Rising atmospheric CO2 concentrations threaten coral reefs globally by causing ocean acidification (OA) and warming. Yet, the combined effects of elevated pCO2 and temperature on coral physiology and resilience remain poorly understood. While coral calcification and energy reserves are important health indicators, no studies to date have measured energy reserve pools (i.e., lipid, protein, and carbohydrate) together with calcification under OA conditions under different temperature scenarios. Four coral species, Acropora millepora, Montipora monasteriata, Pocillopora damicornis, Turbinaria reniformis, were reared under a total of six conditions for 3.5 weeks, representing three pCO2 levels (382, 607, 741 µatm), and two temperature regimes (26.5, 29.0°C) within each pCO2 level. After one month under experimental conditions, only A. millepora decreased calcification (−53%) in response to seawater pCO2 expected by the end of this century, whereas the other three species maintained calcification rates even when both pCO2 and temperature were elevated. Coral energy reserves showed mixed responses to elevated pCO2 and temperature, and were either unaffected or displayed nonlinear responses with both the lowest and highest concentrations often observed at the mid-pCO2 level of 607 µatm. Biweekly feeding may have helped corals maintain calcification rates and energy reserves under these conditions. Temperature often modulated the response of many aspects of coral physiology to OA, and both mitigated and worsened pCO2 effects. This demonstrates for the first time that coral energy reserves are generally not metabolized to sustain calcification under OA, which has important implications for coral health and bleaching resilience in a high-CO2 world. Overall, these findings suggest that some corals could be more resistant to simultaneously warming and acidifying oceans than previously expected.

Net ecosystem production (NEP) and the overall organic carbon budget for the estuaries along the East Coast of the United States are estimated. We focus on the open estuarine waters, excluding the fringing wetlands. We developed empirical models relating NEP to loading ratios of dissolved inorganic nitrogen to total organic carbon, and carbon burial in the sediment to estuarine water residence time and total nitrogen input across the landward boundary. Output from a data-constrained water quality model was used to estimate inputs of total nitrogen and organic carbon to the estuaries across the landward boundary, including fluvial and tidal-wetland sources. Organic carbon export from the estuaries to the continental shelf was computed by difference, assuming steady state. Uncertainties in the budget were estimated by allowing uncertainties in the supporting model relations. Collectively, U.S. East Coast estuaries are net heterotrophic, with the area-integrated NEP of À1.5 (À2.8, À1.0) Tg C yr À1 (best estimate and 95% confidence interval) and area-normalized NEP of. East Coast estuaries serve as a source of organic carbon to the shelf, exporting 3.4 (2.0, 4.3) Tg C yr À1 or 7.6 (4.4, 9.5) mol C m À2 yr À1. Organic carbon inputs from fluvial and tidal-wetland sources for the region are estimated at 5.4 (4.6, 6.5) Tg C yr À1 or 12 (10, 14) mol C m À2 yr À1 and carbon burial in the open estuarine waters at 0.50 (0.33, 0.78) Tg C yr À1 or 1.1 (0.73, 1.7) mol C m À2 yr À1. Our results highlight the importance of estuarine systems in the overall coastal budget of organic carbon, suggesting that in the aggregate, U.S. East Coast estuaries assimilate (via respiration and burial)~40% of organic carbon inputs from fluvial and tidal-wetland sources and allow~60% to be exported to the shelf.

