Limnology and Oceanography最新文献

{"title":"Macrofaunal contributions to benthic nutrient fluxes revealed by radium disequilibrium","authors":"Isabelle J. Cooper, Jasmin A. Godbold, Amber L. Annett","doi":"10.1002/lno.70033","DOIUrl":"https://doi.org/10.1002/lno.70033","url":null,"abstract":"The benthic flux of nutrients underpins marine food webs, influences conditions for life in the oceans, and contributes to climatic feedback. Estimates of these fluxes' contributions to macro‐ and micronutrient cycles are, however, highly variable, generating significant uncertainty in biogeochemical models. Traditional benthic flux methodologies have potentially significant limitations, and in geochemically framed studies, there is a notable omission of contributions from macrofaunal activity. <jats:sup>224</jats:sup>Ra/<jats:sup>228</jats:sup>Th disequilibrium is a cutting‐edge geochemical technique for quantifying benthic flux; however, its capacity to incorporate the influence of benthic fauna has not been assessed. Here we present first results using <jats:sup>224</jats:sup>Ra/<jats:sup>228</jats:sup>Th disequilibrium to examine the influence of four macrobenthic infaunal invertebrate species on the flux of macronutrients (, , , ) between the sediment and water column. Overall, estimates from <jats:sup>224</jats:sup>Ra/<jats:sup>228</jats:sup>Th disequilibrium were up to 15 times greater than those derived from commonly used methods, and both <jats:sup>224</jats:sup>Ra and nutrient fluxes differed in the presence of different macrofauna. The greatest efflux (, ) and influx (, ) occurred in the presence of the burrowing actinarian <jats:italic>Edwardsia claparedii</jats:italic>, and <jats:sup>224</jats:sup>Ra flux patterns suggested different mechanisms of influence between species. Notable variability in flux enhancement was also present between individuals of the same species, highlighting the complex relationship between biodiversity and ecosystem functioning. We conclude that <jats:sup>224</jats:sup>Ra/<jats:sup>228</jats:sup>Th disequilibrium is a powerful tool for interdisciplinary biogeochemical and ecological studies, and if applied widely enough may more holistically represent benthic flux dynamics in the natural environment than standard approaches.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"55 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Picophytoplankton act as the primary consumers of excess phosphorus after the spring bloom in the eutrophic Baltic Sea","authors":"Kristian Spilling, Mari Vanharanta, Mariano Santoro, Cristian Villena‐Alemany, Matthias Labrenz, Hans‐Peter Grossart, Kasia Piwosz","doi":"10.1002/lno.70027","DOIUrl":"https://doi.org/10.1002/lno.70027","url":null,"abstract":"Eutrophication in the Baltic Sea has caused an imbalance in the inorganic nitrogen (N) to phosphorus (P) ratio, leaving excess phosphate (PO<jats:sub>4</jats:sub>) after the phytoplankton spring bloom that terminates after N depletion. Using monitoring data, we demonstrated that the PO<jats:sub>4</jats:sub> concentration has continued to increase in the outermost Gulf of Finland during past decades. We further investigated the fate of such excess PO<jats:sub>4</jats:sub> in a two‐week mesocosm (1.2 m<jats:sup>3</jats:sup>) experiment. The starting concentration of PO<jats:sub>4</jats:sub> was 0.66 <jats:italic>μ</jats:italic>M, and treatments included a non‐treated control (control), nitrate addition (N‐add; 3.6 <jats:italic>μ</jats:italic>M), glucose addition (C‐add; 36 <jats:italic>μ</jats:italic>M) and combined nitrate and glucose addition (N + C‐add). The addition of N, both in N‐add and N + C‐add treatments, stimulated nano‐ and microphytoplankton, while the picophytoplankton abundance increased after N depletion. Also, the copepod biomass was positively affected by the N addition. N<jats:sub>2</jats:sub>‐fixing cyanobacteria were present but in low abundance. Carbon addition did not enhance heterotrophic bacterial uptake of PO<jats:sub>4</jats:sub> contrary to our expectations, nor did it affect the phyto‐ or zooplankton community composition. The PO<jats:sub>4</jats:sub> concentration was reduced to ~ 0.4 <jats:italic>μ</jats:italic>M in the control and C‐add treatments and to 0.16 <jats:italic>μ</jats:italic>M in the two N‐amended treatments, with an inorganic N : P uptake ratio of 6.7. These results underscore the role of picophytoplankton in reducing the excess PO<jats:sub>4</jats:sub> pool after the spring bloom, a function traditionally ascribed to bloom‐forming filamentous cyanobacteria in the Baltic Sea.