Aquatic ecosystems are hotspots of decomposition and sources carbon dioxide to the atmosphere that globally significant. Carbon exported from land (allochthonous) also supplements fixed by photosynthesis in aquatic (autochthonous), contributing organic matter (OM) supports consumers. Although presence terrestrial compounds OM is well known, contribution versus composition has been quantified for only a handful systems. Here we use stable isotopes hydrogen demonstrate (Φ Terr ) particulate...

There is widespread evidence that aquatic consumers use terrestrial resources depending on the features of surrounding catchments.

Directional change in environmental drivers sometimes triggers regime shifts ecosystems. Theory and experiments suggest that can be detected advance, perhaps averted, by monitoring resilience indicators such as variance autocorrelation of key ecosystem variables. However, it is uncertain whether management action prompted a prevent an impending shift. We caused cyanobacterial bloom gradually enriching experimental lake while unenriched reference continuously enriched lake. When exceeded...

Summary Lake food webs can be supported by primary production from within the lake, organic matter imported catchment or some mixture of these two sources. Generalisations about food‐web subsidies to lake ecosystems are often based on data only a few and therefore do not consider potential variability among diverse in landscape. We measured variation terrestrial (allochthonous) utilisation pelagic consumers developed models describe variability. Stable isotope ratios hydrogen carbon were for...

Abstract Ecosystem regime shifts are abrupt changes from one dynamical state to another, such as the shift a clear‐water an algal bloom in lakes. These transitions hard forecast but theory suggests that early warning indicators can predict impending may allow for management intervention prevent or mitigate unwanted change. The efficacy of has been demonstrated modeling and laboratory experiments, rarely field, where environmental drivers numerous interacting. It is unclear if observable...

Abstract Non‐seagrass sources account for ∼ 50% of the sediment organic carbon (SOC) in many seagrass beds, a fraction that may derive from external matter (OM) advected into meadow and trapped by canopy or produced situ. If allochthonous fluxes are responsible non‐seagrass SOC given bed, this should decrease with distance perimeter. Identifying spatial origin is important closing budgets “blue carbon” offset‐credit accounting, but studies have yet to quantify map stocks source. We measured...

Abstract It is well established that lakes are typically sources of CO 2 to the atmosphere. However, it remains unclear what portion efflux from endogenously processed organic carbon or exogenously produced transported into lakes. We estimated high‐frequency and O three north temperate in summer determine proportion total was produced. Two were amended with nutrients experimentally enhance endogenous uptake. In unfertilized lake, 50% exogenous hydrology had a large influence on efflux....

Abstract Terrestrial organic matter can be assimilated by aquatic consumers but implications for biomass and production are unresolved. An ecosystem model was fit to estimate effects of phosphorus (P) load, planktivory, supply rate terrestrial particulate carbon ( TPOC ) on phytoplankton zooplankton in five whole‐lake experiments. Phytoplankton increased with P load planktivory decreased rate. Zooplankton responded weakly allochthony (proportion from sources) Lakes low (< 0.3) had wide...

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 551:95-105 (2016) - DOI: https://doi.org/10.3354/meps11722 Sources of sediment carbon sequestered in restored seagrass meadows J. T. Greiner, G. M. Wilkinson*, K. McGlathery, A. Emery Department Environmental Sciences, University Virginia, Charlottesville, Virginia 22904, USA *Corresponding author:...

Abstract Functional variation among consumer communities can alter ecosystem nutrient cycling. These impacts on function be specifically driven by interspecific in stoichiometric traits; thus, functional trait‐based approaches used to explain the processes controlling stoichiometry. However, eutrophication may reduce importance of consumers ecosystems eliminating heterogeneity recycling taxa. To test whether zooplankton diversity, i.e. aspects trait space occupied communities, varies over...