The biogeochemical seascape of the western Arctic coastal ocean is in rapid transition. Changes in sea ice cover will be accompanied by alterations in sea-air carbon dioxide (CO 2 ) exchange, of which the latter has been difficult to constrain owing to sparse temporal and spatial data sets. Previous assessments of sea-air CO 2 flux have targeted specific subregional areas of the western Arctic coastal ocean. Here a holistic approach is taken to determine the net sea-air CO 2 flux over this broad region. We compiled and analyzed an extensive data set of nearly 600,000 surface seawater CO 2 partial pressure (pCO 2 ) measurements spanning 2003 through 2014. Using space-time colocated, reconstructed atmospheric pCO 2 values coupled with the seawater pCO 2 data set, monthly climatologies of sea-air pCO 2 differences (ΔpCO 2 ) were created on a 0.2°l atitude × 0.5°longitude grid. Sea-air CO 2 fluxes were computed using the ΔpCO 2 grid and gas transfer rates calculated from climatology of wind speed second moments. Fluxes were calculated with and without the presence of sea ice, treating sea ice as an imperfect barrier to gas exchange. This allowed for carbon uptake by the western Arctic coastal ocean to be assessed under existing and reduced sea ice cover conditions, in which carbon uptake increased 30% over the current 10.9 ± 5.7 Tg C (1 Tg = 10 12 g) yr À1 of sea ice-adjusted exchange in the region. This assessment extends beyond previous subregional estimates in the region in an all-inclusive manner and points to key unresolved aspects that must be targeted by future research.

Rising seawater temperature and ocean acidification threaten the survival of coral reefs. The relationship between coral physiology and its microbiome may reveal why some corals are more resilient to these global change conditions. Here, we conducted the first experiment to simultaneously investigate changes in the coral microbiome and coral physiology in response to the dual stress of elevated seawater temperature and ocean acidification expected by the end of this century. Two species of corals, Acropora millepora containing the thermally sensitive endosymbiont C21a and Turbinaria reniformis containing the thermally tolerant endosymbiont Symbiodinium trenchi, were exposed to control (26.5°C and pCO2 of 364 μatm) and treatment (29.0°C and pCO2 of 750 μatm) conditions for 24 days, after which we measured the microbial community composition. These microbial findings were interpreted within the context of previously published physiological measurements from the exact same corals in this study (calcification, organic carbon flux, ratio of photosynthesis to respiration, photosystem II maximal efficiency, total lipids, soluble animal protein, soluble animal carbohydrates, soluble algal protein, soluble algal carbohydrate, biomass, endosymbiotic algal density, and chlorophyll a). Overall, dually stressed A. millepora had reduced microbial diversity, experienced large changes in microbial community composition, and experienced dramatic physiological declines in calcification, photosystem II maximal efficiency, and algal carbohydrates. In contrast, the dually stressed coral T. reniformis experienced a stable and more diverse microbiome community with minimal physiological decline, coupled with very high total energy reserves and particulate organic carbon release rates. Thus, the microbiome changed and microbial diversity decreased in the physiologically sensitive coral with the thermally sensitive endosymbiotic algae but not in the physiologically tolerant coral with the thermally tolerant endosymbiont. Our results confirm recent findings that temperature-stress tolerant corals have a more stable microbiome, and demonstrate for the first time that this is also the case under the dual stresses of ocean warming and acidification. We propose that coral with a stable microbiome are also more physiologically resilient and thus more likely to persist in the future, and shape the coral species diversity of future reef ecosystems.

