Size-dependent nitrogen uptake in micro- and macroalgae

Hein, Mette; Pedersen, Morten Foldager; Sand‐Jensen, Kaj

doi:10.3354/meps118247

Cited by 273 publications

(166 citation statements)

References 30 publications

Supporting

Mentioning

155

Contrasting

Unclassified

Order By: Relevance

“…This shows that the improvement of the hydrodynamics of the system lowered dissolved inorganic nitrogen concentrations, which caused macroalgae with low nitrogen affinity to be nitrogen limited. In fact, nitrogen often appears to be the limiting nutrient in estuarine systems (Hein et al, 1995;Yin et al, 2001), namely in the form of ammonia (Rocha et al, 1995). Ultimately, the response of phytoplankton, green macroalgae and the seagrass Zostera noltii to the changes of nitrogen loading in the Mondego estuary clearly confirms the pattern of relative contribution of these three major groups of producers, in shallow temperate estuaries with shorter water residence time, proposed by Valiela et al (1997) (Fig.…”

Section: Discussionsupporting

confidence: 55%

“…Due to a comparatively higher surface area/ volume relation, phytoplankton have higher affinity for nitrogen forms, with higher uptake rates than macroalgae for both ammonia and nitrate per unit of biomass (Hein et al, 1995;Collos, 1998). However, this only makes phytoplankton competitively superior under low nitrogen availability, which is closely related to nitrogen loading and water residence time (Hein et al, 1995;Valiela et al, 1997). On the other hand, the biomass of green macroalgae was reduced about one order of magnitude after the mitigation measures.…”

Section: Discussionmentioning

confidence: 99%

“…The opportunistic primary producer parameters suggest that phytoplankton is not nutrient limited, since chlorophyll a concentrations did not show any significant changes throughout the period between 1993 and 2003. Due to a comparatively higher surface area/ volume relation, phytoplankton have higher affinity for nitrogen forms, with higher uptake rates than macroalgae for both ammonia and nitrate per unit of biomass (Hein et al, 1995;Collos, 1998). However, this only makes phytoplankton competitively superior under low nitrogen availability, which is closely related to nitrogen loading and water residence time (Hein et al, 1995;Valiela et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Management of a shallow temperate estuary to control eutrophication: The effect of hydrodynamics on the system’s nutrient loading

Lillebø

Neto

Martins

et al. 2005

Estuarine, Coastal and Shelf Science

116

View full text Add to dashboard Cite

The Mondego estuary, a shallow warm-temperate intertidal system located on the west coast of Portugal, has for some decades been under severe ecological stress, mainly caused by eutrophication. Water circulation in this system was, until 1998, mainly dependent on tides and on the freshwater input of a small tributary artificially controlled by a sluice. After 1998, the sluice opening was effectively minimised to reduce the nutrient loading, and the system hydrodynamics improved due to engineering work in the upstream areas. The objective of the present study was to evaluate the effect of the mitigation measures implemented in 1998. Changes to the hydrodynamics of the system were assessed using precipitation and salinity data in relation to the concentrations of dissolved inorganic nutrients, as well as the linkage between dissolved N:P ratios and the biological parameters (phytoplankton chlorophyll a concentrations, green macroalgal biomass and seagrass biomass). Two distinctive periods were compared, over a ten year period: from January 1993 to January 1997 and from January 1999 until January 2003. The effective reduction in the dissolved N:P atomic ratio from 37.7 to 13.2 after 1998 is a result of lowered ammonia, but not the oxidised forms of nitrogen (nitrate plus nitrite), or increased concentrations of dissolved inorganic phosphorus. Results suggest that the phytoplankton is not nutrient limited, yet maximum and mean biomass of green macroalgae was reduced by one order of magnitude after the mitigation measures. This suggests that besides lowering the water residence time of the system, macroalgal growth became nitrogen limited. In parallel to these changes the seagrass-covered area and biomass of Zostera noltii showed signs of recovery.

show abstract

Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Management of a shallow temperate estuary to control eutrophication: The effect of hydrodynamics on the system’s nutrient loading

Lillebø

Neto

Martins

et al. 2005

Estuarine, Coastal and Shelf Science

116

View full text Add to dashboard Cite

show abstract

“…Functional groups were defined by using traits related to anatomical complexity according the scheme of Steneck and Dethier (35). Anatomical complexity is negatively associated with surface to volume ratios (S:V), mass-specific growth, and nutrient uptake rates but positively associated with resistance to herbivory (35,68). The functional groups, listed in increasing order of anatomical complexity, included the following species (69 …”

