A5031963947- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Isotope Analysis in Ecology
- Marine and fisheries research
- Microbial Community Ecology and Physiology
- Ocean Acidification Effects and Responses
- Marine Bivalve and Aquaculture Studies
- Oceanographic and Atmospheric Processes
- Fish Ecology and Management Studies
- Protist diversity and phylogeny
- Marine animal studies overview
- Marine and coastal plant biology
- Conservation, Ecology, Wildlife Education
- Coastal wetland ecosystem dynamics
- Marine and environmental studies
- Tropical and Extratropical Cyclones Research
- Fuel Cells and Related Materials
- Physiological and biochemical adaptations
- Avian ecology and behavior
- Identification and Quantification in Food
- Aquaculture Nutrition and Growth
- Metabolomics and Mass Spectrometry Studies
- Coastal and Marine Management
- Microbial Metabolic Engineering and Bioproduction
- Atmospheric and Environmental Gas Dynamics
Scripps Institution of Oceanography
2010-2025
National Institute of Water and Atmospheric Research
2016-2025
University of California, San Diego
2008-2024
According to modern oceanographic perspectives that emphasize microbial pathways, phagotrophic protists comprise one several levels of intermediate consumers between phytoplankton and larger metazooplankton (copepods krill). However, recent attempts quantify pelagic trophic structure in the open ocean using nitrogen stable isotope techniques have brought into question whether such measurements adequately account for protistan steps. Here, we use a two‐stage chemostat system, with Dunaliella...
Abstract The Southern Ocean contributes substantially to the global biological carbon pump (BCP). Salps in Ocean, particular Salpa thompsoni , are important grazers that produce large, fast-sinking fecal pellets. Here, we quantify salp bloom impacts on microbial dynamics and BCP, by contrasting locations differing presence/absence. Salp blooms coincide with phytoplankton dominated diatoms or prymnesiophytes, depending water mass characteristics. Their grazing is comparable microzooplankton...
We provide an analysis of zooplankton distributions in the circumpolar Southern Ocean based on samples collected by international SCAR Continuous Plankton Recorder Survey (SO-CPR). analysed SO-CPR measurements relation to satellite and oceanographic model hind-cast data over period 1997–2018. These environmental were chlorophyll-a concentration, net primary productivity (VGPM model), sea-surface temperature (SST), mixed layer depth, sea ice spatial gradient SST (as indicator ocean fronts)....
Nitrogen isotopic compositions of zooplankton in the California Current Ecosystem (CCE) are known to vary over inter‐annual scales climate variability, but extent which those changes driven by variations baseline phytoplankton δ 15 N values vs. trophic position (TP) is poorly resolved. We use field samples collected during a large natural environmental perturbation, 1998–1999 alternation between El Niño and La Niña states, test ability dominant CCE Euphausia pacifica Calanus pacificus alter...
Abstract The biological carbon pump is responsible for the transport of ∼5–20 Pg C yr −1 from surface into deep ocean but its variability poorly understood due to an incomplete mechanistic understanding complex underlying planktonic processes. In fact, algorithms designed estimate export satellite products incorporate fundamentally different assumptions about relationships between plankton biomass, productivity, and efficiency. To test alternate formulations efficiency in remote‐sensing...
The Costa Rica Dome is a picophytoplankton-dominated, open-ocean upwelling system in the Eastern Tropical Pacific that overlies ocean's largest oxygen minimum zone. To investigate efficiency of biological pump this unique area, we used shallow (90–150 m) drifting sediment traps and 234Th:238U deficiency measurements to determine export fluxes carbon, nitrogen phosphorus sinking particles. Simultaneous nitrate uptake water nitrification allowed us assess equilibrium balance new production...
Abstract We evaluated differences in the 15 N isotopic enrichment factors of trophic amino acids (AA) for protistan (microzooplankton) and metazoan (mesozooplankton) consumers, testing hypothesis that δ alanine (ala) increases both consumer types, while glutamic acid (glu) enriches mainly mesozooplankton. AA values were measured dinoflagellate ciliate grazers their respective algal prey ( Oxyrrhis marina / Dunaliella tertiolecta Favella sp./ Heterocapsa triquetra ) four two‐stage chemostat...
Abstract We investigated competition between Salpa thompsoni and protistan grazers during Lagrangian experiments near the Subtropical Front in southwest Pacific sector of Southern Ocean. Over a month, salp community shifted from dominance by large (> 100 mm) oozooids small (< 20 blastozooids to (~ 60 blastozooids. Phytoplankton biomass was consistently dominated nano‐ microphytoplankton 2 μ m cells). Using bead‐calibrated flow‐cytometry light scatter estimate phytoplankton size, we...
