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1.
Carlos M. Duarte 《Hydrobiologia》2009,629(1):263-269
An analysis of the contents and conclusions of the papers contained in this issue (Hydrobiologia Volume xxx) suggests that a new vision is taking shape that may correspond to an emerging new paradigm in the way we understand
and manage coastal eutrophication. This new paradigm emphasizes its global dimension and the connections with other global
environmental pressures, and re-evaluates the targets of remedial actions and policies. Eutrophication research must evolve
toward a more integrative, ecosystem perspective which requires that it be extended to include impacts beyond primary producers
and to examine possible cascading effects and feedbacks involving other components of the ecosystem. A quantitative framework
that incorporates the interacting top-down and bottom-up effects in eutrophication models must be urgently developed to guide
diagnostics and establish targets to mitigate coastal eutrophication. The required macroscopic view must also be extended
to the managerial and policy frameworks addressing eutrophication, through the development of policies that examine activities
in the environment in an integrative, rather than sectorial, manner. Recent evidence of complex responses of coastal ecosystems
to nutrient reduction requires that management targets, and the policies that support them, be reconsidered to recognize the
complexities of the responses of coastal ecosystems to reduced nutrient inputs, including non-linear responses and associated
thresholds. While a predictive framework for the complex trajectories of coastal ecosystems subject to changes in nutrient
inputs is being developed, the assessment of managerial actions should be reconsidered to focus on the consideration of the
status achieved as the outcome of nutrient reduction plans against that possibly derived from a ‘do nothing’ scenario. A proper
assessment of eutrophication and the efforts to mitigate it also requires that eutrophication be considered as a component
of global change, in addressing both its causes and its consequences, and that the feedbacks between other components of global
change (e.g., climate change, overfishing, altered biogeochemical cycles, etc.) be explicitly considered in designing eutrophication
research and in managing the problem.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
2.
Management of eutrophication in marine ecosystems requires a good understanding of nutrient cycles at the appropriate spatial
and temporal scales. Here, it is shown that the biogeochemical processes controlling large-scale eutrophication of the Baltic
Sea can be described with a fairly aggregated model: simple as necessary Baltic long-term large scale (SANBALTS). This model
simulates the dynamics of nitrogen, phosphorus, and silica driven by the external inputs, the major physical transports, and
the internal biogeochemical fluxes within the seven major sub-basins. In a long-term hindcast (1970–2003), the model outputs
reasonably matched observed concentrations and fluxes. The model is also tested in a scenario where nutrient inputs are reduced
to levels that existed over 100 years ago. The simulated response of the Baltic Sea trophic state to this very large reduction
is verified by a similar simulation made with a much more complex process-oriented model. Both models indicate that after
initial, rather rapid changes the system goes into much slower evolution, and nutrient cycles would not become balanced even
after 130 years.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
3.
Eutrophication and the macroscope 总被引:4,自引:1,他引:3
Scott W. Nixon 《Hydrobiologia》2009,629(1):5-19
It is important to view eutrophication as an increase in the supply of organic matter to an ecosystem rather than as a simple
problem of nutrient pollution. This emphasizes that eutrophication is a fundamental change in the energetic base that may
propagate through the system in various ways and produce a variety of changes. Some of these changes may be desirable (e.g.,
increased secondary production) and some may not (e.g., hypoxia). Defining eutrophication in terms of changing nutrient concentrations
or chlorophyll levels or species composition confuses symptoms with the underlying phenomenon. While nutrient enrichment is
the most common cause of eutrophication, it is not the only one. As recent and ongoing nutrient reductions make an impact
in the coastal waters of the wealthier nations, we will see an increasing number of systems in which primary production is
decreasing. This reduction in the supply of organic matter is here defined as oligotrophication, a phenomenon now well documented
in lakes. So far, there has been little appreciation of this limnological study by coastal marine ecologists or managers,
but there is much we can learn from it. The great ecologist H.T. Odum long argued that we need ‘macroscopes’ to help ecologists
see the problems they study as they are embedded in the larger scales of nature and society. Marine eutrophication (and oligotrophication)
is a perfect example of a problem that must be studied with a view toward the larger scales as well as toward the microscopic
details. While much of the hardware (e.g., satellite imagery) for the mythical macroscope has been developed in the last 30 years,
many ecologists and managers still look at eutrophication as a local problem linked to local sources of nutrient enrichment.