Organic carbon accumulation in the sediments of inland aquatic and coastal ecosystems is an important process global budget that subject to intense human modification. To date, research has focused on quantifying rates individual or groups quantify sinks. However, there hasn't been a synthesis across ecosystem address variability within among types. Doing so would identify gaps our understanding potentially reveal sinks vulnerable change. We synthesized from literature, compiling 464 rate...

Hydrogen stable isotopes (d 2 H) are used for quantifying resources supporting food webs.However, application of d H in mixing models requires; (1) correction environmental water (x) consumer tissues, (2) consideration differential fractionation among biochemical constituents, and (3) H-exchange samples standards.We present data sensitivity analyses addressing each these issues provide recommendations future isotope web studies.First, we determined from field that maximum x aquatic consumers...

Interannual variability is a pervasive feature of aquatic ecosystems. This results from short- and long-term dynamics biotic abiotic origin, inclusive multiannual trends. Although understanding short-term forecasting directional change are important research efforts, far less attention has been paid to oscillatory, or wave-like that play out over multiple years, in In this essay, we argue these modes variability—in addition trends intraannual patterns—and their underlying causes necessary...

Abstract Algal blooms can have profound effects on the structure and function of aquatic ecosystems potential to interrupt valuable ecosystem services. Despite ecological economic consequences algal blooms, spatial dynamics bloom development in spatially complex such as shallow lakes remain poorly characterised. Our goal was evaluate magnitude drivers variability biomass, dissolved oxygen, pH over course a season, lake order better understand these ecosystems. We sampled 98 locations small...

Theory suggests that alternative resources may begin to support a food web when highly used become less available relative alternatives. To test the potential for consumers, we experimentally darkened lake whose consumers had relied heavily on algal (phytoplankton and benthic algae). We estimated received from before after darkening using Bayesian mixing model stables isotopes of carbon, nitrogen, hydrogen. Between prior year year, phytoplankton biomass diminished by 60%, surface dissolved...

Many lakes have positive, heterograde vertical oxygen (O2) profiles with a metalimnetic maximum usually assumed to be the result of biological O2 production. However, supersaturated maxima are formed by processes (net photosynthetic production O2) and physical (warming gasses trapped below thermocline). Although mechanisms contributing peaks understood, contribution vs. is not well known in lakes. To examine these contributions, we measured argon (Ar) saturation anomalies metalimnia 17...

Studies designed to assess the resources supporting aquatic consumers using stable isotope analysis require measurements of potential end members (basal resources). While some basal are easily measured, it is often difficult physically separate phytoplankton (one member) from other components in seston. Further, terrestrial materials entering ecosystems undergo diagenetic change, potentially altering composition and making assign member values. We tested techniques for determining isotopic...

Abstract Algal blooms in lakes and reservoirs can be considered regime shifts from a clear‐water to algae‐dominated state that often occurs abruptly. Under experimental conditions, these have been predicted rises variance autocorrelation (generic resilience indicators) of variables monitored at high frequency. The goal this study was evaluate the behavior indicators prior critical transition naturally experience algal blooms. Ambient lake conditions provide several potential hurdles could...

Abstract Phosphorus (P) release from lakebed sediments may fuel phytoplankton blooms, especially in shallow waterbodies. A primary mechanism that controls internal P loading is the size and chemical composition of sediment pool. However, variation within among lakes remains poorly quantified. We measured degree spatial heterogeneity pools, both seven lakes. There was a 1.6× difference total study lakes, varied across based on differences watershed soils land cover lake basin morphology....

To assess the diagnostic value of cerebrospinal fluid (CSF) spectrophotometry, cytology, ferritin, and D-dimer measurements in investigation suspected subarachnoid haemorrhage patients with negative or equivocal computed tomography (CT) scans.CSF specimens submitted for assessment xanthochromia were examined erythrophages using a cytospin preparation stained Wright's stain, ferritin Ciba-Corning Magic IRMA assay, D-dimers Dimertest 2 latex agglutination slide test, bilirubin by scanning...