In a recent paper in Marine and Freshwater Research, Nichols et al. called for a reinvestment in national-scale bioassessment in Australia. We agree that the absence of national-scale bioassessment impedes the ability to detect slow-acting impacts such as climate and land-use change. We argue that a reinvigorated national program should go beyond bioassessment and assess river resilience, including the social and ecological parameters that influence river health.

Scarcity of iron limits phytoplankton growth in approximately two-thirds of the world’s oceans. Hydrothermal plumes have recently gained recognition as a long-range source of iron to the deep oceans that, importantly, may also affect surface ocean phytoplankton growth in some regions. This review brings into focus current understanding of hydrothermal systems and their contribution to the global oceanic iron budget.

Constructed wetlands could play a crucial role in integrated agro-environmental management of intensive agricultural landscapes. An experimental wetland was created within the Venetian drainage system to reduce nutrient runoff and test the adaptability of seven macrophyte species in a floating treatment wetland system. A promising depurative effect emerges from the concentration trends throughout the system. Carex spp. adapted best to the floating wetlands.

Reducing invasion rates of aquatic species is an important conservation concern. In this study we investigated whether zooplankton assemblages in ponds subject to fish releases from aquaculture facilities are affected by ‘hitchhiking’ species from these farms, and found differences between ponds with and without carp releases. Management is required to prevent unintentional introductions of invertebrate from aquaculture facilities from which fish are released.

Zooplankton play an important role in transferring energy from primary producers to upper trophic levels. By investigating epipelagic mesozooplankton community and hydrographic features of the Dongsha Atoll, we found that temporal pattern of mesozooplankton community is likely to be more dependent on physical variable than on primary production due to the semi-enclosed topography. Abundant decapod larvae and fish eggs confirmed the importance of the pelagic–benthic coupling in the tropical reef ecosystem.

The Asian water monitor is widespread on the island of Sri Lanka. The present study was a 7-month survey within a 5-km stretch at an urban riverscape in Sri Lanka. The most monitor sightings were made in aquatic habitats. Given variable sighting frequencies of distinct life history stages across different major habitat types, it is likely that there is substantial age-structured niche partitioning among these monitors.

Atmospheric nuclear testing added the radioisotope caesium-137 to the global environment. We sampled depressional wetland soils across three regions of the United States (Southeast, Atlantic Coast, and Midwest) and quantified accumulated sediment, carbon, nitrogen and phosphorus compounds in wetland soil since ‘peak caesium’ deposition in 1964. Substantial accumulation occurred, with only phosphorus differing by region. Depressional wetland management is, thus, important for landscape-scale sediment, nutrient and carbon dynamics.

Reduced turbulence and aeration can affect stream ecosystems, but their effects can differ from the surface to subsurface habitats, and depend, among other things, on sediment size and the availability of organic matter (OM). A microcosm experiment showed that lack of aeration reduced OM consumption, especially on the surface, and sediment size caused differences in performance between the two invertebrate species studied, namely mayfly (Habroleptoides) and stonefly (Capnioneura).

The present study examined the dry-season meso-habitat use by the amphidromous shrimp species, Macrobrachium spinipes, in northern Australia. We found that habitat use changed considerably first, with ontogeny, and, second, with the annual colonisation of habitats with algae and macrophytes as the dry season progressed. The study has provided significant insights into the changes in use of key riverine habitats throughout the dry season by an ecologically important species

Hydrodynamics drive the export of estuarine-derived primary production and nutrients to adjacent, less-productive offshore waters. The present study quantified estuary-to-coast fluxes of detritus and nutrients by sampling the water at the mouth of a small temperate estuary. These types of studies are important to determine the ecosystem services provided by temperate estuaries.

Conventional river models typically ignore the effects of groundwater-storage change on river flow, and, hence, predicted declines in river low flows during drought periods are likely to be compromised. The present study undertakes statistical analysis of low flows in the Namoi River, and highlights implications for river modelling more broadly. The results showed the importance of adopting models that explicitly account for groundwater processes when modelling such river systems.

Amphidromous fish live and spawn in streams, but are widely believed to have an oceanic larval period, resulting in wide dispersal and connective populations. In this study we show that when an alternative larval habitat (i.e. a lake or wetland) is present, freshwater larval rearing is the dominant process sustaining many populations. The retention of larvae in lakes has implications for the dispersal, connectivity and management of amphidromous fish.

Climate change modified the spatial distribution of two sympatric Mediterranean fishes. Does this change have indirect effects on trophic niches and trophic interactions between the two species of fish? The two species have different trophic niches and do not interact for food, regardless of forcing of climate change.

The Cooloola Patterned Fens are a unique wetland in south-eastern Queensland and are potentially at risk from water extraction for the nearby town. Statistical analysis of regional water-chemistry data was used to determine the groundwater source that the ecosystem depends on. The fens were found to use perched aquifer water, whereas local creeks are connected to the deeper regional aquifer.

In this study we investigated the behaviour of cyanobacteria by determining phycocyanin and chlorophyll concentrations using spectroradiometric and fluorometric data. The spectral analyses could only detect phycocyanin at higher concentrations. For lower concentrations, phycocyanin was detected from fluorometric measurements. Therefore, remote sensing complemented by fluorometric analysis seems an effective method for monitoring cyanobacteria in Brazilian inland waters.

The concentration and optical properties of dissolved organic matter (DOM) of lakes provide clues as to the water sources and in-lake microbial and photochemical processes. The present study is the first broad-scale survey of DOM from Patagonian lakes (Chile and Argentina) across a strong west–east precipitation gradient. We conclude that this set of lakes provides a convenient observational system to investigate the effects of contemporary climate change.

Mangroves are one of the most widely distributed types of plants that grow along the coast of Australia. Low winter temperatures and frost are thought to limit the stature and productivity of mangroves in Victoria. Because air and water temperatures will increase markedly over coming decades, it is likely that Victorian mangroves will be among the first plant communities to be noticeably affected by climate change in coastal south-eastern Australia.