Such a parochial view isolates eutrophication from its long intellectual history—a history that is linked to the development
of our understanding of production in coastal waters. It also neglects the intellectual richness and complexity of eutrophication.
One example of the importance of the macroscopic view is the emerging importance of climate-induced changes in phenology and
the consequences of changing phenology on productivity. These changes may lead to eutrophication or oligotrophication. Climate
changes may also exacerbate or alleviate conditions such as hypoxia that are associated with eutrophication. Seeing eutrophication
in the macroscopic view is important for understanding and managing the phenomenon.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
4.
Eutrophication of coastal waters is a serious environmental problem with high costs for society globally. This is a development
which demands immediate environmental action along many coastal sites. Since the 1980s, mussel farming has been recognized
by Swedish environmental authorities as a possible measure to improve coastal water quality. Concepts and management strategies
on how to increase mussel farming and thus combat coastal marine eutrophication has recently been developed in Sweden. The
main principle of this development has been the implementation of nutrient trading as a management tool. This imposes demands
on those who emit the pollution through the establishment of emission quotas, which are traded and bought by the emitter.
The seller is a nutrient harvesting enterprise, e.g., a mussel farmer. This principle is particularly straightforward when
the nutrients are discharged from a point source. When examining the nutrient supply from all diffuse sources, the situation
is more complex. However, since the major part of the nutrient supply to coastal waters in many areas of Europe has its origin
in agricultural operations, we suggest that the EU agro-environmental aid program could be extended into the coastal zone
in order to combat eutrophication. In practice, this should involve support paid to mussel farming enterprises through their
harvest of mussels (and thus their harvest of nutrients) in the same way as support is paid to agricultural farmers for operations
that reduce nutrient leakage from their farmland. This is a simple, cost-effective and straightforward way of improving coastal
water quality at many coastal sites that will, at the same time, provide coastal jobs. However, this eutrophication combat
method depends on the EU agro-environmental aid program being extended beyond the shoreline.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
5.
Ulrich Claussen Wanda Zevenboom Uwe Brockmann Dilek Topcu Peter Bot 《Hydrobiologia》2009,629(1):49-58
Eutrophication (nutrient enrichment and subsequent processes) and its adverse ecosystem effects have been discussed as main
issues over the last 20 years in international conferences and conventions for the protection of the marine environment such
as the North Sea Conferences and the 1992 OSPAR Convention (OSPAR; which combined and updated the 1972 Oslo Convention on
dumping waste at the sea and the 1974 Paris Convention on land-based sources of marine pollution). OSPAR committed itself
to reduce phosphorus and nitrogen inputs (in the order of 50% compared with 1985) into the marine areas and ‘to combat eutrophication
to achieve, by the year 2010, a healthy marine environment where eutrophication does not occur’. Within OSPAR, the Comprehensive
Procedure (COMPP) has been developed and used to assess the eutrophication status of the OSPAR maritime area in an harmonised
way. This is based on classification in terms of the following types of areas Non-Problem Areas (no effects), Potential Problem
Areas (not enough data to assess effects) and Problem Areas (effects due to elevated nutrients and/or due to transboundary
transport from adjacent areas). The COMPP consists of a set of harmonised assessment criteria with their area-specific assessment
levels and an integrated area classification approach. The criteria cover all aspects of nutrient enrichment (nutrient inputs,
concentrations and ratios) as well as possible direct effects (e.g. increased levels of nuisance and/or toxic phytoplankton
species, shifts and/or losses of submerged aquatic vegetation) and indirect effects (e.g. oxygen deficiency, changes and/or
death of benthos, death of fish, algal toxins). The COMPP also includes supporting environmental factors. It takes account
of synergies and harmonisation with the EC Water Framework Directive, and has formed a major basis for the EC eutrophication
guidance. Recently, additional components, such as total nitrogen, total phosphorus and transboundary transports have been
included in the assessment of, e.g. the German Bight. The second application of the COMPP resulting in an update of the eutrophication
status of the OSPAR maritime area will be finalised in 2008, and will include the agreed integrated set of Ecological Quality
Objectives (EcoQOs) with respect to eutrophication.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
6.
