Plankton Assemblage Variability in a River-Dominated Temperate Estuary During Late Spring (High-flow) and Late Summer (Low-flow) Periods

Breckenridge, Joanne K.; Bollens, Stephen M.; Rollwagen‐Bollens, Gretchen; Roegner, G. Curtis

doi:10.1007/s12237-014-9820-7

Cited by 32 publications

(31 citation statements)

References 48 publications

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“…S6) confirming earlier findings that diatoms are the dominant phytoplankton year‐round throughout the system (Haertel et al ; Maier ; Breckenridge et al ). However, concentrations and ratios of fucoxanthin were lower in fall when the higher mass ratios of other pigments suggest a more diverse phytoplankton community (Breckenridge et al ). This seasonal shift corresponds with a decrease in total pigments, suggesting that decreasing river diatom production following spring bloom (Maier ) leads to an increase in estuarine phytoplankton diversity.…”

Section: Discussionsupporting

confidence: 89%

“…, Supporting Information Fig. S6) confirming earlier findings that diatoms are the dominant phytoplankton year‐round throughout the system (Haertel et al ; Maier ; Breckenridge et al ). However, concentrations and ratios of fucoxanthin were lower in fall when the higher mass ratios of other pigments suggest a more diverse phytoplankton community (Breckenridge et al ).…”

Section: Discussionsupporting

confidence: 89%

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Quantity and quality of particulate organic matter controls bacterial production in the Columbia River estuary

Crump

Fine

Fortunato

et al. 2017

Limnology & Oceanography

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Estuaries function as “bioreactors” for fluvial materials in which microbial, biogeochemical, and ecological processes transform organic matter and nutrients prior to export to coastal oceans. The impact of estuarine bioreactors is linked to the bioavailability and residence time of fluvial material, and to rates of microbial activity. In the Columbia River estuary, water residence time is short (approximately 2 d), but particle residence time is extended by estuarine turbidity maxima (ETM). To investigate relationships between organic matter and microbial activity, samples were collected in spring and fall 2012 and summer 2013, and ETM particles were fractionated by settling velocity using an Owen‐style settling column. Data were also analyzed from 16 other sampling campaigns conducted in 1990–2009. The composition of suspended particulate matter shifted seasonally following the spring freshet and river phytoplankton bloom with decreasing organic content, increasing C/N ratio, and an increasing contribution of autochthonous particulate organic matter (POM) produced in four shallow lateral bays (based on del‐PO13C and pigment ratios). Heterotrophic bacterial production responded to seasonal changes in POM and correlated most strongly with estimates of labile particulate nitrogen during any particular season, and with the riverine flux of chlorophyll a (Chl a) across all seasons. Regression models suggest that labile particulate nitrogen and bacterial production can be predicted from sensor‐based measurements including turbidity, salinity, and temperature in the estuary and Chl a in the river. These results demonstrate that heterotrophic activity in the Columbia River estuary is controlled by POM lability, and by the degree to which ETM retain and concentrate POM.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 89%

Quantity and quality of particulate organic matter controls bacterial production in the Columbia River estuary

Crump

Fine

Fortunato

et al. 2017

Limnology & Oceanography

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“…The two longest predicted rbcL peptides (91 and 153 amino acids) corresponded to Aulacoseira granulata and Asterionellopsis glacialis (with 100% and 99% sequence identities observed, respectively, over the full length of the fragments). Both of these species are typically abundant in the Columbia River estuary, mouth, and plume (Breckenridge et al., ; Maier, ). During summers, freshwater Aulacoseira spp.…”

Section: Resultsmentioning

confidence: 99%

“…During summers, freshwater Aulacoseira spp. blooms develop in the river and are transported to the estuary, where they are the dominate phytoplankton species observed and are often found together there with marine A. glacialis from the coastal ocean (Breckenridge et al., ). Several other known chloroplast‐encoded genes in addition to rbcL were also identified in the ES‐5 metagenome, including eight predicted to encode photosystem I PsaA and PsaB proteins (data not shown).…”

Section: Resultsmentioning

confidence: 99%

“…The river‐dominated Columbia River estuary is, in return, affected by strong semi‐diurnal ocean tides (Jay, ). Previous studies of the estuarine microbiota showed that temporally variable tidal forcing and river discharge are major determinants of microbial community composition through formation of steep gradients of environmental factors, including salinity, temperature, oxygen concentrations, and so forth (Breckenridge, Bollens, Rollwagen‐Bollens, & Roegner, ; Fortunato, Herfort, Zuber, Baptista, & Crump, ; Fortunato et al., ; Herfort, Peterson, McCue, & Zuber, ; Smith, Zeigler Allen, Allen, Herfort, & Simon, ; Smith et al., ). Typically, the river flow peaks during the spring freshet (May–June) due to the melting of snowpack, and then decreases to low levels in late summer/early fall (Chawla, Jay, Baptista, Wilkin, & Seaton, ).…”

