The distribution and ecology of the Gammaridea (Crustacea : Amphipoda) of the lower Chesapeake estuaries

Gammarid amphipods of three tidal rivers entering Chesapeake Bay were studied for ten months, particularly in the York River where 40 species were record during the period. Several species moved up or down the rivers with changing salinity. The more abundant species had longer breeding seasons. The number of described species from lower Chesapeake Bay is now 42 and the presence of 10 undescribed species and of several which bracket the region indicates that much remains to be learned about amphipods in the Bay. Nineteen of these have a boreal affinity and seven are limited to the Virginian subprovince. A reference to the most recent significant work on each species is given and a key is included as an appendix

Variability and trends in surface seawater pCO2 and CO2 flux in the Pacific Ocean

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 44 (2017): 5627–5636, doi:10.1002/2017GL073814.Variability and change in the ocean sink of anthropogenic carbon dioxide (CO2) have implications for future climate and ocean acidification. Measurements of surface seawater CO2 partial pressure (pCO2) and wind speed from moored platforms are used to calculate high-resolution CO2 flux time series. Here we use the moored CO2 fluxes to examine variability and its drivers over a range of time scales at four locations in the Pacific Ocean. There are significant surface seawater pCO2, salinity, and wind speed trends in the North Pacific subtropical gyre, especially during winter and spring, which reduce CO2 uptake over the 10 year record of this study. Starting in late 2013, elevated seawater pCO2 values driven by warm anomalies cause this region to be a net annual CO2 source for the first time in the observational record, demonstrating how climate forcing can influence the timing of an ocean region shift from CO2 sink to source.NOAA, OAR, CPO, OOMD Grant Number: 100007298; NOAA, OAR, CPO, OOMD Grant Number: NA09OAR4320129; Ocean Observation and Monitoring Division (OOMD) Grant Number: NA09OAR4320129; National Oceanic and Atmospheric Administration (NOAA) Grant Number: 1000072982017-12-1

Revisiting experimental methods for studies of acidity-dependent ocean sound absorption

Author Posting. © Acoustical Society of America, 2009. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 125 (2009): 1971-1981, doi:10.1121/1.3089591.The practical usefulness of long-range acoustic measurements of ocean acidity-linked sound absorption is analyzed. There are two applications: Determining spatially-averaged pH via absorption measurement and verifying absorption effects in an area of known pH. The method is a differential-attenuation technique, with the difference taken across frequency. Measurement performance versus mean frequency and range is examined. It is found that frequencies below 500 Hz are optimal. These are lower than the frequency where the measurement would be most sensitive in the absence of noise and signal fluctuation (scintillation). However, attenuation serves to reduce signal-to-noise ratio with increasing distance and frequency, improving performance potential at lower frequencies. Use of low frequency allows longer paths to be used, with potentially better spatial averaging. Averaging intervals required for detection of fluctuations or trends with the required precision are computed

Comparison of CO2 dynamics and air-sea exchange in differing tropical reef environments

Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Aquatic Geochemistry 19 (2013): 371-397, doi:10.1007/s10498-013-9214-7.Note from corresponding author: authors Feely and Shamberger were added after the initial submission, but before the final submission.An array of MAPCO2 buoys, CRIMP-2, Ala Wai, and Kilo Nalu, deployed in the coastal waters of Hawaii have produced multiyear high temporal resolution CO2 records in three different coral reef environments off the island of Oahu, Hawaii. This study, which includes data from June 2008-December 2011, is part of an integrated effort to understand the factors that influence the dynamics of CO2-carbonic acid system parameters in waters surrounding Pacific high island coral reef ecosystems and subject to differing natural and anthropogenic stresses. The MAPCO2 buoys are located on the Kaneohe Bay backreef, and fringing reef sites on the south shore of O’ahu, Hawai’i. The buoys measure CO2 and O2 in seawater and in the atmosphere at 3-hour intervals, as well as other physical and biogeochemical parameters (CTD, chlorophyll-a, turbidity). The buoy records, combined with data from synoptic spatial sampling, have allowed us to examine the interplay between biological cycles of productivity/respiration and calcification/dissolution and biogeochemical and physical forcings on hourly to inter-annual time scales. Air-sea CO2 gas exchange was also calculated to determine if the locations were sources or sinks of CO2 over seasonal, annual, and interannual time periods. Net annualized fluxes for CRIMP-2, Ala Wai, and Kilo Nalu over the entire study period were 1.15 mol C m-2 yr-1, 0.045 mol C m-2 yr-1, and -0.0056 mol C m-2 yr-1, respectively, where positive values indicate a source or a CO2 flux from the water to the atmosphere, and negative values indicate a sink or flux of CO2 from the atmosphere into the water. These values are of similar magnitude to previous estimates in Kaneohe Bay as well as those reported from other tropical reef environments. Total alkalinity (AT) was measured in conjunction with pCO2 and the carbonic acid system was calculated to compare with other reef systems and open ocean values around Hawaii. These findings emphasize the need for high-resolution data of multiple parameters when attempting to characterize the carbonic-acid system in locations of highly variable physical, chemical, and biological parameters (e.g. coastal systems, reefs).This work was supported in part by a grant/cooperative agreement from the National Oceanic and Atmospheric Administration, Project R/IR-3, which is sponsored by the University of Hawaii Sea Grant College Program, SOEST, under Institutional Grant No. NA09OAR4170060 from NOAA Office of Sea Grant, Department of Commerce.2014-11-0

