1,738 publications from this institution
Our understanding of the response of reef-building corals to changes in their physical environment is largely based on laboratory experiments, analysis of long-term field data, and model projections. Experimental data provide unique insights into how organisms respond to variation of environmental drivers. However, an assessment of how well experimental conditions cover the breadth of environmental conditions and variability where corals live successfully is missing. Here, we compiled and analyzed a globally distributed dataset of in-situ seasonal and diurnal variability of key environmental drivers (temperature, pCO2 , and O2 ) critical for the growth and livelihood of reef-building corals. Using a meta-analysis approach, we compared the variability of environmental conditions assayed in coral experimental studies to current and projected conditions in their natural habitats. We found that annual temperature profiles projected for the end of the 21st century were characterized by distributional shifts in temperatures with warmer winters and longer warm periods in the summer, not just peak temperatures. Furthermore, short-term hourly fluctuations of temperature and pCO2 may regularly expose corals to conditions beyond the projected average increases for the end of the 21st century. Coral reef sites varied in the degree of coupling between temperature, pCO2 , and dissolved O2 , which warrants site-specific, differentiated experimental approaches depending on the local hydrography and influence of biological processes on the carbonate system and O2 availability. Our analysis highlights that a large portion of the natural environmental variability at short and long timescales is underexplored in experimental designs, which may provide a path to extend our understanding on the response of corals to global climate change.
Both water transparency and lake latitude influence the depths of maximum biomass (Z b ) and maximum depth of colonization (Z c ) of submerged plants. The differences in the depth distribution of plants in lakes differing in water transparency become more pronounced as latitude decreases. Changes in transparency in low-latitude lakes should result in greater changes in macrophyte cover than similar changes in lakes at higher latitudes. The maximum depth of colonization appears to be largely a function of water transparency, whereas the depth of maximum biomass is best related to latitude. Relationships developed here allow better predictions of Z c and Z b for individual lakes than were possible before.
Along the west coast of South America, from the tropical zone to the Patagonian waters, there is a significant latitudinal gradient in seawater temperature, salinity and carbonate chemistry. These physical–chemical changes in seawater induce morphological and physiological responses in calcifying organisms, which may alter their energy budget and calcification processes. In this study, we study the organism energy maintenance (i.e. metabolic rate) and mineralogical composition of the shell of the juvenile marine snails Concholepas concholepas (Gastropoda: Muricidae), collected from benthic populations located ~2000km apart, varies across geographic regions along the Chilean coast. We found that in juvenile snails, the calcite:aragonite ratio in the pallial shell margin (i.e. newly deposited shell) increase significantly from northern to southern populations and this increase in calcite precipitation in the shell of juveniles snails was associated with a decrease in oxygen consumption rates in these populations. Our result suggests that calcite secretion may be favoured when metabolic rates are lowered, as this carbonate mineral phase might be less energetically costly for the organism to precipitate. This result is discussed in relation to the natural process such as coastal upwelling and freshwater inputs that promote geographic variation in levels of pH and carbonate saturation state in seawater along the Chilean coast.
AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 13:101-111 (1997) - doi:10.3354/ame013101 Role of experimental approaches in marine microbial ecology Duarte CM, Gasol JM, Vaqué D Examination of the contribution of experimental approaches to marine microbial ecology shows these approaches to receive 34.8% of the present effort in the field. Most of the experiments focus on bacteria or marine microbial communities and generally examine the importance of trophic interactions and associated flows of carbon and nutrients in these food webs. Microbial ecologists use experimental units ranging 8 orders of magnitude in size (10-3 to 105 l), with a geometric median size of 0.8 l, and an exponential decline in the number of experiments performed at increasingly larger and smaller scales. The duration of experiments is scaled linearly with the characteristic linear dimension of the experimental units, corresponding to 20 d for each meter in characteristic dimension. The majority (70.3%) of the experiments performed in the past 5 yr used natural communities or organisms, particularly in mesocosm (>103 l) experiments. Most (84.5%) of the experiments are conducted under closely controlled conditions in the laboratory and involve the manipulation of particles, resources and the food web structure, usually manipulating a single factor at a time, the fraction of experiments published declining exponentially with the increase in the numbers of factors tested. A major difference between experimental marine microbial ecology and other disciplines of marine ecology is the remarkable paucity of field experiments (only 2.6% of the experiments in marine microbial ecology), where only the treatment factors are controlled, and the total absence of ecosystem experiments, which are field experiments where the treatment is applied to an entire ecosystem. Experimental approaches have played an important role in the development of marine microbial ecology, but no single experiment has had a large impact on the progress of the field, suggesting that the experiments so far conducted in marine microbial ecology have failed to provide the crucial tests of the main hypotheses needed to progress through strong inferences. The future effectiveness of experimental marine microbial ecology will be substantially enhanced through a larger allocation of efforts towards field experiments, designed to interplay with observational and comparative approaches, leading to conclusive tests of key hypotheses and paradigms through carefully designed, crucial ecosystem experiments. Experiments · Marine microbial ecology · Design · Impact · Prospect Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 13, No. 1. Publication date: July 24, 1997 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 1997 Inter-Research.
