Depth Dependent Relationships between Temperature and Ocean Heterotrophic Prokaryotic Production

9 páginas, 2 figuras, 1 tabla.-- This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these termsCorrigendum: Depth Dependent Relationships between Temperature and Ocean Heterotrophic Prokaryotic Production, Frontiers in Marine Science 4: 91 (2017) https://doi.org/10.3389/fmars.2017.00091Marine prokaryotes play a key role in cycling of organic matter and nutrients in the ocean. Using a unique dataset (>14,500 samples), we applied a space-for-time substitution analysis to assess the temperature dependence of prokaryotic heterotrophic production (PHP) in epi- (0–200 m), meso- (201–1000 m) and bathypelagic waters (1001–4000 m) of the global ocean. Here, we show that the temperature dependence of PHP is fundamentally different between these major oceanic depth layers, with an estimated ecosystem-level activation energy (Ea) of 36 ± 7 kJ mol−1 for the epipelagic, 72 ± 15 kJ mol−1 for the mesopelagic and 274 ± 65 kJ mol−1 for the bathypelagic realm. We suggest that the increasing temperature dependence with depth is related to the parallel vertical gradient in the proportion of recalcitrant organic compounds. These Ea predict an increased PHP of about 5, 12, and 55% in the epi-, meso-, and bathypelagic ocean, respectively, in response to a water temperature increase by 1°C. Hence, there is indication that a major thus far underestimated feedback mechanism exists between future bathypelagic ocean warming and heterotrophic prokaryotic activityFinancial support for this project was provided by the Australian Institute of Marine Science (AIMS) and a grant from the Carlsberg Foundation to CL. XA, XM and JG were funded by the Malaspina expedition 2010 (grant n° CSD2008–00077) and HOTMIX (grant n° CTM2011–30010–C02–02) projects. TR was supported by the PADOM project (Austrian Science Fund grant n° P23221-B11). GH was funded by the Austrian Science Fund (FWF) project I486-B09 and by the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No. 268595 (MEDEA project).Peer reviewe

Annual cycles of bacterioplankton biomass and production suggest a general switch between temperature and resource control in temperate coastal ecosystems

Factors regulating the biomass and flux of organic carbon through heterotrophic bacterioplankton were examined monthly in the southern Bay of Biscay during 2006 and 2007. Temperature and resource supply were able to explain significantly changes in bacterial biomass (539–1389 mg C m−2) and production (5.4–93 mg C m−2 day−1), although at different periods of the year. A switch between the relative strength of both factors in the spring–summer transition seems to be a general feature in temperate coastal waters.Versión del edito

Regularidades estacionales en la producción primaria y los parámetros fotosintéticos en una estación costera del NO Mediterráneo

