Predicting marine phytoplankton community size structure from empirical relationships with remotely sensed variables
TL;DR: In this article, the authors describe relationships between the environment and the size composition of phytoplankton communities, using a collation of empirical measurements of size composition from sites that include polar, tropical and upwelling environments.
Abstract: The size composition of primary producers has a potential influence on the length of marine food chains and carbon sinking rates, thus on the proportion of primary production (PP) that is removed from the upper layers and available to higher trophic levels. While total rates of PP are widely reported, it is also necessary to account for the size composition of primary producers when developing food web models that predict consumer biomass and production. Empirical measurement of size composition over large space and time scales is not feasible, so one approach is to predict size composition from environmental variables that are measured and reported on relevant scales. Here, we describe relationships between the environment and the size composition of phytoplankton communities, using a collation of empirical measurements of size composition from sites that include polar, tropical and upwelling environments. The size composition of the phytoplankton communities can be predicted using two remotely sensed variables, chlorophyll-a concentration and sea surface temperature. Applying such relationships in combination allows prediction of the slope and location of phytoplankton size spectra and estimation of the percentage of different sized phytoplankton groups in communities.
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TL;DR: In this article, the authors investigated the feasibility of sustaining current and increased per capita fish consumption rates in 2050 and concluded that meeting current and larger consumption rates is feasible, despite a growing population and the impacts of climate change on potential fisheries production, but only if fish resources are managed sustainably and the animal feeds industry reduces its reliance on wild fish.
Abstract: Expansion in the world's human population and economic development will increase future demand for fish products. As global fisheries yield is constrained by ecosystems productivity and management effectiveness, per capita fish consumption can only be maintained or increased if aquaculture makes an increasing contribution to the volume and stability of global fish supplies. Here, we use predictions of changes in global and regional climate (according to IPCC emissions scenario A1B), marine ecosystem and fisheries production estimates from high resolution regional models, human population size estimates from United Nations prospects, fishmeal and oil price estimations, and projections of the technological development in aquaculture feed technology, to investigate the feasibility of sustaining current and increased per capita fish consumption rates in 2050. We conclude that meeting current and larger consumption rates is feasible, despite a growing population and the impacts of climate change on potential fisheries production, but only if fish resources are managed sustainably and the animal feeds industry reduces its reliance on wild fish. Ineffective fisheries management and rising fishmeal prices driven by greater demand could, however, compromise future aquaculture production and the availability of fish products.
374 citations
Cites background or methods from "Predicting marine phytoplankton com..."
...We estimated a from the total biomass density of phytoplankton and microzooplankton groups from ERSEM output and convert this to numerical density across a realistic size range (10 14 to 10 4 g) assuming a fixed slope b of 1, in keeping with global empirical studies of phytoplankton size spectra (Barnes et al., 2011)....
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...…the total biomass density of phytoplankton and microzooplankton groups from ERSEM output and convert this to numerical density across a realistic size range (10 14 to 10 4 g) assuming a fixed slope b of 1, in keeping with global empirical studies of phytoplankton size spectra (Barnes et al., 2011)....
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TL;DR: Five existing methods that address the needs of monitoring and assessment of marine ecosystems are reviewed, highlighting their main characteristics and analyzing their commonalities and differences.
Abstract: Traditional and emerging human activities are increasingly putting pressures on marine ecosystems and impacting their ability to sustain ecological and human communities. To evaluate the health status of marine ecosystems we need a science-based, integrated Ecosystem Approach, that incorporates knowledge of ecosystem function and services provided that can be used to track how management decisions change the health of marine ecosystems. Although many methods have been developed to assess the status of single components of the ecosystem, few exist for assessing multiple ecosystem components in a holistic way. To undertake such an integrative assessment, it is necessary to understand the response of marine systems to human pressures. Hence, innovative monitoring is needed to obtain data to determine the health of large marine areas, and in an holistic way. Here we review five existing methods that address both of these needs (monitoring and assessment): the Ecosystem Health Assessment Tool; a method for the Marine Strategy Framework Directive in the Bay of Biscay; the Ocean Health Index; the Marine Biodiversity Assessment Tool; and the Nested Environmental status Assessment Tool. We have highlighted their main characteristics and analyzing their commonalities and differences, in terms of: use of the Ecosystem Approach; inclusion of multiple components in the assessment; use of reference conditions; use of integrative assessments; use of a range of values to capture the status; weighting ecosystem components when integrating; determine the uncertainty; ensure spatial and temporal comparability; use of robust monitoring approaches; and address pressures and impacts. Ultimately, for any ecosystem assessment to be effective it needs to be: transparent and repeatable and, in order to inform marine management, the results should be easy to communicate to wide audiences, including scientists, managers and policymakers.
217 citations
Cites methods from "Predicting marine phytoplankton com..."
