A healthy symbiotic relationship between corals and S ymbiodiniaceae relies on suitable temperature and adequate nutrients including trace metals. Besides global warming, trace metal deficiency has been shown to cause coral bleaching, a phenomenon responsible for extensive coral reef degradation around the world. How trace metal deficiency impacts Symbiodiniaceae and coral symbiosis is poorly understood, however . In this study, we applied RNA -seq to investigate how Fugacium kawagutii responds to the deficiency of five trace metal s (Fe2+, Zn2+, Cu2+ , Mn2+, Ni2+). We identified 685 to 2805 differentially expressed genes (DEGs) from these trace metal deficiency conditions, among which 372 were commonly regulated by all the five trace metal s and were significantly enriched in energy metabolism (e.g. fatty acid synthesis) . Furthermore, genes associated with extracellular matrix (ECM), cell surface structure and cell adhesion were impacted, suggesting that the ability of recognition and adhesion of F. kawagutii may be altered by trace metal deficiencies. In addition, among the five metals, Fe2+ deficiency exhibited the strongest influence, with F e -rich redox elements and many antioxidant synthesis genes being markedly down -regulated, indicative of adaptive reduction of Fe demand but a compromised ability to combat oxidative stress . Overall , deficiency of trace metal s (especially Fe) seems to repress growth and ability of ROS scavenging , elevat e energy metabolism and innate immunity, and alter cell adhesion capability, with implications in symbiosis disruption and coral bleaching.

Introduction

Mutualistic nutritional symbioses between coral animals and photosynthetic dinoflagellates of Symbiodiniaceae are the foundation of the highly biodiverse and productive coral reef ecosystem ( Peixoto et al., 2017). A symbiotic Symbiodiniaceae provide s its coral host with vital photosynthesis product s that can meet up to 95% of the coral ’s energy requirements; in exchange, the coral host provide s inorganic nutrients and serve s as shelter (Muscatine and Porter, 1997) for the symbiont . This mutualistic relationship, however, is delicate and susceptible to the environment factors including thermal stress, high light and extreme salinity (Davy et al., 2012; Kuanui et al., 2015; Nielsen et al., 2018; Skirving et al., 2019). These stress condition s often lead to the expulsion , death, or pigment loss of the Symbiodiniaceae from the host, known as coral bleaching. Global warming and anthropogenic activities have been responsible for massive bleaching and coral degradation , and posed major threats to the precious coral reef ecosystem around the world (Hughes et al ., 2017). Reef coral s liv e in tropical nutrient -poor waters , and they can experience limitation of nutrients, including trace metals ( Measures and Vink 2000; Obata et al ., 2008 ). It has been shown that trace metal deficiency can also induce coral bleaching (Ferrier -Pages et al ., 2018). Trace metal s are essential components of electron transport chains or important cofactors for enzymes involved in various biological processes, such as chlorophyll synthesis, nitrate reduction, and photoprotection or photorepair (Twining and Baines, 2013; Andresen, et al., 2018) .

1- Introduction

2- Materials and methods

3- Results

4- Discussion

References

Abstract

Photosynthesis is an important driver of calcium carbonate deposition on tropical coral reefs largely due to the symbiosis of numerous invertebrates with photosynthetic dinoflagellates in the family Symbiodiniaceae. In bioeroding sponges, however, similar symbioses appear to support the decalcification of carbonate substrates. Compared to its role in calcification, the relative importance of photosynthesis to decalcification processes is less known. Here, the daytime and night-time chemical bioerosion rates of the common Indo-Pacific sponge Cliona orientalis were examined under varying levels of photosynthetic activity and/or varying abundances of intracellular dinoflagellates. Photosynthesis was manipulated either by preconditioning the sponges with the photosynthetic inhibitor diuron (DCMU), or by exposing them to short-term heat stress to achieve bleaching (loss of symbionts). DCMU reduced symbiont numbers and diminished their ability to evolve oxygen. Thermal stress caused a significantly greater loss of symbionts, but photosynthesis was less inhibited. In both cases, decreases in photosynthetic activity and symbiont densities led to proportionately lowered daytime chemical bioerosion rates. Moreover, increased rates of night-time bioerosion were linked to greater daytime rates of photosynthesis, rather than to the night-time respiration of the sponge holobiont. Our findings support the conclusion that photosynthetic products (photosynthates) and/or by-products (oxygen) stimulate sponge bioerosion. This work further reveals the importance of symbionts in the ecology of such sponges and in their ability to sustain high bioerosion activity in otherwise nutrient-poor ecosystems.