We carried out monthly photosynthesis-irradiance (P-E) experiments with the 14C-method for 12 years (2003–2014) to determine the photosynthetic parameters and primary production of surface phytoplankton in the Blanes Bay Microbial Observatory, a coastal sampling station in the NW Mediterranean Sea. Our goal was to obtain seasonal trends and to establish the basis for detecting future changes of primary production in this oligotrophic area. The maximal photosynthetic rate PBmax ranged 30-fold (0.5-15 mg C mg Chl a–1 h–1), averaged 3.7 mg C mg Chl a–1 h–1 (±0.25 SE) and was highest in August and lowest in April and December. We only observed photoinhibition twice. The initial or light-limited slope of the P-E relationship, αB, was low, averaging 0.007 mg C mg Chl a–1 h–1 (μmol photons m–2 s–1)–1 (±0.001 SE, range 0.001-0.045) and showed the lowest values in spring (April-June). The light saturation parameter or saturation irradiance, EK, averaged 711 μmol photons m–2 s–1 (± 58.4 SE) and tended to be higher in spring and lower in winter. Phytoplankton assemblages were typically dominated by picoeukaryotes in early winter, diatoms in late autumn and late winter, dinoflagellates in spring and cyanobacteria in summer. Total particulate primary production averaged 1.45 mg C m-3 h–1 (±0.13 SE) with highest values in winter (up to 8.50 mg C m-3 h–1) and lowest values in summer (summer average, 0.30 mg C m-3 h–1), while chlorophyll-specific primary production averaged 2.49 mg C mg Chl a–1 h–1 (±0.19, SE) and peaked in summer (up to 12.0 mg C mg Chl a–1 h–1 in August). 14C-determined phytoplankton growth rates varied between ca. 0.3 d–1 in winter and 0.5 d–1 in summer and were within 60-80% of the maximal rates of growth, based on PBmax. Chlorophyll a was a good predictor of primary production only in the winter and autumn. Seasonality appeared to explain most of the variability in the studied variables, while phytoplankton composition played a minor role. Daily integrated primary production was fairly constant throughout the year: similar to previous oxygen-based estimates in winter but considerably lower than these in summer. The difference between 14C- and oxygen-based estimates of primary production could be explained by community respiration. Annually integrated primary production amounted to a rather modest 48 g C m–2 yr–1 (equivalent to 130 mg C m–2 d–1). Although no interannual patterns were detected, our work soundly establishes the seasonal trends for the coastal NW Mediterranean, therefore setting the basis for future detection of change.Hemos llevado a cabo mediciones mensuales de la relación entre fotosíntesis e irradiancia (curvas P-E) con el método del 14C durante 12 años (2003-2014), para obtener los parámetros fotosintéticos y la producción primaria del fitoplancton superficial en el Observatorio Microbiano de la Bahía de Blanes, una estación de muestreo costera en el noroeste del Mediterráneo. Nuestro objetivo era determinar las tendencias estacionales y establecer la línea de base para detectar cambios futuros de la producción primaria en esta área oligotrófica. La tasa fotosintética máxima PBmaxosciló 30 veces (0.5 a 15 mg C mg Chl a–1 h–1), con un promedio de 3.7 mg C mg Chl a–1 h–1 (±0.25, error estándar), y fue máxima en agosto y mínima en abril y diciembre. Sólo se observó fotoinhibicion dos veces. La pendiente inicial de la curva P-E, αB, fue baja, con un promedio de 0.007 mg C mg Chl a–1 h–1 (µmol fotones m–2 s–1)–1 (error estándar ±0.001, rango de 0.001-0.045) y presentó los valores más bajos en primavera (abril-junio). El parámetro de saturación de irradiancia, EK, presentó un promedio de 711 µmol fotones m–2 s–1 (±58.4, error estándar) y tendió a ser mayor en primavera y menor en invierno. El fitoplancton estuvo típicamente dominado por picoeucariotas a principios de invierno, diatomeas a finales de otoño y en el invierno avanzado, dinoflagelados en primavera, y cianobacterias en verano. La producción primaria particulada total promedió 1.45 m–3 h–1 (±0.13 error estándar) con máximos en invierno (hasta 8.50 mg C m–3 h–1) y mínimos en verano (media en verano, 0.30 mg C m–3 h–1), mientras que la producción primaria por unidad de clorofila promedió 2.49 mg C mg Chl a–1 h–1 (±0.19, error estándar) y alcanzó su punto máximo en verano (hasta 12.0 mg C mg Chl a–1 h–1 en agosto). Las tasas de crecimiento del fitoplancton determinadas por 14C oscilaron entre ca. 0.3 d–1 en invierno y 0.5 d–1 en verano, siendo 60-80% de las tasas máximas de crecimiento basadas en los valores de PBmax. La clorofila a resultó ser un buen predictor de la producción primaria sólo en el invierno y el otoño. La estacionalidad explica la mayor parte de la variabilidad en las variables estudiadas, mientras que la composición del fitoplancton juega un papel menor. La producción primaria integrada diaria fue bastante constante durante todo el año, similar a estimaciones anteriores con mediciones de oxígeno en invierno, pero considerablemente más bajas en verano. La diferencia entre las estimaciones de la producción primaria por 14C y las estimaciones en base al oxígeno podrían explicarse por la respiración de la comunidad. Anualmente la producción primaria integrada ascendió a valores más bien modestos de 48 g C m–2 año–1 (equivalentes a 130 mg C m–2 d–1). Aunque no se detectaron patrones interanuales, nuestro trabajo establece las tendencias estacionales para la producción primaria en el litoral Mediterráneo noroccidental, y supone la línea de base para la detección de cambios futuros

