Influence of physico-chemical parameters and pCO2 concentration on mangroves-associated polychaetes at Pichavaram, southeast coast of India

Research Article Influence of physico‑chemical parameters and pCO2 concentration on mangroves‑associated polychaetes at Pichavaram, southeast coast of India Palanivel Partha Sarathy1 · Veeraiyan Bharathidasan1 · Palingam Gnanamoorthy2,3 · Perumal Murugesan1 Received: 10 August 2019 / Accepted: 26 October 2019 / Published online: 5 November 2019 © Springer Nature Switzerland AG 2019 Abstract Studies related to partial pressure of carbon dioxide ( pCO2) concentration linking with polychaete diversity in mangrove ecosystems are limited in time and space. Therefore, the present study was conducted during July 2017–June 2018 on a monthly interval and reported the concentration of p CO2 coupled with physico-chemical parameters in relation to polychaetes diversity in Pichavaram mangroves ecosystem, southeast coast of India. Totally, 41 species were identified and the most dominant species were Prionospio cirrifera, P. cirrobranchiata, P. sexoculata, Prionospio sp. and Capitella capitata. Among the stations, higher polychaete diversity was found in marine zone compared to other zones. The correlation reflected a significant positive linear relationship between dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), particulate organic carbon (POC) and CO2 versus pCO2. The carbon species DIC, DOC, POC and pCO2 concentration ranged from 1100.1 to 2053.3(µmol/kg), 165.7–1954.0(µmol/kg), 4.5–89.2(µmol/kg) and 184.7–3763.1(µatm), respectively. Further, the statistical analyses revealed that there was a strong correlation among carbon species with distribution of polychaete species in various zones of mangroves and thus indicating pivotal role in occurrence of polychaetes in mangroves. Keywords Mangrove · Blue carbon · CO2 emission · Polychaete diversity 1 Introduction Urbanization, industrialization, afforestation and burning of fossil fuel are the major anthropogenic activities, responsible for the proliferation of greenhouse gas emission into the atmosphere. In recent years, the increasing concentration of CO2 (global warming) has resulted in rise of sea surface temperature (0.3–0.6 °C) and fall in seawater pH (0.1), referred to as ocean acidification, which are considered to be the most universal problem, particularly more vulnerable to marine ecosystem [1]. Of the various ecosystems, the mangroves, seagrass meadows and coral reef account for storing high rate (~ 70%) of organic carbon [2]. Among these three ecosystems, mangroves are said to be the most productive and biologically important ecosystem in tropical and subtropical region. Being productive, it also plays an important role in the global carbon cycle, and thus, estimated net primary production (NPP) of the world’s mangroves is about 218 ± 72 TgC per year [3, 4]. Consequently, the Electronic supplementary material The online version of this article (https://doi.org/10.1007/s42452-019-1581-2) contains supplementary material, which is available to authorized users. * Perumal Murugesan, | 1Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Tamilnadu 608 502, India. 2Key Laboratory of Tropical Forest Ecology, Xishuangbanna, Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla County, Yunnan Province, China. 3Coastal Systems Research, M.S. Swaminathan Research Foundation, Chennai, India. SN Applied Sciences (2019) 1:1550 | https://doi.org/10.1007/s42452-019-1581-2 Vol.:(0123456789) Research Article SN Applied Sciences (2019) 1:1550 | https://doi.org/10.1007/s42452-019-1581-2 mangrove forests are the largest carbon sink, leading to reduction in carbon emissions [5]. True to its sense, several researchers pointed out that the mangroves are considered as the potential source of atmospheric C O2 and CH4 [6, 7]. Justifiably, the water columns of the mangroves ecosystem are rich in organic carbon derived from the mangrove litter. Despite its own high organic production, mangroves also receive considerable amount of organic carbon through freshwater influx during monsoon season. Added to it, discharges accruing from industrial effluents and shrimp ponds are the additional sources of CO2 to mangrove wetlands as stated by Purvaja [8] and Regnier et al. [9]. In his study, Kathiresan [10] compiled as many as 4011 species of fauna and flora to occur in the mangrove environment. Of this, 920 nos. belonged to floral species (23%) and 3091 to faunal (77%). Among the various faunal groups, benthic infauna are responsible for a significant amount of sediment secondary productivity, bioturbation and nutrient recycling [11, 12]. These organisms show numerous feeding behaviors at different levels of the complex mangroves food web, representing suitable bio-indicators of regional structure and environmental status and disturbances [13]. Of these benthic taxa, polychaetes play a pivotal role in decomposition of dead organic matter and break down of leaf litter in this productive ecosystem [14]. On the contrary, in recent years, mangrove forests are vulnerable to anthropogenic activities like tourism, urban development and natural disturbance [15, 16]. Under these circumstances, over the years, a large number of studies related to diversity of benthic fauna in mangrove ecosystem have been undertaken in India and elsewhere [14, 17]. Nevertheless, studies related to p CO 2 concentration linking with benthic community in mangrove ecosystems are very limited, that too in Pichavaram mangroves skirting around ten fishing villages, vast extent of agricultural lands and aquaculture ponds besides being attracted by a large number of tourists regularly [18, 19]. Even though a suite of environmental parameters that determine the distribution of benthic organisms, temperature, pH and p CO 2 are the most important environmental factors determining the distribution, physiological performance, morphology and behavior of marine invertebrates [20, 21]. Taking cognizance of the facts stated above, the present study was aimed to investigate the seasonal variation of pCO2 concentration and its influence coupled with environmental parameters on the polychaete diversity at Pichavaram mangrove environment. Vol:.(1234567890) 2 Materials and methods 2.1 Study area Pichavaram mangrove (Lat.11° 25′ N; Long.79° 47′ E) is situated amidst the Vellar and Coleroon estuarine complex. This mangrove has 51 islets of varying size with an area of 1200 ha, of which 40% is occupied by urban waterways (for fishing), 50% by mangrove forests and the rest by mud and sand flats [22]. This sprawling mangrove is criss-crossed by numerous channels and creeks linking other water bodies to this region. The tides are semidiurnal in nature with a range of 0.5–1.0 m. Besides this, a patchy occurrence of shrimp farms and agriculture lands with 2207 ha also borders this productive ecosystem [18]. The depth of the water here is generally low, varied from about 0.3 to 3.0 m. To achieve the object (...truncated)