Carbon and nitrogen resources available to kelp bed filter feeders in an upwelling environment

Stable carbon and nitrogen isotope ratios of benthic invertebrates and their potential food sources, such as suspended particulate organic matter (POM), benthic microalgae, attached algae and seagrass, were identified in Dong-dae Bay during the winter. The carbon stable isotope ratios demonstrate that filter feeders, such as oysters (−19.5 ± 1.0‰), use benthic microalgae (−21.2 ± 0.2‰) as a major food, and polychaetes such as Glycera spp. (−14.0 ± 0.6 ‰) preferentially use meiofauna, such as nematodes (−14.0 ± 0.4‰) and copepods (−13.3 ± 1.0‰). These meiofauna may feed on mixed resources (including bacteria) with the isotope ratios between benthic microalgae (−21.2 ± 0.2‰) and seagrass (−9.3 ± 01.0‰). These findings are consistent with the trophic enrichment in the nitrogen isotope ratios (by 3–4‰) between consumers and food sources. Moreover, the results of the MixSIR model based on the observed isotope ratios suggest a large seagrass contribution to the food sources of benthic organisms such as meiofauna (~53.7–62.6%) and macrobenthos (~41.1–68%) through the food web. This model additionally suggests a relatively large contribution of benthic microalgae to the food sources of filter feeders (i.e. 26.4% for oysters).

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Metabolic signalling and the partitioning of resources in plant storage organs

The Journal of Agricultural Science ◽

10.1017/s0021859699006978 ◽

1999 ◽

Vol 133 (3) ◽

pp. 243-249 ◽

Cited By ~ 3

Author(s):

NIGEL G. HALFORD

Keyword(s):

Dry Weight ◽

Wild Relatives ◽

Crop Plants ◽

Wild Plants ◽

Young Plant ◽

Carbon And Nitrogen ◽

Cultivated Potato ◽

Metabolic Signalling ◽

Storage Organs ◽

Plant Storage

The most important harvested organs of crop plants, such as seeds, tubers and fruits, are often described as assimilate sinks. They play little or no part in the fixation of carbon through the production of sugars through photosynthesis, or in the uptake of nitrogen and sulphur, but import these assimilated resources to support metabolism and to store them in the form of starch, oils and proteins. Wild plants store resources in seeds and tubers to later support an emergent young plant. Cultivated crops are effectively storing resources to provide us with food and many have been bred to accumulate much more than would be required otherwise. For example, approximately 80% of a cultivated potato plant's dry weight is contained in its tubers, ten times the proportion in the tubers of its wild relatives (Inoue & Tanaka 1978). Cultivation and breeding has brought about a shift in the partitioning of carbon and nitrogen assimilate between the organs of the plant.

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Precipitation in silicon: Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104431 ◽

1988 ◽

Vol 46 ◽

pp. 474-475

Author(s):

R.W. Carpenter

Keyword(s):

Transition Metals ◽

Spatial Resolution ◽

Thin Foil ◽

Precipitation Reaction ◽

High Current ◽

Reaction Products ◽

Carbon And Nitrogen ◽

Dielectric Layers ◽

Precipitation Processes ◽

Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

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