Ecosystem regimes and responses in a coupled ancient lake system from MIS 5b to present: the diatom record of lakes Ohrid and Prespa

We reconstruct the aquatic ecosystem interactions since the last interglacial period in the oldest, most diverse, hydrologically connected European lake system, by using palaeolimnological diatom and selected geochemistry data from Lake Ohrid “DEEP site” core and equivalent data from Lake Prespa core, Co1215. Driven by climate forcing, the lakes experienced two adaptive cycles during the last 92 ka: "interglacial and interstadial" and "glacial" cycle. The short-term ecosystems reorganizations, e.g. regime shifts within these cycles substantially differ between the lakes, as evident from the inferred amplitudes of variation. The deeper Lake Ohrid shifted between ultra oligo- and oligotrophic regimes in contrast to the much shallower Lake Prespa, which shifted from a deeper, (oligo-) mesotrophic to a shallower, eutrophic lake and vice versa. Due to the high level of ecosystem stability (e.g. trophic state, lake level), Lake Ohrid appears relatively resistant to external forcing, such as climate and environmental change. Recovering in a relatively short time from major climate change, Lake Prespa is a resilient ecosystem. At the DEEP site, the decoupling between the lakes' response to climate change is marked in the prolonged and gradual changes during the MIS 5/4 and 2/1 transitions. These response differences and the lakes' different physical and chemical properties may limit the influence of Lake Prespa on Lake Ohrid. Regime shifts of Lake Ohrid due to potential hydrological change in Lake Prespa are not evident in the data presented here. Moreover, a complete collapse of the ecosystems functionality and loss of their diatom communities did not happen in either lake for the period presented in the study.

Dynamics of ecosystem metabolism and flocculent detritus transport in estuarine Taylor River

Estuaries and estuarine wetlands are ecologically and societally important systems, exhibiting high rates of primary production that fuel offshore secondary production. Hydrological processes play a central role in shaping estuarine ecosystem structure and function by controlling nutrient loading and the relative contributions of marine and terrestrial influences on the estuary. The Comprehensive Everglades Restoration Plan includes plans to restore freshwater delivery to Taylor Slough, a shallow drainage basin in the southern Everglades, ultimately resulting in increased freshwater flow to the downstream Taylor River estuary. The existing seasonal and inter-annual variability of water flow and source in Taylor River affords the opportunity to investigate relationships between ecosystem function and hydrologic forcing. Estimates of aquatic ecosystem metabolism, derived from free-water, diel changes in dissolved oxygen, were combined with assessments of wetland flocculent detritus quality and transport within the context of seasonal changes in Everglades hydrology. Variation in ecosystem gross primary production and respiration were linked to seasonal changes in estuarine water quality using multiple autoregression models. Furthermore, Taylor River was observed to be net heterotrophic, indicating that an allochthonous source of carbon maintained ecosystem respiration in excess of autochthonous primary production. Wetland-derived detritus appears to be an important vector of energy and nutrients across the Everglades landscape; and in Taylor River, is seasonally flushed into ponded segments of the river where it is then respired. Lastly, seasonal water delivery appears to govern feedbacks regulating water column phosphorus availability in the Taylor River estuary.

Hydrological Conditions Control P Loading and Aquatic Metabolism in an Oligotrophic, Subtropical Estuary

Using high-resolution measures of aquatic ecosystem metabolism and water quality, we investigated the importance of hydrological inputs of phosphorus (P) on ecosystem dynamics in the oligotrophic, P-limited coastal Everglades. Due to low nutrient status and relatively large inputs of terrestrial organic matter, we hypothesized that the ponds in this region would be strongly net heterotrophic and that pond gross primary production (GPP) and respiration (R) would be the greatest during the “dry,” euhaline estuarine season that coincides with increased P availability. Results indicated that metabolism rates were consistently associated with elevated upstream total phosphorus and salinity concentrations. Pulses in aquatic metabolism rates were coupled to the timing of P supply from groundwater upwelling as well as a potential suite of hydrobiogeochemical interactions. We provide evidence that freshwater discharge has observable impacts on aquatic ecosystem function in the oligotrophic estuaries of the Florida Everglades by controlling the availability of P to the ecosystem. Future water management decisions in South Florida must include the impact of changes in water delivery on downstream estuaries.

