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Pollution from land‐based run‐off threatens coastal ecosystems and the services they provide, detrimentally affecting the livelihoods of millions people on the world's coasts. Planning for linkages among terrestrial, freshwater and marine ecosystems can help managers mitigate the impacts of land‐use change on water quality and coastal ecosystem services.We examine the approaches used for land‐sea planning, with particular focus on the models currently used to estimate the impacts of land‐use change on water quality and fisheries. Our findings could also be applied to other ecosystem services. This Review encompasses modelling of: large scale drivers of land‐use change; local activities that cause such change; run‐off, dispersal and transformation of pollutants in the coastal ocean; ecological responses to pollutants; socio‐economic responses to ecological change; and finally, the design of a planning response.We find that there is a disconnect between the dynamical models that can be used to link land to sea processes and the simple tools that are typically used to inform planning. This disconnect may weaken the robustness of plans to manage dynamic processes. Land‐sea planning is highly interdisciplinary, making the development of effective plans a challenge for small teams of managers and decision makers.Synthesis and applications. We propose some guiding principles for where and how dynamic land‐sea connections can most effectively be built into planning tools. Tools that can capture pertinent processes are needed, but they must be simple enough to be implemented in regions with limited resources for collecting data, developing models and developing integrated land‐sea plans. We propose some guiding principles for where and how dynamic land‐sea connections can most effectively be built into planning tools. Tools that can capture pertinent processes are needed, but they must be simple enough to be implemented in regions with limited resources for collecting data, developing models and developing integrated land‐sea plans. [ABSTRACT FROM AUTHOR]

Traditional models describing the relationship between photosynthesis (P) and irradiance (I) do not account for photoacclimation to short-term variation in irradiance. Here we develop and test a model that predicts the rate of photosynthesis under fluctuating irradiances at the scale of days to weeks. Using oxygen respirometry, we measured the rates of change in the P-I model parameters Pmax (maximum rate of gross photosynthesis) and Ik (sub-saturation irradiance) of the photo-symbiotic coral Turbinaria mesenterina (Lamarck) following large and small increases and decreases in growth irradiance. We analyse the behaviour of the dynamic P-I model in turbid-water conditions using a dataset of 3-month continuous irradiance as the input variable. In response to upward or downward changes in experimental growth irradiance, Ik values decreased or increased exponentially, reaching new and stable levels within 5–10 days. Ik responded 4 times stronger than Pmax to changes in growth irradiance. The kinetics of Ik did not show hysteresis, and changed in similar ways when irradiance was increased or decreased in small or large amounts. This suggests that mechanisms associated with photo-protection during increases in irradiance, and the maximisation of photosynthetic efficiency during decreases in irradiance, are equally potent. On the scale of months, the dynamic P-I model did not predict higher rates of photosynthesis than the static P-I model, but buffered the variation in photosynthesis during periods of reduced irradiance. Fourier analysis indicated that the kinetics of Ik closely matches the main periodicities in daily irradiance (1–2 weeks). The recorded kinetics of photoacclimation in the Turbinaria-zooxanthella symbiosis is comparable to that of free-living phytoplankton and faster than that of higher plants. [ABSTRACT FROM AUTHOR]

Coralline algae are among the most sensitive calcifying organisms to ocean acidification as a result of increased atmospheric carbon dioxide ( pCO2). Little is known, however, about the combined impacts of increased pCO2, ocean acidification, and sea surface temperature on tissue mortality and skeletal dissolution of coralline algae. To address this issue, we conducted factorial manipulative experiments of elevated CO2 and temperature and examined the consequences on tissue survival and skeletal dissolution of the crustose coralline alga (CCA) Porolithon (= Hydrolithon) onkodes (Heydr.) Foslie (Corallinaceae, Rhodophyta) on the southern Great Barrier Reef (GBR), Australia. We observed that warming amplified the negative effects of high pCO2 on the health of the algae: rates of advanced partial mortality of CCA increased from <1% to 9% under high CO2 (from 400 to 1,100 ppm) and exacerbated to 15% under warming conditions (from 26°C to 29°C). Furthermore, the effect of pCO2 on skeletal dissolution strongly depended on temperature. Dissolution of P. onkodes only occurred in the high- pCO2 treatment and was greater in the warm treatment. Enhanced skeletal dissolution was also associated with a significant increase in the abundance of endolithic algae. Our results demonstrate that P. onkodes is particularly sensitive to ocean acidification under warm conditions, suggesting that previous experiments focused on ocean acidification alone have underestimated the impact of future conditions on coralline algae. Given the central role that coralline algae play within coral reefs, these conclusions have serious ramifications for the integrity of coral-reef ecosystems. [ABSTRACT FROM AUTHOR]