Nutrient enrichment and fisheries exploitation: interactive effects on estuarine living resources and their management 总被引:3,自引:1,他引:2
D. L. Breitburg J. K. Craig R. S. Fulford K. A. Rose W. R. Boynton D. C. Brady B. J. Ciotti R. J. Diaz K. D. Friedland J. D. Hagy III D. R. Hart A. H. Hines E. D. Houde S. E. Kolesar S. W. Nixon J. A. Rice D. H. Secor T. E. Targett 《Hydrobiologia》2009,629(1):31-47
Both fisheries exploitation and increased nutrient loadings strongly affect fish and shellfish abundance and production in
estuaries. These stressors do not act independently; instead, they jointly influence food webs, and each affects the sensitivity
of species and ecosystems to the other. Nutrient enrichment and the habitat degradation it sometimes causes can affect sustainable
yields of fisheries, and fisheries exploitation can affect the ability of estuarine systems to process nutrients. The total
biomass of fisheries landings in estuaries and semi-enclosed seas tends to increase with nitrogen loadings in spite of hypoxia,
but hypoxia and other negative effects of nutrient over-enrichment cause declines in individual species and in parts of systems
most severely affected. More thoroughly integrated management of nutrients and fisheries will permit more effective management
responses to systems affected by both stressors, including the application of fisheries regulations to rebuild stocks negatively
affected by eutrophication. Reducing fishing mortality may lead to the recovery of depressed populations even when eutrophication
contributes to population declines if actions are taken while the population retains sufficient reproductive potential. New
advances in modeling, statistics, and technology promise to provide the information needed to improve the understanding and
management of systems subject to both nutrient enrichment and fisheries exploitation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
7.
Using primary productivity as an index of coastal eutrophication: the units of measurement matter 总被引:1,自引:0,他引:1
Eutrophication is a serious environmental and economic problemin coastal marine ecosystems worldwide. It has recently beenrecommended that measurements of primary productivity, beinga sensitive and accurate indicator of eutrophication, shouldbe mandatory when monitoring and assessing the ecological statusof coastal waters. The units of primary productivity chosenfor eutrophication assessment will be very important becausenot all measures of primary productivity vary monotonically(or even straightforwardly) with changes in aquatic fertility.Volumetric expressions of primary productivity (rates of carbonfixation per unit volume of seawater) may prove to be the mostsensitive and most reliable measures to use when evaluatingthe eutrophication status of coastal marine ecosystems. Anotherpotential measure of primary productivity, the light-saturatedrate of photosynthesis per unit Chlorophyll a (P:BChl) ratio,is unsuitable for the assessment of aquatic ecosystem responsesto nutrient enrichment. 相似文献
8.
Response of eutrophication in the eastern Gulf of Finland to nutrient load reduction scenarios 总被引:1,自引:1,他引:0
Oleg P. Savchuk Tatjana R. Eremina Alexey V. Isaev Ivan A. Neelov 《Hydrobiologia》2009,629(1):225-237
The trophic status of the eastern Gulf of Finland, where the largest Baltic metropolis St. Petersburg sits at the mouth of
the largest Baltic river Neva, is elevated but existing recommendations on water protection measures are controversial. In
this study, the effects of nutrient load reductions on this ecosystem were estimated with the aid of a three-dimensional coupled
hydrodynamic-biogeochemical model. As a reference, the contemporary seasonal dynamics were simulated with nutrient inputs
corresponding to the recent estimates of point and riverine sources. In order to eliminate the effects of natural inter-annual
variations, the computations were run under recurrent annual forcing for 3 years, until quasi steady-state seasonal dynamics
were reached. Reasonable comparability of simulated concentrations and biogeochemical fluxes to available field estimates
provides credibility to scenario simulations. These simulations show that substantial reductions of nutrient point sources
in St. Petersburg would affect only the Neva Bay as the immediate receptor of treated sewage waters, where primary production
could decrease by up to 20%. Eutrophication in the other parts of the Neva Estuary and in the entire eastern Gulf of Finland
would change insignificantly owing to increased nutrient import from the offshore waters. Therefore, more significant changes
can occur only via a reduction in nutrient pools in the open Gulf of Finland and the Baltic Proper, which would require a
longer time.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
9.