Ecosystem structure of Gomishan Wetland

Gomishan Wetland is situated in the extreme southern part of the eastern coast of Caspian Sea. It is connected to the Caspian Sea, so its hydrological features are directly generated from the sea. The whole wetland area (which also consists of the northern part of the wetland that is situated in Turkmenistan republic) is calculated with the aid of the Satellite Images for the years of 1977, 1987 and 1998 respectively 5070, 16320 and 29520 hectares. To have better ideas about food chains in the aquatic ecosystem, five permanent stations was appointed in different parts of the wetland. During one year field study, at the beginning of each month, physical, chemical and biological characteristics of the water and the sediment was surveyed and different specimens were gathered, fixed and took to the laboratories for the relevant analyses. The factors measured in water samples were mainly consist of turbidity, pH, EC, DO, BOD, PO4, NO3, alkalinity, Cl and hardness . The factors measured from sediment samples were the percentage of Sand, Very Fine Sand, Silt, Clay, K, P, N, and Organic Carbon. Biological examinations of the water has been consist of planktonic sample collections, determination, counting and analysis of both phyto and zoo planktons of the wetland. For example the zooplanktons of the Gomishan Wetland are determined in 15 groups, belonging to 5 phyla. The seasonal changes are recognized considerable. The least density of the zooplanktons is occurred in February. The density of most of the groups is seen from the beginning of the summer until the mid autumn. The annual mean density for any 15-zooplankton groups and also the minimum and maximum density with %95 confidences, for each of them, is calculated for the environment of all of the stations and also for the whole wetland. The spatial distribution of the individuals within the population of each of the groups is introduced, according to regular or contagious or random distribution. Diversity indices are calculated for the zooplanktons living in the environment of the stations. Comparison of the wetland, with the southeastern Caspian Sea, from the point of view of zooplankton density and diversity is also obtained. Benthos invertebrates in each station from sediment samples were also extracted. The specimens were colored by Rose Bengal solvent and then were determinate and counted, in separate groups of macro and meio benthos. Among the macro benthos, the highest density was seen in the species of Fyrgula caspia. After that, more density was seen respectively in Apra ovata, Cerastoderma sp., Balanus sp., Nerds divesicolarr, lifytilaster lineatus and Dreissena sp. Among the meio benthos, the most density was seen in Foraminifera and then respectively in Ostracoda, Nernatoda and Bivalve larvae. The indices of diversity and distribution are also calculated. As the birds in this lagoon are of prime importance, all mid winter waterfowl censuses available from recent 13 years are gathered and analysis. Also a whole year (12 times, each at the beginning of one month) waterfowl census was undertaken, throughout the wetland. According to this study, the Eastern Ecosystem of the wetland, is supporting the most population (%75) of the waterfowls, the Middle Open Water Ecosystem and the Western Reed bed Ecosystem, are supporting respectively %14 and %11 of the population. Four of the species are found in the global threatened red list, and the wintering population of the 20 species of the site, in some years, are observed more than %I of the global populations. The Waterfowl Species Diversity and Similarity Indices are given also.

Environmental Dynamics of Dissolved Black Carbon in Aquatic Ecosystems

Black carbon (BC), the incomplete combustion product from biomass and fossil fuel burning, is ubiquitously found in soils, sediments, ice, water and atmosphere. Because of its polyaromatic molecular characteristic, BC is believed to contribute significantly to the global carbon budget as a slow-cycling, refractory carbon pool. However, the mass balance between global BC generation and accumulation does not match, suggesting a removal mechanism of BC to the active carbon pool, most probable in a dissolved form. The presence of BC in waters as part of the dissolved organic matter (DOM) pool was recently confirmed via ultrahigh resolution mass spectrometry, and dissolved black carbon (DBC), a degradation product of charcoal, was found in marine and coastal environments. However, information on the loadings of DBC in freshwater environments and its global riverine flux from terrestrial systems to the oceans remained unclear. The main objectives of this study were to quantify DBC in diverse aquatic ecosystems and to determine its environmental dynamics. Surface water samples were collected from aquatic environments with a spatially significant global distribution, and DBC concentrations were determined by a chemical oxidation method coupled with HPLC detection. While it was clear that biomass burning was the main sources of BC, the translocation mechanism of BC to the dissolved phase was not well understood. Data from the regional studies and the developed global model revealed a strong positive correlation between DBC and dissolved organic carbon (DOC) dynamics, indicating a co-generation and co-translocation between soil OC and BC. In addition, a DOC-assistant DBC translocation mechanism was identified. Taking advantage of the DOC-DBC correlation model, a global riverine DBC flux to oceans on the order of 26.5 Mt C yr-1 (1 Mt = 1012 g) was determined, accounting for 10.6% of the global DOC flux. The results not only indicated that DOC was an important environmental intermediate for BC transfer and storage, but also provided an estimate of a major missing link in the global BC budget. The ever increasing DBC export caused by global warming will change the marine DOM quality and may have important consequences for carbon cycling in marine ecosystem.

