A5078806202- Marine and coastal ecosystems
- Oceanographic and Atmospheric Processes
- Isotope Analysis in Ecology
- Marine Biology and Ecology Research
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Arctic and Antarctic ice dynamics
- Groundwater and Isotope Geochemistry
- Coastal wetland ecosystem dynamics
- Marine and fisheries research
- Aquatic Invertebrate Ecology and Behavior
- Atmospheric chemistry and aerosols
- Ocean Acidification Effects and Responses
- Marine and coastal plant biology
- Marine Bivalve and Aquaculture Studies
- Microbial Community Ecology and Physiology
- Fish Ecology and Management Studies
- RNA and protein synthesis mechanisms
- Aquatic Ecosystems and Phytoplankton Dynamics
- Coastal and Marine Management
- Climate variability and models
- Climate change and permafrost
- Tropical and Extratropical Cyclones Research
- Coastal and Marine Dynamics
Wellesley College
2015-2024
Woods Hole Oceanographic Institution
2010-2023
Princeton University
2009-2010
Massachusetts Institute of Technology
1999-2007
National Oceanography Centre
2005
Parsons (United States)
1999
Boston University
1999
Ocean ecosystems play a critical role in the Earth's carbon cycle and quantification of their impacts for both present conditions predictions into future remains one greatest challenges oceanography. The goal EXport Processes from Remote Sensing (EXPORTS) Science Plan is to develop predictive understanding export fate global ocean net primary production (NPP) its implications climates. achievement this requires mechanisms that control euphotic zone as well underlying "twilight zone" where...
Air‐sea gas exchange is an important part of the biogeochemical cycles many climatically and biologically relevant gases including CO 2 , O dimethyl sulfide CH 4 . Here we use a three year observational time series five noble (He, Ne, Ar, Kr, Xe) at Bermuda Atlantic Time Study (BATS) site in tandem with one‐dimensional upper ocean model to develop improved parameterization for air‐sea that explicitly includes separate components diffusive bubble processes. Based on seasonal timescale data,...
Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that the proportion of active microbes environment how they vary when perturbed is critical anticipating global change. Increasing supplies anthropogenic nitrogen ecosystems globally makes it imperative we understand nutrient supply alters communities. Here show additions salt marshes cause a...
Abstract Nitrite is a central intermediate in the marine nitrogen cycle and represents critical juncture where can be reduced to less bioavailable N 2 gas or oxidized nitrate retained more form. We present an analysis of rates microbial transformations oxygen deficient zone (ODZ) within eastern tropical North Pacific Ocean (ETNP). determined using novel one‐dimensional model distribution nitrite concentrations, along with their natural abundance (N) (O) isotope profiles. predict rate...
Net community production (NCP) and gross primary (GPP) are two key metrics for quantifying the biological carbon cycle. In this study, we present a detailed characterization of NCP GPP in western equatorial Pacific during August September 2006. We use continuous measurements dissolved gases (O 2 Ar) surface water order to quantify at subkilometer scale resolution. constrain discrete samples using triple isotopic composition O . find average is 5.9 ± 0.9 mmol m −2 d −1 (equivalent 1.5 0.2 mol...
Abstract Determinations of the net community production (NCP) in upper ocean and particle export (EP) should balance over long time large spatial scales. However, recent modeling studies suggest that a horizontal decoupling flux‐regulating processes on submesoscales (≤10 km) could lead to imbalances between individual determinations NCP EP. Here we sampled mixed‐layer biogeochemical parameters proxies for EP during 10, high‐spatial resolution (~2 surface transects across strong physical...
Abstract Climatic changes have decreased the stability of Gulf Stream (GS), increasing frequency at which its meanders interact with Mid‐Atlantic Bight (MAB) continental shelf and slope region. These intrusions are thought to suppress biological productivity by transporting low‐nutrient water otherwise productive edge Here we present evidence widespread, anomalously intense subsurface diatom hotspots in MAB sea that likely resulted from a GS intrusion July 2019. The (at ∼50 m) were...
The triple oxygen isotopic composition of dissolved ( 17 Δ) is a promising tracer gross productivity P ) in the ocean. Recent studies have inferred high and variable ratio to 14 C net primary (12–24 h incubations) (e.g., :NPP( C) 5–10) using Δ method, which implies very low efficiency phytoplankton growth rates relative photosynthetic rates. We added isotopes one‐dimensional mixed layer model assess role physical dynamics potentially biasing estimates method at Bermuda Atlantic Time‐series...
Abstract. We present three years of Apparent Oxygen Utilization Rates (AOUR) estimated from oxygen and tracer data collected over the ocean thermocline at monthly resolution between 2003 2006 Bermuda Atlantic Time-series Study (BATS) site. estimate water ages by calculating a transit time distribution tritium helium-3 data. The vertically integrated AOUR upper 500 m, which is regional export, during 3.1 ± 0.5 mol O2 m−2 yr−1. This comparable to previous AOUR-based estimates export production...