Low ratios of silica to dissolved nitrogen supplied to rivers arise from agriculture not reservoirs 下载免费PDF全文
Coastal marine systems are greatly altered by toxic marine algae, eutrophication and hypoxia. These problems have been linked to decreased ratios of dissolved silica to inorganic nitrogen (Si : DIN) delivered from land. Two mechanisms for this decline under consideration are enhanced nitrogen (N) fertiliser losses from agricultural lands or Si sequestration in reservoirs. Here we examine these mechanisms via nutrient concentrations in impoundments receiving water from 130 watersheds in a landscape representative of the agriculture that often dominates coastal nutrient inputs. Decreased Si : DIN was correlated with agriculture, not impoundment. Watersheds with > 60% agricultural land yielded highest DIN, whereas Si was uncorrelated with agricultural intensity. Furthermore, eutrophic lakes were dominated by Cyanobacteria that use little Si, so reservoirs did not diminish Si : DIN. Instead, Si : DIN increased slightly as reservoir residence time increased. These data suggest that impoundments in agricultural watersheds may enhance the water quality of coastal ecosystems, whereas fertiliser losses are detrimental. 相似文献
10.
Estela Romero Josette Garnier Luis Lassaletta Gilles Billen Romain Le Gendre Philippe Riou Philippe Cugier 《Biogeochemistry》2013,113(1-3):481-505
We provide data on nutrient export for 28 rivers in southwestern Europe and analyze long-term changes in the context of anthropogenic pressures and regulation policies. Special attention is given to seasonal variations, because the integrated annual values that are usually provided do not allow us to establish comparisons with seasonal phytoplankton dynamics. The eutrophication risk associated with river inputs is addressed by means of an indicator (Index of Coastal Eutrophication Potential, ICEP, Billen and Garnier, Mar Chem 106:148–160, 2007). An overview of the temporal evolution and the intra-annual variability of the ICEP is discussed for specific rivers and integrated coastal regions. The annual dynamics of the eutrophication indicator is analyzed to delimit those periods when the risk of eutrophication is particularly high. The trends in nutrient fluxes and coastal phytoplankton are compared by means of a case study (Seine Bay). The decrease in phosphorus matches a general decrease in phytoplankton biomass in the summer. However, sustained high values of nitrogen still foster the emergence of harmful algal blooms, and we found an increase in the summer abundance of dinoflagellates. The abatement of phosphorus alone is not enough to shortcut harmful blooms and toxic outbreaks in the Seine Bay. A reduction in nitrogen inputs may be necessary to effectively minimize eutrophication problems. 相似文献
11.
Potential phytoplankton indicator species for monitoring Baltic coastal waters in the summer period 总被引:2,自引:1,他引:1
Andres Jaanus Kaire Toming Seija Hällfors Kaire Kaljurand Inga Lips 《Hydrobiologia》2009,629(1):157-168
There are very few time series documenting clear trends of change in the biomass of total phytoplankton or single taxa that
coincide with trends of increasing nutrient concentrations. Weekly or biweekly monitoring since 1997 on a cross section of
the central Gulf of Finland (NE Baltic Sea) with similar climatic and hydrographic conditions, but different nutrient levels,
provided a uniform dataset. In order to evaluate seasonal (June–September) patterns of phytoplankton succession, more than
1,200 samples were statistically analyzed by selecting 12 dominant taxa using wet weight biomass values. In addition, the
continuously measured hydrographic parameters on board the ships of opportunity, and simultaneous nutrient analyses gave high
frequency information on the water masses. The objective of this study was to identify the taxa that may prove indicative
in the assessment of eutrophication in the appropriate monitoring time periods. None of the most common bloom-forming species
(Aphanizomenon sp., Nodularia spumigena, and Heterocapsa triquetra) showed reliable correlations with enhanced nutrient concentrations. The species we suggest as reliable eutrophication indicators—oscillatorialean
cyanobacteria and the diatoms Cyclotella choctawhatcheeana and Cylindrotheca closterium—showed the best relationships with total phosphorus concentrations. Their maxima appear toward the end of July or in August–September
when phytoplankton community structure is more stable, and less frequent observations may give adequate results. Another diatom,
Skeletonema costatum, exhibited stronger correlations with dissolved inorganic and total nitrogen in June, during the period of the summer phytoplankton
minimum.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
12.