a b s t r a c tAs part of an effort to monitor changes in inorganic carbon chemistry of the coastal ocean, near-synoptic cruises are being conducted in the Northern Gulf of Mexico and along the East Coast of the United States.Here we describe observations obtained on a cruise in the summer of 2012 and compare them with results from a cruise following a similar track in 2007. The focus is on describing spatial patterns of aragonite saturation state (Ω Ar ). This parameter is an indicator of ecosystem health, in particular for calcifying organisms. The results show large-scale regional trends from different source waters at the northeastern and southwestern edges of the domain, along with the modulating effects of remineralization/respiration and riverine inputs. The broader patterns and changes over five years along the coast can be well described by the impacts of large-scale circulation, notably changes in source water contributions. Changes in the well-buffered Loop Current and Gulf Stream with high Ω Ar impact the waters in the southern part of the study area. The less buffered southward coastal currents with low Ω Ar originating from the Labrador Sea and Gulf of St. Lawrence impact the Ω Ar patterns in the Northern regions. The expected 2% average decrease in Ω Ar in the surface mixed layer due to increasing atmospheric CO 2 levels over the 5-year period is largely overshadowed by local and regional variability from changes in hydrography and mixed layer dynamics.Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Abstract. Distributions of surface water partial pressure of carbon dioxide (pCO 2 ) were measured on nine cruises in the Delaware Estuary (USA). The Delaware River was highly supersaturated in pCO 2 with respect to the atmosphere during all seasons, while the Delaware Bay was undersaturated in pCO 2 during spring and late summer and moderately supersaturated during mid-summer, fall, and winter. While the smaller upper tidal river was a strong CO 2 source (27.1 ± 6.4 mol-C m −2 yr −1 ), the much larger bay was a weak source (1.2 ± 1.4 mol-C m −2 yr −1 ), the latter of which had a much greater area than the former. In turn, the Delaware Estuary acted as a relatively weak CO 2 source (2.4 ± 4.8 mol-C m −2 yr −1 ), which is in great contrast to many other estuarine systems. Seasonally, pCO 2 changes were greatest at low salinities (0 ≤ S < 5), with pCO 2 values in the summer nearly 3-fold greater than those observed in the spring and fall. Undersaturated pCO 2 was observed over the widest salinity range (7.5 ≤ S < 30) during spring. Near to supersaturated pCO 2 was generally observed in mid-to high-salinity waters (20 ≤ S < 30) except during spring and late summer. Strong seasonal trends in internal estuarine production and consumption of CO 2 were observed throughout both the upper tidal river and lower bay. Positive correlations between river-borne and air-water CO 2 fluxes in the upper estuary emphasize the significance of river-borne CO 2 degassing to overall CO 2 fluxes. While river-borne CO 2 degassing heavily influenced CO 2 dynamics in the upper tidal river, these forces were largely compensated for by internal biological processes within the extensive bay system of the lower estuary.

Using data from four field investigations between 2003 and 2009 along the Yellow River mainstream, we examined the transport features and seasonal variations of organic carbon, with a focus on contrasting the impacts of human activities with those of natural processes. Particulate organic carbon (POC) in the Yellow River originated mainly from the Loess Plateau, and thus the POC content in suspended sediments was much lower than in the world's other large rivers. Owing to both natural and human influences, dissolved organic carbon (DOC) has only a weak correlation with discharge. DOC varied as a result of human activities such as agricultural irrigation and pollution in the whole basin except for the upstream Qinghai–Tibetan Plateau. Our study also suggested that while reservoirs are a POC sink over short periods, a long-term POC storage flux cannot be easily estimated as discharge and sediment regulations have completely changed the relationship between the fluxes of water, sediments, and rainfall. However, this carbon sink can be obtained reliably through high-frequency sampling over long time periods. In addition, the annual water and sediment regulation (WSR) scheme has imposed an extremely severe human disturbance on the transport pattern of river organic carbon. Our study demonstrated for the first time that in a WSR event of less than 20 days, large proportions of the annual DOC (35%) and POC (56%) fluxes of the Yellow River were transported to the estuarine and coastal zone, potentially influencing estuarine and coastal geochemistry and ecosystems profoundly

Endocrine-disrupting compounds (EDCs), represented by steroidal estrogens (estrone (E1), 17β-estradiol (E2), estradiol (E3) and 17α-ethinylestradiol (EE2) and xenoestrogens (bisphenol A (BPA) and nonylphenol (NP)), are pollutants with estrogenic activity at very low Downloaded by [University of Sussex Library] at 01:37 14 August 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2concentrations and are emerging as a major concern for water quality. They enter into aqueous environment mainly through discharge of wastewater treatment plant (WWTP) effluents. The paper completely reviews recent studies on the occurrence of the six categories of EDCs in different aqueous environment, namely surface water, groundwater, drinking water and wastewater in WWTPs all over the world. Furthermore, due to the high bioactivity, ubiquitous distribution, potential ecological effects and persistence of the six categories of EDCs, the work summarizes current knowledge of their bacterial biodegradation, which is considered to be an efficient and promising method of removing EDCs. A wide range of bacteria isolated from various environments and affiliated to all kinds of genera with different degradation powers for EDCs are collected in this review in order to select specific strains adapting well to local conditions for bioremediation of freshwater, seawater, soil, sediment with low or high levels of EDCs. Finally, it emphasizes the need for further research and summarizes the future tasks that emerge from the data gathered here.