...…has long been used to monitor chlorophyll a (Coppini et al., 2012), it has only recently been applied to determine phytoplankton size structure (Barnes et al., 2011; Brewin et al., 2011), composition and functionality (Moisan et al., 2013; Palacz et al., 2013; Rousseaux et al., 2013) and…...
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TL;DR: Warming may enhance phytoplankton losses to microzooplankton herbivory in eutrophic but not in oligotrophic waters, and the GAM analysis provides important insights into underlying system relationships and reasons why community-level responses in natural systems may depart from theory.
Abstract: We evaluated a hypothesis derived from the metabolic theory of ecology (MTE) that the ratio of microzooplankton herbivory (m) to phytoplankton growth (m) will arise in a warming ocean because of the different temperature dependencies of autotrophic and heterotrophic organisms. Using community-level growth and grazing data from dilution experiments, generalized additive models (GAMs) were constructed to describe the effects of temperature and chlorophyll on m:m. At low chlorophyll levels, m:m decreases with increasing temperature, whereas at high chlorophyll levels, m:m increases initially with temperature before reaching a peak and then declines. These complex responses of m:m result from mixed effects of temperature and chlorophyll on microzooplankton biomass (Bz), biomass-specific microzooplankton grazing rate (m:Bz), and phytoplankton growth rate (m). Bz decreases with rising temperature and increases with rising chlorophyll. m:Bz increases with temperature and decreases with chlorophyll. Nutrient-enriched growth rate of phytoplankton (mn) and m increase with increasing temperature and chlorophyll. Holding chlorophyll constant, the calculated activation energies of m:Bz and mn are 0.67 6 0.05 and 0.36 6 0.05 eV, respectively, both consistent with previous MTE estimates for heterotrophs and autotrophs. Our study indicates that warming may enhance phytoplankton losses to microzooplankton herbivory in eutrophic but not in oligotrophic waters. The GAM analysis also provides important insights into underlying system relationships and reasons why community-level responses in natural systems may depart from theory based on laboratory data and individual species.
125 citations
Cites background from "Predicting marine phytoplankton com..."
...Thus, as mean cell size of phytoplankton is well related to total chlorophyll (Chen and Liu 2010; Barnes et al. 2011), an increasing trend of ln mn with chlorophyll should be expected....
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...Phytoplankton mean cell size, another factor affecting mn, is well correlated with total chlorophyll concentration (Chen and Liu 2010; Barnes et al. 2011)....
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TL;DR: Predicted latitudinal shifts are, on average, reduced by 20% when species interactions are incorporated, compared to DBEM predictions, with pelagic species showing the greatest reductions.
Abstract: Climate change has already altered the distribution of marine fishes. Future predictions of fish distributions and catches based on bioclimate envelope models are available, but to date they have not considered interspecific interactions. We address this by combining the species-based Dynamic Bioclimate Envelope Model (DBEM) with a size-based trophic model. The new approach provides spatially and temporally resolved predictions of changes in species' size, abundance and catch potential that account for the effects of ecological interactions. Predicted latitudinal shifts are, on average, reduced by 20% when species interactions are incorporated, compared to DBEM predictions, with pelagic species showing the greatest reductions. Goodness-of-fit of biomass data from fish stock assessments in the North Atlantic between 1991 and 2003 is improved slightly by including species interactions. The differences between predictions from the two models may be relatively modest because, at the North Atlantic basin scale, (i) predators and competitors may respond to climate change together; (ii) existing parameterization of the DBEM might implicitly incorporate trophic interactions; and/or (iii) trophic interactions might not be the main driver of responses to climate. Future analyses using ecologically explicit models and data will improve understanding of the effects of inter-specific interactions on responses to climate change, and better inform managers about plausible ecological and fishery consequences of a changing environment.
114 citations
Cites background from "Predicting marine phytoplankton com..."
...Thus, the median and mean body sizes of phytoplankton decrease with decreasing rates of primary production (Barnes et al., 2011)....
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TL;DR: It is shown that marine location can be inferred from animal tissues, and carbon isotope ratios can be used to identify the location of open ocean feeding grounds for any pelagic animals for which tissue archives and matching records of sea surface temperature are available.
Abstract: Knowing the distribution of marine animals is central to understanding climatic and other environmental influences on population ecology. This information has proven difficult to gain through capture-based methods biased by capture location. Here we show that marine location can be inferred from animal tissues. As the carbon isotope composition of animal tissues varies with sea surface temperature, marine location can be identified by matching time series of carbon isotopes measured in tissues to sea surface temperature records. Applying this technique to populations of Atlantic salmon (Salmo salar L.) produces isotopically-derived maps of oceanic feeding grounds, consistent with the current understanding of salmon migrations, that additionally reveal geographic segregation in feeding grounds between individual philopatric populations and age-classes. Carbon isotope ratios can be used to identify the location of open ocean feeding grounds for any pelagic animals for which tissue archives and matching records of sea surface temperature are available.