Denitrification efficiency for defining critical loads of carbon in shallow coastal ecosystems 总被引:2,自引:2,他引:0
Denitrification efficiency [DE; (N2 − N/(DIN + N2 − N) × 100%)] as an indicator of change associated with nutrient over-enrichment was evaluated for 22 shallow coastal ecosystems
in Australia. The rate of carbon decomposition (which can be considered a proxy for carbon loading) is an important control
on the efficiency with which coastal sediments in depositional mud basins with low water column nitrate concentrations recycle
nitrogen as N2. The relationship between DE and carbon loading is due to changes in carbon and nitrate (NO3) supply associated with sediment biocomplexity. At the DE optimum (500–1,000 μmol m−2 h−1), there is an overlap of aerobic and anaerobic respiration zones (caused primarily by the existence of anaerobic micro-niches
within the oxic zone, and oxidized burrow structures penetrating into the anaerobic zone), which enhances denitrification
by improving both the organic carbon and nitrate supply to denitrifiers. On either side of the DE optimum zone, there is a
reduction in denitrification sites as the sediment loses its three-dimensional complexity. At low organic carbon loadings,
a thick oxic zone with low macrofauna biomass exists, resulting in limited anoxic sites for denitrification, and at high carbon
loadings, there is a thick anoxic zone and a resultant lack of oxygen for nitrification and associated NO3 production. We propose a trophic scheme for defining critical (sustainable) carbon loading rates and possible thresholds
for shallow coastal ecosystems based on the relationship between denitrification efficiency and carbon loading for 17 of the
22 Australian coastal ecosystems. The denitrification efficiency “optimum” occurs between carbon loadings of about 50 and
100 g C m−2 year−1. Coastal managers can use this simple trophic scheme to classify the current state of their shallow coastal ecosystems and
for determining what carbon loading rate is necessary to achieve any future state.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
13.
Nitrogen cycling in coastal marine ecosystems 总被引:34,自引:0,他引:34
R.A. Herberta 《FEMS microbiology reviews》1999,23(5):563-590
It is generally considered that nitrogen availability is one of the major factors regulating primary production in temperate coastal marine environments. Coastal regions often receive large anthropogenic inputs of nitrogen that cause eutrophication. The impact of these nitrogen additions has a profound effect in estuaries and coastal lagoons where water exchange is limited. Such increased nutrient loading promotes the growth of phytoplankton and fast growing pelagic macroalgae while rooted plants (sea-grasses) and benthic are suppressed due to reduced light availability. This shift from benthic to pelagic primary production introduces large diurnal variations in oxygen concentrations in the water column. In addition oxygen consumption in the surface sediments increases due to the deposition of readily degradable biomass. In this review the physico-chemical and biological factors regulating nitrogen cycling in coastal marine ecosystems are considered in relation to developing effective management programmes to rehabilitate seagrass communities in lagoons currently dominated by pelagic macroalgae and/or cyanobacteria. 相似文献
14.
大型海藻的营养盐代谢及其与近岸海域富营养化的关系 总被引:2,自引:0,他引:2
大型海藻是近岸海域重要的初级生产者,近年来人们愈来愈认识到大型海藻在近岸海域富营养化生物修复中的重要性,同时,富营养化也可能招致某些机会主义大型海藻种类的爆发生长,因此,进一步理解大型海藻与营养盐供应变化的关系就显得非常重要。本文从大型海藻营养盐代谢与海水中营养盐供应变化(主要是富营养化)的生理生态关系角度对相关问题进行评述,主要包括影响大型海藻营养盐吸收特性的重要因素、海水中营养盐的供应及大型海藻对营养盐的细胞贮存、大型海藻对营养盐的生态需求、大型海藻对近岸海域富营养化的生态响应等问题。文章还对今后的研究提出了展望。 相似文献
15.
Eutrophication and agriculture in Denmark: 20 years of experience and prospects for the future 总被引:2,自引:1,他引:1
During the past two decades there has been growing public and political awareness of the consequences of eutrophication in
Denmark. By the mid-1980s, the environmental status of inland and coastal waters had deteriorated due to high nutrient loads.
