Health & Environmental Research Online (HERO)


ISA NOxSOxPM Ecology (2018)

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290 References Were Found:

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Multiple stressors threaten the imperiled coastal foundation species eelgrass (Zostera marina) in Chesapeake Bay, USA

Authors: Lefcheck, JS; Wilcox, DJ; Murphy, RR; Marion, SR; Orth, RJ (In Press) Global Change Biology. HERO ID: 3841164

[Less] Interactions among global change stressors and their effects at large scales are often proposed, but . . . [More] Interactions among global change stressors and their effects at large scales are often proposed, but seldom evaluated. This situation is primarily due to lack of comprehensive, sufficiently long-term, and spatially extensive datasets. Seagrasses, which provide nursery habitat, improve water quality, and constitute a globally important carbon sink, are among the most vulnerable habitats on the planet. Here, we unite 31 years of high-resolution aerial monitoring and water quality data to elucidate the patterns and drivers of eelgrass (Zostera marina) abundance in Chesapeake Bay, USA, one of the largest and most valuable estuaries in the world, with an unparalleled history of regulatory efforts. We show that eelgrass area has declined 29% in total since 1991, with wide-ranging and severe ecological and economic consequences. We go on to identify an interaction between decreasing water clarity and warming temperatures as the primary drivers of this trend. Declining clarity has gradually reduced eelgrass cover the past two decades, primarily in deeper beds where light is already limiting. In shallow beds, however, reduced visibility exacerbates the physiological stress of acute warming, leading to recent instances of decline approaching 80%. While degraded water quality has long been known to influence underwater grasses worldwide, we demonstrate a clear and rapidly emerging interaction with climate change. We highlight the urgent need to integrate a broader perspective into local water quality management, in the Chesapeake Bay and in the many other coastal systems facing similar stressors.

Data/Software
Data/ Software

Northern Gulf of Mexico hypoxic zone

Author: U.S. EPA (2017) Washington, DC: U.S. Environmental Protection Agency. HERO ID: 4121236


The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Phytoplankton assemblage response to changing nutrients in Florida Bay: Results of mesocosm studies

Authors: Shangguan, Y; Glibert, PM; Alexander, J; Madden, CJ; Murasko, S (2017) Journal of Experimental Marine Biology and Ecology 494:38-53. HERO ID: 3857490

[Less] The ongoing restoration of the Florida Everglades has changed the hydrology in south Florida and increasing . . . [More] The ongoing restoration of the Florida Everglades has changed the hydrology in south Florida and increasing freshwater discharge has contributed to a shift in nutrients and phytoplankton in northern Florida Bay. To understand the effect of the changing nitrogen (N) forms and nitrogen:phosphorus (N:P) ratios on phytoplankton biomass and assemblage composition, five mesocosm experiments were conducted. Nutrient additions included a matrix of different forms of N (NO3-, NH4+, and DON) and P (as sodium beta(-)glycerophosphate pentahydrate) in differing N:P molar ratios (4, 16, 32), a P alone addition, and a control. In general, chlorophyll a increased threefold in the + P treatments and ten-fold in the + N + P treatments, while it did not increase in the + N treatments. Typically the + N + P treatments, particularly the + NO3- +P at the N:P molar ratio of 32, promoted high concentrations of fucoxanthin (generally indicative of diatoms) relative to chlorophyll a. While chlorophyll a did not increase significantly in the + N alone treatments, there was a change in the phytoplankton assemblage. The + N treatments, when N was in the form of + NH4+ yielded proportionally higher zeaxanthin (generally indicative of picocyanobacteria). When the + N:P ratio increased, the relative concentrations of fucoxanthin and alloxanthin (generally indicative of cryptophytes) to chlorophyll a increased, whereas the relative concentrations of zeaxanthin and dinoflagellates (generally indicative of photosynthetic dinoflagellates) declined. This study highlights the importance of dual P and N control, particularly N in the forms of NH4+ and DON if picocyanobacterial blooms are to be controlled.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Variation in growth rate, carbon assimilation, and photosynthetic efficiency in response to nitrogen source and concentration in phytoplankton isolated from upper San Francisco Bay

Authors: Berg, GM; Driscoll, S; Hayashi, K; Ross, M; Kudela, R (2017) HERO ID: 3844787

