Regulation of estuarine primary production by watershed rainfall and river flow

Mallin, Michael A.; Paerl, Hans W.; Rudek, J.; Bates, Pamela

doi:10.3354/meps093199

Cited by 252 publications

(148 citation statements)

References 19 publications

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“…From the PCA analysis, it is clear that spatial differences arose mostly along PC2, contrasting mostly larger nitrate þ nitrite concentrations and N:P ratios (upper station) to higher salinities, TPM and POM concentrations (lower station). This suggests that the upper estuary is more productive than the lower estuary as a result of higher nitrogen concentrations from riverine origin (Mallin et al, 1993;Malej et al, 1995). Also, higher chlorophyll biomass from the reservoir (Bordalo and Vieira, 2005) may help to explain these trends, but to a lesser extent (Table 5).…”

Section: Discussionmentioning

confidence: 93%

Pelagic metabolism of the Douro estuary (Portugal) – Factors controlling primary production

Azevedo

Duarte

Bordalo

2006

Estuarine, Coastal and Shelf Science

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The pelagic metabolism of the Douro estuary (Portugal) and the factors influencing primary production (PP) and community respiration (CR) in this system were studied during an annual cycle (December 2002eDecember 2003. Sampling surveys were conducted twice a month during ebb and flood spring tides and water samples were collected for PP and CR assessments at three stations along the estuary (lower, middle and upper stretches). During the study period, PP values were in the range of 4.7e1878.5 mg C m ÿ2 d ÿ1 (average, 319.9 mg C m ÿ2 d ÿ1 ). River discharge controlled phytoplankton biomass inputs into the estuary as well as residence time. A decreasing trend in water column PP from the upper to the lower estuary related to higher nitrogen concentrations and phytoplankton biomass from riverine origin was observed. An inverse trend was found for CR, i.e., higher values were found in the lower, more urbanized stretch. During the study period, averaged CR values reached 1154 mg C m ÿ2 d ÿ1 . In general, heterotrophy dominated the entire estuary, except in the upper stretch from May through July, when increased PP, but also lower CR values were recorded. A positive correlation between chlorophyll a and P max was found which is unusual in coastal ecosystems, where a decreasing trend of the P/B ratio as a function of net primary production is generally observed. This could be explained by the relatively low phytoplankton biomass, preventing intraspecific competition from lowering photosynthetic capacity, on one hand, and the physiology of phytoplankton related to their origin in a semi-lotic (reservoir) ecosystem. No significant differences between tides were observed for all variables, except for the water light extinction coefficient (k) values, reflecting higher turbidity during the ebb.

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Section: Discussionmentioning

confidence: 93%

Pelagic metabolism of the Douro estuary (Portugal) – Factors controlling primary production

Azevedo

Duarte

Bordalo

2006

Estuarine, Coastal and Shelf Science

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“…Although there is little evidence that river inputs of terrestrial carbon make a direct contribution to coastal food webs, such exported nutrients may stimulate in situ production in estuaries and thus enhance the survivorship and growth of fish and crustaceans in these systems (Loneragan et al, 1999). Moreover, river discharge into estuaries is characterized by variability under natural conditions, influencing plankton community composition and dynamics in the receiving waters (Haertel et al, 1967;Hodgkin et al, 1971;Ambler et al, 1985;Mallin et al, 1993). It is believed that reductions in the freshwater influx into estuaries will have a dramatic effect on ecosystem function, including zooplankton productivity, with subsequent shifts in energy flow patterns (Whitfield et al, 1988).…”

Section: Tidesmentioning

confidence: 99%

Zooplankton spatial and diurnal variations in the Changjiang River estuary before operation of the Three Gorges Dam

Gao

Song

2011

Chin. J. Ocean. Limnol.

