13 research outputs found
Changes in the location of biodiversity–ecosystem function hot spots across the seafloor landscape with increasing sediment nutrient loading
Declining biodiversity and loss of ecosystem function threatens the ability of habitats to contribute ecosystem services. However, the form of the
relationship between biodiversity and ecosystem function (BEF) and how relationships change with environmental change is poorly understood. This limits our ability to predict the consequences of biodiversity loss on ecosystem function, particularly in real-world marine ecosystems that are species rich, and where multiple ecosystem functions are represented by multiple indicators. We investigated spatial variation in BEF relationships across a 300 000 m2 intertidal sandflat by nesting experimental manipulations of sediment pore water nitrogen concentration into sites with contrasting macrobenthic community composition. Our results highlight the significance of many different elements of biodiversity associated with environmental characteristics, community structure, functional diversity, ecological traits or particular species (ecosystem engineers) to important functions of coastal marine sediments (benthic oxygen consumption, ammonium pore water concentrations and flux across the sediment–water interface). Using the BEF relationships developed from our experiment, we demonstrate patchiness across a landscape in functional performance and the potential for changes in the location of functional hot and cold spots with increasing nutrient loading that have important implications for mapping and predicating change in functionality and the concomitant delivery of ecosystem services
Macrofaunal Functional Diversity Provides Resilience to Nutrient Enrichment in Coastal Sediments
The degradation of ecosystems is often associated
with losses of large organisms and the concomitant
losses of the ecological functions they mediate.
Conversely, the resilience of ecosystems to stress is
strongly influenced by faunal communities and
their impacts on processes. Denitrification in
coastal sediments is a process that may provide
ecosystem resilience to eutrophication by removing
excess bioavailable nitrogen. Here, we conducted a
large-scale field experiment to test the effect of
macrofaunal community composition on denitrification
in response to two levels of nutrient
enrichment at 28 sites across a biologically
heterogeneous sandflat. After 7 weeks of enrichment,
we measured denitrification enzyme activity
(DEA) along with benthic macrofaunal community
composition and environmental variables. We
normalised treatment site specific DEA values by
those in ambient sediments (DEACN) to reveal the
underlying response across the heterogeneous
landscape. Nutrient enrichment caused reductions
in DEACN as well as functional changes in the
community; these were both more pronounced
under the highest level of nutrient loading (on
average DEACN was reduced by 34%). The degree
of suppression of DEACN following moderate
nitrogen loading was mitigated by a key bioturbating
species, but following high nitrogen loading
(which reduced the key species density) the
abundance and diversity of other nutrient processing
species were the most important factors
alleviating negative effects. This study provides a
prime example of the context-dependent role of
biodiversity in maintaining ecosystem functioning,
underlining that different elements of biodiversity
can become important as stress levels increase. Our
results emphasise that management and conservation
strategies require a real-world understanding
of the community attributes that facilitate nutrient
processing and maintain resilience in coastal
ecosystems
Nachweis genetischer Veraenderungen in repetitiven DNA Sequenzen in somatischen menschlichen Zellen nach Bestrahlung im niedrigen Dosisbereich
Bestimmung der Instabilitaet von Mikrosatelliten in Zellpopulationen nach Behandlung mit niedrigen Dosen ionisierender Strahlung und in strahlenassoziierten Schilddruesentumoren aus Weissrussland. (orig.)Determination of microsatellite instability in cells after low-dose irradiation, as well as in radiation-associated thyroid tumor in Belarus people.SIGLEAvailable from TIB Hannover: RO 3190(2002-606) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Environmental effects of dredging on sediment nutrients, carbon and granulometry in a tropical estuary
10.1007/s10661-006-9253-2Environmental Monitoring and Assessment1271-31-13EMAS