Summary This study explores some of the physiological mechanisms responsible for high productivity near shelf in W estern A ntarctic P eninsula despite a short growing season and cold temperature. We measured gross net primary production at Palmer Station during summer 2012/2013 via three different techniques: incubation with H 2 18 O ; 14 CO situ measurements / r triple oxygen isotope. Additional laboratory experiments were performed psychrophilic diatom F ragilariopsis cylindrus . During...
Abstract The triple oxygen isotopic composition of dissolved ( 17 Δ dis ) was added to the ocean ecosystem and biogeochemistry component Community Earth System Model, version 1.1.1. Model simulations were used investigate biological physical dynamics assess its application as a tracer gross photosynthetic production (gross GOP )) O 2 in mixed layer. model reproduced large‐scale patterns found observational data across diverse biogeographical provinces. Mixed layer performance best Pacific...
A method is presented for precisely measuring all five noble gases and their isotopic ratios in water samples using multiple programmed multistage cryogenic traps conjunction with quadrupole mass spectrometry magnetic sector spectrometry. Multiple automated traps, including a two‐stage cryotrap used removal of vapor, an activated charcoal helium separation, stainless steel neon, argon, krypton, xenon allow reproducible gas purification separation. The precision this standards ±0.10% He,...
Noble gases dissolved in natural waters are useful tracers for quantifying physical processes. Here, we describe a field-deployable gas equilibration mass spectrometer (GEMS) that provides continuous, real-time measurements of Ne, Ar, Kr, and Xe mole ratios waters. Gas is equilibrated with membrane contactor cartridge measured quadrupole spectrometer, after in-line purification reactive metal alloy getters. We use an electron energy 35 V Ne to eliminate isobaric interferences, higher the...
Abstract. Because of its temperate location, high dynamic range environmental conditions, and extensive human activity, the long-term ecological research site in coastal Northeastern US Shelf (NES) northwestern Atlantic Ocean offers an ideal opportunity to understand how productivity shifts response changes planktonic community composition. production trophic transfer rates, including net (NCP), primary (NPP), gross oxygen (GOP), microzooplankton grazing are key metrics for understanding...
Abstract Integrating spatial heterogeneity into assessments of salt marsh biogeochemistry is becoming increasingly important because disturbances that reduce plant productivity and soil drainage may contribute to an expansion shallow ponds. These permanently inundated sometimes prominent landscape features can exist for decades, yet little known about pond or their role in ecosystem functioning. We characterized three ponds a temperate (MA, USA) over alternating periods tidal isolation...
Gas exchange between the atmosphere and ocean interior profoundly impacts global climate biogeochemistry. However, our understanding of relevant physical processes remains limited by a scarcity direct observations. Dissolved noble gases in deep are powerful tracers air-sea interaction due to their chemical biological inertness, yet isotope ratios have remained underexplored. Here, we present high-precision gas elemental from North Atlantic (~32°N, 64°W) evaluate parameterizations using an...
The Arctic Ocean is changing rapidly as the global climate warms but it not well known how these changes are affecting biological productivity and carbon cycle. Here we study Beaufort Gyre region of Canada Basin in August use large reduction summertime sea ice extent from 2011 to 2012 investigate potential impacts warming on productivity. We gas tracers O2/Ar triple oxygen isotopes quantify rates net community production (NCP) gross (GOP) gyre. Comparison summer with 2012, latter which had...
Abstract Mixed layer (ML) gross (GOP) and net (NOP) oxygen production rates based on in situ mass balances of triple isotopes (TOI) O 2 /Ar are influenced by vertical transport from below, a term traditionally difficult to constrain. Here we present new approach estimate eddy diffusivity ( K z ) density gradients the upper thermocline wind speed‐based turbulent shear at ML depth. As an example, use this , verified independent 7 Be‐based estimate, /TOI budget site oligotrophic South Pacific...
Abstract The Arctic Ocean is experiencing profound environmental changes as the climate warms. Understanding how these will affect biological productivity key for predicting future ecosystems and global CO 2 balance. Here we use in situ gas measurements to quantify rates of gross oxygen production (GOP, total photosynthesis) net community (NCP, drawdown by pump) mixed layer summer or fall from 2011 2016 Beaufort Gyre. NCP GOP show spatial temporal variations with higher values linked lower...
Abstract The Mid‐Atlantic Bight (MAB) hosts a large and productive marine ecosystem supported by high phytoplankton concentrations. Enhanced surface chlorophyll concentrations at the MAB shelf‐break front have been detected in synoptic measurements, yet this feature is not present seasonal means. To understand why, we assess conditions associated with enhanced shelf break. We employ in‐situ remote sensing data, 2‐dimensional model to show that Ekman restratification driven upfront winds...