Major Changes in Macroalgae Community Composition Affectthe Food and Habitat Preference of Idotea baltica

Kotta, Jonne; Paalme, Tiina; Martin, Georg; Mäkinen, Anita

doi:10.1002/1522-2632(200011)85:5/6<697::aid-iroh697>3.3.co;2-s

Cited by 33 publications

(52 citation statements)

References 13 publications

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“…We found, consistent with former fertilisation experiments, increased algal nitrogen and phosphorus content and a higher epiphytic algae to Fucus ratio on cormorant islands with an increased nutrient availability (Pedersen & Borum 1996, Kraufvelin et al 2006, Kraufvelin 2007, Råberg & Kautsky 2008. Contrary to previous studies investigating the effect of nutrient enrichment, on grazers in the Baltic Sea (Kotta et al 2000, Kraufvelin et al 2006, Kraufvelin 2007, Korpinen et al 2010) and chironomids in Lake Michigan, USA (Blumenshine et al 1997), not all invertebrates responded with increased abundance. Among the 5 invertebrate groups, only Jaera albifrons showed significantly higher density and biomass near cormorant islands with high nest densities.…”

Section: Discussionsupporting

confidence: 90%

“…Fourth, we investigated if aquatic invertebrates responded to the high nutrient loads around cormorant islands by comparing the abundance and biomass of invertebrate grazers and chironomids from the 3 cormorant island categories with reference islands. Based on previous studies -both nutrient enrichment studies in the Baltic Sea (Kotta et al 2000, Kraufvelin 2007) and studies investigating the effects of seabirds on aquatic consumers (Bosman & Hockey 1986, Palomo et al 1999, Michelutti et al 2009) -we expected increased invertebrate abundances and biomasses near cormorant islands.…”

Section: Introductionmentioning

confidence: 98%

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Effects of seabird nesting colonies on algae and aquatic invertebrates in coastal waters

Kolb

Ekholm²,

Hambäck³

2010

Mar. Ecol. Prog. Ser.

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Seabirds concentrate nutrients from large marine areas on their nesting islands. The high nutrient load may cause runoff into surrounding waters and affect marine communities in similar ways to those reported from marine fertilization experiments. In order to test if cormorant colonies affect algae and invertebrates in surrounding coastal waters, we collected Fucus vesiculosus fronds, its epiphytic algae, and associated invertebrate fauna near abandoned and active cormorant nesting islands as well as reference islands without nesting cormorants in the Stockholm archipelago in the northern Baltic Sea, Sweden. First, we showed, with δ 15 N analyses, that ornithogenic nitrogen provided a significant nitrogen source for algae and invertebrate consumers near islands with high nest density. Second, the nitrogen and phosphorus content of algae near active cormorant islands with high nest density was elevated, and epiphytic algae increased relative to F. vesiculosus. Third, 3 of 5 invertebrate taxa (Jaera albifrons, Gammarus spp., and Chironomidae) showed increased biomasses near islands with high nest density; but, contrary to former fertilization studies, only J. albifrons increased in abundance compared to reference islands. We conclude that runoff from seabird colonies has a profound effect on primary producers and some consumers in the surrounding water, but only if the colonies exceed a certain nest density. Thus, seabirds not only affect marine communities via top-town forces as commonly assumed, but also via bottom-up forces by concentrating nutrients around their nesting islands. Consequently, seabird islands can be seen as natural fertilization experiments and give important insights to the effects of eutrophication of marine systems.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 98%

Effects of seabird nesting colonies on algae and aquatic invertebrates in coastal waters

Kolb

Ekholm²,

Hambäck³

2010

Mar. Ecol. Prog. Ser.

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“…In concurrent with filamentous algal blooms the diversity of macroalgal species has significantly declined (Rönn-berg et al 1992;Kotta et al 2006). Our experiments and earlier studies have shown that among dominant macrophytes P. littoralis is the most rewarding food for mesoherbivores in the northern Baltic Sea (Kotta et al 2000Orav-Kotta and Kotta 2004). Hence, we may expect stronger competition for this resource in the study area.…”

Section: Discussionsupporting

confidence: 52%

“…However, this figure actually reflects a strong negative effect of G. tigrinus on G. salinus within P. littoralis. Following the increasing eutrophication the biomass of ephemeral algae especially P. littoralis have increased tremendously in the last decades and currently P. littoralis prevails in the northern Baltic Sea (Rönnberg et al 1992;Karez et al 2000;Kotta et al 2000;Lauringson and Kotta 2006). In concurrent with filamentous algal blooms the diversity of macroalgal species has significantly declined (Rönn-berg et al 1992;Kotta et al 2006).…”

