Margareth S. Copertino

Global environmental changes: setting priorities for Latin American coastal habitats

As the effects of the Global Climate Changes on the costal regions of Central and South Americas advance, there is proportionally little research being made to understand such impacts. This commentary puts forward a series of propositions of strategies to improve performance of Central and South American science and policy making in order to cope with the future impacts of the Global Climate Changes in their coastal habitats.

The prevalence and production of turf-forming algae on a temperate subtidal coast

M. Copertino, S.D. Connell and A. Cheshire. 2005. The prevalence and production of turf-forming algae on a temperate subtidal coast. Phycologia 44: 241–248. This study shows that canopy-forming algae, composed mainly of fucoids and the kelp Ecklonia radiata (both Phaeophycea), dominated space on South Australian coasts relative to turf-forming algae. However, where canopy-forming algae are absent turf-forming algae are the primary occupiers of space (~ 70%). On some reefs where canopy-forming algae are restricted in spatial extent, turfs can occupy as much as 40% of reefs. Turf-forming algae are an abundant component of algal assemblages, but relatively little is known about their contribution to the primary productivity on temperate reefs, relative to canopy-forming species. This study reveals that net productivity rates of turfs at one South Australian location were very high across depths (1.3–2.9 g C m−2 day−1 or 23.2–88.0 mg C g ash-free dry weight−1 day−1), comparable to the values discovered on tropical reefs. Although turf-forming algae are much more productive than canopy-forming algae on a biomass basis, the annual net production per area is two to seven times lower for turfs than for canopy-forming algae. However, if negligible exudation rates are assumed for turfs (up to 1%), the biomass of carbon produced by turf algae represents 44–71% of the carbon incorporated into biomass of kelps. Taken together, these results suggest that while canopy-forming algae can be correctly assumed to be the major source of total carbon produced on temperate reefs, the contribution of turf-forming algae may be substantial to the biomass production and turnover on South Australian reefs.

PHOTOPHYSIOLOGY OF A TURF ALGAL COMMUNITY: INTEGRATED RESPONSES TO AMBIENT LIGHT AND STANDING BIOMASS1

This study investigated the variation in the relationship between photosynthesis and ambient light (P‐E curves) for turf algal communities on a temperate reef off the coast of South Australia, analyzing the integrated effects of ambient light and standing biomass. The photophysiology of turfs was studied in situ on a seasonal basis, examining algal communities growing on artificial substrate (plates) at depths of 4 m and 10 m. P‐E curves and estimates for the photokinetic parameters (Pm, Rd, α, Ek, and Ec) were obtained through oxygen evolution methods, using an automated underwater respirometer. Photoacclimation responses to changes in ambient light were strongly affected by the biomass of the community. Pm showed an inverse relationship to standing biomass, irrespective of depth and season, which was considered to be a response to self‐shading and boundary layer effects. Biomass effects imposed a high variance on estimates for all photosynthetic parameters, overshadowing differences observed for season and depth. Biomass also affected photoinhibition on turf communities, where significant afternoon depression of photosynthesis was observed in sparse turf patches when compared to denser patches. High areal productivity rates were maintained across all seasons with a significant decrease only being observed during winter.

The Western South Atlantic Ocean in a High-CO2 World: Current Measurement Capabilities and Perspectives.

An international multi-disciplinary group of 24 researchers met to discuss ocean acidification (OA) during the Brazilian OA Network/Surface Ocean-Lower Atmosphere Study (BrOA/SOLAS) Workshop. Fifteen members of the BrOA Network (www.broa.furg.br) authored this review. The group concluded that identifying and evaluating the regional effects of OA is impossible without understanding the natural variability of seawater carbonate systems in marine ecosystems through a series of long-term observations. Here, we show that the western South Atlantic Ocean (WSAO) lacks appropriate observations for determining regional OA effects, including the effects of OA on key sensitive Brazilian ecosystems in this area. The impacts of OA likely affect marine life in coastal and oceanic ecosystems, with further social and economic consequences for Brazil and neighboring countries. Thus, we present (i) the diversity of coastal and open ocean ecosystems in the WSAO and emphasize their roles in the marine carbon cycle and biodiversity and their vulnerabilities to OA effects; (ii) ongoing observational, experimental, and modeling efforts that investigate OA in the WSAO; and (iii) highlights of the knowledge gaps, infrastructure deficiencies, and OA-related issues in the WSAO. Finally, this review outlines long-term actions that should be taken to manage marine ecosystems in this vast and unexplored ocean region.

Temporal variability in assimilation of basal food sources by an omnivorous fish at Patos Lagoon Estuary revealed by stable isotopes (2010–2014)

ABSTRACT Estuarine systems are characterized by complex physicochemical and hydrological changes occurring across multiple scales, which determine spatiotemporal variation in distribution and abundance of consumers and their resources. However, little is known about the effects of these biophysical interactions on the interannual dynamics of estuarine food webs. In this work, a five-year stable isotope data set was used to investigate interannual variability in trophic links between basal production sources (seagrass, macroalgae, saltmarsh, particulate organic matter in suspension and in the sediment) and an omnivorous fish (Jenynsia multidentata) in a subtropical estuary emptying in the Southwestern Atlantic. The isotopic variability (δ13C, δ15N) of basal sources and the consumer was analysed seasonally on a mudflat from 2010 to 2014. Jenynsia multidentata showed significant interannual variation in their trophic links with primary producers. In most seasons and years, the consumer relied heavily on benthic-associated food resources, but shifted to pelagic food resources during certain seasons. A ‘green tide’ caused by a massive bloom of vicariant macroalgae occurred on the mudflat, but our findings suggested that the carbon-derived portion of this basal production source was not assimilated by J. multidentata. Instead, seagrass was the most assimilated benthic basal food source in most seasons and years. These results suggest that the intensity of benthic and pelagic trophic pathways sustaining estuarine consumers are not static, but change in response to intra- and interannual variation in the availability of basal production sources. Our findings reinforce the need to account for interannual trends in availability of resources when modelling estuarine food web dynamics.

Evaluation of impacts of climate change and local stressors on the biotechnological potential of marine macroalgae: a brief theoretical discussion of likely scenarios

Climate change can be associated with variations in the frequency and intensity of extreme temperatures and precipitation events on the local and regional scales. Along coastal areas, flooding associated with increased occupation has seriously impacted products and services generated by marine life, in particular the biotechnological potential that macroalgae hold. Therefore, this paper analyzes the available information on the taxonomy, ecology and physiology of macroalgae and discusses the impacts of climate change and local stress on the biotechnological potential of Brazilian macroalgae. Based on data compiled from a series of floristic and ecological works, we note the disappearance in some Brazilian regions of major groups of biotechnological interest. In some cases, the introduction of exotic species has been documented, as well as expansion of the distribution range of economically important species. We also verify an increase in the similarities between the Brazilian phycogeographic provinces, although they still remain different. It is possible that these changes have resulted from the warming of South Atlantic water, as observed for its surface in southeastern Brazilian, mainly during the winter. However, unplanned urbanization of coastal areas can also produce similar biodiversity losses, which requires efforts to generate long-term temporal data on the composition, community structure and physiology of macroalgae.