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"58 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phytoplankton absorb mainly red light in lakes with high chromophoric dissolved organic matter","authors":"Salla A. Ahonen, Roger I. Jones, Jukka Seppälä, Kristiina M. Vuorio, Marja Tiirola, Anssi V. Vähätalo","doi":"10.1002/lno.70034","DOIUrl":"https://doi.org/10.1002/lno.70034","url":null,"abstract":"The impact of chromophoric dissolved organic matter (CDOM) on the spectral underwater light field within photosynthetically active radiation (PAR), and the related responses of spectral phytoplankton light absorption are poorly documented in the mixed layer of lakes. We examined how CDOM influences the spectrum of lake optical properties, underwater light field, photons absorbed by phytoplankton, photoacclimation, and chromatic adaptation of phytoplankton in 127 boreal lakes. In lakes with increasing CDOM content, light intensity decreased steeply with depth, but mixed layer depth and mean light intensity of the mixed layer decreased only moderately. Increasing CDOM content red‐shifted the central wavelengths of lake optical properties, underwater light fields, and the photons absorbed by phytoplankton. In study lakes with increasing CDOM content, the highest light availability shifted stepwise from 580 to 650 nm and close to 700 nm. The ratio of chlorophyll <jats:italic>a</jats:italic> concentration to phytoplankton biomass decreased slightly in lakes with higher CDOM content. The absorption coefficient of phytoplankton at blue relative to red wavelengths decreased with increasing CDOM content, indicating decreased blue‐absorbing pigmentation in response to decreased availability of blue light. Surprisingly, the number of red photons (600–700 nm) absorbed by phytoplankton increased with CDOM content below the mid‐point of the euphotic zone. Over the entire water column, red light (600–700 nm) accounted for &gt; 50% of PAR absorption by phytoplankton in 69% of the lakes. The high contribution of red photons to the absorption of PAR by phytoplankton may have photobiological consequences, which are poorly understood and require further study.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi‐endmember mixing and primary productivity drive carbonate system variability on a highly heterogeneous, shallow productive bank","authors":"F. Dylan Titmuss, Jennie E. Rheuban, Louise P. Cameron, Jonathan H. Grabowski, Zhaohui Aleck Wang","doi":"10.1002/lno.70030","DOIUrl":"https://doi.org/10.1002/lno.70030","url":null,"abstract":"This study presents the first high‐resolution spatial analysis of carbonate chemistry on Georges Bank, a highly productive shallow bank located at the southeastern edge of the Gulf of Maine. Despite numerous studies on the hydrography, nutrient chemistry, and biology, regional carbonate chemistry remains unexplored, in particular for near‐bottom conditions. Observations from cruises in May and October 2021 were used to identify multi‐endmember mixing, and a Bayesian mixing model was applied to temperature and salinity to separate water mass mixing from non‐conservative drivers such as net community production, air–sea exchange, and other biogeochemical processes/errors. Major findings from this study indicate that carbonate chemistry is highly heterogeneous and driven by multi‐endmember mixing, although biological production and respiration were notable while air–sea CO<jats:sub>2</jats:sub> exchange was minimal. Five water masses with unique carbonate chemistry were observed that varied by season and with depth, showing complexity that is uncommon in other regions along the US Atlantic coast. In both cruises, a Warm Slope Water intrusion was identified at depth that contained a strong signal of CaCO<jats:sub>3</jats:sub> dissolution during the October cruise, observed in situ for the first time in this region. Under a high emissions scenario, our results suggest that much of the bank's bottom waters may become undersaturated with respect to aragonite by 2100. Together, these findings suggest that the in situ dissolution observed may only worsen with future ocean acidification, with potentially significant implications for ecologically and economically important shellfish species on Georges Bank.