Developments in German Bight benthic ecology driven by climate change and anthropogenic utilization

Marine ecosystems are subjected to an unprecedented range of natural and anthropogenic disturbance with an increasing frequency of occurrence over recent decades. Among others, rising sea water temperature, ocean acidification, and coastal water pollution have resulted in alteration of habitats and subsequent changes in the structures of species assemblages. In the face of these challenges, ecological research needs to predict responses of assemblages to global change, a requisite for the adequate prevention of further environmental degradation. However, predicting assemblage responses requires a thorough understanding of ecological processes and of the structure and functioning of assemblages. The present thesis comprises four manuscripts which address in detail a) the temporal variability of benthic macrozoobenthos assemblages and the relative role of different environmental drivers of abundance variations in the North Sea, b) the functional diversity and the dominant functional characteristics of benthic species of the southern North Sea, c) the temporal variations in the functional trait composition, the contribution of different biotic and abiotic predictors to the variation in ecological functioning, the relationship between species diversity and functional diversity and the extent of functional redundancy within benthic communities and d) the degree of functional homogenization and the identification of dynamically-dominant-traits that likely have the greatest effect on biodiversity and ecosystem function. In â Manuscript I,â the model results revealed that temperature and anomalies of the North Atlantic Oscillation Index (NAOI) play a distinct role in controlling the temporal variation of the benthic assemblages. The results also showed substantial variation in the composition of macrozoobenthos assemblages in the North Sea at decadal and sub-decadal scales. Species react differently to environmental disturbances with generalist species being dominant in the region. â Manuscript IIâ and â Manuscript IIIâ on the functional characteristics of macrozoobenthos assemblages revealed that changes in trait composition were more similar among monitoring sites than changes in the taxonomic composition, emphasizing the role of environmental disturbances in the determination of trait associations in the North Sea system. The relationship between species richness and functional diversity indicates a relatively high functional redundancy within benthic assemblages of the southern North Sea. â Manuscripts II - IVâ showed that some trait modalities such as small body size, high dispersal potential, interface- and deposit-feeding were relatively common in the North Sea benthic assemblages. In fact, this suite of traits represents an â adaptive strategyâ enabling species to survive and thrive in a stressful environment. The replacement of specialist species by generalist species (Manuscripts I and III), less site-specific temporal variations in functional composition as compared to the taxonomic composition (Manuscript III) and a high degree of functional niche overlap (Manuscript IV), imply functional similarity among species assemblages. An increased spatial similarity of assemblages, in turn, generated â functional homogenizationâ in the North Sea benthic system. In contrast to the considerable temporal variation in species abundance, the temporal development of functional diversity was relatively stable with only two incidental inconsistencies coinciding with extreme events (i.e. cold winter 1995/96 and extreme negative NAO winter of 2009/10) in the North Sea. Following the temporary changes, the functional diversity rebounded to previous levels after almost one year. The rapid recovery of functionality after disturbance may be attributed to the high functional redundancy in the ecosystem. The results of the present thesis contribute to the understanding of the structural and functional processes of macrozoobenthos in the southern North Sea. The study highlights that a comprehensive understanding of long-term dynamics of benthic ecosystems requires a combined analysis of functionality and taxonomic structure

Assessing the ecological quality status of arid mangroves in the Gulf of Oman, Iran, using benthic indices of AMBI, M-AMBI, and BENTIX

Polychaetes are suitable indicators to evaluate the benthic ecological status and respond to natural and anthropogenic. We evaluated the ecosystem health of the mangroves of Azini and Gwadar based on benthic indices including AMBI, M-AMBI, and BENTIX using polychaete communities. The results showed that in both regions, EcoQ classifications ranged from "high" to "moderate" in BENTIX, "good" to "excellent" in AMBI, and "good" in M-AMBI. The M-AMBI was significantly correlated with sediment variables, including total organic matter (TOM), total organic carbon (TOC), and silt/clay. The result revealed a significant correlation between the biotic indices and the TOC content of sediments. According to the results, TOC can be used as a descriptor and indicator to evaluate the health of mangrove ecosystems in relation to benthic indices. In addition, it is necessary to combine several indices to assess the status of ecosystems