104 citations
References
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01 Jan 2000
TL;DR: This paper presents the results of a large-scale study of sampling and experimental design of Zooplankton dynamics in response to the prokaryoticarming crisis in the Southern Ocean.
Abstract: J. Lenz, Introduction. H-R. Skjoldal, P.H. Wiebe, and K.G. Foote, Sampling and Experimental Design. D. Sameoto, P. Wiebe, J. Runge, L. Postel, J. Dunn, C. Miller, and S. Coombs, Collecting Zooplankton. L. Postel, H. Fock, and W. Hagen, Biomass and Abundance. D. Gifford and D. Caron, Sampling, Preservation, Enumeration, and Biomass of Marine Protozooplankton. K. Foote and T.K. Stanton, Acoustical Methods. K. Foote, Optical Methods. U. Bamstedt, D.J. Gifford, X. Irigoien, A. Atkinson, and M. Roman, Feeding. J. Runge and J.C. Roff, The Measurement of Growth and Reproductive Rates. T. Ikeda, J.J. Torres, S. Hernandez-Leon, and S.P. Geiger, Metabolism. A. Bucklin, Methods for Population Genetic Analysis of Zooplankton. F. Carlotti, J. Giske, and F. Werner, Modeling Zooplankton Dynamics.
868 citations
TL;DR: In this article, the potential of using the near-surface chlorophyll a concentration (Chla) as it can be derived from ocean color observation, to infer the column-integrated phytoplankton biomass, its vertical distribution, and ultimately the community composition.
Abstract: [1] The present study examines the potential of using the near-surface chlorophyll a concentration ([Chla]surf), as it can be derived from ocean color observation, to infer the column-integrated phytoplankton biomass, its vertical distribution, and ultimately the community composition. Within this context, a large High-Performance Liquid Chromatography (HPLC) pigment database was analyzed. It includes 2419 vertical pigment profiles, sampled in case 1 waters with various trophic states (0.03–6 mg Chla m � 3 ). The relationships between [Chla]surf and the chlorophyll a vertical distribution, as previously derived by Morel and Berthon (1989), are fully confirmed. This agreement makes it possible to go further and to examine if similar relationships between [Chla]surf and the phytoplankton assemblage composition along the vertical can be derived. Thanks to the detailed pigment composition, and use of specific pigment biomarkers, the contribution to the local chlorophyll a concentration of three phytoplankton groups can be assessed. With some cautions, these groups coincide with three size classes, i.e., microplankton, nanoplankton and picoplankton. Corroborating previous regional findings (e.g., large species dominate in eutrophic environments, whereas tiny phytoplankton prevail in oligotrophic zones), the present results lead to an empirical parameterization applicable to most oceanic waters. The predictive skill of this parameterization is satisfactorily tested on a separate data set. With such a tool, the vertical chlorophyll a profiles of each group can be inferred solely from the knowledge of [Chla]surf. By combining this tool with satellite ocean color data, it becomes possible to quantify on a global scale the phytoplankton biomass associated with each of the three algal assemblages.
724 citations
"Predicting marine phytoplankton com..." refers background in this paper
...For example, Uitz et al. (Uitz et al. 2006; Uitz et al. 2008) have determined size-spectra of phytoplankton communities from near-surface chlorophyll a concentration using accessory pigments as markers for pico, nano and micro-plankton to infer the column-integrated phytoplankton biomass, its vertical distribution, and ultimately the community composition by quantifying on a global scale the phytoplankton biomass associated with each of the three algal assemblages....
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...For example, Uitz et al. (Uitz et al. 2006; Uitz et al. 2008) have determined size-spectra of phytoplankton communities from near-surface chlorophyll a concentration using accessory pigments as markers for pico, nano and micro-plankton to infer the column-integrated phytoplankton biomass, its…...
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California Institute of Technology1, Old Dominion University2, Virginia Institute of Marine Science3, Stanford University4, Tokyo University of Information Sciences5, Centre national de la recherche scientifique6, Duke University7, Oregon State University8, University of Hawaii9, Max Planck Society10, University of New Hampshire11, Sao Paulo State University12, University of Connecticut13, Geophysical Fluid Dynamics Laboratory14, Goddard Space Flight Center15, Plymouth Marine Laboratory16, Nagasaki University17, University of East Anglia18, Lamont–Doherty Earth Observatory19, University of California, Irvine20, Monterey Bay Aquarium Research Institute21, University of Rome Tor Vergata22, National Oceanic and Atmospheric Administration23
TL;DR: The third primary production algorithm round robin (PPARR3) as discussed by the authors compares output from 24 models that estimate depth-integrated primary production from satellite measurements of ocean color, as well as seven general circulation models (GCMs) coupled with ecosystem or biogeochemical models.
