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Sea-Nine211 has been introduced as a new biocide in antifouling paints with an immediate degradation when it is released from ship hulls. The active component of Sea-Nine211 is 4,5-dichloro-2-n-octyl-isothiazoline-3-one (DCOI). In the present study, the toxicity of DCOI and the occurrence of Pollution Induced Community Tolerance (PICT) were tested in microcosms containing eutrophic coastal water with its natural composition of phytoplankton. The experiment was performed in closed systems with a single addition of the nominal concentrations 0, 3.2, 10, 32 and 100 nM DCOI, for a period of 16 days. Pollution induced community tolerance (PICT) was observed in the phytoplankton communities exposed to the nominal concentrations 32 and 100 nM DCOI. Chemical analysis of DCOI in the coastal water utilised in the toxicity and PICT experiment was performed by GC-MS using a solid- phase extraction method. Half-life was calculated to be 2.5 days for the nominal concentrations 32 and 100 nM DCOI. The results of the present study show that nominal concentrations of 32 and 100 nM DCOI significantly increased the community tolerance already after 2 days of exposure and that the tolerance was maintained for a period of 16 days even when DCOI was degraded during this period. The causes for the persistent tolerance are discussed in relation to the degradation of DCOI and structural changes in the phytoplankton communities.

Bats of the species Eptesicus fuscus have been trained to discriminate a stationary simulated target from a target with a virtual distance that jitters from sound to sound. Similar to Simmons [Science 207, 1336-1338 (1979)], a jitter-detection threshold below 1 microsecond was found. However, Simmons' decreased performance at a time delay jitter of 30 microseconds could not be replicated, a critical feature used to postulate the idea that bats employ a coherent cross-correlation receiver for ranging. Such a receiver uses all phase information in the signal for delay estimation and therefore will be biased by phase manipulations. To test for such a bias, a phase jitter of +/- 45 degrees and a time jitter in the echo were overlaid. It was not found that there was a combination of both where their effects canceled. Full phase information is thus not used in delay estimation. However, bats were able to detect a pure phase jitter, e.g., polarity inversion of the signal. Bats could also detect phase jitter in the presence of randomized time jitter and vice versa. Phase jitter and time jitter, therefore, are separable features for a bat. The underlying physiological mechanism is not clear.

The life spans, the soluble/insoluble collagen ratios in skin, and disease patterns in relation to age of normal and irradiated Syrian hamsters of the Bezanson strain were recently reported from this laboratory (1). The study revealed that this strain of hamster is relatively short-lived, with a mean survival time for normal animals of 22 months, and that mean survival time could be reduced to 14 months by 425 R of total-body irradiation. A decline of soluble/insoluble collagen ratios in skin of normal and irradiated animals appeared to be a reliable biochemical indicator of chronologic age. The decline was not significantly influenced by irradiation. The present study extends these prior experiments and was designed to investigate other possible biochemical parameters of aging in this animal population. Stored frozen organs from animals used in the earlier experiment plus tissues from additional, normal, young and old Bezanson hamsters were analyzed for quantity of ethanol-extractable and ethanol-nonextractable liver "age" pigment, specific activity of liver histidase, and specific activity of renal lysozyme. Age dependence has been shown in previous studies to occur for one variety of age pigment (lipofuscin) (2), for liver histidase (3), and for renal lysozyme (G. M. Troup and R. L. Walford, unpublished observations, 1966) in other animals.