Section: Discussionmentioning

confidence: 99%

Nutrient loading and consumers: Agents of change in open-coast macrophyte assemblages

Nielsen

2003

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Human activities are significantly altering nutrient regimes and the abundance of consumers in coastal ecosystems. A field experiment in an open-coast, upwelling ecosystem showed that small increases in nutrients increased the biomass and evenness of tide pool macrophytes where consumer abundance and nutrient loading rates were low. Consumers, when abundant, had negative effects on the diversity and biomass of macrophytes. Nutrient loading increases and consumers are less abundant and efficient as wave exposure increases along open coastlines. Experimentally reversing the natural state of nutrient supply and consumer pressure at a wave-protected site to match wave-exposed sites caused the structure of the macrophyte assemblage to converge on that found naturally in wave-exposed pools. The increases in evenness and abundance were driven by increases in structurally complex functional groups. In contrast, increased nutrient loading in semienclosed marine or estuarine ecosystems is typically associated with declines in macrophyte diversity because of increases in structurally simple and opportunistic functional groups. If nutrient concentration of upwelled waters changes with climatic warming or increasing frequency of El Niñ os, as predicted by some climate models, these results suggest that macrophyte abundance and evenness along wave-swept open-coasts will also change. Macrophytes represent a significant fraction of continental shelf production and provide important habitat for many marine species. The combined effects of shifting nutrient regimes and overexploitation of consumers may have unexpected consequences for the structure and functioning of open-coast communities.

show abstract

“…Perhaps different frond shape provide different surface-tovolume ratios, which in turn alter nitrogen uptake. Hein et al (1995) showed that the ratio of surFace to volume in Q 102 a . l .…”

mentioning

confidence: 99%

Macroalgal blooms in shallow estuaries: Controls and ecophysiological and ecosystem consequences

Valiela

McClelland

Hauxwell

et al. 1997

Limnology & Oceanography

1,154

755

View full text Add to dashboard Cite

Macroalgal blooms arc produced by nutrient enrichment of estuaries in which the sea floor lies within the photic zone. We review fcaturcs of macroalgal blooms pointed out in recent literature and summarize work done in the Waquoit Bay Land Margin Ecosystems Research project which suggests that nutrient loads, water residcncc times, presence of fringing salt marshes, and grazing affect macroalgal blooms.Increases in nitrogen supply raise macroalgal N uptake rates, N contents of tissues, photosynthesis-irradiance curves and P,,,.,, and accelerate growth of fronds. The resulting increase in macroalgal biomass is the macroalgal bloom, which can displace other estuarine producers, Fringing marshes and brief water residence impair the intensity of macroalgal blooms. Grazing pressure may control blooms of palatable macroalgac, but only at lower N loading rates. Macroalgal blooms end when growth of the phytoplankton attenuates irradiation reaching the bottom. In cstuarics with brief water rcsidencc times, phytoplankton may not have enough time to grow and shade macrophytcs. High phytoplankton division rates achieved at high nutrient concentrations may compensate for the brief time to divide before cells arc transported out of the estuary.Increased N loads and associated macroalgal blooms pervasively and fundamentally alter estuarinc ecosystems. Macroalgae intercept nutrients regenerated from sediments and thus uncoupIe biogeochemical sedimentary cycles from those in the water column. Macroalgae take up so much N that water quality seen:? high even where N loads are high. Macroalgal C moves more readily through microbial and consumer food webs than C derived from seagrasscs that were replaced by macroalgae. Macroalgae dominate 0, profiles of the water columns of shallow estuaries and thus alter the biogeochemistry of the sediments. Marc frequent hypoxia and habitat changes associated with macroalgal blooms also changes the abundance of bcnthic fauna in affected estuaries.Approaches to rcmediation of the many pervasive cffccts of macroalgal blooms riced to include interception of nutrients at their watcrshcd sources and perhaps removal by harvest of macroalgae or by increased flushing. Although we have much knowledge of macroalgal dynamics, all such management initiatives will require additional information.

show abstract

Size-dependent nitrogen uptake in micro- and macroalgae

Cited by 273 publications

References 30 publications

Management of a shallow temperate estuary to control eutrophication: The effect of hydrodynamics on the system’s nutrient loading

Management of a shallow temperate estuary to control eutrophication: The effect of hydrodynamics on the system’s nutrient loading

Nutrient loading and consumers: Agents of change in open-coast macrophyte assemblages

Macroalgal blooms in shallow estuaries: Controls and ecophysiological and ecosystem consequences

Contact Info

Product

Resources

About