Section: Discussionmentioning

confidence: 99%

“…grazers effects on macrophytes operate at small scales and are weak in comparison to abiotic forcing in the Baltic Sea (Salemaa 1979;Malm et al 1999;Engkvist et al 2000;Malm and Kautsky 2003;Herkül et al 2006;Kotta et al 2006). Mesograzers have only shown to have deleterious effects on macrophyte populations when the density of grazers are abnormally high (Fralick et al 1974;Kangas et al 1982;Arrontes 1999;Kotta et al 2000). More likely food type is a prime factor that determines the presence of grazer in macrophyte assemblages (Brawley 1992;Boström and Mattila 1999) and the seasonal biomass cycle of the macrophyte species is likely to explain the fluctuation of gammarid amphipods in field.…”

Section: Discussionmentioning

confidence: 99%

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Seasonal variability in the grazing potential of the invasive amphipod Gammarus tigrinus and the native amphipod Gammarus salinus (Amphipoda: Crustacea) in the northern Baltic Sea

et al. 2008

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Mesograzers are known to reduce the biomass of their host plant and modify the structure of the whole macrophyte community in many ecosystems. Thus, the introduction of an efficient mesograzer may destabilize macrophyte community and also affect the native grazers. We estimated how large proportion of macrophyte production are consumed by the alien gammarid G. tigrinus and the native gammarid G. salinus in the species poor ecosystem of the northern Baltic Sea. We analysed whether G. tigrinus consumes different diet as the native G. salinus and whether the effect of G. tigrinus on the survival of the native G. salinus is macrophyte species specific. Grazing experiments showed that there was a clear difference in the grazing rates of gammarids among the studied macrophyte species in summer and autumn but not in spring. The grazing rates were significantly higher in the prevailing macrophyte Pilayella littoralis as compared to other macrophytes. The grazing was inversely related to the diurnal net photosynthetic values of macrophytes. The gammarid amphipods potentially removed only a minor part of plant primary production except for summer and autumn when grazing of a few perennial species exceeded macrophyte production. Macrophyte species and presence of G. salinus had no effect on the survival of G. tigrinus. The presence of G. tigrinus, however, reduced the survival of the native gammarids within P. littoralis in summer. To conclude it is likely that both native and alien gammarid amphipods do not exert significant pressure on the macroalgal communities in the northern Baltic Sea. Competitive interactions between G. tigrinus and G. salinus within the prevailing macrophyte P. littoralis is the likely explanation of the decline of the native gammarid amphipods after the establishment of G. tigrinus in the northern Baltic Sea.

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Effects of temperature on carbon circulation in macroalgal food webs are mediated by herbivores

et al. 2019

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Warming is one of the most dramatic aspects of climate change and threatens future ecosystem functioning. It may alter primary productivity and thus jeopardize carbon sequestration, a crucial ecosystem service provided by coastal environments. Fucus vesiculosus is an important canopy-forming macroalga in the Baltic Sea, and its main consumer is Idotea balthica. The objective of this study is to understand how temperature impacts a simplified food web composed of macroalgae and herbivores to quantify the effect on organic carbon storage. The organisms were exposed to a temperature gradient from 5 to 25 °C. We measured and modeled primary production, respiration, growth and epiphytic load on the surface of Fucus and respiration, growth and egestion of Idotea. The results show that temperature affects physiological responses of Fucus and Idotea separately. However, Idotea proved more sensitive to increasing temperatures than the primary producers. The lag between the collapse of the grazer and the decline of Fucus and epiphytes above 20 °C allows an increase of carbon storage of the primary productivity at higher temperatures. Therefore, along the temperature gradient, the simplified food web stores carbon in a non-monotonic way (reaching minimum at 20 °C). Our work stresses the need of considering the combined metabolic performance of all organisms for sound predictions on carbon circulation in food webs.

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Major Changes in Macroalgae Community Composition Affectthe Food and Habitat Preference of Idotea baltica

Cited by 33 publications

References 13 publications

Effects of seabird nesting colonies on algae and aquatic invertebrates in coastal waters

Effects of seabird nesting colonies on algae and aquatic invertebrates in coastal waters

Seasonal variability in the grazing potential of the invasive amphipod Gammarus tigrinus and the native amphipod Gammarus salinus (Amphipoda: Crustacea) in the northern Baltic Sea

Effects of temperature on carbon circulation in macroalgal food webs are mediated by herbivores

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