Characterizing biogeochemical fluctuations in a world of extremes: A synthesis for temperate intertidal habitats in the face of global change.

Coastal and intertidal habitats are at the forefront of anthropogenic influence and environmental change. The species occupying these habitats are adapted to a world of extremes, which may render them robust to the changing climate or more vulnerable if they are at their physiological limits. We characterized the diurnal, seasonal and interannual patterns of flux in biogeochemistry across an intertidal gradient on a temperate sandstone platform in eastern Australia over 6 years (2009-2015) and present a synthesis of our current understanding of this habitat in context with global change. We used rock pools as natural mesocosms to determine biogeochemistry dynamics and patterns of eco-stress experienced by resident biota. In situ measurements and discrete water samples were collected night and day during neap low tide events to capture diurnal biogeochemistry cycles. Calculation of pHT using total alkalinity (TA) and dissolved inorganic carbon (DIC) revealed that the mid-intertidal habitat exhibited the greatest flux over the years (pHT 7.52-8.87), and over a single tidal cycle (1.11 pHT units), while the low-intertidal (pHT 7.82-8.30) and subtidal (pHT 7.87-8.30) were less variable. Temperature flux was also greatest in the mid-intertidal (8.0-34.5°C) and over a single tidal event (14°C range), as typical of temperate rocky shores. Mean TA and DIC increased at night and decreased during the day, with the most extreme conditions measured in the mid-intertidal owing to prolonged emersion periods. Temporal sampling revealed that net ecosystem calcification and production were highest during the day and lowest at night, particularly in the mid-intertidal. Characterization of biogeochemical fluctuations in a world of extremes demonstrates the variable conditions that intertidal biota routinely experience and highlight potential microhabitat-specific vulnerabilities and climate change refugia.

Temperature, but not pH, compromises sea urchin fertilization and early development under near-future climate change scenarios.

Global warming is causing ocean warming and acidification. The distribution of Heliocidaris erythrogramma coincides with the eastern Australia climate change hot spot, where disproportionate warming makes marine biota particularly vulnerable to climate change. In keeping with near-future climate change scenarios, we determined the interactive effects of warming and acidification on fertilization and development of this echinoid. Experimental treatments (20-26 degrees C, pH 7.6-8.2) were tested in all combinations for the 'business-as-usual' scenario, with 20 degrees C/pH 8.2 being ambient. Percentage of fertilization was high (>89%) across all treatments. There was no difference in percentage of normal development in any pH treatment. In elevated temperature conditions, +4 degrees C reduced cleavage by 40 per cent and +6 degrees C by a further 20 per cent. Normal gastrulation fell below 4 per cent at +6 degrees C. At 26 degrees C, development was impaired. As the first study of interactive effects of temperature and pH on sea urchin development, we confirm the thermotolerance and pH resilience of fertilization and embryogenesis within predicted climate change scenarios, with negative effects at upper limits of ocean warming. Our findings place single stressor studies in context and emphasize the need for experiments that address ocean warming and acidification concurrently. Although ocean acidification research has focused on impaired calcification, embryos may not reach the skeletogenic stage in a warm ocean.

[Inhaled foreign bodies in 50 patients in South Vietnam, mainly caused by naseberry (Sapodilla)]. / Une série de 50 cas d'inhalation de corps étranger au Sud Viêt-nam (cause principale: le noyau de sapotier).

Inhalation of foreign bodies is relatively frequent in children, but exceptional in adults. Various kinds of foreign bodies can be inhaled, the type generally depends on eating habits in adults. We reviewed a series of 50 consecutive cases of inhaled foreign bodies and found that naseberry fruits (Sapodilla plum) was the primary cause, followed by bone debris. This series is typical of Eastern Asia, particularly South Vietnam. Most of the foreign bodies were extracted under local anesthesia using fibroscopy with a foreign body forceps. Most of the foreign bodies were on the right side. The naseberry nut is not radio-opaque, so diagnosis was generally established late after infectious complications. The endoscopic aspect was typical and should be recognized by endoscopists working in Vietnam.