Introduction

Tropical coral reefs thrive in shallow clear waters where sunlight powers productive and diverse food chains. Symbioses between invertebrates and a variety of photosynthetic microorganisms enable high rates of productivity on reefs despite low environmental concentrations of inorganic nutrients (Muscatine and Porter, 1977; Seckbach, 2004; Yellowlees et al., 2008). The evolutionary success that results from hosting phototrophic microbes such as dinoflagellates, diatoms, chlorophytes, rhodophytes, or cyanobacteria is seen in a wide range of diverse invertebrates belonging to taxa such as Cnidaria, Mollusca, Foraminifera, Platyhelminthes, and Porifera (Trench, 1993; Stat et al., 2006; Lipps and Stanley, 2016). Presently almost 200 sponge species (Porifera) are known to host microbial photosynthetic symbionts (“photosymbiotic” sponges), which may contribute to the nutrition and health of the sponge (e.g. Wilkinson, 1987; Hill et al., 2011; Thacker and Freeman, 2012). Sponge species that receive substantial contributions in this way are often named “phototrophic” after the nutritional mode of their symbionts, or “mixotrophic” given that they also depend on filter-feeding by specialized food-trapping sponge cells. The nutrition of sponges is often further supplemented by inputs from intimate associations formed with heterotrophic bacterial populations of varying density and diversity (e.g. Hentschel et al., 2003; Taylor et al., 2007).

1- Introduction

2- Research framework and methodology

3- China’s EIP development

4- Analysis of EIP standard modification

5- Concluding remarks

References

Abstract

Eco-industrial Parks (EIP) have become a central element in China’s industrial strategy to combine industrial development while minimizing environmental impacts and improving resource efficiency. National standard system has been developed as a main tool for assessing EIPs. This paper provides a review of the development of China’s EIP standard system. The focus of the analysis is the new national demonstration EIP standard (HJ/T274-2015), including a review of calculation methods for some key indicators. The analysis also provides a comparison with previous standards to identify the main changes and improvements in the assessment of EIPs. Comparison findings illustrate that the new standard provides a more consistent indicator system by providing a consolidated standard system, and offering more comprehensive and quantitative indicators. Moreover, the new standard aims to better manage environmental issues by supplementing more comprehensive environmental indicators. The standard also strengthens the emphasis of the industrial symbiosis dimension in the evaluation of EIPs. By offering optional indicators and giving distinct targets based on contextual conditions for a number of indicators, the flexibility and rationality of the EIP assessments are also enhanced. Although many positive changes have been identified, there are still some shortcomings exist in the new EIP standard. The paper proposes a number of recommendations based on analyzing shortcomings, for instance further improving of the industrial symbiosis indicators, offering social benefit evaluation indicators, and strengthening the reduction action evaluation. China’s experience of setting EIP standards and indicators may provide lessons for other countries’ attempts to develop industrial estate indicators. In order to observe and effectively promote industrial estates at the global range, several remaining research questions that need further exploration are put forward in this study.