The number of trophic steps within a plankton food web plays an important role in determining the energy available to support higher-level consumers by affecting transfer efficiency (TE): fewer can enhance TE decreasing respiration and predation losses. In this study, structure zooplankton community was investigated using stable isotopes size-fractionated mesozooplankton, related 2 biomass proxies TE: normalized size spectra (NBSS) ratio zooplankton:phytoplankton (log 10 (zoo:phyto)). Four...
Abstract Gravitational particle sinking is the main mechanism for carbon export in biological pump. However, dynamics of particle-associated protist community are not fully understood. We used 18S rRNA gene metabarcoding to characterise exported within particles and bathypelagic surficial sediments oligotrophic subtropical high-nutrient, low-chlorophyll subantarctic waters. Sinking were collected with formalin-fixed preservative-free interceptor traps (fixed live traps, respectively)...
The marine system plays a critical role in the global climate cycle, as major control of atmospheric carbon dioxide (CO2). Marine primary production (photosynthesis) and remineralisation organic (respiration, degradation) determine amount CO2 sequestered sediments deep-water environments on century to millennial timescales. stocks fluxes cycle are susceptible change impacts other anthropogenic activities that modify key processes. Oceanographic studies Aotearoa New Zealand's Exclusive...
Phytoplankton community structure is crucial to pelagic food webs and biogeochemical processes. Understanding size-based biomass distribution carbon dynamics essential for assessing their contributions oceanic cycling. This study quantifies plankton (C) based size spectra, composition, living total particulate organic (POC) C:Chlorophyll a (C:Chl ) ratios across biogeographical provinces in the Pacific sector of Southern Ocean near Subtropical Front (Chatham Rise, Aotearoa-New Zealand). We...
We investigated standing stocks and grazing rates of mesozooplankton assemblages in the Costa Rica Dome (CRD), an open-ocean upwelling ecosystem eastern tropical Pacific. While phytoplankton biomass CRD is dominated by picophytoplankton (<2-µm cells) with especially high concentrations Synechococcus spp., we found (∼5 g dry weight m-2) impact (12-50% integrated water column chlorophyll a), indicative efficient food web transfer from primary producers to higher levels. In contrast relative...
Abstract Pyrosomes are an important but often overlooked component of marine zooplankton communities, with limited existing information regarding their ecological and trophic roles in pelagic ecosystems. We present the first estimates grazing interactions large tropical pyrosome, Pyrostremma spinosum , Eastern Tropical Pacific. While patchy distribution, spinosum's impact was substantial, up to 17.5% chlorophyll a standing stock d −1 certain areas. In contrast, these organisms cleared very...
We investigated phytoplankton production rates and grazing fates in the Costa Rica Dome (CRD) during summer 2010 based on dilution depth profiles analyzed by flow cytometry pigments mesozooplankton assessed gut fluorescence. Three community estimates, from 14C uptake (1025 ± 113 mg C m-2 day-1) experiments for total Chla (990 106 populations (862 71 day-1), exceeded regional ship-based values 2-3-fold. Picophytoplankton accounted 56% of biomass 39% production. Production extended deeper...
Abstract The importance of the trophic link between &lt;200-µm protistan microzooplankton and mesozooplankton is a cornerstone modern understanding foodweb structure marine pelagic ecosystems that well demonstrated in experimentally measured contributions consumers to diets, constrained global budgets, regional studies show inadequacies meeting zooplankton metabolic requirements by herbivory alone. Nonetheless, steps are poorly reflected stable isotope analyses standard methods...
Abstract The Costa Rica Dome (CRD) is an open‐ocean upwelling ecosystem, with high biomasses of picophytoplankton (especially Synechococcus ), mesozooplankton, and higher trophic levels. To elucidate the food web pathways supporting structure carbon export in this unique we used Markov Chain Monte Carlo techniques to assimilate data from four independent realizations δ 15 N planktonic rate measurements CRD into steady state, multicompartment ecosystem box models (linear inverse models)....
The Subtropical Convergence Zone (SCZ) in the Chatham Rise region east of New Zealand supports productive fisheries and benthic ecosystems is an important CO2 sink. SCZ trophic system underpinned by a microbially-dominated food web, requiring efficient link between pico-sized producers larger consumers to support necessary transfers. However, role mesozooplankton (>200 μm body size) as intermediaries this transfer not well understood. This study investigated subantarctic (SA) subtropical...
Abstract The environmental drivers of zooplankton variability are poorly explored for the central subtropical Pacific, where a direct bottom‐up food‐web connection is suggested by increasing trends in primary production and mesozooplankton biomass at station ALOHA (A Long‐term Oligotrophic Habitat Assessment) over past 20 years (1994–2013). Here we use generalized additive models (GAMs) to investigate how these relate major modes North Pacific climate variability. A GAM based on monthly mean...