Consequently, a number of different Action Plans against water pollution were introduced. In the agricultural sector, focus
has been on reductions in nitrogen leaching obtained by the introduction of various measures: a maximum limit to the density
of livestock, 9 months’ storage capacity for manure, catch crops for at least 6% of the land, enhanced utilization (up to
75%) of nitrogen in manure, etc. The agricultural sector in Denmark has implemented all of these measures, and as a result
of the effort, the target for reductions in nitrogen leaching will be reached. Currently, the total loss of nitrogen from
farmland is likely to be reduced by approximately 50% compared to the level in the mid-1980s. Some of the measures have been
fair and based on sound arguments, and have been implemented with only minor difficulties, whereas others have proved troublesome
and in our opinion disproportionately expensive. Today, further general regulation with equal restrictions toward all farmers
regardless of differences in environmental impacts is no longer an acceptable path to follow. In the future, it will be necessary
to pinpoint new measures in the most sensitive areas, where the potential for further reductions in nutrient loads is large.
Danish Agriculture calls for specific actions—and consequently a shift in environmental management and policy making. Such
a revised management strategy is the only path to follow in order to obtain further improvements in environmental conditions.
Meanwhile, future development in the agricultural sector will be possible and a win–win situation can be reached.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
16.
This article reports the first demonstration of the impact of climate change on benthic–pelagic coupling and the biogeochemical
cycles of a coastal marine system. Over the last 30 years Narragansett Bay, a 328-km2 temperate estuary on the east coast of the United States, has undergone a variety of ecological changes. Building on a robust
data set that spans three decades, we present a link between warming (+1.7°C in annual mean water temperature) in the bay
and a marked decrease in sediment oxygen consumption, in the fluxes of ammonium and phosphate from sediments to the overlying
water, and in sediment denitrification. We attribute this reduction in biogeochemical exchange to a dramatic drop in the standing
crop of water-column chlorophyll as the system has shifted from one characterized by a dominant winter–spring bloom to one
supported by more ephemeral and less intense summer–autumn blooms. The recent climate-induced oligotrophication of the bay
will be further exacerbated by forthcoming nitrogen reductions due to tertiary sewage treatment.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
17.
Irene Olivé M. Paz García-Sánchez Fernando G. Brun Juan J. Vergara J. Lucas Pérez-Lloréns 《Hydrobiologia》2009,629(1):199-208
Light reduction in the water column and enhanced organic matter (OM) load into the sediments are two main consequences of
eutrophication in marine coastal areas. This study addresses the combined effects of light, OM, and clonal traits in the seagrass
Zostera noltii. Large Z. noltii plants were grown in sand with or without the addition of OM and under two light levels (high light and low light). Whereas
some complete plant replicates were grown under homogeneous light and/or OM conditions, other replicates were grown under
contrasting light and/or OM levels between the apical and the distal parts of the same plant. The three-way factorial design
(light, OM load, and apex position) allowed us to determine the harmful effect of light reduction and OM enrichment on the
growth, photosynthetic performance, and biochemical composition of Z. noltii. The addition of OM to the sediment promoted a decrease, or even an inhibition, in net plant growth regardless of the light
level when the whole plants were grown under homogeneous light conditions. However, the results differed when plants were
grown under contrasting light and/or OM conditions between apical and distal parts. In this case, the harmful effect of OM
load was alleviated when apical parts were grown under high light conditions. OM loads also negatively affected the photosynthetic
performance, evaluated as leaf fluorescence. The results indicate the importance of clonal traits in the response of Z. noltii growth to light conditions and OM enrichment.
Guest editors: J. H. Andersen & D. J. Conley
Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of
Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark 相似文献
18.