Dužinsko-maseni odnos 18 vrsta riba iz Persijskog zaliva

Dužinsko-maseni odnos (LWR) je opisan kod osamnaest vrtsa riba ulovljenih duž obala Hormoz moreuza u Persijskom zalivu, Iran. Izlovljeno je ukupno 2328 jedinki od jeseni 2013. do zime 2014. godine sa strašinom za lov gambora i obalnom klopkom. LWR je izračunat korišćenjem stepene jednačine Vrednosti parametra b su bile bliske vrednosti 3 kod malabarskog crvenog pagara (Lutjanus malabaricus), tigrozube kavale (Otolithes ruber), srebrnastog silaga (Sillago sihama), salaha (Equulites lineolatus), glatkozubog konja (Leiognathus equulus) i konjića (Secutor ruconius), vrednosti parametra b značajno veće od 3 su zabeležene kod prugastog konjića (Aurigequula fasciata) i indijskog iverka (Psettodes erumei), a vrednosti parametra b značajno manje od 3 su zabeležene kod vrste pagar žutoperajar (Acanthopagrus latus), srpa (Drepane longimana), indijskog arbuna (Lethrinus lentjan), skakavice (Liza klunzingeri), indijskog pagra (Lutjanus johnii), plotice (Parastromateus niger), kopljastog gruntera (Pomadasys kaakan), zmijičnjaka (Trichiurus lepturus), šarenog konjića (Nuchequula gerreoides) i vrste Photopectoralis bindus. Do sada nisu postojale u bazi FishBase LWR kod četiri istraživane vrste u ovom radu, a takođe je zabeležena i nova maksimalna dužina za vrstu pagar žutoperajar. Rezultati dobijeni u ovom radu mogu biti od pomoći biolozima i upravljačima koji se bave ribarstvom u Persijskom zalivu

Species Composition and Functiona Traits of Macrofauna in Different Mangrove Habitats in the Persian Gulf

Macrofauna play a key role in the functioning of mangrove ecosystems. Nevertheless, our understanding of the diversity and functional structure of macrofaunal communities across different habitats in the mangrove forests of the Persian Gulf is limited. In this study, we investigated species diversity and biological trait patterns of macrofauna in different mangrove-associated habitats, i.e., encompassing actual mangrove forests, and adjacent Beaches and Creeks, which exhibit different levels of habitat heterogeneity. Samples were collected from the different habitats in five different locations, over four seasons. A total of 122 macrofauna taxa were identified. The diversity of species was higher in summer than in winter. In the Beach habitats, species diversity showed an increasing trend from land toward the mangrove, whereas in Creek habitats diversity decreased from the Creek toward the mangrove. Multivariate community analysis showed differences in the distribution of abundant species and biological traits across all habitats. Deposit-feeding, crawlers, medium-size, and free-living were the dominant trait modalities in all habitats. The similarities within habitats over the four seasons had the same specific pattern of species and biological trait abundance in the Beach and the Creek, increasing from the non-covered habitat into the mangrove trees. Although many species shared similar traits, the abundance-driven differences in trait expression between habitats showed the importance of habitat filtering. The results of this study will be useful in the conservation of mangrove forests and they give a deeper understanding of the ecological patterns and functions of benthic macrofaunal communities in the Persian Gulf.Peer reviewe

Monitoring of fisheries resources in artificial reefs in east of Kish Island waters

Artificial reefs are manmade materials deployed under water in order to improve environment and increase the exploitation of fishing area. Usage of artificial technic has developed due to increase of world population and need to supply of protein, aim to restoring of natural specially rehabilitation of demersal fishes. It has effected to increase the production in order sustainable exploitation. Coasts and Islands have destruction due to over harvesting from ecosystems and other activities by humans and natural, these caused many aquatic as demersal fishes has endangered in Persian Gulf and Oman Sea. The artificial reef is one way or method that can improve the environment and restore the aquatic. Iranian fisheries has established an artificial reefs area in west of Kish Island. This area has studied during one year, Data of assembled fishes and physical sampling were collected in seasonal during spring, summer, autumn and wintered. There were tow treatment for sampling as artificial reefs site and a control site. Collected data has analyzed and evaluated by SPSS and Exel. The results showed that there was significant difference between the sites and assembled fishes in artificial reefs were more than control site. Consequently the artificial reefs can be a tool and technic to improve the marine environment and increase the production of fishes, especially the demersal fishes