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"183 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Activity and control of methanol metabolism in the seawaters across the estuary–coast–shelf continuum","authors":"Guang‐Chao Zhuang, Zhen Zhou, Shi‐Hai Mao, Shuang Li, Xiao‐Jun Li, Qiao Liu, Gui‐Peng Yang","doi":"10.1002/lno.70026","DOIUrl":"https://doi.org/10.1002/lno.70026","url":null,"abstract":"Methanol metabolism is important in marine carbon cycling, while the control of metabolic mode and activity remains poorly constrained, particularly in coastal waters. Here, we investigated the biogeochemical cycling of methanol across the estuary–coast–shelf continuum of the East China Sea. Methanol concentrations varied from &lt; 12.3 to 617.3 nmol L<jats:sup>−1</jats:sup>, decreasing from coast to shelf. The total uptake rates of methanol in the estuary (143.4 ± 29.6 nmol L<jats:sup>−1</jats:sup> d<jats:sup>−1</jats:sup>) and coast (92.3 ± 86.9 nmol L<jats:sup>−1</jats:sup> d<jats:sup>−1</jats:sup>) were much higher than those in the shelf (20.4 ± 33.8 nmol L<jats:sup>−1</jats:sup> d<jats:sup>−1</jats:sup>). While methanol was primarily used as an energy source in the coast and shelf (oxidation/total uptake: &gt; 72.2%), much more methanol was channeled to the biomass (assimilation/total uptake: 31.9–49.7%) in the estuarine waters. As supported by incubation experiments with the addition of nutrients and other C1 compounds, enhanced methanol assimilation suggests the use of methanol as a supplementary source of carbon, while reduced methanol oxidation indicated the competitive utilization of other C1 compounds as an energy source. The estuary and coastal waters acted as net sources of methanol to the atmosphere, while ventilation accounted for &lt; 5.7% of total loss, suggesting that microbial consumption was the dominant pathway of methanol removal. In the shelf, atmospheric deposition replenished surface methanol pools and contributed up to 17.5% ± 16.9% of microbial consumption. These results provided insights into the control of methanol metabolism and assessed the relative importance of different methanol sources and sinks along the estuary–coast–shelf continuum.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"199 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143635725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gross oxygen production and microbial community respiration in the oligotrophic ocean","authors":"Sara Ferrón, Karin M. Björkman, Matthew J. Church, David M. Karl","doi":"10.1002/lno.70023","DOIUrl":"https://doi.org/10.1002/lno.70023","url":null,"abstract":"Uncertainties in the temporal and spatial patterns of marine primary production and respiration limit our understanding of the ocean carbon (C) cycle and our ability to predict its response to environmental changes. Here we present a comprehensive time‐series analysis of plankton metabolism at the Hawaii Ocean Time‐series program site, Station ALOHA, in the North Pacific Subtropical Gyre. Vertical profiles of gross oxygen production (GOP) and community respiration (CR) were quantified using the <jats:sup>18</jats:sup>O‐labeled water method together with net changes in O<jats:sub>2</jats:sub> to Ar ratios during dawn to dusk in situ incubations. Rates of <jats:sup>14</jats:sup>C‐bicarbonate assimilation (<jats:sup>14</jats:sup>C‐based primary production [<jats:sup>14</jats:sup>C‐PP]) were also determined concurrently. During the observational period (April 2015 to July 2020), euphotic zone depth‐integrated (0–125 m) GOP and <jats:sup>14</jats:sup>C‐PP ranged from 35 to 134 mmol O<jats:sub>2</jats:sub> m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup> and 18 to 75 mmol C m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup>, respectively, while CR ranged from 37 to 187 mmol O<jats:sub>2</jats:sub> m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup>. All biological rates varied with depth and season, with seasonality most pronounced in the lower portion of the euphotic zone (75–125 m). The mean annual ratio of GOP to <jats:sup>14</jats:sup>C‐PP was 1.7 ± 0.1 mol O<jats:sub>2</jats:sub> (mol C)<jats:sup>−1</jats:sup>. While previous studies have reported convergence of GOP and <jats:sup>14</jats:sup>C‐PP with depth, we find a less pronounced vertical decline in the GOP to <jats:sup>14</jats:sup>C‐PP ratios, with GOP exceeding <jats:sup>14</jats:sup>C‐PP by 50% or more in the lower euphotic zone. Variability in CR was higher than for GOP, driving most of the variability in the balance between the two.