Bacterial vs. zooplankton control of sinking particle flux in the ocean\u27s twilight zone

The downward flux of particulate organic carbon (POC) decreases significantly in the oceanÂs mesopelagic or ‘twilight’ zone due both to abiotic processes and metabolism by resident biota. Bacteria and zooplankton solubilize and consume POC to support their metabolism, but the relative importance of bacteria vs. zooplankton in the consumption of sinking particles in the twilight zone is unknown. We compared losses of sinking POC, using differences in export flux measured by neutrally buoyant sediment traps at a range of depths, with bacteria and zooplankton metabolic requirements at the Hawaii Ocean Time‐series station ALOHA in the subtropical Pacific and the Japanese times‐series site K2 in the subarctic Pacific. Integrated (150‐1,000 m) mesopelagic bacterial C demand exceeded that of zooplankton by up to 3‐fold at ALOHA, while bacteria and zooplankton required relatively equal amounts of POC at K2. However, sinking POC flux was inadequate to meet metabolic demands at either site. Mesopelagic bacterial C demand was 3‐ to 4‐fold (ALOHA), and 10‐fold (K2) greater than the loss of sinking POC flux, while zooplankton C demand was 1‐ to 2‐fold (ALOHA), and 3‐ to 9‐fold (K2) greater (using our ‘middle’ estimate conversion factors to calculate C demand). Assuming the particle flux estimates are accurate, we posit that this additional C demand must be met by diel vertical migration of zooplankton feeding at the surface and by carnivory at depth—with both processes ultimately supplying organic C to mesopelagic bacteria. These pathways need to be incorporated into biogeochemical models that predict global C sequestration in the deep sea

CTD profile data from the R/V Neil Armstrong cruise AR16 in the Western North Atlantic Ocean from 2017-05-04 to 2017-05-20

Dataset: AR16_CTDCTD profile data from the R/V Neil Armstrong cruise AR16 in the Western North Atlantic Ocean from 2017-05-04 to 2017-05-20. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/747051NSF Division of Ocean Sciences (NSF OCE) OCE-153634

Inorganic nutrients (PO4, SiOH4, NO3, NO2, NH4) from R/V Knorr cruise KN207-01 from the southern tip of Nova Scotia to Bermuda in 2012 (SargassoSeaLipids project)

Dataset: inorganic nutrientsInorganic nutrients (PO4, SiOH4, NO3, NO2, NH4) from R/V Knorr cruise KN207-01 from the southern tip of Nova Scotia to Bermuda in 2012. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/3985NSF Division of Ocean Sciences (NSF OCE) OCE-103114

Bottle profile data from the R/V Neil Armstrong cruise AR16 in the Western North Atlantic Ocean from 2017-05-04 to 2017-05-20

Dataset: AR16_BottleBottle profile data from the R/V Neil Armstrong cruise AR16 in the Western North Atlantic Ocean from 2017-05-04 to 2017-05-20. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/747267NSF Division of Ocean Sciences (NSF OCE) OCE-153634

Water column phosphate data from RV/Atlantic Explorer AE1812, May 2018

Dataset: AE1812 Water column phosphate dataThis dataset includes water column phosphate data from RV/Atlantic Explorer AE1812, May 2018. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/762824NSF Division of Ocean Sciences (NSF OCE) OCE-1558490, NSF Division of Ocean Sciences (NSF OCE) OCE-1558506, NSF Division of Ocean Sciences (NSF OCE) OCE-153634

Redox data from RV/Atlantic Explorer AE1812 in the northwest Atlantic, May 2018

Dataset: AE1812 Redox dataThis dataset includes redox data from RV/Atlantic Explorer AE1812 in the northwest Atlantic, May 2018. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/762772NSF Division of Ocean Sciences (NSF OCE) OCE-1558490, NSF Division of Ocean Sciences (NSF OCE) OCE-1558506, NSF Division of Ocean Sciences (NSF OCE) OCE-153634

Station location information from R/V Atlantic Explorer cruise AE1409 in the Western Tropical North Atlantic from May 2014 (P Processing by Tricho project)

Dataset: Stations_AE1409Station location information from R/V Atlantic Explorer cruise AE1409 in the Western Tropical North Atlantic from May 2014 (P Processing by Tricho project). For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/709693NSF Division of Ocean Sciences (NSF OCE) OCE-1332898, NSF Division of Ocean Sciences (NSF OCE) OCE-133291

Trichodesmium data from R/V Atlantic Explorer cruise AE1409 in the Western Tropical North Atlantic from May 2014 (P Processing by Tricho project)

Dataset: Trichodesmium_AE1409Trichodesmium data from R/V Atlantic Explorer cruise AE1409 in the Western Tropical North Atlantic from May 2014 (P Processing by Tricho project). For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/709621NSF Division of Ocean Sciences (NSF OCE) OCE-1332898, NSF Division of Ocean Sciences (NSF OCE) OCE-133291

Phosphate redox data from cruise AE1409 from R/V Atlantic Explorer AE1409 in the Western Tropical North Atlantic from May 2014 (P Processing by Tricho project)

Dataset: P_redox_AE1409Phosphate redox data from cruise AE1409 from R/V Atlantic Explorer AE1409 in the Western Tropical North Atlantic from May 2014 (P Processing by Tricho project). Sampling was conducted aboard the R/V Atlantic Explorer during a cruise in May of 2014. Water samples for whole community analyses were collected from Niskin bottles deployed on a rosette with a CTD. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/709104NSF Division of Ocean Sciences (NSF OCE) OCE-1332898, NSF Division of Ocean Sciences (NSF OCE) OCE-133291

Trichodesmium AHL amendment metatranscriptomic reads accessions and metadata

Dataset: Trichodesmium AHL metatranscriptomes_AE1409Trichodesmium is a marine, diazotrophic cyanobacterium that plays a central role in the biogeochemical cycling of carbon and nitrogen. Colonies ubiquitously co-occur with a diverse microbiome of heterotrophic bacteria. Here we show that manipulation of the microbiome with quorum sensing acyl homoserine lactone (AHL) molecules significantly modulated rates of N2 fixation by Trichodesmium collected from the western North Atlantic, with both positive and negative effects of varied magnitude. Changes in Trichodesmium N2 fixation did not clearly correlate with changes in microbiome composition or geochemical patterns. Metatranscriptome sequencing revealed significant changes in the relative abundance of microbiome transcripts encoding metabolic functions consistent with quorum sensing responses in model bacteria. There was little overlap in specific microbiome transcriptional responses to AHL addition between stations, and this variability in microbiome gene expression may underpin the heterogeneous changes in Trichodesmium N2 fixation. These data suggest the microbiome could play a large and previously overlooked role in modulating Trichodesmium N2 fixation. This metadata form describes the metatranscriptomic sequencing reads that were used in the study. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/746654NSF Division of Ocean Sciences (NSF OCE) OCE-1332898, NSF Division of Ocean Sciences (NSF OCE) OCE-133291