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Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variability in zooplankton abundance and biomass over almost entire salinity gradient of the Changjiang (Yangtze) River estuary and to provide a background reference for future studies. To accomplish this, data were collected from 29 stations in the estuary from May 19 to 26, 2003, including two anchor stations. The spatial and diurnal variations in zooplankton characteristics, i.e. abundance, biomass, and gross taxonomic composition, were examined. Generally, both the abundance and biomass gradually increased seaward and presented distinct spatial variations. In addition, the spatial data revealed a significant correlation between abundance and biomass; however, there was no significant correlation between abundance and biomass for the diurnal data. Although the zooplankton composition indicated distinct spatial differences in terms of dominant groups, copepods accounted for >50% of the total zooplankton abundance in most regions and times. Three zooplankton assemblages were recognized through hierarchical cluster analysis. These assemblages existed along the salinity gradient from fresh water to seawater, and their positions coincided with those of the three principal water masses in the estuary. The assemblages were classified as: (1) true estuarine, (2) estuarine and marine, and (3) euryhaline marine, which were characterized by the copepods Sinocalanus dorrii, Labidocera euchaeta, and Calanus sinicus, respectively. Both spatial and diurnal data indicated that there was no significant correlation between zooplankton abundance/biomass and depth-integrated phytoplankton abundance.

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“…At the end of that decade, atmospheric nitrogen deposition to marine systems began to be investigated and its importance for the global ocean was assessed (DUCE, 1986). For example, it has been noted that the atmospheric input of nitrogen may be partly responsible for the eutrophication of estuarine or coastal waters and the appearance of harmful algal blooms, by either direct input or through the watershed (FISHER et al, 1988;MALLIN et al, 1993;PAERL et al,1993).…”

Section: Atmospheric Input Of Nutrients: Estimates and Impactsmentioning

confidence: 99%

The role of atmospheric deposition in the biogeochemistry of the Mediterranean Sea

Guerzoni

Chester

Dulac

et al. 1999

Progress in Oceanography

393

269

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Estimates of atmospheric inputs to the Mediterranean (MED) and some coastal areas are reviewed, and uncertainities in these estimates considered. Both the magnitude and the mineralogical composition of atmospheric dust inputs indicate that eolian deposition is an important (50%) or prevailing (>80%) contribution to sediments in the offshore waters of the entire Guerzoni et al.,"The role of atmospheric deposition in the biogeochemistry of the Mediterranean Sea"2 Mediterranean (MED) basin. Model data for trace metals and nutrients indicate that the atmosphere delivers more than half the lead and nitrogen, one-third of total phosphorus, and 10% of the zinc entering the entire basin. Measured data in sub-basins, such as the north-western MED and northern Adriatic indicate an even greater proportion of atmospheric versus riverine inputs.When dissolved fluxes are compared (the form most likely to impinge on surface water biogeochemical cycles), the atmosphere is found to be 5 to 50 times more important than rivers for dissolved Zn and 15 to 30 times more important for Pb fluxes.Neglecting co-limitation by other nutrients, new production supported by atmospheric nitrogen deposition ranges from 2-4 g C m -2 yr -1 , whereas atmospheric phosphorus deposition appears to support less than 1 g C m -2 yr -1 . In spite of the apparently small contribution of atmospheric deposition to overall production in the basin it has been suggested that certain episodes of phytoplankton blooms are triggered by atmospheric deposition of N, P or Fe. Future studies are needed to clarify the extent and causal links between these episodic blooms and atmospheric/oceanographic forcing functions. A scientific program aimed at elucidating the possible biogeochemical effects of Saharan outbreaks in the MED through direct sampling of the ocean and atmosphere before and after such events is therefore highly recommended.

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Regulation of estuarine primary production by watershed rainfall and river flow

Cited by 252 publications

References 19 publications

Pelagic metabolism of the Douro estuary (Portugal) – Factors controlling primary production

Pelagic metabolism of the Douro estuary (Portugal) – Factors controlling primary production

Zooplankton spatial and diurnal variations in the Changjiang River estuary before operation of the Three Gorges Dam

The role of atmospheric deposition in the biogeochemistry of the Mediterranean Sea

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