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"24 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143627459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclical prey abundance drives interannual variation in predator diel vertical movement","authors":"Jonathan B. Armstrong, Mark W. Buktenica, Scott F. Girdner, Eric J. Ward","doi":"10.1002/lno.70022","DOIUrl":"https://doi.org/10.1002/lno.70022","url":null,"abstract":"Diel vertical movement (DVM) is a widespread behavior in aquatic ecosystems, occurring across a variety of taxa and water bodies. The factors hypothesized to drive DVM can vary tremendously through time, yet little is known about how DVM changes at interannual timescales. Here we explore how cyclical prey abundance affects predator DVM. Higher consumption levels increase the optimal temperatures for growth in fishes. Thus, annual variation in prey abundance should generate corresponding variation in the depths and temperatures selected during predator DVM. In Crater Lake, one of the deepest and most oligotrophic lakes in the world, <jats:italic>Daphnia</jats:italic> zooplankton exhibit cyclical patterns of abundance. We compiled data spanning four distinct pulses of <jats:italic>Daphnia</jats:italic> and analyzed the response of their predator, kokanee salmon (<jats:italic>Oncorhynchus nerka</jats:italic>). Our data spanned 36 yr for <jats:italic>Daphnia</jats:italic> abundance and kokanee body condition, and 24 yr for kokanee DVM (measured by hydroacoustic surveys). Kokanee exhibited four pulses in body weight and condition that corresponded to the four <jats:italic>Daphnia</jats:italic> pulses, suggesting a strong bottom‐up response. Kokanee altered their DVM in years with <jats:italic>Daphnia</jats:italic> by occurring deeper during the day, where <jats:italic>Daphnia</jats:italic> were concentrated, and shallower at night, where temperatures were &gt; 5°C warmer. By selecting warmer habitat in years with <jats:italic>Daphnia</jats:italic>, kokanee increased their estimated overnight digestion by ~ 25%. Understanding how predators alter DVM and other patterns of cyclical habitat use in response to variation in prey abundance has important implications for understanding predator–prey dynamics, which are highly sensitive to prey encounter rates and maximum consumption rates.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"14 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143627458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Daily Sun-induced chlorophyll fluorescence vs. irradiance curves reflect the photoadaptation of phytoplankton in surface waters","authors":"Yannick Huot,&nbsp;David Antoine,&nbsp;Vincenzo Vellucci","doi":"10.1002/lno.70001","DOIUrl":"10.1002/lno.70001","url":null,"abstract":"<p>Phytoplankton chlorophyll Sun-induced fluorescence is observable in the upwelling light field of the ocean. This allows its observation by radiometers in situ or on satellite sensors. Since it is influenced by both biomass and physiology it can potentially provide information about both. Since fluorescence yield is complementary to photosynthesis and heat in photosystem II, its observation throughout the day provides information on the response of phytoplankton to diel light cycles. Here we use a time series collected in the northwestern Mediterranean Sea (BOUSSOLE site) to extract photophysiological parameters of phytoplankton using the Sun-induced fluorescence and as well as with an active chlorophyll fluorometer. The daily resolved patterns are consistent with photoacclimation and photoadaptation processes and reflect seasonal variations of the mixed-layer average irradiance. We also show that fluorescence yields derived from satellite measurements (MODIS) at the same location are not correlated to these patterns, confirming the limited influence of photoacclimation and photoadaptation on the satellite-derived chlorophyll fluorescence yield near solar noon.