Benthos-ökologische Entwicklungen in der Deutschen Bucht als Folge von Klimawandel und menschlicher Nutzung

Marine ecosystems are subjected to an unprecedented range of natural and anthropogenic disturbance with an increasing frequency of occurrence over recent decades. Among others, rising sea water temperature, ocean acidification, and coastal water pollution have resulted in alteration of habitats and subsequent changes in the structures of species assemblages. In the face of these challenges, ecological research needs to predict responses of assemblages to global change, a requisite for the adequate prevention of further environmental degradation. However, predicting assemblage responses requires a thorough understanding of ecological processes and of the structure and functioning of assemblages. The present thesis comprises four manuscripts which address in detail a) the temporal variability of benthic macrozoobenthos assemblages and the relative role of different environmental drivers of abundance variations in the North Sea, b) the functional diversity and the dominant functional characteristics of benthic species of the southern North Sea, c) the temporal variations in the functional trait composition, the contribution of different biotic and abiotic predictors to the variation in ecological functioning, the relationship between species diversity and functional diversity and the extent of functional redundancy within benthic communities and d) the degree of functional homogenization and the identification of dynamically-dominant-traits that likely have the greatest effect on biodiversity and ecosystem function. In Manuscript I, the model results revealed that temperature and anomalies of the North Atlantic Oscillation Index (NAOI) play a distinct role in controlling the temporal variation of the benthic assemblages. The results also showed substantial variation in the composition of macrozoobenthos assemblages in the North Sea at decadal and sub-decadal scales. Species react differently to environmental disturbances with generalist species being dominant in the region. Manuscript II and Manuscript III on the functional characteristics of macrozoobenthos assemblages revealed that changes in trait composition were more similar among monitoring sites than changes in the taxonomic composition, emphasizing the role of environmental disturbances in the determination of trait associations in the North Sea system. The relationship between species richness and functional diversity indicates a relatively high functional redundancy within benthic assemblages of the southern North Sea. Manuscripts II - IV showed that some trait modalities such as small body size, high dispersal potential, interface- and deposit-feeding were relatively common in the North Sea benthic assemblages. In fact, this suite of traits represents an adaptive strategy enabling species to survive and thrive in a stressful environment. The replacement of specialist species by generalist species (Manuscripts I and III), less site-specific temporal variations in functional composition as compared to the taxonomic composition (Manuscript III) and a high degree of functional niche overlap (Manuscript IV), imply functional similarity among species assemblages. An increased spatial similarity of assemblages, in turn, generated functional homogenization in the North Sea benthic system. In contrast to the considerable temporal variation in species abundance, the temporal development of functional diversity was relatively stable with only two incidental inconsistencies coinciding with extreme events (i.e. cold winter 1995/96 and extreme negative NAO winter of 2009/10) in the North Sea. Following the temporary changes, the functional diversity rebounded to previous levels after almost one year. The rapid recovery of functionality after disturbance may be attributed to the high functional redundancy in the ecosystem. The results of the present thesis contribute to the understanding of the structural and functional processes of macrozoobenthos in the southern North Sea. The study highlights that a comprehensive understanding of long-term dynamics of benthic ecosystems requires a combined analysis of functionality and taxonomic structure

Life history traits of ribbonfish Trichiurus lepturus in the ROPME sea area (Persian Gulf)

Ribbonfish, Trichiurus lepturus, is an important component of subsistence fisheries throughout its tropical and subtropical distribution. The data set consist of parameters that used to estimate growth and mortality parameters, sex ratio, morphological relationships and life history traits of Trichiurus lepturus on the northern coasts of the Persian Gulf and Oman Sea