The vulnerability of aquatic systems of the Upper Napo River Basin (Ecuadorian Amazon) to human activities

Aquatic ecosystems exhibit different vulnerabilities to anthropogenic disturbances. I examined this problem in the Upper Napo River Basin (UNRB), Ecuador. I ranked from 1 to 5 aquatic ecosystem uniqueness, health and threats. I stratified the basin into five Ecological Drainage Units (EDU), 48 Aquatic Ecological Systems (AES), and 203 macrohabitats. I found main threats (habitat conversion/degradation, land development, mining, oil industries, and water diversion) cover 54% of the UNRB, but have different scores and extents in each EDU. I assessed the health of 111 AESs, under three land use treatments, by analyzing the streamside zone, physical forms, water quality, aquatic life, and hydrology. Overall, health of AESs varied from 5 to 2.58, with 5 being the highest level of health. Threats and health of AESs were inversely related (F=34.119, P

Risk assessment of the herbicide clomazone in the aquatic life.

Clomazone (2-(2-chlorophenyl)methyl-4.4-dimethyl-3-isoxazolidinone) is a post emergence herbicide widely used in rice fields in Rio Grande do Sul (Brazil) with high activity against Gramineae at the recommended application rate(AR).of 700g/ha. The herbicide input into the aquatic ecosystem may occur by aerial application or water drainage. The presence of this chemical in the water may affect non-target organisms leading to impairments in the aquatic food chain. Studies were conducted in this work to evaluate the risk of Clomazone using the estimated mean affective concentration (EC50) for the microalgae Selenastrum capricornutum(96h), the duckweed Lemna valdiviana(96h) and the crustacean Daphnia similis(48h). The EC50 values were 11.2; 31.7 and 13.8 mg/l, respectively. According to the obtained data, and considering a direct input of the herbicide in a 10cm column water, the estimated maximum application rate that doesn't cause acute effects is 5.3 AR for S. capricornutum, 6.5 AR for D. similis and 15.0 AR for L. valdiviana. The estimated maximum application rate that doesn't cause chronic effects is 2.0 AR for D. similis, 1.6 AR for S. capricornutum and 4.5 AR for L. valviana.

Integrating science through Bayesian Belief Networks : case study of Lyngbya in Moreton Bay

Bayesian Belief Networks (BBNs) are emerging as valuable tools for investigating complex ecological problems. In a BBN, the important variables in a problem are identified and causal relationships are represented graphically. Underpinning this is the probabilistic framework in which variables can take on a finite range of mutually exclusive states. Associated with each variable is a conditional probability table (CPT), showing the probability of a variable attaining each of its possible states conditioned on all possible combinations of it parents. Whilst the variables (nodes) are connected, the CPT attached to each node can be quantified independently. This allows each variable to be populated with the best data available, including expert opinion, simulation results or observed data. It also allows the information to be easily updated as better data become available ----- ----- This paper reports on the process of developing a BBN to better understand the initial rapid growth phase (initiation) of a marine cyanobacterium, Lyngbya majuscula, in Moreton Bay, Queensland. Anecdotal evidence suggests that Lyngbya blooms in this region have increased in severity and extent over the past decade. Lyngbya has been associated with acute dermatitis and a range of other health problems in humans. Blooms have been linked to ecosystem degradation and have also damaged commercial and recreational fisheries. However, the causes of blooms are as yet poorly understood.