Annual sea-air CO2fluxes in the Bering Sea: insights from new autumn and winter observations of a seasonally ice-covered continental shelf

High-resolution data collected from several programs have greatly increased the spatiotemporal resolution of pCO2(sw) data in the Bering Sea, and provided the first autumn and winter observations. Using data from 2008 to 2012, monthly climatologies of sea-air CO2 fluxes for the Bering Sea shelf area from April to December were calculated, and contributions of physical and biological processes to observed monthly sea-air pCO2 gradients (?pCO2) were investigated. Net efflux of CO2 was observed during November, December, and April, despite the impact of sea surface cooling on ?pCO2. Although the Bering Sea was believed to be a moderate to strong atmospheric CO2 sink, we found that autumn and winter CO2 effluxes balanced 65% of spring and summer CO2 uptake. Ice cover reduced sea-air CO2 fluxes in December, April, and May. Our estimate for ice-cover corrected fluxes suggests the mechanical inhibition of CO2 flux by sea-ice cover has only a small impact on the annual scale (<2%). An important data gap still exists for January to March, the period of peak ice cover and the highest expected retardation of the fluxes. By interpolating between December and April using assumptions of the described autumn and winter conditions, we estimate the Bering Sea shelf area is an annual CO2 sink of ?6.8 Tg C yr?1. With changing climate, we expect warming sea surface temperatures, reduced ice cover, and greater wind speeds with enhanced gas exchange to decrease the size of this CO2 sink by augmenting conditions favorable for greater wintertime outgassing

Sea surface pCO2 and O2 in the Southern Ocean during the austral fall, 2008

The physical and biological processes controlling surface mixed layer pCO2 and O2 were evaluated using in situ sensors mounted on a Lagrangian drifter deployed in the Atlantic sector of the Southern Ocean (∼50°S, ∼37°W) during the austral fall of 2008. The drifter was deployed three times during different phases of the study. The surface ocean pCO2 was always less than atmospheric pCO2 (−50.4 to −76.1 μatm), and the ocean was a net sink for CO2 with fluxes averaging between 16.2 and 17.8 mmol C m−2 d−1. Vertical entrainment was the dominant process controlling mixed layer CO2, with fluxes that were 1.8 to 2.2 times greater than the gas exchange fluxes during the first two drifter deployments, and was 1.7 times greater during the third deployment. In contrast, during the first two deployments the surface mixed layer was always a source of O2 to the atmosphere, and air-sea gas exchange was the dominant process occurring, with fluxes that were 2.0 to 4.1 times greater than the vertical entrainment flux. During the third deployment O2 was near saturation the entire deployment and was a small source of O2 to the atmosphere. Net community production (NCP) was low during this study, with mean fluxes of 3.2 to 6.4 mmol C m−2 d−1 during the first deployment and nondetectable (within uncertainty) in the third. During the second deployment the NCP was not separable from lateral advection. Overall, this study indicates that in the early fall the area is a significant sink for atmospheric CO2

Autonomous Ocean Measurements in the California Current Ecosystem

Event-scale phenomena, of limited temporal duration or restricted spatial extent, often play a disproportionately large role in ecological processes occurring in the ocean water column. Nutrient and gas fluxes, upwelling and downwelling, transport of biogeochemically important elements, predator-prey interactions, and other processes may be markedly influenced by such events, which are inadequately resolved from infrequent ship surveys. The advent of autonomous instrumentation, including underwater gliders, profiling floats, surface drifters, enhanced moorings, coastal high-frequency radars, and satellite remote sensing, now provides the capability to resolve such phenomena and assess their role in structuring pelagic ecosystems. These methods are especially valuable when integrated together, and with shipboard calibration measurements and experimental programs

Assessment of the Carbonate Chemistry Seasonal Cycles in the Southern Ocean From Persistent Observational Platforms

Observations from Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemical profiling Argo floats are used to characterize the climatological seasonal cycles and drivers of dissolved inorganic carbon, total alkalinity, pH, the partial pressure of carbon dioxide (CO2), and the saturation state of aragonite at the surface and at 200 m across five Southern Ocean frontal regimes, including under sea ice. The Southern Ocean ranges from a temperature-dominated system in the northernmost Subtropical Zone to a biologically dominated system in the most poleward Seasonal Sea Ice Zone. In all zones, the ingassing or outgassing of CO2 must be balanced by geostrophic and Ekman transport, mixing from below, and particle transport of carbon into or out of the euphotic zone. The climatological seasonal cycles spanning the period from 2014 to 2017 compare favorably with existing climatologies in spring and summer and less so during winter months, at higher latitudes, and in ice-covered regions due, in part, to limited wintertime observations before SOCCOM. We observe increases in the carbon and nutrient content of surface waters south of the Subantarctic Front between climatological data products and the SOCCOM float climatologies, even after adjusting for anthropogenic change, suggesting a large-scale increase in the amount of upwelled carbon- and nutrient-rich deep waters. This increased upwelling corresponds to a positive Southern Annular Mode Index over 2014-2017 and likely acts to decrease the magnitude of the Southern Ocean sink of total carbon by increasing outgassing of natural CO2, especially during winter months

