Biomass response and changes in composition of ephemeral macroalgal assemblages along an experimental gradient of nutrient enrichment

Karez, Rolf; Engelbert, Silke; Kraufvelin, Patrik; Pedersen, Morten Foldager; Sommer, Ulrich

doi:10.1016/j.aquabot.2003.09.008

Cited by 93 publications

(48 citation statements)

References 35 publications

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“…Effects of nutrient enrichment on the structure of macroalgal assemblages were lower than those described in other studies (Karez et al 2004, Kraufvelin 2007 of nutrient enrichment, nor was there an increase in cover of typical species of polluted habitats. Probably the length of the experiment (about 4 mo) allowed observation of only the early phases of the eutrophication process in deep subtidal Mediterranean rocky assemblages.…”

Section: Discussioncontrasting

confidence: 82%

“…The spread of introduced species, such as C. taxifolia in the Mediterranean Sea, C. brachypus f. parvifolia (Harvey) Cribb in Florida and C. ollivierii Dostál in the Bahamas is also considered to be enhanced by eutrophication (Chisholm et al 1995, Lapointe et al 2005, Lapointe & Beldford 2010. Results of the present study showed that invasion by C. racemosa may also be faster in eutrophic areas, suggesting that it could be favored by an increase of pollution in the coastal water of the Mediterranean Sea.Effects of nutrient enrichment on the structure of macroalgal assemblages were lower than those described in other studies (Karez et al 2004, Kraufvelin 2007 of nutrient enrichment, nor was there an increase in cover of typical species of polluted habitats. Probably the length of the experiment (about 4 mo) allowed observation of only the early phases of the eutrophication process in deep subtidal Mediterranean rocky assemblages.…”

contrasting

confidence: 82%

“…Effects of nutrient enrichment on the structure of macroalgal assemblages were lower than those described in other studies (Karez et al 2004, Kraufvelin 2007 Table 5. Results of SIMPER test showing taxa contributing most to differences between experimental treatments.…”

Section: Discussioncontrasting

confidence: 61%

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Synergism between two anthropic impacts: Caulerpa racemosa var. cylindracea invasion and seawater nutrient enrichment

Gennaro¹,

Piazzi²

2011

Mar. Ecol. Prog. Ser.

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Although eutrophication and biological invasions are recognized as important elements of global change, few studies have assessed how their synergism can affect structural and functional traits of marine ecosystems. The present study aimed to evaluate the effect of seawater nutrient enrichment on the spread of the introduced Chlorophyta Caulerpa racemosa var. cylindracea and the interactive effects of nutritional enrichment and C. racemosa invasion on the native macroalgal assemblages of a subtidal rocky bottom. To achieve these objectives, a manipulative field experiment was carried out at 24 m depth in the northwestern Mediterranean Sea by adding C. racemosa and supplying the water column with nutrients. The following treatments were applied: non-manipulated assemblages, nutrient enrichment, addition of C. racemosa, and both nutrient enrichment and addition of C. racemosa. Results showed that C. racemosa spread was enhanced by nutrient enrichment. Moreover, a significant interaction between nutritional increase and C. racemosa invasion was detected: the effects of C. racemosa invasion on native macroalgal assemblages were amplified by nutrient enrichment. Results suggested that synergism between effects of different anthropogenic impacts can have severe consequences on the integrity of marine ecosystems. KEY WORDS: Biological invasions · Nutrients · Rocky bottom · Macroalgal assemblages · Mediterranean Sea Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 427: 59-70, 2011 60 logical invasions has been examined mainly in terrestrial habitats (Burke & Grime 1996, Gross et al. 2005, Leishman & Thomson 2005; in contrast, only a few experimental studies have been carried out to investgate this phenomenon in marine ecosystems (but see Steen 2003, Sánchez & Fernández 2006, Incera et al. 2009). Eutrophication is a growing problem in the marine habitats of coastal waters all over the world (Nixon 1995, Livingston 2001, Howarth & Marino 2006 and is considered one of the main causes of deteriorating coastal water quality and loss of ecosystem complexity (Soltan et al. 2001, Arevalo et al. 2007). Biotic homogenization due to the proliferation of opportunistic species has been attributed mostly to high loading of nutrients derived from industrial and urban sewage effluents (Valiela et al. 1992, Morand & Briand 1996. Furthermore, nutrient enrichment can aid the spread of introduced macroalgae through different mechanisms (Stimson et al. 2001, Torres et al. 2004). Nutrient availability is usually an important factor in determining the species composition of seaweed assemblages (Teichberg et al. 2008). An increase in nutrients in natural systems is detrimental to slow-growing plants which are adapted to nutrient-poor habitats and creates favorable conditions for faster-growing plants, such as many invasive seaweeds. Moreover, the degradation of benthic systems caused by pollution can reduce the native assemblage's resistance to invasions (Stachowicz et al. 1999). Thu...