[Less] Six species of phytoplankton recently isolated from upper San Francisco Bay were tested for their sensitivity . . . [More] Six species of phytoplankton recently isolated from upper San Francisco Bay were tested for their sensitivity to growth inhibition by ammonium (NH4(+) ), and for differences in growth rates according to inorganic nitrogen (N) growth source. The quantum yield of photosystem II (Fv /Fm ) was a sensitive indicator of NH4(+) toxicity, manifested by a suppression of Fv /Fm in a dose-dependent manner. Two chlorophytes were the least sensitive to NH4(+) inhibition, at concentrations of >3,000 μmoles NH4(+)  · L(-1) , followed by two estuarine diatoms that were sensitive at concentrations >1,000 μmoles NH4(+)  · L(-1) , followed lastly by two freshwater diatoms that were sensitive at concentrations between 200 and 500 μmoles NH4(+)  · L(-1) . At non-inhibiting concentrations of NH4(+) , the freshwater diatom species grew fastest, followed by the estuarine diatoms, while the chlorophytes grew slowest. Variations in growth rates with N source did not follow taxonomic divisions. Of the two chlorophytes, one grew significantly faster on nitrate (NO3(-) ), whereas the other grew significantly faster on NH4(+) . All four diatoms tested grew faster on NH4(+) compared with NO3(-) . We showed that in cases where growth rates were faster on NH4(+) than they were on NO3(-) , the difference was not larger for chlorophytes compared with diatoms. This holds true for comparisons across a number of culture investigations suggesting that diatoms as a group will not be at a competitive disadvantage under natural conditions when NH4(+) dominates the total N pool and they will also not have a growth advantage when NO3(-) is dominant, as long as N concentrations are sufficient.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Macrophyte community response to nitrogen loading and thermal stressors in rapidly flushed mesocosm systems

Authors: Kaldy, JE; Brown, CA; Nelson, WG; Frazier, M (2017) Journal of Experimental Marine Biology and Ecology 497:107-119. HERO ID: 4143948

[Less] A mesocosm system was developed to simulate estuarine conditions characteristic of short water-residence . . . [More] A mesocosm system was developed to simulate estuarine conditions characteristic of short water-residence time ecosystems of the Pacific Coast of North America, and used to evaluate the response of multiple macrophyte metrics to gradients of NO3 loading and temperature. Replicated experiments found that few responses could be directly attributed to NO3 loading up to 6 x ambient. Some response metrics exhibited weak relationships with nutrient loading but could not be resolved with available statistical power. While direct nutrient responses were found for some species-specific metrics (e.g. green macroalgal growth and biomass, tissue N%, etc.), many patterns were confounded with temperature. Temperature generally had a larger effect on response metrics than did nutrient load. Experimental macrophyte communities exhibited community shifts consistent with the predicted effects of nutrient loading at 20 °C, but there was no evidence of other eutrophication symptoms (phytoplankton blooms or hypoxia) due to the short system-residence time. The Z. marina Nutrient Pollution Index (NPI) tracked the NO3 gradient at 10 °C, but exhibited no response at 20 °C, which may limit the utility of this metric in areas with marked thermal seasonality. Results suggest that teasing apart the influence of temperature and nutrients on the expression of eutrophication symptoms will require complex multi-stressor experiments and the use of indicators that are sensitive across a broad range of conditions.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Seagrass ecosystems reduce exposure to bacterial pathogens of humans, fishes, and invertebrates

Authors: Lamb, JB; van de Water, JA; Bourne, DG; Altier, C; Hein, MY; Fiorenza, EA; Abu, N; Jompa, J; Harvell, CD (2017) Science 355:731-733. HERO ID: 4143834

[Less] Plants are important in urban environments for removing pathogens and improving water quality. Seagrass . . . [More] Plants are important in urban environments for removing pathogens and improving water quality. Seagrass meadows are the most widespread coastal ecosystem on the planet. Although these plants are known to be associated with natural biocide production, they have not been evaluated for their ability to remove microbiological contamination. Using amplicon sequencing of the 16S ribosomal RNA gene, we found that when seagrass meadows are present, there was a 50% reduction in the relative abundance of potential bacterial pathogens capable of causing disease in humans and marine organisms. Moreover, field surveys of more than 8000 reef-building corals located adjacent to seagrass meadows showed twofold reductions in disease levels compared to corals at paired sites without adjacent seagrass meadows. These results highlight the importance of seagrass ecosystems to the health of humans and other organisms.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Development of an epiphyte indicator of nutrient enrichment: Threshold values for seagrass epiphyte load