Export and turnover of transparent exopolymer particles into the deep ocean

2nd Meeting of the Iberian Ecological Society (SIBECOL), XXI conference of the Iberian Association of Limnology (AIL) and 21st National Congress of the Portuguese Ecological Society (SPECO), 3-8 July 2022, AveiroAcidic polysaccharides released by phytoplankton and prokaryotic heterotrophs promote the formation of gel-like transparent exopolymer particles (TEPs). TEPs play a key role in the biological carbon pump due to their carbon-rich composition and their ability to coagulate and sink towards the deep ocean. Yet, very little is known about TEP distribution, export, and turnover at a global scale, particularly at deep ocean depths. We provide the first inventory of TEP from the surface up to 4000 m depth in the Atlantic, Indian, and Pacific Oceans and have assessed their contribution to carbon export into the deep ocean. Primary production determines TEP concentration above the deep chlorophyll maximum, and prokaryotic biomass also contributes in deeper waters. In the deep ocean waters, TEP concentrations are lower and mirror the concentrations in the surface, evidencing the importance of TEP sinking both at the export depth (200 m) with a global value of 2.9 Pg C year-1 and at the sequestration depth (1000 m) of 0.9 Pg C year-1 of particulate carbon. However, incubation experiments across ocean basins depicted rapid TEP turnover rates of 71 and 333 days (on average) within the export and sequestration depths, respectively. These findings reveal that the export of carbon by TEP sinking towards deep oceans escapes from long-term paths of the global carbon cycleN

Past and Future Grand Challenges in Marine Ecosystem Ecology

International audienceFrontiers in Marine Science launched the Marine EcosystemsEcology (FMARS-MEE) section in2014, with a paper that identified eight grand challenges for the discipline (Borja, 2014). Sincethen, this section has published a total of 370 papers, including 336 addressing aspects of thosechallenges. As editors of the journal, with a wide range of marine ecology expertise, we felt it wastimely to evaluate research advances related to those challenges; and to update the scope of thesection to reflect the grand challenges we envision for the next 10 years. This output will matchwith the United Nations (UN) Decade on Oceans Science for Sustainable Development (DOSSD;Claudet et al., 2020), UN Decade of Ecosystems Restoration (DER;Young and Schwartz, 2019), andthe UN Sustainable Development Goals (SDGs;Visbeck et al., 2014

Temperature dependence of plankton community metabolism in the subtropical and tropical oceans

Here we assess the temperature dependence of the metabolic rates (gross primary production (GPP), community respiration (CR), and the ratio GPP/CR) of oceanic plankton communities. We compile data from 133 stations of the Malaspina 2010 Expedition, distributed among the subtropical and tropical Atlantic, Pacific, and Indian oceans. We used the in vitro technique to measured metabolic rates during 24 h incubations at three different sampled depths: surface, 20%, and 1% of the photosynthetically active radiation measured at surface. We also measured the % of ultraviolet B radiation (UVB) penetrating at surface waters. GPP and CR rates increased with warming, albeit different responses were observed for each sampled depth. The overall GPP/CR ratio declined with warming. Higher activation energies (Ea) were derived for both processes (GPPChla = 0.97; CRChla = 1.26; CRHPA = 0.95 eV) compared to those previously reported. The Indian Ocean showed the highest Ea (GPPChla = 1.70; CRChla = 1.48; CRHPA = 0.57 eV), while the Atlantic Ocean showed the lowest (GPPChla = 0.86; CRChla = 0.77; CRHPA = 0.13 eV). We believe that the difference between previous assessments and the ones presented here can be explained by the overrepresentation of Atlantic communities in the previous data sets. We found that UVB radiation also affects the temperature dependence of surface GPP, which decreased rather than increased under high levels of UVB. Ocean warming, which causes stratification and oligotrophication of the subtropical and tropical oceans, may lead to reduced surface GPP as a result of increased penetration of UVB radiation.En prens

