Climate-driven range extension of Amphistegina (protista, foraminiferida) : models of current and predicted future ranges

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 8 (2013): e54443, doi:10.1371/journal.pone.0054443.Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa) at 31°S. To project future species distributions, we applied a species distribution model (SDM) based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year−1, and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.This work was supported by grants from the German Science Foundation (DFG; www.dfg.de) to ML and SL (LA 884/10-1, LA 884/5-1)

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

Regional generalisations about the relationships between the environment and foraminifera along the SW Cape coast, South Africa

Factors influencing the composition of shallow water benthic foraminifera along the SW coast of South Africa at two locations (Table Bay, TB; St Helena Bay, SHB) ∼200 km from each other were examined. Small taxa dominated in both locations; living assemblages from SHB (28 species, Ammonia parkinsoniana dominant) differed from TB (34 species, Elphidium articulatum dominant). Environmental parameters were similar in both areas. Patchiness in assemblage structure was pronounced, differences between pipeline and non-pipeline sites within locations were evident in environmental parameters. Diversity was significantly correlated with grain size, the nitrogen and heavy metal content (especially Cd). These data represent the first for extant benthic Foraminifera from the southern Benguela upwelling area and is the first attempt at using foraminifera as indicators of pollution in this region. The data stressed the need for more than one sampling location to better understand the factors influencing foraminiferal assemblages in any regional context.National Research Foundation (SA

EFFECT OF VARIED DAILY FEEDING INTENSITIES ON GROWTH PERFORMANCE AND FEED UTILISATION OF SOUTH AFRICAN DUSKY KOB (ARGYROSOMUS JAPONICUS) JUVENILES REARED IN A RECIRCULATING AQUACULTURE SYSTEM

Several aquaculture studies have concluded that feed constitutes the heaviest cost in aquaculture enterprises. Consequently, researchers continue to investigate strategies that can lower feed costs such as the use of protein rich plant sources and insect meals to partially or completely substitute the expensive fishmeal in aquafeeds. However, this approach has often faced numerous challenges such as anti-nutrients in plant protein sources that limit their use and suboptimal polyunsaturated fatty acids profile in terrestrial protein sources such as insect meal. Precision feeding is a strategy that could also reduce aquafeed feed costs and enhance the economic sustainability of aquaculture. There is discordance regarding the feeding intensity that should be used for fish such as dusky kob. The current study was designed to compare the effect of three feeding intensities (2.8 %, 3.5 % and 4 % of body weight (BW)) on growth performance and feed utilisation of juvenile dusky kob (Argryrosomus japonicus). Dusky kob juveniles were randomly and evenly allocated to 18 tanks with a volume of 465 L. Each feeding intensity was randomly allocated to six tanks carrying 66 fish each. The average temperature and dissolved oxygen were 25°C and 5.5-6.0 mg/l, respectively. Commercial dusky kob diet was offered twice daily at the rate of 2.8%, 3.5% and 4% of body weight (BW). A feeding intensity × fish age (weeks) interaction effect was noted on fish feed intake (P0.05). The 2.8% BW feeding rate promoted 1.06%/day SGR as compared to 1.21%/day and 1.48%/day for 3.5% and 4.0% BW feeding rates, respectively. Similar weight gains and FCR recorded across the three feeding intensities may suggest that the lowest feeding intensity (2.8% BW) should be used for dusky kob feeding to reduce feeding costs

EFFECT OF VARIED DAILY FEEDING INTENSITIES ON GROWTH PERFORMANCE AND FEED UTILISATION OF SOUTH AFRICAN DUSKY KOB (ARGYROSOMUS JAPONICUS) JUVENILES REARED IN A RECIRCULATING AQUACULTURE SYSTEM