Author: Walter G.Nelson (2017) HERO ID: 4153929

[Less] Metrics of epiphyte load on macrophytes were evaluated for use as quantitative biological indicators . . . [More] Metrics of epiphyte load on macrophytes were evaluated for use as quantitative biological indicators for nutrient impacts in estuarine waters, based on review and analysis of the literature on epiphytes and macrophytes, primarily seagrasses, but including some brackish and freshwater rooted macrophyte species. An approach is presented that empirically derives threshold epiphyte loads which are likely to cause specified levels of decrease in macrophyte response metrics such as biomass, shoot density, percent cover, production and growth. Data from 36 studies of 10 macrophyte species were pooled to derive relationships between epiphyte load and −25 and −50% seagrass response levels, which are proposed as the primary basis for establishment of critical threshold values. Given multiple sources of variability in the response data, threshold ranges based on the range of values falling between the median and the 75th quantiles of observations at a given seagrass response level are proposed rather than single, critical point values. Four epiphyte load threshold categories − low, moderate, high, very high, are proposed. Comparison of values of epiphyte loads associated with 25 and 50% reductions in light to macrophytes suggest that the threshold ranges are realistic both in terms of the principle mechanism of impact to macrophytes and in terms of the magnitude of resultant impacts expressed by the macrophytes. Some variability in response levels was observed among climate regions, and additional data collected with a standardized approach could help in the development of regionalized threshold ranges for the epiphyte load indicator.

Archival Material
Archival Material

Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2017 Report to Congress

Author: U.S. EPA (2017) HERO ID: 4153950


The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

The effects of eutrophication and acidification on the ecophysiology of Ulva pertusa Kjellman

Authors: Kang, JinWoo; Chung, IkKyo (2017) Journal of Applied Phycology 29:2675-2683. HERO ID: 4149683

[Less] In coastal environments, acidification and eutrophication affect the physiology of marine macroalgae. . . . [More] In coastal environments, acidification and eutrophication affect the physiology of marine macroalgae. We investigated the responses of Ulva pertusa Kjellman (Ulvales, Chlorophyta) under such conditions. Samples were cultured at two different pH settings (low, 7.5; high, 8.0) and at three different ammonium levels (low, 4; medium, 60; high, 120 mu M NH4 (+)). Our objective was to analyze the influence that elevated CO2 and NH4 (+) might have on pH, oxygen evolution, rates of nutrient uptake, chlorophyll fluorescence, growth, and C/N ratio of that organism. Variability in pH value was enhanced under low pH/high NH4 (+) and was significantly different (p < 0.05) from changes measured when the high pH/low NH4 (+) combination was applied. Rates of NH4 (+) uptake and relative growth rates by U. pertusa were increased under low pH/high NH4 (+) conditions and that response was significantly different (p < 0.05) from the other treatments. The rate of photosynthetic oxygen evolution and chlorophyll fluorescence were increased under elevated NH4 (+) concentrations (p < 0.05). However, the C/N ratio of U. pertusa was not affected by higher concentrations of CO2 and NH4 (+) (p > 0.05). Our results indicated that the physiological reactions of this alga were heightened when exposed to either the elevated combination of CO2/NH4 (+) or even when only the level of NH4 (+) was raised. Although such excessive growth can lead to bloom formations in coastal areas, this species also has greater capacity for taking up nutrients and dissolved inorganic carbon.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Redox reactions and weak buffering capacity lead to acidification in the Chesapeake Bay

Authors: Cai, WJ; Huang, WJ; Luther, GW; Pierrot, D; Li, M; Testa, J; Xue, M; Joesoef, A; Mann, R; Brodeur, J; Xu, YY; Chen, B; Hussain, N; Waldbusser, GG; Cornwell, J; Kemp WM (2017) Nature Communications 8:Article #369. HERO ID: 4154627

[Less] The combined effects of anthropogenic and biological CO2 inputs may lead to more rapid acidification . . . [More] The combined effects of anthropogenic and biological CO2 inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H2S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. We show that a pH minimum occurs in mid-depths where acids are generated as a result of H2S oxidation in waters mixed upward from the anoxic depths. Our analyses also suggest a large synergistic effect from river-ocean mixing, global and local atmospheric CO2 uptake, and CO2 and acid production from respiration and other redox reactions. Together they lead to a poor acid buffering capacity, severe acidification and increased carbonate mineral dissolution in the USA's largest estuary.