Inom forskningsmiljön Man and Biospere Health, förkortat MABH (hkr.se/mabh), bedrivs forskning inom biologi, kemi, biomedicin och psykologi, men också mycket tvärvetenskaplig forskning, med fokus kring människans påverkan på ekosystem och dess effekter på biologiskt liv, mångfald och hälsa. Forskare inom MABH är också involverade i åtgärdsprogram och utveckling av nya tekniker och metoder för att kunna undersöka de negativa effekterna av människans aktiviteter. Forskningsmiljön MABH bildades 2009 med syfte att samla högskolan forskning inom bland annat ekologi, miljöteknik, kemi och biomedicin under ett paraply. Ambitionen var att utveckla tvärvetenskapliga projekt såväl inom som utanför gruppen.

Studies on the responses of tropical microbial communities to changing hydrographic conditions are presently poorly represented. We present here the results from a mesocosm experiment conducted in southwest (SW) coastal India to investigate how changes in temperature and salinity may affect a coastal tropic microbial community. The onset of algal and bacterial blooms, the maximum production and biomass, and the interrelation between phytoplankton and bacteria were studied in replicated mesocosms. The treatments were set up featuring ambient conditions (28 °C, 35 PSU), hyposalinity (31 PSU), warming (31 °C) and a double manipulated treatment with warming and hyposalinity (31 °C, 31 PSU). The hyposaline treatment had the most considerable influence manifested as significantly lower primary production, and the most dissimilar microphytoplankton species community. The increased temperature acted as a catalyst in the double manipulated treatment and higher primary production was maintained. We investigated the dynamics of the microbial community with a structural equation model approach, and found a significant interrelation between phytoplankton biomass and bacterial abundance. Using this methodology, it became evident that temperature and salinity changes, individually and together, mediate direct and indirect effects that influence different compartments of the microbial loop. In the face of climate change, we suggest that in relatively nutrient replete tropical coastal zones, salinity and temperature changes will affect nutrient assimilation with subsequent significant effects on the quantity of microbial biomass and production.

The bacteria Vibrio parahaemolyticus is an important component of coastal ecosystems worldwide, and in recent years, V. parahaemolyticus has caused several cases of food-borne gastroenteritis. However, research investigating which parameters are important in regulating V. parahaemolyticus abundance in tropical areas with relatively stable temperatures and salinity are largely lacking. The objective here was to investigate which environmental forces are driving elevated abundances of V. parahaemolyticus in a tropical oligotrophic coastal area in the Arabian Sea. We analysed a large number of environmental parameters in parallel with cell densities of V. parahaemolyticus and Vibrio spp. Abundance data was obtained using real-time PCR, during two different sampling periods, representative for two distinct seasons. Water temperature and salinity were stable during and between sampling periods, but V. parahaemolyticus abundances were on average six times higher during the first sampling period in December, compared to the second period in February–March. V. parahaemolyticus abundance was found to be positively correlated to inorganic phosphate concentration and copepod abundance. We thus hypothesise that these are important factors regulating V. parahaemolyticus abundance in coastal tropical areas during these periods.

Reported outbreaks of Vibrio parahaemolyticus have increased worldwide, particularly in regions of high seafood consumption. In Mozambique, seafood constitutes an important food resource and diarrheal diseases are common among its inhabitants. Edible clams were collected in Maputo Bay during both the dry and rainy seasons, with the results showing the number of viable counts of vibrios in clams to peak during the latter. Vibrio parahaemolyticus was the predominant species identified among the isolated strains. Although only one of 109 total strains carried the tdh virulence gene, 69% of isolates showed evidence of hemolytic capacity when subjected to a functional test. Similar virulence patterns and biochemical properties were found in strains isolated from Indian and Swedish marine waters. Antibiotic resistance was, however, more pronounced in strains isolated from these latter two environments.