ORCID Profile
0000-0002-2878-2134
Current Organisation
Australian Institute of Marine Science
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: American Geophysical Union (AGU)
Date: 09-04-2017
DOI: 10.1002/2016GL072371
Publisher: Elsevier BV
Date: 06-2019
Publisher: Elsevier BV
Date: 09-2016
Publisher: American Geophysical Union (AGU)
Date: 03-06-2202
DOI: 10.1029/2021GL097538
Abstract: Large ash plumes emitted by the 2019–2020 Australian wildfires were associated with a widespread phytoplankton bloom in the iron‐limited Pacific sector of the Southern Ocean. In this study, we used satellite observations and aerosol reanalysis products to study the regional phytoplankton community response to wildfire emissions. The bloom was stimulated by pyrogenic iron fertilization and coincided with elevated cellular pigment concentrations, increased photochemical efficiency, and apparent community structural shifts. Physiological anomalies were consistent with previously observed phytoplankton responses to iron stress relief and persisted for up to 9 months. Supported by a regional iron budget, we conclude that the bloom was sustained by iron recycling and episodic inputs of pyrogenic and dust‐borne mineral iron. The continuous regeneration of iron was likely facilitated by the bloom's large size, mitigating edge dilution effects, as well as enhanced bioavailability of pyrogenic and mineral iron due to atmospheric and chemical processing during long‐range transport.
Publisher: American Geophysical Union (AGU)
Date: 13-06-2022
DOI: 10.1029/2021GL097616
Abstract: The ratio between fluorescence (F) and chlorophyll‐a (Chl)—where fluorescence is measured with a saturating fluorometer—is variable in the world's oceans, with the highest ratios and highest variability observed in the Southern Ocean. While species composition and Chl packaging per cell are strong drivers for the observed variability, additional factors, including iron limitation, have to this date not specifically been evaluated. Radiometers on biogeochemical (BGC)‐Argo floats allow for an independent estimate of Chl concentration that is based on the light attenuation coefficient, K d . Making use of 4,000 radiometry profiles from BGC‐Argo floats in the Southern Ocean, we estimate Chl based on K d and investigate the variability in F/Chl. Our analysis reveals a positive correlation between F/Chl and a proxy for iron limitation based on non‐photochemical quenching dynamics. The strong influence of iron limitation on F/Chl is further corroborated by data from Southern Ocean phytoplankton cultures.
Publisher: American Geophysical Union (AGU)
Date: 08-2022
DOI: 10.1029/2022JC018494
Abstract: Light absorption by phytoplankton drives marine primary production and determines ocean color. Phytoplankton absorption is a function of the pigment composition, wavelength, intracellular pigment concentration, and the cells' type. This paper presents phytoplankton absorption spectra reconstructed from in situ pigment concentration and a library of pigment‐specific absorption coefficients from 32 in idual pigment standards, including chlorophylls, caretonoids and phycobilins. The s les dominated by small phytoplankton show no significant difference between calculated absorption and that measured by a spectrophotometer. The component of absorption due to large cells, determined by diagnostic pigments analysis, required correction for the package effect. For the global ocean, the reconstructed phytoplankton absorption was overestimated by 16% at 443 nm and underestimated by 13% over the range between 400 and 700 nm. Following our reconstruction protocol, this approach allows the estimation of phytoplankton absorption spectra from many locations where pigment concentration has been measured, but no directly observed phytoplankton absorption measurements are available.
Publisher: Journal of Marine Research/Yale
Date: 2011
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 03-2021
Publisher: Springer Science and Business Media LLC
Date: 14-01-2016
Publisher: Elsevier BV
Date: 05-2018
Publisher: American Meteorological Society
Date: 11-2018
DOI: 10.1175/JTECH-D-18-0027.1
Abstract: Development of autonomous profiling floats, allowing for long-term continuous measurement of bio-optical variables, promises to significantly increase our knowledge of the variability of the particulate optical backscattering coefficient b bp in marine environments. However, because autonomous floats are designed for unattended data collection and only rarely are recovered for analysis of the condition of the sensors in situ, the quality-control analysis of float data streams is of paramount importance in both a particular dataset and the larger understanding of the response of sensors over the lifetime of the floats. Anomalous data from a backscattering sensor (MCOMS) mounted on autonomous profiling floats are reported here. The observed sensor behavior, which presents itself as significant differences in the values observed at the parking depth between profiles, caused by a steady increase in the signal during the profiling time, is neither common to all sensors nor can it be a function of changes in the particle population. A simple quality-control procedure that is able to detect this spurious sensor response is proposed. Further characterization of this effect will require laboratory experimentation under controlled conditions of temperature and pressure.
Publisher: Frontiers Media SA
Date: 06-09-2019
Publisher: Journal of Marine Research/Yale
Date: 11-2007
Publisher: Elsevier BV
Date: 2018
Publisher: MDPI AG
Date: 04-04-2017
DOI: 10.3390/RS9040343
Publisher: Elsevier BV
Date: 07-2020
No related grants have been discovered for Bozena Wojtasiewicz.