Sustainable urban stormwater management : water sensitive urban design perceptions, drivers and barriers

Stormwater has been recognised as one of the main culprits of aquatic ecosystem pollution and as a significant threat to the goal of ecological sustainable development. Water sensitive urban design is one of the key responses to the need to better manage urban stormwater runoff, the objectives of which go beyond rapid and efficient conveyance. Underpinned by the concepts of sustainable urban development, water sensitive urban design has proven to be an efficient and environmentally-friendly approach to urban stormwater management, with the necessary technical know-how and skills already available. However, large-scale implementation of water sensitive urban design is still lacking in Australia due to significant impediments and negative perceptions. Identification of the issues, barriers and drivers that affect sustainability outcomes of urban stormwater management is one of the first steps towards encouraging the wide-scale uptake of water sensitive urban design features which integrate sustainable urban stormwater management. This chapter investigates key water sensitive urban design perceptions, drivers and barriers in order to improve sustainable urban stormwater management efforts.

Investigating challenges and opportunities of water sensitive urban design for knowledge based development of Australian cities

A new approach that is slowly replacing neoclassical models of economic growth and commodity based industrial activities, knowledge based urban development (KBUD) aims to provide opportunities for citiesw to foster knowledge creation, exchange and innovation, and is based on the concepts of both sustainable urban development and economic prosperity; sustainable uses and protection of natural resources are therefore integral parts of KBUD. As such, stormwater, which has been recognised as one of the main culprits of aquatic ecosystem pollution and as therefore a significant threat to the goal of sustainable urban development, needs to be managed in a manner that produces ecologically sound outcomes. Water sensitive urban design (WSUD) is one of the key responses to the need to better management urban stormwater runoff and supports KBUD by providing an alternative, innovative and effective strategy to traditional stormwater management.

Water sensitive urban design through the lens of urban metabolism

Stormwater pollution has been recognised as one of the main causes of aquatic ecosystem degradation and poses a significant threat to both the goal of ecological sustainable development as well as human health and wellbeing. In response, water sensitive urban design (WSUD) practices have been put forward as a strategy to mitigate the detrimental impacts of urban stormwater runoff quality and to safeguard ecosystem functions. However, despite studies that support its efficiency in urban stormwater management, the mainstreaming of WSUD remains a significant challenge. This paper proposes that viewing WSUD through the lens of the integrated urban metabolism framework which encourages an interdisciplinary approach and facilitates dialogue through knowledge transfer is a strategy in which the implementation of WSUD can be mainstreamed.

Sustainable urban stormwater management : water sensitive urban design perceptions, drivers and barriers

Stormwater has been recognised as one of the main culprits of aquatic ecosystem pollution and as a significant threat to the goal of ecological sustainable development. Water sensitive urban design is one of the key responses to the need to better manage urban stormwater runoff, the objectives of which go beyond rapid and efficient conveyance. Underpinned by the concepts of sustainable urban development, water sensitive urban design has proven to be an efficient and environmentally-friendly approach to urban stormwater management, with the necessary technical know-how and skills already available. However, large-scale implementation of water sensitive urban design is still lacking in Australia due to significant impediments and negative perceptions. Identification of the issues, barriers and drivers that affect sustainability outcomes of urban stormwater management is one of the first steps towards encouraging the wide-scale uptake of water sensitive urban design features which integrate sustainable urban stormwater management. This chapter investigates key water sensitive urban design perceptions, drivers and barriers in order to improve sustainable urban stormwater management efforts.

Development and application of a predictive model of freshwater fish assemblage composition to evaluate river health in eastern Australia

Multivariate predictive models are widely used tools for assessment of aquatic ecosystem health and models have been successfully developed for the prediction and assessment of aquatic macroinvertebrates, diatoms, local stream habitat features and fish. We evaluated the ability of a modelling method based on the River InVertebrate Prediction and Classification System (RIVPACS) to accurately predict freshwater fish assemblage composition and assess aquatic ecosystem health in rivers and streams of south-eastern Queensland, Australia. The predictive model was developed, validated and tested in a region of comparatively high environmental variability due to the unpredictable nature of rainfall and river discharge. The model was concluded to provide sufficiently accurate and precise predictions of species composition and was sensitive enough to distinguish test sites impacted by several common types of human disturbance (particularly impacts associated with catchment land use and associated local riparian, in-stream habitat and water quality degradation). The total number of fish species available for prediction was low in comparison to similar applications of multivariate predictive models based on other indicator groups, yet the accuracy and precision of our model was comparable to outcomes from such studies. In addition, our model developed for sites sampled on one occasion and in one season only (winter), was able to accurately predict fish assemblage composition at sites sampled during other seasons and years, provided that they were not subject to unusually extreme environmental conditions (e.g. extended periods of low flow that restricted fish movement or resulted in habitat desiccation and local fish extinctions).