GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Multiple zooplankton species alter the stoichiometric interactions between producer and consumer levels (2019)
    SPRINGER
    In:  EPIC3Marine Biology, SPRINGER, 166(163), ISSN: 0025-3162
    Details
    Publication Date: 2020-05-27
    Description: Planktonic primary consumers have been shown to strongly influence phytoplankton communities via top-down effects such as grazing and nutrient recycling. However, it remains unclear how changes in consumer richness may alter the stoichiometric constrains between producer and consumer assemblages. Here we test whether the stoichiometry of producer–consumer interactions is affected by the species richness of the consumer community (multispecies consumer assemblage vs single consumer species). Therefore, we fed a phytoplankton assemblage consisting of two flagellates and two diatom species reared under a 2 × 2 factorial combination of light and nitrogen supply to three planktonic consumer species in mono- and polycultures. As expected, phytoplankton biomass and C:nutrient ratios significantly increased with light intensity while nitrogen limitation resulted in reduced phytoplankton biomass and increasing phytoplankton C:N but lower N:P. Differences in phytoplankton stoichiometry were partly transferred to the consumer level, i.e., consumer C:N significantly increased with phytoplankton C:N. Consumer diversity significantly increased consumer biomass, resource use efficiency and nutrient uptake. In turn, consumer N:P ratios significantly decreased in consumer assemblages under high resource supply due to unequal changes in nutrient uptake. Consumer diversity further altered phytoplankton biomass, stoichiometry and species composition via increased consumption. Whether the effects of consumer diversity on phytoplankton and consumer performance were positive or negative strongly depended on the resource supply. In conclusion, the stoichiometric constraints of trophic interactions in multispecies assemblages cannot be predicted from monoculture traits alone, but consumer diversity effects are constrained by the resources supplied.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 2
    facet.materialart.
    Unknown
    Sea surface phytoplankton community response to nutrient and light changes (2020)
    SPRINGER
    In:  EPIC3Marine Biology, SPRINGER, 167(123), ISSN: 0025-3162
    Details
    Publication Date: 2020-08-13
    Description: The sea surface microlayer (SML) is the boundary layer between the ocean and the atmosphere and plays a unique role in marine biogeochemistry. Phytoplankton communities in this uppermost surface layer are exposed to extreme ultraviolet (UV) radiation and potentially high nutrient supplies. In order to understand the response of SML communities to such contrasting conditions, we conducted experiments at three different sites, the North Sea (open ocean) and two sites, outer and middle fjord, in the Sognefjord, Norway, with differing physical and chemical parameters. We manipulated light, nitrogen (N) and phosphorus (P) supply to natural communities collected from the SML and compared their response to that of the underlying water (ULW) communities at 1-m depth. Phytoplankton communities in both SML and ULW responded significantly to N addition, suggesting the upper 1-m surface phytoplankton communities were N-limited. While phytoplankton growth rates were higher with high N and high light supply, biomass yield was higher under low light conditions and with a combined N and P supply. Furthermore, biomass yield was generally higher in the ULW communities compared to SML communities. Nutrient and light effects on phytoplankton growth rates, particulate organic carbon (POC) and stoichiometry varied with geographical location. Phytoplankton growth rates in both SML and ULW at the open ocean station, the site with highest salinity, did not respond to light changes, whereas the communities in the middle fjord, characterized by high turbidity and low salinity, did experience light limitation. This work on the upper surface phytoplankton communities provides new insights into possible effects of coastal darkening and increases understanding of oceanic biogeochemical cycling.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 3
    facet.materialart.
    Unknown
    Planktotrons: A novel indoor mesocosm facility for aquatic biodiversity and food web research (2017)
    AMER SOC LIMNOLOGY OCEANOGRAPHY
    In:  EPIC3Limnology and Oceanography-Methods, AMER SOC LIMNOLOGY OCEANOGRAPHY, 15(7), pp. 663-677, ISSN: 1541-5856
    Details
    Publication Date: 2017-08-29
    Description: We established a new indoor mesocosm facility, 12 fully controlled “Planktotrons”, designed to conduct marine and freshwater experiments for biodiversity and food web approaches using natural or artificial, benthic or planktonic communities. The Planktotrons are a unique and custom-tailored facility allowing long-term experiments. Wall growth can be inhibited by a rotating gate paddle with silicone lips. Additionally, temperature and light intensity are individually controllable for each Planktotron and the large volume (600 L) enables high-frequency or volume-intense measurements. In a pilot freshwater experiment various trophic levels of a pelagic food web were maintained for up to 90 d. First, an artificially assembled phytoplankton community of 11 species was inoculated in all Planktotrons. After 22 d, two ciliates were added to all, and three Daphnia species were added to six Planktotrons. After 72 d, dissolved organic matter (DOM, an alkaline soil extract) was added as an external disturbance to six of the 12 Planktotrons, involving three Planktotrons stocked with Daphnia and three without, respectively. We demonstrate the suitability of the Planktotrons for food web and biodiversity research. Variation among replicated Planktotrons (n = 3 minimum) did not differ from other laboratory systems and field experiments. We investigated population dynamics and interactions among the different trophic levels, and found them affected by the sequence of ciliate and Daphnia addition and the disturbance caused by addition of DOM.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 4
    facet.materialart.
    Unknown
    Stoichiometric constraints on phytoplankton resource use efficiency in monocultures and mixtures (2020)
    AMER SOC LIMNOLOGY OCEANOGRAPHY
    In:  EPIC3Limnology and Oceanography, AMER SOC LIMNOLOGY OCEANOGRAPHY, ISSN: 0024-3590
    Details
    Publication Date: 2020-06-18
    Description: A central concept for understanding the mechanisms linking diversity and primary production or more general, ecosystem functioning, is resource use efficiency (RUE). It quantifies the amount of biomass production over time relative to unit resource supplied, that is, represents a quota of matter use efficiency. Given anthropogenic alterations of biogeochemical cycles, the consequent changes in supply rate and especially supply ratio of nutrients will change. Using four species of freshwater phytoplankton, and their mixture, we asked how the RUE for nitrogen and phosphorus depends on the stoichiometry of resource supply and how this differs between single species and their mixture. We conducted a factorial laboratory experiment spanning 25 different nutrient supply treatments with differing absolute and relative nitrogen (N) and phosphorus (P) concentrations. N and P supply increased biomass production and decreased C : nutrient ratios and RUE for the respective nutrient, but always significantly affected by the supply of the respective other nutrient. Biomass peaked at molar N : P supply ratios above the Redfield ratio (18-22). Species tended to respond similarly to the resource gradients. Consequently, mixtures outperformed the component species only during early growth responses, but not regarding maximum biomass and RUE. Bioassays performed at the end of the main experiment revealed predominance of N-limitation, but again strongly depending on the interaction between both nutrient gradients. Our study suggests that stoichiometric constraints of resource incorporation and RUE need to be accounted for when studying the response of phytoplankton to natural and anthropogenic variation in resource availability.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...