Section: Introductionmentioning

confidence: 99%

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Microbial players and processes involved in phytoplankton bloom utilization in the water column of a fast‐flowing, river‐dominated estuary

et al. 2017

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Fueled by seasonal phytoplankton blooms, the Columbia River estuary is a natural bioreactor for organic matter transformations. Prior metagenome analyses indicated high abundances of diverse Bacteroidetes taxa in estuarine samples containing phytoplankton. To examine the hypothesis that Bacteroidetes taxa have important roles in phytoplankton turnover, we further analyzed metagenomes from water collected along a salinity gradient at 0, 5, 15, 25, and 33 PSU during bloom events. Size fractions were obtained by using a 3‐μm prefilter and 0.2‐μm collection filter. Although this approach targeted bacteria by removing comparatively large eukaryotic cells, the metagenome from the ES‐5 sample (5 PSU) nevertheless contained an abundance of diatom DNA. Biogeochemical measurements and prior studies indicated that this finding resulted from the leakage of cellular material due to freshwater diatom lysis at low salinity. Relative to the other metagenomes, the bacterial fraction of ES‐5 was dramatically depleted of genes annotated as Bacteroidetes and lysogenic bacteriophages, but was overrepresented in DNA of protists and Myxococcales bacterivores. We suggest the following equally plausible scenarios for the microbial response to phytoplankton lysis: (1) Bacteroidetes depletion in the free‐living fraction may at least in part be caused by their attachment to fluvial diatoms as the latter are lysed upon contact with low‐salinity estuarine waters; (2) diatom particle colonization is likely followed by rapid bacterial growth and lytic phage infection, resulting in depletion of lysogenic bacteriophages and host bacteria; and (3) the subsequent availability of labile organic matter attracted both grazers and predators to feed in this estuarine biogeochemical “hotspot,” which may have additionally depleted Bacteroidetes populations. These results represent the first detailed molecular analysis of the microbial response to phytoplankton lysis at the freshwater–brackish water interface in the fast‐flowing Columbia River estuary.

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Hydrodynamics structure plankton communities and interactions in a freshwater tidal estuary

Smits

Loken

Nieuwenhuyse

et al. 2023

Ecological Monographs

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Drivers of phytoplankton and zooplankton dynamics vary spatially and temporally in estuaries due to variation in hydrodynamic exchange and residence time, complicating efforts to understand controls on food web productivity. We conducted approximately monthly (2012–2019; n = 74) longitudinal sampling at 10 fixed stations along a freshwater tidal terminal channel in the San Francisco Estuary, California, characterized by seaward to landward gradients in water residence time, turbidity, nutrient concentrations, and plankton community composition. We used multivariate autoregressive state space (MARSS) models to quantify environmental (abiotic) and biotic controls on phytoplankton and mesozooplankton biomass. The importance of specific abiotic drivers (e.g., water temperature, turbidity, nutrients) and trophic interactions differed significantly among hydrodynamic exchange zones with different mean residence times. Abiotic drivers explained more variation in phytoplankton and zooplankton dynamics than a model including only trophic interactions, but individual phytoplankton–zooplankton interactions explained more variation than individual abiotic drivers. Interactions between zooplankton and phytoplankton were strongest in landward reaches with the longest residence times and the highest zooplankton biomass. Interactions between cryptophytes and both copepods and cladocerans were stronger than interactions between bacillariophytes (diatoms) and zooplankton taxa, despite contributing less biovolume in all but the most landward reaches. Our results demonstrate that trophic interactions and their relative strengths vary in a hydrodynamic context, contributing to food web heterogeneity within estuaries at spatial scales smaller than the freshwater to marine transition.

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Plankton Assemblage Variability in a River-Dominated Temperate Estuary During Late Spring (High-flow) and Late Summer (Low-flow) Periods

Cited by 32 publications

References 48 publications

Quantity and quality of particulate organic matter controls bacterial production in the Columbia River estuary

Quantity and quality of particulate organic matter controls bacterial production in the Columbia River estuary

Microbial players and processes involved in phytoplankton bloom utilization in the water column of a fast‐flowing, river‐dominated estuary

Hydrodynamics structure plankton communities and interactions in a freshwater tidal estuary

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