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 459:29-38 (2012) - DOI: https://doi.org/10.3354/meps09746 Krill excretion and its effect on primary production Pascal Lehette1,*, Antonio Tovar-Sánchez2, Carlos M. Duarte2,3, Santiago Hernández-León1 1Institute of Oceanography and Global Change, Universidad de Las Palmas de Gran Canaria, Spain 2Department of Global Change Research, IMEDEA, CSIC-UIB, Instituto Mediterráneo de Estudios Avanzados, Esporles, Mallorca, Spain 3The UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia *Email: pascal.lehette101@doctorandos.ulpgc.es ABSTRACT: During the austral summer, zooplankton excretion along the western Antarctic Peninsula was studied in a contrasting hydrographic regime including coastal and oceanic waters. In coastal waters, ammonium supply by mesozooplankton indicated a low contribution to fuel primary production. In oceanic waters, however, Antarctic krill Euphausia superba contributed a significant percentage to the nitrogen requirements of primary producers. Thus, the ontogenetic migration of adult krill during austral summer should be a key factor regulating the regenerated ammonium for primary production. A significant coupling of ammonium concentration in the water column and in situ krill biomass supported the significant role of krill excretion in the epipelagic realm. Results from short-term experiments with E. superba indicated that ammonium excretion rates were much higher than previously found. Because the use of experimental metabolic rates that are close to field rates would be more appropriate, we suggest to re-assess the ammonium supplied by the epipelagic marine biota. Moreover, the outcomes of experimental krill excretion rates, in situ measurements of ammonium and a review of data on primary production suggest that Antarctic krill sustain a high proportion of the daily phytoplankton production. KEY WORDS: Krill · Ammonium · Primary production · Euphausia superba · Southern Ocean · Austral summer · Western Antarctic Peninsula Full text in pdf format PreviousNextCite this article as: Lehette P, Tovar-Sánchez A, Duarte CM, Hernández-León S (2012) Krill excretion and its effect on primary production. Mar Ecol Prog Ser 459:29-38. https://doi.org/10.3354/meps09746 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 459. Online publication date: July 12, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.
Data on nutrient contents of 27 seagrass species at 30 locations were compiled from the literature.Mean ( f SE) concentrations of carbon, nitrogen and phosphorus in seagrass leaves were 33.6 2 0.31, 1.92 f 0.05, and 0.23 2 0.011 % dry wt, respectively.The median C:N:P ratio was 474 :24: 1, which represents a C:P ratio more than 4 times, and a N:P ratio more than 1.5 times that of oceanic seston.These ratios are, however, less than those previously reported for marine macrophytes (550 : 30 : 1) by Atkinson & Smith (1984).Nitrogen and phosphorus variability within species was large, but carbon contents exhibited little variability.Accordingly, carbon:nutrient (N and P) ratios were inversely related to changes in nutrient content, and the rate of change in C:N and C:P ratios with increasing nitrogen or phosphorus content in plant tissues should shift from high to small as nutrient supply meets the plant's demands.The median nitrogen and phosphorus contents reported here (1.8 % N and 0.20 % P as % DW) correctly discriminated between seagrass stands that did or did not respond to nutrient enrichment, thus offering a useful reference for comparisons of seagrass nutrient contents.