Informe sobre la actividad realizada en el laboratorio de radioactividad del BIO Hespérides durante la campaña MATER 3 (18 mayo-27 mayo 1998)

Peer Reviewe

Producción primaria particulada y disuelta en sistemas planctónicos marinos: variabilidad de mesoescala y acoplamiento con la producción bacteriana heterotrófica

Memoria de tesis doctoral presentada por Xosé Angelu Gutiérrez Morán para obtener el título de Doctor en Biología por la Universidad de Oviedo (UAB), realizada bajo la dirección de la Dra. Marta Estrada Miyares del Institut de Ciències del Mar (ICM-CSIC).-- 254 pagesLa tesis se centra en el reparto de la producción fitoplanctónica de carbono orgánico en particulado(POC) y disuelto (DOC) en ecosistemas pelágicos, y el acoplamiento fitoplancton-bacterioplancton a través del DOC fitoplanctónico. Se abordan aspectos metodológicos relacionados con la filtración, y se describen los cambios que el uso de diferentes tipos de filtro tienen sobre la estructura de las comunidades picoplanctónicas, la actividad bacteriana en la fracción filtrada y las estimaciones de ambas fracciones de la producción primaria. Se estudiaron las relaciones entre fotosíntesis e irradiancia y la producción primaria integrada en dos áreas del Mediterranea SO caracterizadas por una elevada heterogeneidad física, traducida en las variables biológicas estudiadas. En aguas antárticas se usó una aproximación cinética y análisis compartimental, para identificar algunos patrones en el porcentaje de la producción primaria que se libera en forma disuelta y un estrecho grado de acoplamiento entre algas y bacterias heterotróficas por medio de los compuestos algales.Peer reviewedPeer Reviewe

Short-term variability of photosynthetic parameters and particulate and dissolved primary production in the Alboran Sea (SW Mediterranean)

15 pages, 11 figures, 4 tablesThe short-term variability of photosynthesis-irradiance ( P -E) relationships and inte- grated primary production at 3 stations (Stns A, B, C in a coastal-offshore gradient) located across the Western Alboran Sea Gyre (SW Mediterranean) were investigated during a High Frequency Flux Experiment (1 to 16 May 1998). Photosynthetic production of total, particulate and dissolved organic carbon (TOC, POC and DOC respectively) was considered separatedly in 34 experiments. Photosynthetic parameters were calculated for TOC and POC data. For POC measurements, maximum photo- synthetic rate (P Bm POC) and the initial slope of the P-E curve (α) varied between 0.59 and 6.25 mg C (mg chl a) –1 h –1 and 0.0023 and 0.0182 mg C (mg chla)–1 h–1 (μmol photons m–2 s –1) –1, respectively, and were significantly correlated, showing a similar decrease with depth. No photoinhibition was detected at any depth and the light saturation parameter ( E k ) was on average 251 μmol photons m –2 s –1, suggesting that phytoplankton assemblages were acclimated to high irradiance levels in the whole area. Percent extracellular release (PER) obtained for each experimental irradiance (PER E = DOC/ [POC+DOC]) showed an inverse relationship with irradiance when data from all the P-E experiments were pooled. A light-saturated chl a-normalized DOC production rate ( P Bm DOC) was calculated as P Bm TOC – P Bm POC, and PERm values calculated as P Bm DOC /P Bm TOC tended to increase with depth. Integrated particulate and total primary production varied considerably (23- and 35-fold, respectively), but tended to decrease along a coastal-offshore gradient. During the cruise, a subsurface phytoplankton bloom was advected into Stn A, increasing primary production rates up to 1 g C m–2 d–1. Average particulate primary production was 632 mg C m–2 d–1 at Stn A, 388 mg C m–2 d–1 at Stn B and 330 mg C m–2 d –1 at Stn C, with dissolved primary production ranging from 4 to 44% of total values. Integrated primary production was significantly correlated with surface chl a but not with integrated chla. This finding has implications for the estimation of regional primary production based on remote sensing of near-surface pigments. Altogether, the results confirmed that the high hydrodynamism of the Alboran Sea was associated with marked biological variability and episodic high primary production eventsPeer reviewe