Context-dependency in the effects of nutrient loading and consumers on the availability of space in marine rocky environments

Background: Enhanced nutrient loading and depletion of consumer populations interact to alter the structure of aquatic plant communities. Nonetheless, variation between adjacent habitats in the relative strength of bottom-up (i.e. nutrients) versus top-down (i.e. grazing) forces as determinants of community structure across broad spatial scales remains unexplored. We experimentally assessed the importance of grazing pressure and nutrient availability on the development of macroalgal assemblages and the maintenance of unoccupied space in habitats differing in physical conditions (i.e. intertidal versus subtidal), across regions of contrasting productivity (oligotrophic coasts of South Australia versus the more productive coasts of Eastern Australia). Methodology/Principal findings: In Eastern Australia, grazers were effective in maintaining space free of macroalgae in both intertidal and subtidal habitats, irrespective of nutrient levels. Conversely, in South Australia, grazers could not prevent colonization of space by turf-forming macroalgae in subtidal habitats regardless of nutrients levels, yet in intertidal habitats removal of grazers reduced unoccupied space when nutrients were elevated. Conclusions/Significance: Assessing the effects of eutrophication in coastal waters requires balancing our understanding between local consumer pressure and background oceanographic conditions that affect productivity. This broader-based understanding may assist in reconciling disproportionately large local-scale variation, a characteristic of ecology, with regional scale processes that are often of greater relevance to policy making and tractability to management.Fabio Bulleri, Bayden D. Russell, Sean D. Connel

UNDERSØKELSE AV DE HYDROGRAFISKE OG BIOLOGISKE FORHOLD I INDRE OSLOFJORD OVERVÅKINGSPROGRAM. PROGRAMFORSLAG FOR 1976

UNDERSØKELSE AV DE HYDROGRAFISKE OG BIOLOGISKE FORHOLD, VANNUTSKIFTNINGEN OG KARTLEGGING AV TILFØRSLER TIL FJORDEN FRA LAND FOR Å STUDERE UTVIKLINGEN AV FORURENSNINGSSITUASJONEN I OSLOFJORDE

Review of existing data on cadmium and PCB in marine waters, biota and sediments of Norway

Oversikt over eksisterende data om kadmium og polyklorerte bifenyler i organismer, vann og sedimenter fra norske marine farvann

Undersøkelse av hydrografiske og biologiske forhold i indre Oslofjord. Overvåkingsprogram. Årsrapport 1977

Overvåkingsprogram for oppfølging av forurensningsutviklingen i Oslofjorden 1977 ved beskrivelse av fjordens hydrografi, algevekst i overflatelaget og fastsittende alger

Undersøkelse av hydrografiske og biologiske forhold i indre Oslofjord. Overvåkingsprogram. Årsrapport 1975 -1976

Overvåkingsprogram for oppfølging av forurensningsutviklingen i Oslofjorden 1975 - 78 ved beskrivelser av fjordens hydrografi, algevekst i overflatelaget, fastsittende alger og fisk i relasjon til tidligere år. Klorerte hydrokarboner i blåskjell samt metallinnhold i alger.Oslo kommun

Resipientundersøkelse av nedre Skienselva, Frierfjorden og tilliggende fjordområder. Rapport nr. 8. Sluttrapport

Forurensningssituasjonen i Frierfjorden og tilliggende områder ble undersøkt i en periode på 3 år. Man fant en betydelig forurensning både av fosfor- og nitrogenforbindelser, organisk stoff, partikulært materiale og miljøgifter som kvikksølv og klorerte hydrokarboner. Forholdene bedret seg noe mot slutten av perioden

Euclid near infrared spectrophotometer instrument concept and first test results at the end of phase B

The Euclid mission objective is to understand why the expansion of the Universe is accelerating by mapping the geometry of the dark Universe by investigating the distance-redshift relationship and tracing the evolution of cosmic structures. The Euclid project is part of ESA's Cosmic Vision program with its launch planned for 2020. The NISP (Near Infrared Spectro-Photometer) is one of the two Euclid instruments and is operating in the near-IR spectral region (0.9-2µm) as a photometer and spectrometer. The instrument is composed of: - a cold (135K) optomechanical subsystem consisting of a SiC structure, an optical assembly (corrector and camera lens), a filter wheel mechanism, a grism wheel mechanism, a calibration unit and a thermal control system - a detection subsystem based on a mosaic of 16 Teledyne HAWAII2RG cooled to 95K with their front-end readout electronic cooled to 140K, integrated on a mechanical focal plane structure made with Molybdenum and Aluminum. The detection subsystem is mounted on the optomechanical subsystem structure - a warm electronic subsystem (280K) composed of a data processing / detector control unit and of an instrument control unit that interfaces with the spacecraft via a 1553 bus for command and control and via Spacewire links for science data This presentation describes the architecture of the instrument at the end of the phase B (Preliminary Design Review), the expected performance, the technological key challenges and preliminary test results obtained on a detection system demonstration model. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only. Copyright 2014 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited

The response of experimental rocky shore communities to nutrient additions

The aim of this study was to determine whether the experimental nutrient enrichment of littoral rocky shore communities would be followed by a predicted accumulation of fast-growing opportunistic algae and a subsequent loss of perennial benthic vegetation. Inorganic nitrogen (N) and potassium (P) was added to eight concrete mesocosms inhabited by established littoral communities dominated by fucoids. The response to nutrient enrichment was followed for almost 2 1/2 years. Fast-growing opportunistic algae (periphyton and ephemeral green algae) grew significantly faster in response to nutrient enrichment, but the growth of red filamentous algae and large perennial brown algae was unaffected. However, these changes were not followed by comparable changes in the biomass and composition of the macroalgae. The biomass of opportunistic algae was stimulated only marginally by the nutrient enrichment, and perennial brown algae (fucoids) remained dominant in the mesocosm regardless of nutrient treatment level. Established rocky shore communities thus seem able to resist the effects of heavy nutrient loading. We found that the combined effects of the heavy competition for space and light imposed by canopy-forming algae, preferential grazing on opportunistic algae by herbivores, and physical disturbance, succeeded by a marked export of detached opportunistic algae, prevented the fast-growing algae from becoming dominant. However, recruitment studies showed that the opportunistic algae would become dominant when free space was available under conditions of high nutrient loading and low grazing pressure. These results show that established communities of perennial algae and associated fauna in rocky shore environments can prevent or delay the accumulation of bloom-forming opportunistic algae and that the replacement of long-lived macroalgae by opportunistic species at high nutrient loading may be a slow process. Nutrient enrichment may not, in itself, be enough to stimulate structural changes in rocky shore communities

Nutrients in European ecosystems

this report. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the European Community or the European Environment Agency concerning the legal status of any country, territory, city or area or its authorities. All rights reserved No part of this publication may be reproduced in any form or by any means electronic or mechanical, including photocopying, recording or by any information storage retrieval system without the permission in writing from the copyright holder. For rights of translation or reproduction please contact EEA, project manager Ove Caspersen (address information below). A great deal of additional information on the European Union is available on the Internet. It can be accessed through the Europa server (http://europa.eu.int) Cataloguing data can be found at the end of this publication. Luxembourg: Office for Official Publications of the European Communities, 1999 ISBN: EEA, Copenhagen, 1999 Printed in Printed on recycled and chlorine-free bleached paper European Environment Agenc