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 4","pages":"1001-1015"},"PeriodicalIF":3.8,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Responses of microbial communities and greenhouse gas production to land use change in mangrove wetland sediments","authors":"Xianbiao Lin, Bingqian Zhu, Yongyi Peng, Genmei Lin, Dongyao Sun, Wangwang Ye","doi":"10.1002/lno.70028","DOIUrl":"https://doi.org/10.1002/lno.70028","url":null,"abstract":"Tidal wetland reclamation is a worldwide issue that profoundly alters ecological functions and ecosystem service provisions; however, its impacts on sediment microbial communities and functions remain poorly understood. Here, we investigated the spatial and seasonal patterns of greenhouse gas (GHG) production in response to land use change in mangrove wetlands and elucidated the underlying mechanisms by integrating environmental parameters and microbial community characteristics. In the time period studied, land use change substantially reduced the sediment organic matter content, microbial community richness and diversity, and CO<jats:sub>2</jats:sub> production rates. Converting mangroves to drier land cover types, namely orchard and vegetable field, significantly diminished reducing substrates (sulfide, Fe<jats:sup>2+</jats:sup>, and NH<jats:sub>4</jats:sub><jats:sup>+</jats:sup>), microbial network complexity and stability, and CH<jats:sub>4</jats:sub> production rates, while increasing N<jats:sub>2</jats:sub>O production rates. In contrast, these parameters showed the opposite trend following the conversion of mangroves to flooded aquaculture pond. Overall GHG production rate in mangrove wetlands was 399.8 mg CO<jats:sub>2</jats:sub>e kg<jats:sup>−1</jats:sup> d<jats:sup>−1</jats:sup>, which respectively decreased by 68.83%, 69.86%, and 30.84% in orchard, vegetable field, and aquaculture pond. Microbial community richness and network complexity and stability were strongly related to the production rates of CH<jats:sub>4</jats:sub> and N<jats:sub>2</jats:sub>O, rather than CO<jats:sub>2</jats:sub>, which can be better indicators of specialized functions (CH<jats:sub>4</jats:sub> and N<jats:sub>2</jats:sub>O production). Therefore, preserving microbial “interaction” could be important to mitigate the negative effects of microbial community richness and diversity loss caused by human activities in aquatic environments. Future research should consider environmental conditions and microbial community diversity, composition, interactions, and activities to gain a comprehensive understanding of ecosystem functions.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"183 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Autonomous observations enhance our ability to observe the biological carbon pump across diverse carbon export regimes","authors":"Shawnee Traylor, David P. Nicholson, Samantha J. Clevenger, Ken O. Buesseler, Eric D'Asaro, Craig M. Lee","doi":"10.1002/lno.70002","DOIUrl":"https://doi.org/10.1002/lno.70002","url":null,"abstract":"The expansion of autonomous observation platforms offers vast opportunities for analyzing ocean ecosystems and their role in carbon export. As part of the EXport Processes in the Ocean from RemoTe Sensing campaign, we autonomously measured the productivity regimes in two contrasting end‐member ecosystem states. The first campaign occurred in the subpolar North Pacific near Ocean Station Papa (Site 1), characterized by iron limitation and a highly regenerative regime. The second captured a springtime bloom in the North Atlantic (Site 2), which typically drives efficient export of productivity. Using a combination of floats and gliders carrying biogeochemical sensors, we quantified gross primary productivity, net community production, and organic carbon export potential (<jats:italic>f</jats:italic>C<jats:sub>org</jats:sub>) to assess biological carbon pump strength. Site 2 demonstrated higher cruise‐period productivity, with roughly 5× the gross primary productivity and 13× the euphotic zone net community production seen at Site 1. Greater export efficiency at Site 2 was reflected in numerous indices, such as the ratio of new production to net primary productivity (<jats:italic>ef</jats:italic>‐ratio; Site 1: 0.33; Site 2: 0.73), the ratio of sinking particulate organic carbon to net primary productivity (<jats:italic>ez</jats:italic>‐ratio; Site 1: 0.24; Site 2: 0.69), and mean daily <jats:italic>f</jats:italic>C<jats:sub>org</jats:sub> (Site 1: 3.4 ± 0.7; Site 2: 20.3 ± 2.3 mmol C m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup>). Together with particulate organic carbon flux derived from thorium‐234 measurements, we infer that observed low net community production was almost entirely routed to sinking particulate organic carbon at Site 1, while the much higher net community production at Site 2 resulted in near‐equal proportions routed to dissolved organic carbon production and sinking particulate organic carbon.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"11 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143607807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}