Description: Impacts of climate change on heat budget in the Eastern China Seas (ECSs) are estimated under the historical, RCP4.5 and RCP8.5 scenarios using an atmosphere-ocean coupled regional climate model system (REMO/MPIOM). The results suggest that the recent and future ocean warming over the ECSs is linked overall to an increased oceanic heat transport by currents, which is partly compensated by the air-sea heat exchange. The Taiwan Strait is the major source of oceanic heat into the ECSs, whereas the shelf break section (SBS) acts as a heat sink. An increased net oceanic heat transport into the ECSs is projected under both considered RCP scenarios, mainly resulting from a reduction of the outward heat transport through the SBS. The mean relative contribution of SBS to the oceanic heat transport thus decreases by 4%–5% under both RCP scenarios, relative to historical run. Regarding the surface air-sea exchange, the heat loss caused by thermal radiation, latent and sensible heat in the ECSs exceeds the heat gain achieved by solar radiation. Under the RCP scenarios, warmer SST and stronger surface wind will enhance the upward latent heat flux, eventually leading to a more pronounced heat loss from the ECSs. The mean relative contributions of the latent heat flux to the air-sea heat exchange notably increases by 2%–3% under both projection scenarios, relative to historical run. Taking into account all components of the ECSs heat balance, we deduce that the increased horizontal heat transport will enhance the surface evaporation over the ECSs under future warming.

Description: We employed 3-D biophysical modeling and dispersion kernel analysis to explore inter-annual and inter-specific differences in the drift trajectories of eggs and yolksac larvae of plaice (Pleuronectes platessa), Atlantic cod (Gadus morhua), sprat (Sprattus sprattus) and horse mackerel (Trachurus trachurus) in the North Sea. In this region, these four species exhibit peak spawning during the boreal winter, late winter/early spring, late spring/early summer, and mid-summer respectively, but utilize the same spawning locations (our simulations included Dogger Bank, Southern Bight and the German Bight). Inter-annual differences in the temperature history, and an increase in the area of dispersion and final distribution at the end of the yolksac phase were more pronounced (and related to the North Atlantic Oscillation) for winter- and early spring-spawners compared to late spring/summer spawners. The progeny of the latter experienced the largest (up to 10-fold) inter-annual differences in drift distances, although absolute drift distances were modest (~2 to 30 km) when compared to those of the former (~ 20 to 130 km). Our results highlight the complex interplay that exists between the specific life history strategies of the different species and the impacts of the variability in (climate-driven) physical factors during the earliest life stages of marine fish. Resumen: Diferencias interanuales e interespecíficas en la deriva de huevos y larvas lecitotróficas en el mar Norte: Aproximación a través un modelo biofísico. – En este trabajo utilizamos un modelo 3-D físico-biológico y un análisis de dispersión del núcleo para investigar las diferencias interespecíficas e interanuales en las trayectorias de la deriva de huevos y larvas lecitotróficas de la solla (Pleuronectes platessa), el bacalao Atlántico (Gadus morhua), el espadín (Sprattus sprattus) y el jurel (Trachurus trachurus) en el Mar del Norte. En esta región, las especies estudiadas muestran distintos picos de distintos desoves en el tiempo: invierno boreal, invierno tardío/primavera temprana, primavera tardía/verano temprano y mitad del verano, respectivamente, aunque comparten las mismas zonas de desove. Las simulaciones efectuadas corresponden a tres de estas zonas: Dogger Bank, Southern Bight y German Bight. Los resultados mostraron diferencias interanuales en la temperatura experimentada por las larvas, en el área de dispersión y en el patrón de distribución al final del estadio lecitotrófico, que fueron más evidentes en el bacalao Atlántico, en comparacion con el espadín. Así mismo, estos factores estuvieron correlacionados con la Oscilación del Atlántico Norte. La progenie del espadín, además, mostró la mayor variación interanual en la distancia de dispersión, siendo hasta 10 veces mayor, aunque la distancia absoluta alcanzada fue relativamente modesta (~2-30 km) en comparación con la observada para el bacalao Atlántico (~20-130 km). Nuestros resultados subrayan la compleja interacción que existe, durante los estadios tempranos del desarrollo de peces marinos, entre las estrategias ecológicas

Description: We employed a coupled biological–physical, individual-based model (IBM) to estimate spatial and temporal changes in larval fish habitat suitability (the potential for areas to support survival and high rates of growth) of the German Bight, southern North Sea. In this Lagrangian approach, larvae were released into a size-structured prey field that was constructed from in situ measurements of the abundance and prosome lengths of stages of three copepods (Acartia spp., Temora longicornis, Pseudocalanus elongatus) collected on a station grid repeatedly sampled from February to October 2004. The choice of prey species and the model parameterisations for larval fish foraging and growth were based on field data collected for sprat (Sprattus sprattus) and other clupeid larvae. A series of 10-day simulations were conducted using 20 release locations to quantify spatial–temporal differences in projected larval sprat growth rates (mm d− 1) for mid-April, mid-May and mid-June 2004. Based upon an optimal foraging approach, modeled sprat growth rates agreed well with those measured in situ using larval fish ototliths. On the German GLOBEC station grid, our model predicted areas that were mostly unsuitable habitats (areas of low growth potential), e.g. north of the Frisian Islands, and others that were consistently suitable habitats (areas that had high growth potential), e.g. in the inner German Bight. In some instances, modelled larvae responded rapidly (~ 5 days) to changing environmental characteristics experienced along their drift trajectory, a result that appears reasonable given the dynamic nature of frontal regions such as our study area in the southern North Sea.

Description: This paper is chapter 5.2 of the ICES CRR “Structure and dynamics of the North Sea benthos” (ICES 2007) compiled by the ICES Study Group on the North Sea Benthos Project 2000. The North Sea Benthos Project 2000 (NSBP) was initiated as a follow-up to the earlier 1986 ICES North Sea Benthos Survey (NSBS). One major aim of the NSBP 2000 was to compare the outcome with that of the 1986 NSBS, in order to identify any significant changes in the community structure and their likely causes. In general, the spatial distribution of the macrofaunal communities in 2000 was rather similar to that in 1986. But changes were found within communities which were addressed to changes in the hydroclimate caused by changes in the North Atlantic Oscillation influencing changes in currents and sediment structure as well as food availability.

Description: The Indonesian government plans to move the national capital city from Jakarta to Penajam Paser Utara (PPU) of Balikpapan Bay, East Kalimantan next year. Oceanographic and ecosystem observations in Balikpapan Bay were carried out in early March 2020, June and October 2021, and May 2022 to get an overview of the actual condition of the marine ecosystem. Field observations showed that the level of phytoplankton diversity is low, dominated by diatom (62% until 93%). From the 14 identified species, 6 of them can cause Harmful Algal Bloom (HAB), namely Dinophysis sp., Nitzschia sp., Pseudonitzschia sp., Ceratium sp., Chaetoceros sp., and Cyclotella sp. The Principal Component Analysis (PCA) between the abundance, diversity, and dominance of phytoplankton with seawater quality parameters show a strong correlation. The hydrodynamic model shows that water mass in the Balikpapan Bay is more uniform during spring tide compared to neap tide. The vertical structure of salt volume and transport shows a different direction in the neap tides and the similar direction in the spring tides during a tidal cycle. The effect of river runoff is less pronounced during spring tides. From the modelling results of sea and river water exchanges as well as the presence of phytoplankton that can cause HAB, it can be predicted that nutrients from human activities that entering the Balikpapan Bay can potentially triggered the HAB and change the bay ecosystem in future.