Particle dynamics in the rising plume at Piccard Hydrothermal Field, Mid-Cayman Rise

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 16 (2015): 2762–2774, doi:10.1002/2015GC005831.Processes active in rising hydrothermal plumes, such as precipitation, particle aggregation, and biological growth, affect particle size distributions and can exert important influences on the biogeochemical impact of submarine venting of iron to the oceans and their sediments. However, observations to date of particle size distribution within these systems are both limited and conflicting. In a novel buoyant hydrothermal plume study at the recently discovered high-temperature (398°C) Piccard Hydrothermal Field, Mid-Cayman Rise, we report optical measurements of particle size distributions (PSDs). We describe the plume PSD in terms of a simple, power-law model commonly used in studies of upper and coastal ocean particle dynamics. Observed PSD slopes, derived from spectral beam attenuation and laser diffraction measurements, are among the highest found to date anywhere in the ocean and ranged from 2.9 to 8.5. Beam attenuation at 650 nm ranged from near zero to a rarely observed maximum of 192 m−1 at 3.5 m above the vent. We did not find large (>100 μm) particles that would settle rapidly to the sediments. Instead, beam attenuation was well-correlated to total iron, suggesting the first-order importance of particle dilution, rather than precipitation or dissolution, in the rising plume at Piccard. Our observations at Piccard caution against the assumption of rapid deposition of hydrothermal, particulate metal fluxes, and illustrate the need for more particle size and composition measurements across a broader range of sites, globally.This work was funded by the National Science Foundation (OCE-1029223; OCE-1061863), NASA (NNX09AB75G) and Woods Hole Oceanographic Institution's Deep Ocean Exploration Institute and Ocean Ridge Initiative. Ship time (R/V Falkor cruise FK008) was funded by the Schmidt Ocean Institute and M.L.E. was supported by a WHOI Postdoctoral Scholar fellowship.2016-02-2

Using present-day observations to detect when anthropogenic change forces surface ocean carbonate chemistry outside preindustrial bounds

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biogeosciences 13 (2016): 5065-5083, doi:10.5194/bg-13-5065-2016.One of the major challenges to assessing the impact of ocean acidification on marine life is detecting and interpreting long-term change in the context of natural variability. This study addresses this need through a global synthesis of monthly pH and aragonite saturation state (Ωarag) climatologies for 12 open ocean, coastal, and coral reef locations using 3-hourly moored observations of surface seawater partial pressure of CO2 and pH collected together since as early as 2010. Mooring observations suggest open ocean subtropical and subarctic sites experience present-day surface pH and Ωarag conditions outside the bounds of preindustrial variability throughout most, if not all, of the year. In general, coastal mooring sites experience more natural variability and thus, more overlap with preindustrial conditions; however, present-day Ωarag conditions surpass biologically relevant thresholds associated with ocean acidification impacts on Mytilus californianus (Ωarag < 1.8) and Crassostrea gigas (Ωarag < 2.0) larvae in the California Current Ecosystem (CCE) and Mya arenaria larvae in the Gulf of Maine (Ωarag < 1.6). At the most variable mooring locations in coastal systems of the CCE, subseasonal conditions approached Ωarag =  1. Global and regional models and data syntheses of ship-based observations tended to underestimate seasonal variability compared to mooring observations. Efforts such as this to characterize all patterns of pH and Ωarag variability and change at key locations are fundamental to assessing present-day biological impacts of ocean acidification, further improving experimental design to interrogate organism response under real-world conditions, and improving predictive models and vulnerability assessments seeking to quantify the broader impacts of ocean acidification.The CO2 and ocean acidification observations were funded by NOAA’s Climate Observation Division (COD) in the Climate Program Office and NOAA’s Ocean Acidification Program. The maintenance of the Stratus and WHOTS Ocean Reference Stations were also supported by NOAA COD (NA09OAR4320129). Additional support for buoy equipment, maintenance, and/or ancillary measurements was provided by NOAA through the US Integrated Ocean Observing System office: for the La Parguera buoy under a Cooperative Agreement (NA11NOS0120035) with the Caribbean Coastal Ocean Observing System, for the Chá b˘a buoy under a Cooperative Agreement (NA11NOS0120036) with the Northwest Association of Networked Ocean Observing System, for the Gray’s Reef buoy under a Cooperative Agreement (NA11NOS0120033) with the Southeast Coastal Ocean Observing Regional Association, and for the Gulf of Main buoy under a Cooperative Agreement (NA11NOS0120034) with the Northeastern Regional Association of Coastal and Ocean Observing Systems