Several aquaculture studies have concluded that feed constitutes the heaviest cost in aquaculture enterprises. Consequently, researchers continue to investigate strategies that can lower feed costs such as the use of protein rich plant sources and insect meals to partially or completely substitute the expensive fishmeal in aquafeeds. However, this approach has often faced numerous challenges such as anti-nutrients in plant protein sources that limit their use and suboptimal polyunsaturated fatty acids profile in terrestrial protein sources such as insect meal. Precision feeding is a strategy that could also reduce aquafeed feed costs and enhance the economic sustainability of aquaculture. There is discordance regarding the feeding intensity that should be used for fish such as dusky kob. The current study was designed to compare the effect of three feeding intensities (2.8 %, 3.5 % and 4 % of body weight (BW)) on growth performance and feed utilisation of juvenile dusky kob (Argryrosomus japonicus). Dusky kob juveniles were randomly and evenly allocated to 18 tanks with a volume of 465 L. Each feeding intensity was randomly allocated to six tanks carrying 66 fish each. The average temperature and dissolved oxygen were 25°C and 5.5-6.0 mg/l, respectively. Commercial dusky kob diet was offered twice daily at the rate of 2.8%, 3.5% and 4% of body weight (BW). A feeding intensity × fish age (weeks) interaction effect was noted on fish feed intake (P0.05). The 2.8% BW feeding rate promoted 1.06%/day SGR as compared to 1.21%/day and 1.48%/day for 3.5% and 4.0% BW feeding rates, respectively. Similar weight gains and FCR recorded across the three feeding intensities may suggest that the lowest feeding intensity (2.8% BW) should be used for dusky kob feeding to reduce feeding costs

Metal concentrations in mytilus galloprovincialis along the West coast of the Cape Peninsula, Cape Town, South Africa

ArticleConcentrations of metals (Fe, Mn, Cu, Cd, Zn and Pb) in the mediterranean mussel Mytilus galloprovincialis were investigated at five sites along the west coast of the Cape Peninsula, Cape Town. The mussels were collected seasonally for one year starting from autumn 2010 and analysed using an ICP-MS. On the spatial and temporal scales, metal concentrations differed, with no clear trends. Of the five sites sampled, metal concentrations were lowest at Scarborough, the southernmost site, and seasonally, lowest during summer.The results indicated that most metals in the soft tissue of mussels were below the recommended concentrations (internationally), permissible legal limit (for South Africa) as well as historical data (for the same area) suggesting that biota in the coastal area sampled was not contaminated by metals. There is however a need for continuous biomonitoring the coastal area of South Africa as the results found here might not apply to the rest of the South African coastline.The research was funded by the Cape Peninsula University of Technology (CPUT)(University Research Fund). We thank the technical staff at CPUT for assistance with collecting samples and laboratory analysi

Macro-benthic invertebrate assemblages in the Betty’s Bay Marine Protected Area (Kogelberg region South Africa)

ArticleThe Betty’s Bay Marine Protected Area (MPA) was established to protect endangered species like the African penguin (Spheniscus demersus), abalone (Haliotis midae) and the west coast rock lobster (Jasus lalandii). Very little is known about the effects their protection has had on other assemblages within the MPA. To this end, a photo-quadratic survey of the macro-benthic invertebrates was conducted to provide more information on these communities. The photo-quadratic survey was conducted within two depth zones at 10 sites, seven inside and three outside the MPA. Representative samples were collected to assist in the identification of organisms. Eight hundred and eighty one photo-quadrats were analysed to determine percentage cover, diversity and community structure of the invertebrate assemblages. A mean evenness of 0.88 species was recorded for the entire study area and a total of 250 species were documented. Location (inside or outside MPA) had a significant effect on species richness (F1,637.4 = 32, p < 0.001) and diversity (F1,5.47 = 24.18, p < 0.001), while depth had a significant effect on percentage cover (F1,761 = 5.9, p < 0.05) and community structure. Colonial taxa such as Porifera, Cnidaria and algae were dominant, while semi-motile Mollusca were in relatively low abundance