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Section: Discussioncontrasting

confidence: 82%

contrasting

confidence: 82%

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Synergism between two anthropic impacts: Caulerpa racemosa var. cylindracea invasion and seawater nutrient enrichment

Gennaro¹,

Piazzi²

2011

Mar. Ecol. Prog. Ser.

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“…However, at the scale of 10 s of kilometres, like in our study, these processes seem to have a homogenous effect along the whole studied area except for the foliose functional group. The latter was mainly composed by species of the genus Ulva that are ephemeral, fast-growing macroalgae with a high capacity to respond to nutrient pulses (Karez et al 2004). Due to their ecophysiological traits, the abundance of these species is very variable (Rubal et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Spatial variability in intertidal macroalgal assemblages on the North Portuguese coast: consistence between species and functional group approaches

et al. 2012

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Natural assemblages are variable in space and time; therefore, quantification of their variability is imperative to identify relevant scales for investigating natural or anthropogenic processes shaping these assemblages. We studied the variability of intertidal macroalgal assemblages on the North Portuguese coast, considering three spatial scales (from metres to 10 s of kilometres) following a hierarchical design. We tested the hypotheses that (1) spatial pattern will be invariant at all the studied scales and (2) spatial variability of macroalgal assemblages obtained by using species will be consistent with that obtained using functional groups. This was done considering as univariate variables: total biomass and number of taxa as well as biomass of the most important species and functional groups and as multivariate variables the structure of macroalgal assemblages, both considering species and functional groups. Most of the univariate results confirmed the first hypothesis except for the total number of taxa and foliose macroalgae that showed significant variability at the scale of site and area, respectively. In contrast, when multivariate patterns were examined, the first hypothesis was rejected except at the scale of 10 s of kilometres. Both uni-and multivariate results indicated that variation was larger at the smallest scale, and thus, smallscale processes seem to have more effect on spatial variability patterns. Macroalgal assemblages, both considering species and functional groups as surrogate, showed consistent spatial patterns, and therefore, the second hypothesis was confirmed. Consequently, functional groups may be considered a reliable biological surrogate to study changes on macroalgal assemblages at least along the investigated Portuguese coastline.

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“…The presence or absence of species in the quadrats may be caused by epibiosis and other complex interactions among species, depending on characteristics such as their life history and phenology and the environmental conditions (BENEDETTI-CECCHI, 2000;MOHRING et al, 2013). Environmental conditions can benefit the reproduction, dispersion and recruitment of macroalgal species in different ways (LOBBAN; HARRISON, 1997), resulting in the continuous proliferation and disappearance of species, most of them ephemeral, at small temporal scales (KAREZ et al, 2004;PHILLIPS, 2006). The higher diversity indexes at IM2 and BP4 may be related to the intermediary disturbance hypothesis (CONNELL, 1978), as both sites were considered as moderately exposed to wave action.…”

Section: Discussionmentioning

confidence: 99%

The Structure of Subtidal Macroalgal Assemblages at the Tamoios Ecological Station, a Threatened Conservation Unit in Rio De Janeiro, Brazil

2015

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The structure of subtidal rocky bottom communities at Tamoios Ecological Station (TES), situated in Ilha Grande Bay, Rio de Janeiro State, as well as in other Brazilian marine protected areas, is insufficiently characterized. The present study describes the macroalgal assemblages of shallow subtidal rocky bottoms on two islands of the TES-Imboassica (IM) and Búzios Pequena (BP)adopting species and genera as observational units. Two sites were surveyed on each island in summer 2011. Random 30x30 cm quadrats (n=3) were scraped to collect all macroalgae except crustose species. The subtidal assemblages, in which 58 macroalgal species occurred, were characterized by the high frequency and percent cover of Sargassum vulgare C. Agardh (56.8±8.4%). The sites differed significantly in total number of species and Shannon-Weiner diversity index (PERMANOVA, p<0.05). According to SIMPER, the macroalgal genera that most contributed to the dissimilarities of cover between the sites (contribution >5%) were Sargassum, Laurencia, Wrangelia, Canistrocarpus, Asparagopsis, Hypnea, Ceratodictyon, Gayliella, Spyridia and Chondria.Dissimilarities within and between the islands, as shown by nMDS of the cover data, suggest that different spatial scales should be considered in monitoring the rocky bottom communities of Ilha Grande Bay.

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Biomass response and changes in composition of ephemeral macroalgal assemblages along an experimental gradient of nutrient enrichment

Cited by 93 publications

References 35 publications

Synergism between two anthropic impacts: Caulerpa racemosa var. cylindracea invasion and seawater nutrient enrichment

Synergism between two anthropic impacts: Caulerpa racemosa var. cylindracea invasion and seawater nutrient enrichment

Spatial variability in intertidal macroalgal assemblages on the North Portuguese coast: consistence between species and functional group approaches

The Structure of Subtidal Macroalgal Assemblages at the Tamoios Ecological Station, a Threatened Conservation Unit in Rio De Janeiro, Brazil

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