Abstract: The third primary production algorithm round robin (PPARR3) compares output from 24 models that estimate depth-integrated primary production from satellite measurements of ocean color, as well as seven general circulation models (GCMs) coupled with ecosystem or biogeochemical models. Here we compare the global primary production fields corresponding to eight months of 1998 and 1999 as estimated from common input fields of photosynthetically-available radiation (PAR), sea-surface temperature (SST), mixed-layer depth, and chlorophyll concentration. We also quantify the sensitivity of the ocean-color-based models to perturbations in their input variables. The pair-wise correlation between ocean-color models was used to cluster them into groups or related output, which reflect the regions and environmental conditions under which they respond differently. The groups do not follow model complexity with regards to wavelength or depth dependence, though they are related to the manner in which temperature is used to parameterize photosynthesis. Global average PP varies by a factor of two between models. The models diverged the most for the Southern Ocean, SST under 10 degrees C, and chlorophyll concentration exceeding 1 mg Chlm(-3). Based on the conditions under which the model results diverge most, we conclude that current ocean-color-based models are challenged by high-nutrient low-chlorophyll conditions, and extreme temperatures or chlorophyll concentrations. The GCM-based models predict comparable primary production to those based on ocean color: they estimate higher values in the Southern Ocean, at low SST, and in the equatorial band, while they estimate lower values in eutrophic regions (probably because the area of high chlorophyll concentrations is smaller in the GCMs). Further progress in primary production modeling requires improved understanding of the effect of temperature on photosynthesis and better parameterization of the maximum photosynthetic rate. (c) 2006 Elsevier Ltd. All rights reserved.
635 citations
TL;DR: The results of mesocosm nutrient addition experiments during summer in the Mediterranean Sea allowed the dissociation of the effects of temperature from those of nutrients on picophytoplankton production and biomass and validated the magnitude at which picoplankton dominates ($50%) autotrophic biomass and production obtained in the comparative analysis.
Abstract: The observation that the relative importance of picophytoplankton is greatest in warm and nutrient-poor waters was tested here based on a comprehensive review of the data available in the literature from oceanic and coastal estuarine areas. Results show that picophytoplankton dominate ($50%) the biomass and production in oligotrophic (chlorophyll a [Chl a] , 0.3 mg m 23 ), nutrient poor (NO3 1 NO2 , 1 mM), and warm (.268C) waters, but represent ,10% of autotrophic biomass and production in rich (Chl a . 5m g m 23 ) and cold (,38C) waters. There is, however, a strong covariation between temperature and nutrient concentration (r 52 0.95, P , 0.001), but the number of observations where both temperature and nutrient concentrations are available is too small to allow attempts to statistically separate their effects. The results of mesocosm nutrient addition experiments during summer in the Mediterranean Sea allowed the dissociation of the effects of temperature from those of nutrients on picophytoplankton production and biomass and validated the magnitude at which picoplankton dominates ($50%) autotrophic biomass and production obtained in the comparative analysis. The fraction contributed by picoplankton significantly declined (r 2 5 0.76 and 0.90, respectively, P , 0.001) as total autotrophic production and biomass increased. These results support the increasing importance of picophytoplankton in warm, oligotrophic waters. The reduced contribution of picophytoplankton in warm productive waters is hypothesized here to be due to increased loss rates, whereas the dominance of picophytoplankton in warm, oligotrophic waters is attributable to the differential capacity to use nutrients as a function of differences in size and capacity of intrinsic growth of picophytoplankton and larger phytoplankton cells.
635 citations
"Predicting marine phytoplankton com..." refers result in this paper
...The relationship to chlorophyll is consistent with the findings of Agawin et al. (Agawin et al. 2000) who reported that picophytoplankton dominated (> 50...
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TL;DR: In the Arctic Ocean, phytoplankton cell sizes have decreased with warming temperatures and fresher surface waters, and since 2004, there has been an increase in the smallest algae and bacteria along with a concomitant decrease in somewhat larger algae.
Abstract: As climate changes and the upper Arctic Ocean receives more heat and fresh water, it becomes more difficult for mixing processes to deliver nutrients from depth to the surface for phytoplankton growth. Competitive advantage will presumably accrue to small cells because they are more effective in acquiring nutrients and less susceptible to gravitational settling than large cells. Since 2004, we have discerned an increase in the smallest algae and bacteria along with a concomitant decrease in somewhat larger algae. If this trend toward a community of smaller cells is sustained, it may lead to reduced biological production at higher trophic levels.
628 citations
"Predicting marine phytoplankton com..." refers background in this paper
...(Li et al. 2009) concur that a reduction in community average cell size...
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...Li et al. (Li et al. 2009) concur that a reduction in community average cell size because of an increase in the abundance of individuals belonging to small-sized species may be a common response to increasing sea temperatures....
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