Introduction

With the aim of responding to environmental pollution and global warming, many countries are seeking innovative ways to relieve these problems. Establishing Eco-industrial Parks (EIPs) is considered as one effective way for coordinating environmental pollution and economic development (Lai, 2013; UNEP, 1997; Zhang et al., 2010; Song and Shen, 2015). Though being a policy-concept which is infused with different meanings depending on political, socio-economic and cultural context (Boons et al., 2017), EIP is usually proposed as a community of manufacturing and service businesses seeking enhanced environmental, economic, and social performance through collaboration in managing environmental and resource issues (Lowe, 1997; Valenzuela-Venegas et al., 2016). Practically, a precursor to EIP is the regional industrial symbiosis1 at Kalundborg in Denmark, uncovered in 1990 (Ehrenfeld and Gertler, 1997; Chertow, 2000). Other eco-innovation park cases were also initiated and investigated, such as in the US (Chertow, 2000), Canada (Cote and Cohen-Rosenthal, 1998; Fleig, 2000), Korea (Kim and Powell, 2008; Park et al., 2008, 2016), Japan (Van Berkel et al., 2009; Geng et al., 2010), European countries (Massard et al., 2014) and Australia (Roberts, 2004; Van Berkel, 2007; Van Beers et al., 2007). China began to facilitate the EIP strategy in early 2000s and actively promoted it with the enactment of both cleaner production promotion law and circular economy promotion law (Geng and Cote, 2003; Geng et al., 2009, 2013, 2016; Chiu, 2001; Fang et al., 2007; Shi et al., 2012a, 2012b; McDowall et al., 2017). The first reported EIP case in China is the Guitang sugar-making complex approved by the State Environmental Protection Administration (SEPA)2 (Zhu and Cote, 2004; Zhu et al., 2007). China developed large amount of EIP networks since then. Although EIP can be developed and promoted in different forms, setting of standards and guidelines is found helpful for promoting EIP development in China (Shi et al., 2012a, 2012b). Several regions also designed their own EIP criteria, including Port of Cape Charles in the US, Virginia in the US, Thailand, and the Eco-star criteria in Devens, Massachusetts (Cote and Liu, 2016). Yet only China designed a national EIP standard that is applied in large number of parks, and there is no internationally accepted standard for EIP. Several studies discussed about the EIP evaluation standard system in China. Geng et al. (2008) argued that some of the criteria in EIP standard released by SEPA in 2006 are vague and difficult to evaluate. Meanwhile, the standard is criticized having not considered the principles of eco-industrial development and local realities (Geng et al., 2009). Yu et al. (2014) and Liu et al. (2007) reviewed the EIP performance according to the Chinese EIP standards, and found indicators such as reuse rate of reclaimed water, recycling rate of solid waste are usually challenging for industrial parks to execute.

1- Introduction

2- Framework

3- Organizational dimension

4- Sustainability dimension

5- Characterizing EIPs through the proposed framework

6- Cluster analysis

7- Conclusions

References

Abstract

Eco-Industrial Parks (EIPs) are defined as a community of firms located in the same area and linked in a network of collaborative relationships mainly aimed at enhancing sustainability. A number of EIPs have recently spread in both developed and developing countries through diverse formation processes, resulting in different configurations. The topic has received a growing attention by the literature, even though to our knowledge the available studies lack to characterize the EIPs’ organizational models and analyse how models reflect on the EIP’s sustainability. The aim of this paper is to fill this gap, proposing a framework that characterizes EIPs along two dimensions related to organization and sustainability, which are further described through specific variables. We apply the framework on 28 EIPs and conduct cluster analysis to group them according to the organizational dimension. We then identify different organizational models of EIPs and discuss the possible linkages between such models and the adopted sustainability practices. The research findings have practical implications concerning policies and strategies to enhance EIPs sustainability.

Introduction

Since the seminal paper of Frosch and Gallopulos (1989) an extensive body of research has flourished, leveraging on the analogies between natural and industrial ecosystems. As industrial ecosystem we mean “a community or network of companies and other organizations in a region who chose to interact by exchanging or making use of by-products and/or energy” (Gertler, 1995) so as to benefit from the systemic reduction in the use of virgin resources and in the waste to be disposed, as well as from the increase in variety and amount of outputs that have market value. Ayres and Ayres (2002) remark that several aspects of industrial networks mimic distinctive phenomena of biological systems, such as the cycling of materials, nutrients, and energy, or the interactions among individuals playing the role of producers, consumers, or decomposers (Liwarska-Bizukojc et al., 2009). According to this research stream, which is usually called industrial ecology (Allenby and Graedel, 1993; Ehrenfeld, 2004a), rather than emphasizing the independence and competitiveness of companies, studies should stress their collaborations and interdependence (Côté and Cohen-Rosenthal, 1998). These characteristics, indeed, move the focus from monadic individuals to their interconnectedness, which is considered crucial in assuring the resilience of industrial ecosystems and giving them efficiency and persistency over time (Zhu and Ruth, 2013). Moreover, in the last decades studies on industrial ecology have been also spread due to the increasing prominence gained by the concept of sustainability: scholars and strategic consultants have stressed that greening production processes is a key factor for both single companies and local networks of firms to gain competitive advantage (Shrivastava, 1995; Tudor et al., 2007). In addition, the promotion of sustainable development has been the focus of many governmental policies and international initiatives, which have been recently multiplied: in 2012, the United Nations Conference on Sustainable Development “Rio+20” reaffirmed the inter-linkages between environmental and social goals in building an economically, socially, and environmentally sustainable future (United Nations, 2012).