes and waters stratify (e.g., dinoflagellates, nanoflagellates). The selection of dinoflagellates under the salinity-driven experimentally stratified conditions in the mesocosm, as well as the warm conditions brought about by the coastal El Niño, may be an indication of how EBUS will respond under the global environmental changes (i.e., increases in surface temperature and freshwater input, leading to increased stratification) forecast by the IPCC. [ABSTRACT FROM AUTHOR]

Long-term biological time series that monitor ecosystems across the ocean’s full water column are extremely rare. As a result, classic paradigms are yet to be tested. One such paradigm is that variations in coastal upwelling drive changes in marine ecosystems throughout the water column. We examine this hypothesis by using data from three multidecadal time series spanning surface (0 m), midwater (200 to 1,000 m), and benthic (~4,000 m) habitats in the central California Current Upwelling System. Data include microscopic counts of surface plankton, video quantification of midwater animals, and imaging of benthic seafloor invertebrates. Taxon-specific plankton biomass and midwater and benthic animal densities were separately analyzed with principal component analysis. Within each community, the first mode of variability corresponds to most taxa increasing and decreasing over time, capturing seasonal surface blooms and lower-frequency midwater and benthic variability. When compared to local wind-driven upwelling variability, each community correlates to changes in upwelling damped over distinct timescales. This suggests that periods of high upwelling favor increase in organism biomass or density from the surface ocean through the midwater down to the abyssal seafloor. These connections most likely occur directly via changes in primary production and vertical carbon flux, and to a lesser extent indirectly via other oceanic changes. The timescales over which species respond to upwelling are taxon-specific and are likely linked to the longevity of phytoplankton blooms (surface) and of animal life (midwater and benthos), which dictate how long upwelling-driven changes persist within each community. [ABSTRACT FROM AUTHOR]

Omic BON is a thematic Biodiversity Observation Network under the Group on Earth Observations Biodiversity Observation Network (GEO BON), focused on coordinating the observation of biomolecules in organisms and the environment. Our founding partners include representatives from national, regional, and global observing systems; standards organizations; and data and sample management infrastructures. By coordinating observing strategies, methods, and data flows, Omic BON will facilitate the co-creation of a global omics meta-observatory to generate actionable knowledge. Here, we present key elements of Omic BON's founding charter and first activities. [ABSTRACT FROM AUTHOR]