Nutrient over-enrichment is a major threat to marine environments, but system-specific attributes of coastal ecosystems may
result in differences in their sensitivity and susceptibility to eutrophication. We used fertilization experiments in nitrogen
(N)- and phosphorus (P)-limited mangrove forests to test the hypothesis that alleviating different kinds of nutrient limitation
may have different effects on ecosystem structure and function in natural systems. We compared a broad range of ecological
processes to determine if these systems have different thresholds where shifts might occur in nutrient limitation. Growth
responses indicated N limitation in Avicennia germinans (black mangrove) forests in the Indian River Lagoon (IRL), Florida, and P limitation at Twin Cays, Belize. When nutrient
deficiency was relieved, A. germinans grew out of its stunted form by increasing wood relative to leaf biomass and shoot length relative to lateral growth. At
the P-limited site, P enrichment (+P) increased specific leaf area, N resorption, and P uptake, but had no effect on P resorption.
At the N-limited site, +N increased both N and P resorption, but did not alter biomass allocation. Herbivory was greater at
the P-limited site and was unaffected by +P, whereas +N led to increased herbivory at the N-limited site. The responses to
nutrient enrichment depended on the ecological process and limiting nutrient and suggested that N- versus P-limited mangroves
do have different thresholds. +P had a greater effect on more ecological processes at Twin Cays than did +N at the IRL, which
indicated that the P-limited site was more sensitive to nutrient loading. Because of this sensitivity, eutrophication is more
likely to cause a shift in nutrient limitation at P-limited Twin Cays than N-limited IRL. 相似文献
19.
Devin A. Lyons Christos Arvanitidis Andrew J. Blight Eva Chatzinikolaou Tamar Guy‐Haim Jonne Kotta Helen Orav‐Kotta Ana M. Queirós Gil Rilov Paul J. Somerfield Tasman P. Crowe 《Global Change Biology》2014,20(9):2712-2724
Eutrophication, coupled with loss of herbivory due to habitat degradation and overharvesting, has increased the frequency and severity of macroalgal blooms worldwide. Macroalgal blooms interfere with human activities in coastal areas, and sometimes necessitate costly algal removal programmes. They also have many detrimental effects on marine and estuarine ecosystems, including induction of hypoxia, release of toxic hydrogen sulphide into the sediments and atmosphere, and the loss of ecologically and economically important species. However, macroalgal blooms can also increase habitat complexity, provide organisms with food and shelter, and reduce other problems associated with eutrophication. These contrasting effects make their overall ecological impacts unclear. We conducted a systematic review and meta‐analysis to estimate the overall effects of macroalgal blooms on several key measures of ecosystem structure and functioning in marine ecosystems. We also evaluated some of the ecological and methodological factors that might explain the highly variable effects observed in different studies. Averaged across all studies, macroalgal blooms had negative effects on the abundance and species richness of marine organisms, but blooms by different algal taxa had different consequences, ranging from strong negative to strong positive effects. Blooms' effects on species richness also depended on the habitat where they occurred, with the strongest negative effects seen in sandy or muddy subtidal habitats and in the rocky intertidal. Invertebrate communities also appeared to be particularly sensitive to blooms, suffering reductions in their abundance, species richness, and diversity. The total net primary productivity, gross primary productivity, and respiration of benthic ecosystems were higher during macroalgal blooms, but blooms had negative effects on the productivity and respiration of other organisms. These results suggest that, in addition to their direct social and economic costs, macroalgal blooms have ecological effects that may alter their capacity to deliver important ecosystem services. 相似文献
20.
G.W. Scarth MA 《Plant Ecology & Diversity》2013,6(2):195-210
Summary World-wide, our coastal waters have been subject to an increased nutrient input since the latter part of the nineteenth century. This has led to the eutrophication or ‘nutrient pollution’ of many coastal sites, including Langstone Harbour and the Ythan Estuary here in the UK. Eutrophication at these and, indeed, at other nutrient enriched sites is evident by the appearance of large blooms of fast-growing opportunistic macroalgae. Blooms of macroscopic species of green algae (Chlorophyta: Ulvophyceae) are particularly common and the phenomenon is often referred to as the occurrence of green tides. Green tides may have a dramatic environmental impact, causing much damage to the local ecosystem. Numerous strategies have hence been employed in order to combat the problem, but to date there has been limited success. For this reason, current research in the UK is aimed at increasing our knowledge of green tide algae in terms of their ecophysiology, whilst further investigation of the nutrient pathways and fluxes within specific ecosystems has been deemed necessary. It is anticipated that this ‘backto basics’ approach will ultimately contribute to the development of new, successful eutrophication management strategies. 相似文献